http://guidelines.beefimprovement.org/api.php?action=feedcontributions&user=Menns&feedformat=atomBIF Guidelines Wiki - User contributions [en]2024-03-29T15:59:56ZUser contributionsMediaWiki 1.35.2http://guidelines.beefimprovement.org/index.php?title=Pulmonary_arterial_pressure_(PAP)&diff=1695Pulmonary arterial pressure (PAP)2019-12-07T00:26:14Z<p>Menns: /* References */</p>
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<div>Pulmonary arteries and arterioles carry venous blood from the right side of the heart to the lungs with the purpose of replenishing the blood oxygen. Oxygenated blood then returns through the pulmonary veins to the left chambers (atrium and ventricle) of the heart to be pumped to the rest of the body. Pulmonary hypertension (PH) is a condition where the pressure inside the pulmonary artery is abnormally high. In response to this increased pressure in the pulmonary artery, the right side of the heart is required to pump with increased force to move blood toward this area of high Pulmonary Arterial Pressure (PAP). This response of the heart results in excessive muscle contraction, stretching of muscle fibers, ultimately leading to increased right atrium and ventricle size. Because the right side of the heart is working harder than normal, its walls thicken (hypertrophy), leading to heart failure and ultimately animal death. These mortality rates are typically very low even though cattle often experience PH. Currently, the impact of PH is primarily quantified in the form of death loss but increasingly there is evidence of reduced performance associated with PH.<ref>Holt, T. N., and R. J. Callan. 2007. Pulmonary arterial pressure testing for high mountain disease in cattle. Vet. Clin. Food. Anim. 23:575-596.</ref><ref>Thomas et al…CAB White paper…https://www.cabcattle.com/wp-content/uploads/Pulmonary-Hypertension-PH-in-Beef-Cattle-Complicated-Threat-to-Health-and-Productivity-in-Multiple-Beef-Industry-Segments.pdf.</ref> <br />
<br />
==Usage==<br />
The PAP test is used as an indicator of PH and as a selection/culling criterion. The procedure/technique for performing a Pulmonary Artery Catheterization (PAP test) begins by securing the animal within a chute with a moderate amount of squeeze applied so as to reduce body movement. The pressure applied is monitored throughout the test, adjusting to maintain animal comfort. The head is secured in place with a halter at the level of the point of the shoulder to expose the lateral jugular furrow. Care must be taken to avoid securing the head too high as the animal can often then manipulate its head, resulting in cutting of the catheter within the animal; in turn, resulting in pulmonary foreign body emboli. The proximal lateral aspect of the jugular furrow is scrubbed with a chlorhexidine/alcohol/water and dawn soap solution and all debris is removed making for clean needle insertion. The jugular vein at the level of the thoracic inlet or just proximal to this is occluded to allow blood flow resistance causing jugular vein distension. The proximal jugular vein is then punctured with a 12-13g, 3.5-inch needle until there is free blood flow from the needle. The needle is then gently threaded down the jugular vein leaving 1 cm of the needle out of the skin to allow for needle control. An Intramedic polyethylene catheter (internal diameter 1.19mm, outside diameter 1.7mm) is then passed through the needle and into the jugular vein. The catheter tubing is flushed with .9 % NaCl (approximately 1 ml) prior to placing in the needle and is also flushed while the catheter is being gently advanced down the jugular vein. The constant flushing of the .9 % NaCl aids in the movement of the catheter down the vein. The amount of total saline that is injected into the animal during the procedure is minimal and in most cases less than 1 ml. The external end of the catheter is then connected to a transducer via 3-way stopcocks after approximately 1-1.5 feet of the catheter has been passed into the jugular vein. The transducer must be placed at the level equal to the base of the heart, which is approximately just caudal to the point of the elbow. The transducer and catheter are again flushed to assure no air has entered the system. The catheter is then advanced to the distal jugular vein and the first pressure taken to help evaluate catheter location. The catheter is passed into the right atrium through the right A-V valve and into the right ventricle of the heart where the second measurement is taken. The catheter is then advanced from the right ventricle through the pulmonary valve and into the main pulmonary artery. The catheter is allowed to stay in this location until the pressure remains constant, approximately 5 seconds. The location of the catheter within the animal’s vasculature, as well as the pressure reading, is determined by monitoring the pressure changes and characteristics of the pressure wavelengths on a data scope. This allows accurate knowledge of the location of the end of the catheter at all times. Once the catheter reaches the pulmonary artery and the pressure is allowed to stabilize; the mean, systolic, and diastolic pressure are recorded. After the PAP is recorded, the catheter is slowly pulled back through the pulmonary valve into the right ventricle. A drop in the mean pressure is noted as well as a distinct pressure wave character change as the catheter is moved from the pulmonary artery into the right ventricle. This mean pressure drop is approximately 6-10mmHg. If this ventricular drop in pressure was not noted, the catheter placement is re-evaluated. If the pressure remains unchanged, the animal was auscultated for the presence of valvular damage (murmurs) or other respiratory or cardiac pathology.<br />
<br />
Hypoxic conditions (low atmospheric oxygen) that stimulate a pulmonary response are usually not seen until approximately 5,000 feet of elevation. For this reason, PAP measurements taken at low elevations (< 5,000 feet) have historically been used only to identify those animals that are very sensitive to hypoxic conditions. These cattle are hypertensive at these lower elevations, as evidenced by an elevated PAP measure, and therefore are not suitable for elevations above 5,000 feet. There is evidence; however, that PAP observations taken between 3,000 and 5,000 feet of elevation are genetically correlated to observations taken at higher elevations<ref name="culbertson">Culbertson, M.M., M.G. Thomas, L.L. Leachman, R.M. Enns, and S.E. Speidel. 2017. Multivariate analysis of beef cattle pulmonary arterial pressures measured at differing elevations. J. Anim. Sci. 95(E. Suppl. 4):86.</ref><ref name="pauling">Pauling, R. C., S. E. Speidel, M. G. Thomas, T. N. Holt, R. M. Enns. 2018. Evaluation of moderate to high elevation effects on pulmonary arterial pressure measures in Angus cattle. J. Anim. Sci. 96:3599-3605.</ref> and therefore could be used as an indicator trait in the production of a high elevation PAP EPD. Currently, the number of observations of PAP taken below 3,000 feet is insufficient to determine the genetic relationship between these measures and measures taken above 5,000 feet of elevation.<br />
<br />
Historically raw PAP measures have been used as a tool for deciding what animals should/could remain at elevation and likely survive. These phenotypic measures were often used as a tool to select animals for breeding as well. The growth of data sets over time, such as at the CSU John E. Rouse Beef Improvement Center and at other high elevation seedstock programs, and the subsequent accumulation of data in centralized locations has enabled the calculation of PAP EPD (e.g. www.angus.org). The release of PAP EPD and a long history of using PAP measures have brought about confusion for many breeders. Susceptibility to pulmonary hypertension as indicated by PAP has a considerable genetic influence with heritability estimates for PAP ranging from .25 to .46<ref>Enns, R. M., J. Brinks, R. Bourdon and T. Field. 1992. Heritability of pulmonary arterial pressure in Angus cattle. Proc. West. Sect. Am. Soc. Anim. Sci. 43:111-112.</ref><ref name="shirley">Shirley, K. L., D. W. Beckman, and D. J. Garrick. 2008. Inheritance of pulmonary arterial pressure in Angus cattle and its correlation with growth. J. Anim. Sci. 86:815–819.</ref><ref>Crawford, N. F., M. G. Thomas, T. N. Holt, S. E. Speidel, and R. M. Enns. 2016. Heritabilities and genetic correlations of pulmonary arterial pressure and performance traits in Angus cattle at high altitude. J. Anim. Sci. 94:4483–4490.</ref><ref>Zeng, X. 2016. Angus cattle at high altitude: Pulmonary arterial pressure, estimated breeding value and genome-wide association study. PhD Diss. Colorado State Univ., Fort Collins, CO.</ref><ref name="culbertson" /><ref name="pauling" /> but also indicating that environment has a considerable influence on PAP measures. Therefore, non-genetic factors (i.e. environment) may result in a high PAP score and unsuitability for high elevation environments. These non-genetic effects could include lung damage from bovine respiratory disease and other factors, PAP measurements taken under extreme cold, and feeding of rations for rapid weight gain among others.<br />
<br />
==Pulmonary Arterial Pressure Measurement Considerations==<br />
Cattle moved from low elevations to high elevations should remain at the altitude for a period of 4 weeks or more to accurately PAP test for adaptation to high altitude. Hypoxic pulmonary changes have been seen immediately in cattle as they have been moved to high altitude. However, to most accurately test those that are to be used for breeding, a longer stay at high altitude is recommended. In practicality, it is important for the rancher to know at what elevation the PAP measurement was performed as it has been shown that the PAP measurement will increase as the animal is moved or travels to higher elevations. It is not uncommon to see clinical PH in animals that have a PAP measurement of greater than 49mmHg. Using repeated measures on the same animal it has been shown that the PAP measurement generally increases 1-2 mmHg per 1,000 feet rise in elevation. For simple guidelines to the rancher and veterinarian, an animal should be tested at an elevation of at least 5,000 feet after 4 weeks if testing for suitability for residing at high elevations. The higher the elevation of the test the more accurate and reliable the outcome.<br />
<br />
The equipment, materials and process needed to perform PAP testing in cattle are listed below:<br />
<br />
* Cattle chute equipped with a squeeze and scissor head catch is best. Other types of head catches tend to bind the head and neck, making passing of the catheter difficult. The animal should be secured within the chute with a moderate amount of squeeze applied to reduce body movement. Monitoring the squeeze is very important, too little squeeze allows too much movement, making measurement difficult. Too much squeeze can increase thoracic pressure and result in a false high PAP measure. The chutes must allow securing the head with a halter and turning of the head to allow for jugular exposure<br />
* Adequate labor for handling cattle efficiently and safely. This is best done by having one person responsible for running the chute, catching the head, and applying a consistent level of squeeze to the animal during the procedure.<br />
* Two people securing the halter (nose tongs cannot be used) and turning the heads. This allows for one person to pull the head to the side while the other tightens the halter safely securing the head into the correct position. <br />
* Movement and animal handling processes should be conducted in a low stress manner. The use of dogs and cattle prods should be limited to those animals in a life threating situation or those that have refused movement. Minimal use of these tools is recommended.<br />
<br />
==PAP Scheduling Considerations==<br />
* No vaccinations should be given in the 2 weeks prior to PAP testing although vaccination can be given at the time of PAP test.<br />
* Avoid testing two weeks after weaning to avoid stress on the animal and resulting potential for elevated PAP.<br />
<br />
==PAP Data Recording==<br />
* Name and address of owner/owners<br />
* Test Location and elevation. Note: If other breeders bring animals to the testing location from other nearby ranches then the location of the cattle’s origin and elevation should be recorded.<br />
* Breed of each animal<br />
* Sex of each animal (e.g. steer, bull, heifer, and cow)<br />
* Date (to enable calculation of age at PAP test)<br />
* Mean PAP, systolic, and diastolic pressure. <br />
* Sire identification if possible, including the registration number of sire if available. <br />
* If the sire is not known, then this should be noted (may occur under commercial production circumstances in an effort to determine whether an animal should remain/reside at altitude).<br />
<br />
==Inherent risks associated with PULMONARY ARTERIAL PRESSURE Testing==<br />
Complications and accidents are very rare but may include infection at needle site as well as systemic septicemia and/or endocarditis, chute injury, loss of catheter in the vascular system, pulmonary cardiac trauma and emboli, acute cardiac failure, local abscess formation, and death resulting from one of the previous.<br />
<br />
==UTILIZATION OF THE PAP TEST FOR VARYING ELEVATION==<br />
===AGE OF ANIMAL BEING TESTED===<br />
When evaluating a PAP score in the context of animals residing at elevation, the age of the animal at the time of testing should always be considered. The PAP test is less predictable as an indicator of disease for animals tested at younger than 10 months of age. An exception to this inconsistency is in those animals that have a high PAP measurement (> 49mmHg). High scores, even at young ages, suggest an animal should not remain, nor be moved to elevations above 5000 feet. For example, if the animal scores a measurement of 49mmHg or greater there is still a great degree of confidence that this animal is a high-risk candidate for high altitude problems while conversely, animals with low PAP scores may not be indicative of high-altitude suitability. From the perspective of EPD generation, research continues on the genetic relationship between PAP taken at younger ages and those observations taken after 10 months of age. Recent research indicates that while less predictable at ages less than 10 months, there is a genetic relationship between measures taken after 10 months of age and therefore younger measures are useful for genetic prediction.<ref>Zeng, X, R. M. Enns, S. E. Speidel, M. G. Thomas. 2015. Angus Cattle at High Altitude: Relationship Between Age and Pulmonary Arterial Pressure. In: Proc. West. Sec. Am. Soc. Anim. Sci. 66:119–121. </ref><br />
<br />
PAP has been shown to increase with age<ref name="shirley" />(and Speidel, pers. Comm.) and therefore indicate a need for adjusting for age in the context of genetic evaluation.<br />
<br />
==PHENOTYPIC PAP SCORE EVALUATION==<br />
The following chart has been developed to help the breeder evaluate a PAP measurement on an animal for suitability for residing at high altitudes. This must be viewed in the context of animal survival at elevations. An animal may have a high PAP value for reasons other than genetic predisposition (e.g. lung damage as a result of respiratory disease) and therefore not be adapted to living in high altitude environments. As such the chart reflects recommendations for use at elevation based on phenotypic PAP measures rather than genetic recommendations and should be used only for selecting animals that are likely themselves to survive at the elevations listed. Whereas PAP EPD should be used in the context of genetic improvement and production of progeny likely to survive at higher elevations.<br />
<br />
===PAP Risk Factor Low Elevation Test Chart===<br />
PAP Measurements taken between 3,000- and 4,000-feet elevation<br />
should be considered a screening measurement only<br />
<center><br />
PAP test conducted at elevation < 4,000 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | ModerateRisk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | High Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|}<br />
</center><br />
<br />
===PAP Risk Factor Moderate Elevation Test Chart===<br />
<center><br />
PAP test conducted at elevation 4,000-5,500 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|}<br />
</center><br />
<br />
===PAP Risk Factor High Elevation Test Chart===<br />
<center><br />
PAP test conducted at elevation 5,500-7,000 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low/Moderate Risk<br />
| style="text-align: center;" | Low/Moderate Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | High Risk<br />
|}<br />
</center><br />
===PAP Risk Factor High Elevation Test Chart===<br />
<center><br />
PAP test conducted at elevation 5,500-7,000 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | High Risk<br />
|}<br />
</center><br />
* Special consideration should be given to the amount of time the animal was exposed to elevation (>5,500 ft) prior to testing. The predictability and repeatability of the PAP measurement improves with longer the exposure to higher elevation (minimum of 4 weeks is required).<br />
* This chart is based on animals greater than 10 months of age. <br />
* Testing of younger animals (<10 months) may result in a greater variability to the predictive ability of the measurement.<br />
* Risk—Defined as the likelihood of an animal developing pulmonary hypertension themselves or being at risk for having a genetic predisposition for the disease.<br />
<br />
==Original Attribution==<br />
R. Mark Enns, Colorado State University<br><br />
Tim Holt, Colorado State University<br><br />
Scott E. Speidel, Colorado State University<br><br />
Milton G. Thomas, Colorado State University<br><br />
<br />
==References==</div>Mennshttp://guidelines.beefimprovement.org/index.php?title=Bovine_respiratory_disease_(BRD)&diff=1694Bovine respiratory disease (BRD)2019-12-05T19:42:38Z<p>Menns: /* Attribution */</p>
<hr />
<div><!--Bovine Respiratory Disease Complex --><br />
Despite the fact that bovine respiratory disease (BRD) complex is the leading cause of mortality in the beef industry nationally, disease incidence data that may be routinely recorded at the feedlot level is not currently being fed back into the national genetic evaluation systems. However, BRD susceptibility is clearly a very valuable trait <ref>Neibergs, H. L., J. S. Neibergs, A. J. Wojtowicz, J. F. Taylor, C. M. Seabury and J. E. Womack (2014). Economic Benefits of using Genetic Selection to Reduce the Prevalence of Bovine Respiratory Disease Complex in Beef Feedlot Cattle. 46th Annual Research Symposium and Annual Meeting. Lincoln, Nebraska. </ref>. In an economic simulation of the relative economic value of selection, it was determined that BRD incidence should be weighted approximately 7 times more heavily in a terminal sire selection index than weaning weight, postweaning average daily gain, or feed intake, and that these traits should receive 2-3 times more emphasis than marbling score and yield grade <ref>Van Eenennaam, A. L. and M. D. MacNeil (2011). What weighting should be given bovine respiratory disease (BRD) resistance in selection decisions? 43rd Annual Research Symposium and Annual Meeting Bozeman, Montana. 43: 61-68.</ref>. <br />
<br />
Several studies show that the use of direct health observations is an effective way to incorporate heath traits into breeding programs. Such observations require a standardized system of recording diagnoses to ensure phenotypes are comparable between farms. Consistent recording of health data is more difficult than for other traits due to subjectivity of diagnosis and reporting. Several studies have shown that for use in genetic evaluations, common health disorders recorded by farmers are of a similar quality as those documented by veterinarians.<ref>Egger-Danner, C., J. B. Cole, J. E. Pryce, N. Gengler, B. Heringstad, A. Bradley and K. F. Stock (2015). "Invited review: overview of new traits and phenotyping strategies in dairy cattle with a focus on functional traits." Animal 9(2): 191-207.</ref> A recent study showed that genetic selection for health traits (including cystic ovaries, displaced abomasum, ketosis, lameness, mastitis, metritis, and retained placenta) using producer-recorded health data collected from on-farm computer systems is feasible in the United States.<ref>Parker Gaddis, K. L., J. B. Cole, J. S. Clay and C. Maltecca (2014). "Genomic selection for producer-recorded health event data in US dairy cattle." J Dairy Sci 97(5): 3190-3199.</ref><br />
<br />
==Commercially available records on BRD in beef cattle==<br />
<br />
Many feedlots record data on BRD incidence and treatment. Currently this data is not being used for genetic improvement, and often is not shared beyond the feedyard. Yet this information, if appropriately collected, recorded, and submitted could result in valuable selection tools, especially if used in concert with DNA marker tests that may result from ongoing research.<br />
<br />
The following is a summary of data recorded relative to BRD that are available from US feedlots using commercially available feedlot management software packages. A survey conducted by the BIF BRD Guidelines Committee in cooperation with Production Animal Consultation, LLC; summarized the data currently being collected in two feedlot management software packages with the results shown below where the numbers in parentheses indicate the percent of records containing non-null entries for the data fields listed. Note that this data summary does not imply all data are correctly recorded and the committee acknowledges that the numbers may be skewed by situations where the data in question is not necessary (i.e. no severity score present when it represents a lung score for a non-BRD pull). However, as this summary indicates there is considerable potential to leverage information already routinely collected in the feedlot sector.<br />
<br />
Lot info<br />
* In date (100%)<br />
* Out date (100% if closed)<br />
* Sex (100%)<br />
* Owner (74%)<br />
* Buyer (41%)<br />
* Origin (71%)<br />
* Starting average weight (100%)<br />
* Ending average weight (100% if closed)<br />
* Starting head (100%)<br />
* Ending head (100% if closed)<br />
* Risk (1%)<br />
* Breed (0%)<br />
<br />
Processing info<br />
* Date given (100%)<br />
* Products applied (100%)<br />
* Head applied to (92%)<br />
* Charges for products applied (95%)<br />
<br />
Treatment info<br />
* Date (100%)<br />
* Weight (99%)<br />
* Temperature (74%)<br />
* Severity score (41%; Note: Current data appears to be relatively vague in nature)<br />
* Products applied (100%)<br />
* Cost of products applied (69%)<br />
* Pen rider (6%)<br />
* Doctor (4%)<br />
* Diagnosis (100% - doesn't mean it isn't unknown or other occasionally)<br />
<br />
Animal info<br />
* Date died (100%)<br />
* Date railed (100%)<br />
* Pen rider for rail/death (1%)<br />
* Doctor for rail/death (1%)<br />
* Diagnosis for death/rail (100%)<br />
* Death/rail weight (1%)<br />
<br />
Feed info (when available)<br />
* Daily ration formulation (25%)<br />
* Daily pounds fed per lot (25%)<br />
* Ration fed to lot per day (25%)<br />
<br />
==Feedlot Data Collection Recommendations:==<br />
<br />
Based on the survey results above, BIF suggests collection and reporting of a basic set of phenotype and management information that will ultimately be useful for genetic evaluation:<br />
<br />
* Animal IDs for entire lot of cattle.<br />
* Lot information: In and out dates, sex, owner/origin.<br />
* Treatment information (tied to animal, only available on treated animals): Date, Temperature, Diagnosis (if available)<br />
* Animal info: date died/railed for reason of clinical case of BRD, breed<br />
<br />
The above information should then be applied to produce the following phenotype for BRD—a binary outcome indicating a “yes/no” for clinical signs of BRD. This will likely be the most widely available BRD-related phenotype. <br />
<br />
==Value-added information==<br />
<br />
In some scenarios, additional information may be available given a individual feedlot’s health protocol and/or diagnoses process. Of particular interest as additional data, given standard data recorded above, would be results from either Thoracic Ultrasound or scores from computer-aided auscultation systems (e.g. Whisper ®). In those cases where more detailed information is available animals exhibiting clinical signs of BRD could be further classified into 2 categories, Presumed BRD and Confirmed BRD as follows:<br />
<br />
* Presence of a presumed case of BRD (pBRD) is associated with an Increased Respiratory Rate and/or Effort, Evidence of Depression and Evidence of Reduced Feed Intake (lack of gut fill) although recording of these secondary symptoms beyond temperature may not occur.<br />
* Confirmed BRD (oBRD) will be defined as a case where there is objective evidence of lung pathology consistent with pneumonia. This evidence would either be Thoracic Ultrasound results obtained by a trained technician or Results of >1 on the “Whisper automated auscultation system”.<br />
<br />
Depending on feedlot-specific protocols and recording, oBRD animals as defined above may be further classes as Active BRD or Chronic BRD as follows:<br />
<br />
* Active BRD (aBRD) cases will be defined as an oBRD case plus a rectal temperature over 104F (40C) demonstrating evidence of an active inflammatory response.<br />
* Chronic BRD (cBRD) cases will be defined as an oBRD case plus a rectal temperature below 104F (40C) or a record of previous treatment for BRD demonstrating evidence of the lack of an active inflammatory response <br />
<br />
==Genetic Evaluation Recommendations==<br />
<br />
Data collected above is best utilized for genetic improvement through genetic evaluation. As such, appropriate statistical models much be used for the calculation of those EPD. At a minimum this includes appropriate accounting for relevant fixed effects.<br />
<br />
We fully expect pen to be an important environmental factor when conducting either traditional (i.e. quantitative) or genomic analyses of BRD phenotypes. In terms of shedding and transmission, the most likely vectors will be pen mates. Historically, we would have suggested adding pen to the contemporary group definition which would likely be defined similarly to currently used weaning contemporary group definitions (herd or origin, weight/arrival date, etc.). However, in the case of BRDC phenotypes, we are concerned such an approach may not result in useful data due to over specifying and subdividing contemporary group structure to the point that little variability exists. We suggest two approaches to alleviate this situation:<br />
<br />
# Fit pen(lot) as a separate main effect outside of the traditional contemporary group structure. Thus, there will be fewer class effects to account for overall. This pen definition will likely require a season component to accommodate the reuse of the pen. <br />
# Consider at least pen(lot) and possibly the traditional contemporary group effect as random rather than fixed. As a result, pen effects will be regressed (shrunk) relative to the information content of the pen. Given the undefined nature of the epidemiology involved and the fact the pens will often be confounded with genetics of the animal (due to animals from the same source being grouped), we feel this would be the best compromise in model fitting. This approach would also allow correlation structures amongst pens based on proximity to account for disease transmission across pens (should that data become available).<br />
<br />
Contemporary groups without variability for incidence of BRD should be excluded from the analysis. Sex should be included in the statistical model. <br />
<br />
If data are available with multiple levels of BRD categories (pBRD, aBRD, cBRD, oBRD), we suggest fitting a multi-trait model to account for the differences in specificity of the traits being recorded. For example, the multiple trait model would include BRD with multiple categories as a trait, and also utilize incidence data (yes/no for BRD) as a second trait; thereby maximizing use of data from both recording systems. We also suggest running other indicator traits such as entry weight, weaning weight, or carcass weight as correlated traits that may indicate fitness going into the lot or animals that are suffering from a lack of fitness upon harvest. Eventual use of these indicator traits will depend on their perceived relevance after estimating genetic correlations. <br />
<br />
<br />
==Future Guidelines Considerations==<br />
Defining BRD phenotypes is considerably more complex than other phenotypes typically recorded and used in genetic evaluation such as birth weight, weaning weight, etc. Given current ongoing research on BRD disease etiology, diagnoses, prevention, and treatment these recommendations will likely need to be revisited on a more frequent basis than is typical for other performance traits.<br />
<br />
One of the challenges the committee struggled with was whether the best approach were guidelines for simple, easy to collect and record observations (e.g. treated for BRD; yes/no) as opposed to more detailed, costly phenotypes requiring laboratory samples and analysis and/or analysis of post-mortem samples. There will likely be more observations recorded for simpler, less-detailed phenotypes but with a correspondingly lower heritability. Conversely more detailed, sparse phenotypes are likely more heritable with a greater degree of accuracy. Ultimately the committee chose to develop guidelines that allow for both approaches and could then be used in a multi-trait setting for genetic evaluation of susceptibility to BRD.<br />
<br />
==Attribution==<br />
Recognizing the time and effort of BRD Guidelines Committee:<br />
<blockquote><br />
Dr. Larry Kuehn, USDA Meat Animal Research Center, Nebraska<br><br />
Dr. Dee Griffin, DVM, Great Plain Veterinary Educational Center, University of Nebraska<br><br />
Dr. James Lowe, DVM, College of Veterinary Medicine, University of Illinois<br><br />
Dr. Holly Neibergs, Department of Animal Sciences, Washington State University<br><br />
Dr. Chris Seabury, Veterinary Medicine & Biomedical Sciences, Texas A&M University<br><br />
Dr. Alison Van Eenennaam, University of California Cooperative Extension, University of California-Davis.<br><br />
Dr. R. Mark Enns, Department of Animal Sciences, Colorado State University, BIF Western Region Secretary<br><br />
</blockquote><br />
<br />
==Literature Cited==</div>Mennshttp://guidelines.beefimprovement.org/index.php?title=User:Menns&diff=1693User:Menns2019-12-05T19:21:05Z<p>Menns: </p>
<hr />
<div>[[File:ENNS, R MARK.jpg|thumb]]<br />
<big>'''R. Mark Enns<br><br />
<br />
Campus Delivery 1171<br><br />
<br />
Department of Animal Sciences<br><br />
<br />
Colorado State University<br><br />
<br />
Fort Collins, CO 80523-1171<br />
'''</big><br></div>Mennshttp://guidelines.beefimprovement.org/index.php?title=File:ENNS,_R_MARK.jpg&diff=1692File:ENNS, R MARK.jpg2019-12-05T19:20:39Z<p>Menns: </p>
<hr />
<div>Photo</div>Mennshttp://guidelines.beefimprovement.org/index.php?title=User:Menns&diff=1685User:Menns2019-12-05T18:22:19Z<p>Menns: </p>
<hr />
<div><big>'''R. Mark Enns<br><br />
<br />
Campus Delivery 1171<br><br />
<br />
Department of Animal Sciences<br><br />
<br />
Colorado State University<br><br />
<br />
Fort Collins, CO 80523-1171<br />
'''</big><br></div>Mennshttp://guidelines.beefimprovement.org/index.php?title=User:Menns&diff=1684User:Menns2019-12-05T18:21:42Z<p>Menns: Created page with "<big>'''R. Mark Enns Campus Delivery 1171 Department of Animal Sciences Colorado State University Fort Collins, CO 80523-1171 '''</big>"</p>
<hr />
<div><big>'''R. Mark Enns<br />
Campus Delivery 1171<br />
Department of Animal Sciences<br />
Colorado State University<br />
Fort Collins, CO 80523-1171<br />
'''</big></div>Mennshttp://guidelines.beefimprovement.org/index.php?title=Pulmonary_arterial_pressure_(PAP)&diff=1682Pulmonary arterial pressure (PAP)2019-12-05T18:07:20Z<p>Menns: </p>
<hr />
<div>Pulmonary arteries and arterioles carry venous blood from the right side of the heart to the lungs with the purpose of replenishing the blood oxygen. Oxygenated blood then returns through the pulmonary veins to the left chambers (atrium and ventricle) of the heart to be pumped to the rest of the body. Pulmonary hypertension (PH) is a condition where the pressure inside the pulmonary artery is abnormally high. In response to this increased pressure in the pulmonary artery, the right side of the heart is required to pump with increased force to move blood toward this area of high Pulmonary Arterial Pressure (PAP). This response of the heart results in excessive muscle contraction, stretching of muscle fibers, ultimately leading to increased right atrium and ventricle size. Because the right side of the heart is working harder than normal, its walls thicken (hypertrophy), leading to heart failure and ultimately animal death. These mortality rates are typically very low even though cattle often experience PH. Currently, the impact of PH is primarily quantified in the form of death loss but increasingly there is evidence of reduced performance associated with PH.<ref>Holt, T. N., and R. J. Callan. 2007. Pulmonary arterial pressure testing for high mountain disease in cattle. Vet. Clin. Food. Anim. 23:575-596.</ref><ref>Thomas et al…CAB White paper…https://www.cabcattle.com/wp-content/uploads/Pulmonary-Hypertension-PH-in-Beef-Cattle-Complicated-Threat-to-Health-and-Productivity-in-Multiple-Beef-Industry-Segments.pdf.</ref> <br />
<br />
==Usage==<br />
The PAP test is used as an indicator of PH and as a selection/culling criterion. The procedure/technique for performing a Pulmonary Artery Catheterization (PAP test) begins by securing the animal within a chute with a moderate amount of squeeze applied so as to reduce body movement. The pressure applied is monitored throughout the test, adjusting to maintain animal comfort. Once the head is secured in place, secured and tied in order to expose the lateral jugular furrow. The head is secured with a halter at the level of the point of the shoulder. Care must be taken to avoid securing the head too high as the animal can often then manipulate its head, resulting in cutting of the catheter within the animal; in turn resulting in pulmonary foreign body emboli. The proximal lateral aspect of the jugular furrow is scrubbed with chlorohexidine/alcohol/water and dawn soap solution and all debris is removed making for a clean needle insertion. The jugular vein at the level of the thoracic inlet or just proximal to this is occluded to allow blood flow resistance causing jugular vein distension. The proximal jugular vein is then punctured with a 12-13g, 3.5 inch needle until there is free blood flow from the needle. The needle is then gently threaded down the jugular leaving 1 cm of needle out of the skin to allow for needle control. An Intramedic polyethylene catheter (internal diameter 1.19mm, outside diameter 1.7mm) is then passed through the needle and into the jugular vein. The catheter tubing is flushed with .9 % NaCl (approximately 1 ml) prior to placing in the needle and is also flushed while the catheter is being gently advanced down the jugular vein. The constant flushing of the .9 % NaCl aids in the movement of the catheter down the vein. The amount of total saline that is injected into the animal during the procedure is minimal, and in most cases less than 1 ml. The external end of the catheter is then connected to a transducer via 3-way stopcocks after approximately 1-1.5 feet of catheter has been passed into the jugular vein. The transducer must be placed at the level equal to the base of the heart, which is approximately just caudal to the point of the elbow. The transducer and catheter are again flushed to assure no air has entered the system. The catheter is then advanced to the distal jugular vein and the first pressure taken to help evaluate catheter location. The catheter is passed into the right Atrium through the right A-V value and into the right ventricle of the heart where the second measurement is taken. The catheter is then advanced from the right ventricle through the pulmonary value and into the main pulmonary artery. The catheter is allowed to stay in this location until the pressure remains constant, approximately 5 seconds. The location of the catheter within the animal’s vasculature as well as the pressure reading is done by monitoring the pressure changes and characteristics of the pressure wave lengths on a Data scope. This allows accurate knowledge of the location of the end of the catheter at all times. Once the catheter reaches the pulmonary artery and the pressure is allowed to stabilize; the mean, systolic, and diastolic pressure are recorded. After the PAP is recorded, the catheter is slowly pulled back through the pulmonary valve into the right ventricle. A drop in the mean pressure is noted as well as a distinct pressure wave character change as the catheter is moved from the pulmonary artery into the right ventricle. This mean pressure drop is approximately 6-10mmHg. If this ventricular drop in pressure was not noted, the catheter placement is re-evaluated. If the pressure remains unchanged, the animal was auscultated for presence of valvular damage (murmurs) or other respiratory or cardiac pathology.<br />
<br />
Hypoxic conditions (low atmospheric oxygen) that stimulate a pulmonary response are usually not seen until approximately 5,000 feet of elevation. For this reason, PAP measurements taken at low elevations (< 5,000 feet) have historically been used only to identify those animals that are very sensitive to hypoxic conditions. These cattle are hypertensive at these lower elevations, as evidenced by an elevated PAP measure, and therefore are not suitable for elevations above 5,000 feet. There is evidence; however, that PAP observations taken between 3,000 and 5,000 feet of elevation are genetically correlated to observations taken at higher elevations<ref name="culbertson">Culbertson, M.M., M.G. Thomas, L.L. Leachman, R.M. Enns, and S.E. Speidel. 2017. Multivariate analysis of beef cattle pulmonary arterial pressures measured at differing elevations. J. Anim. Sci. 95(E. Suppl. 4):86.</ref><ref name="pauling">Pauling, R. C., S. E. Speidel, M. G. Thomas, T. N. Holt, R. M. Enns. 2018. Evaluation of moderate to high elevation effects on pulmonary arterial pressure measures in Angus cattle. J. Anim. Sci. 96:3599-3605.</ref> and therefore could be used as an indicator trait in the production of a high elevation PAP EPD. Currently, the number of observations of PAP taken below 3,000 feet are insufficient to determine the genetic relationship between these measures and measures taken above 5,000 feet of elevation.<br />
<br />
Historically raw PAP measures have been used as a tool for deciding what animals should/could remain at elevation and likely survive. These phenotypic measures were often used as a tool to select animals for breeding as well. The growth of data sets over time, such as at the CSU John E. Rouse Beef Improvement Center and at other high elevation seedstock programs, and the subsequent accumulation of data in centralized locations has enabled the calculation of PAP EPD (e.g. www.angus.org). The release of PAP EPD and a long history of using PAP measures has brought about confusion for many breeders. Susceptibility to pulmonary hypertension as indicated by PAP has a considerable genetic influence with heritability estimates for PAP ranging from .25 to .46<ref>Enns, R. M., J. Brinks, R. Bourdon and T. Field. 1992. Heritability of pulmonary arterial pressure in Angus cattle. Proc. West. Sect. Am. Soc. Anim. Sci. 43:111-112.</ref><ref name="shirley">Shirley, K. L., D. W. Beckman, and D. J. Garrick. 2008. Inheritance of pulmonary arterial pressure in Angus cattle and its correlation with growth. J. Anim. Sci. 86:815–819.</ref><ref>Crawford, N. F., M. G. Thomas, T. N. Holt, S. E. Speidel, and R. M. Enns. 2016. Heritabilities and genetic correlations of pulmonary arterial pressure and performance traits in Angus cattle at high altitude. J. Anim. Sci. 94:4483–4490.</ref><ref>Zeng, X. 2016. Angus cattle at high altitude: Pulmonary arterial pressure, estimated breeding value and genome-wide association study. PhD Diss. Colorado State Univ., Fort Collins, CO.</ref><ref name="culbertson" /><ref name="pauling" /> but also indicating that environment has a considerable influence on PAP measures. Therefore, non-genetic factors (i.e. environment) may result in a high PAP score and unsuitability for high elevation environments. These non-genetic effects could include lung damage from bovine respiratory disease and other factors, PAP measurements taken under extreme cold, and feeding of rations for rapid weight gain among others. <br />
<br />
==Pulmonary Arterial Pressure Measurement Considerations==<br />
Cattle moved from low elevations to high elevations should remain at the altitude for a period of 4 weeks or more to accurately PAP test for adaptation to high altitude. Hypoxic pulmonary changes have been seen immediately in cattle as they have been moved to high altitude. However, to most accurately test those that are to be used for breeding, a longer stay at high altitude is recommended. In practicality, it is important for the rancher to know at what elevation the PAP measurement was performed as it has been shown that the PAP measurement will increase as the animal is moved or travels to higher elevations. It is not uncommon to see clinical PH in animals that have a PAP measurement of greater than 49mmHg. Using repeated measures on the same animal it has been shown that the PAP measurement generally increases 1-2 mmHg per 1,000 feet rise in elevation. For simple guidelines to the rancher and veterinarian, an animal should be tested at an elevation of at least 5,000 feet after 4 weeks if testing for suitability to residing at high elevations. The higher the elevation of the test the more accurate and reliable the outcome.<br />
<br />
The equipment, materials and process needed to perform PAP testing in cattle are listed below:<br />
<br />
* Cattle chute equipped with a squeeze and scissor head catch is best. Other types of head catches tend to bind the head and neck, making passing of the catheter difficult. The animal should be secured within the chute with a moderate amount of squeeze applied to reduce body movement. Monitoring the squeeze is very important, too little squeeze allows too much movement, making measurement difficult. Too much squeeze can increase thoracic pressure and result in a false high PAP measure. The chutes must allow securing the head with a halter and turning of the head to allow for jugular exposure<br />
* Adequate labor for handling cattle efficiently and safely. This is best done by having one person responsible for running the chute, catching the head, and applying a consistent level of squeeze to the animal during the procedure.<br />
* Two people securing the halter (nose tongs cannot be used) and turning the heads. This allows for one person to pull the head to the side while the other tightens the halter safely securing the head into the correct position. <br />
* Movement and animal handling processes should be conducted in a low stress manner. The use of dogs and cattle prods should be limited to those animals in a life threating situation or those that have refused movement. Minimal use of these tools is recommended.<br />
<br />
==PAP Scheduling Considerations==<br />
* No vaccinations should be given in the 2 weeks prior to PAP testing although vaccination can be given at time of PAP test.<br />
* Avoid testing two weeks after weaning to avoid stress on the animal and resulting potential for elevated PAP.<br />
<br />
==PAP Data Recording==<br />
* Name and address of owner/owners<br />
* Test Location and elevation. Note: If other breeders bring animals to the testing location from other nearby ranches then the location of the cattle’s origin and elevation should be recorded.<br />
* Breed of each animal<br />
* Sex of each animal (e.g. steer, bull, heifer and cow)<br />
* Date (to enable calculation of age at PAP test)<br />
* Mean PAP, systolic, and diastolic pressure. <br />
* Sire identification if possible, including the registration number of sire if available. <br />
* If the sire is not known, then this should be noted (may occur under commercial production circumstances in an effort to determine whether an animal should remain/reside at altitude).<br />
<br />
==Inherent risks associated with PULMONARY ARTERIAL PRESSURE Testing==<br />
Complications and accidents are very rare but may include infection at needle site as well as systemic septicemia and/or endocarditis, chute injury, loss of catheter in the vascular system, pulmonary cardiac trauma and emboli, acute cardiac failure, local abscess formation, and death resulting from one of the previous.<br />
<br />
==UTILIZATION OF THE PAP TEST FOR VARING ELEVATION==<br />
===AGE OF ANIMAL BEING TESTED===<br />
When evaluating a PAP score in the context of animals residing at elevation, the age of the animal at the time of testing should always be considered. The PAP test is less predictable as an indicator for disease for animals tested at younger than 10 months of age. An exception to this inconsistency is in those animals that have a high PAP measurement, (> 49mmHg). High scores, even at young ages, suggest an animal should not remain, nor be moved to elevations above 5000 feet. For example, if the animal scores a measurement of 49mmHg or greater there is still a great degree of confidence that this animal is a high-risk candidate for high altitude problems while conversely, animals with low PAP scores may not be indicative of a high-altitude suitability. From the perspective of EPD generation, research continues on the genetic relationship between PAP taken at younger ages and those observations taken after 10 months of age. Recent research indicates that while less predictable at ages less than 10 months, there is a genetic relationship with measures taken after 10 months of age and therefore younger measures are useful for genetic prediction<ref>Zeng, X, R. M. Enns, S. E. Speidel, M. G. Thomas. 2015. Angus Cattle at High Altitude: Relationship Between Age and Pulmonary Arterial Pressure. In: Proc. West. Sec. Am. Soc. Anim. Sci. 66:119–121. </ref><br />
<br />
PAP has been shown to increase with age<ref name="shirley" />(and Speidel, pers. Comm.) and therefore indicate a need for adjusting for age in the context of a genetic evaluation.<br />
<br />
==PHENOTYPIC PAP SCORE EVALUATION==<br />
The following chart has been developed to help the breeder evaluate a PAP measurement on an animal for suitability for residing at high altitudes. This must be viewed in the context of animal survival at elevations. An animal may have a high PAP value for reasons other than genetic predisposition (e.g. lung damage as a result of respiratory disease) and therefore not be adapted to living in high altitude environments. As such the chart reflects recommendations for use at elevation based on phenotypic PAP measures rather than genetic recommendations and should be used only for selecting animals that are likely themselves to survive at the elevations listed. Whereas PAP EPD should be used in the context of genetic improvement and production of progeny likely to survive at higher elevations.<br />
<br />
===PAP Risk Factor Low Elevation Test Chart===<br />
PAP Measurements taken between 3,000- and 4,000-feet elevation<br />
should be considered a screening measurement only<br />
<center><br />
PAP test conducted at elevation < 4,000 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | ModerateRisk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | High Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|}<br />
</center><br />
<br />
===PAP Risk Factor Moderate Elevation Test Chart===<br />
<center><br />
PAP test conducted at elevation 4,000-5,500 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|}<br />
</center><br />
<br />
===PAP Risk Factor High Elevation Test Chart===<br />
<center><br />
PAP test conducted at elevation 5,500-7,000 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low/Moderate Risk<br />
| style="text-align: center;" | Low/Moderate Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | High Risk<br />
|}<br />
</center><br />
===PAP Risk Factor High Elevation Test Chart===<br />
<center><br />
PAP test conducted at elevation 5,500-7,000 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | High Risk<br />
|}<br />
</center><br />
* Special consideration should be given to the amount of time the animal was exposed to elevation (>5,500 ft) prior to testing. The predictability and repeatability of the PAP measurement improves with longer the exposure to higher elevation (minimum of 4 weeks is required).<br />
* This chart is based on animals greater than 10 months of age. <br />
* Testing of younger animals (<10 months) may result in a greater variability to the predictive ability of the measurement.<br />
* Risk—Defined as the likelihood of an animal developing pulmonary hypertension themselves or being at risk for having a genetic predisposition for the disease.<br />
<br />
==References==</div>Mennshttp://guidelines.beefimprovement.org/index.php?title=Pulmonary_arterial_pressure_(PAP)&diff=1681Pulmonary arterial pressure (PAP)2019-12-05T17:53:16Z<p>Menns: Created page with "Pulmonary arteries and arterioles carry venous blood from the right side of the heart to the lungs with the purpose of replenishing the blood oxygen. Oxygenated blood then ret..."</p>
<hr />
<div>Pulmonary arteries and arterioles carry venous blood from the right side of the heart to the lungs with the purpose of replenishing the blood oxygen. Oxygenated blood then returns through the pulmonary veins to the left chambers (atrium and ventricle) of the heart to be pumped to the rest of the body. Pulmonary hypertension (PH) is a condition where the pressure inside the pulmonary artery is abnormally high. In response to this increased pressure in the pulmonary artery, the right side of the heart is required to pump with increased force to move blood toward this area of high Pulmonary Arterial Pressure (PAP). This response of the heart results in excessive muscle contraction, stretching of muscle fibers, ultimately leading to increased right atrium and ventricle size. Because the right side of the heart is working harder than normal, its walls thicken (hypertrophy), leading to heart failure and ultimately animal death. These mortality rates are typically very low even though cattle often experience PH. Currently, the impact of PH is primarily quantified in the form of death loss but increasingly there is evidence of reduced performance associated with PH.<ref>Holt, T. N., and R. J. Callan. 2007. Pulmonary arterial pressure testing for high mountain disease in cattle. Vet. Clin. Food. Anim. 23:575-596.</ref><ref>Thomas et al…CAB White paper…https://www.cabcattle.com/wp-content/uploads/Pulmonary-Hypertension-PH-in-Beef-Cattle-Complicated-Threat-to-Health-and-Productivity-in-Multiple-Beef-Industry-Segments.pdf.</ref> <br />
<br />
==Usage==<br />
The PAP test is used as an indicator of PH and as a selection/culling criterion. The procedure/technique for performing a Pulmonary Artery Catheterization (PAP test) begins by securing the animal within a chute with a moderate amount of squeeze applied so as to reduce body movement. The pressure applied is monitored throughout the test, adjusting to maintain animal comfort. Once the head is secured in place, secured and tied in order to expose the lateral jugular furrow. The head is secured with a halter at the level of the point of the shoulder. Care must be taken to avoid securing the head too high as the animal can often then manipulate its head, resulting in cutting of the catheter within the animal; in turn resulting in pulmonary foreign body emboli. The proximal lateral aspect of the jugular furrow is scrubbed with chlorohexidine/alcohol/water and dawn soap solution and all debris is removed making for a clean needle insertion. The jugular vein at the level of the thoracic inlet or just proximal to this is occluded to allow blood flow resistance causing jugular vein distension. The proximal jugular vein is then punctured with a 12-13g, 3.5 inch needle until there is free blood flow from the needle. The needle is then gently threaded down the jugular leaving 1 cm of needle out of the skin to allow for needle control. An Intramedic polyethylene catheter (internal diameter 1.19mm, outside diameter 1.7mm) is then passed through the needle and into the jugular vein. The catheter tubing is flushed with .9 % NaCl (approximately 1 ml) prior to placing in the needle and is also flushed while the catheter is being gently advanced down the jugular vein. The constant flushing of the .9 % NaCl aids in the movement of the catheter down the vein. The amount of total saline that is injected into the animal during the procedure is minimal, and in most cases less than 1 ml. The external end of the catheter is then connected to a transducer via 3-way stopcocks after approximately 1-1.5 feet of catheter has been passed into the jugular vein. The transducer must be placed at the level equal to the base of the heart, which is approximately just caudal to the point of the elbow. The transducer and catheter are again flushed to assure no air has entered the system. The catheter is then advanced to the distal jugular vein and the first pressure taken to help evaluate catheter location. The catheter is passed into the right Atrium through the right A-V value and into the right ventricle of the heart where the second measurement is taken. The catheter is then advanced from the right ventricle through the pulmonary value and into the main pulmonary artery. The catheter is allowed to stay in this location until the pressure remains constant, approximately 5 seconds. The location of the catheter within the animal’s vasculature as well as the pressure reading is done by monitoring the pressure changes and characteristics of the pressure wave lengths on a Data scope. This allows accurate knowledge of the location of the end of the catheter at all times. Once the catheter reaches the pulmonary artery and the pressure is allowed to stabilize; the mean, systolic, and diastolic pressure are recorded. After the PAP is recorded, the catheter is slowly pulled back through the pulmonary valve into the right ventricle. A drop in the mean pressure is noted as well as a distinct pressure wave character change as the catheter is moved from the pulmonary artery into the right ventricle. This mean pressure drop is approximately 6-10mmHg. If this ventricular drop in pressure was not noted, the catheter placement is re-evaluated. If the pressure remains unchanged, the animal was auscultated for presence of valvular damage (murmurs) or other respiratory or cardiac pathology.<br />
<br />
Hypoxic conditions (low atmospheric oxygen) that stimulate a pulmonary response are usually not seen until approximately 5,000 feet of elevation. For this reason, PAP measurements taken at low elevations (< 5,000 feet) have historically been used only to identify those animals that are very sensitive to hypoxic conditions. These cattle are hypertensive at these lower elevations, as evidenced by an elevated PAP measure, and therefore are not suitable for elevations above 5,000 feet. There is evidence; however, that PAP observations taken between 3,000 and 5,000 feet of elevation are genetically correlated to observations taken at higher elevations<ref name="culbertson">Culbertson, M.M., M.G. Thomas, L.L. Leachman, R.M. Enns, and S.E. Speidel. 2017. Multivariate analysis of beef cattle pulmonary arterial pressures measured at differing elevations. J. Anim. Sci. 95(E. Suppl. 4):86.</ref><ref name="pauling">Pauling, R. C., S. E. Speidel, M. G. Thomas, T. N. Holt, R. M. Enns. 2018. Evaluation of moderate to high elevation effects on pulmonary arterial pressure measures in Angus cattle. J. Anim. Sci. 96:3599-3605.</ref> and therefore could be used as an indicator trait in the production of a high elevation PAP EPD. Currently, the number of observations of PAP taken below 3,000 feet are insufficient to determine the genetic relationship between these measures and measures taken above 5,000 feet of elevation.<br />
<br />
Historically raw PAP measures have been used as a tool for deciding what animals should/could remain at elevation and likely survive. These phenotypic measures were often used as a tool to select animals for breeding as well. The growth of data sets over time, such as at the CSU John E. Rouse Beef Improvement Center and at other high elevation seedstock programs, and the subsequent accumulation of data in centralized locations has enabled the calculation of PAP EPD (e.g. www.angus.org). The release of PAP EPD and a long history of using PAP measures has brought about confusion for many breeders. Susceptibility to pulmonary hypertension as indicated by PAP has a considerable genetic influence with heritability estimates for PAP ranging from .25 to .46<ref>Enns, R. M., J. Brinks, R. Bourdon and T. Field. 1992. Heritability of pulmonary arterial pressure in Angus cattle. Proc. West. Sect. Am. Soc. Anim. Sci. 43:111-112.</ref><ref name="shirley">Shirley, K. L., D. W. Beckman, and D. J. Garrick. 2008. Inheritance of pulmonary arterial pressure in Angus cattle and its correlation with growth. J. Anim. Sci. 86:815–819.</ref><ref>Crawford, N. F., M. G. Thomas, T. N. Holt, S. E. Speidel, and R. M. Enns. 2016. Heritabilities and genetic correlations of pulmonary arterial pressure and performance traits in Angus cattle at high altitude. J. Anim. Sci. 94:4483–4490.</ref><ref>Zeng, X. 2016. Angus cattle at high altitude: Pulmonary arterial pressure, estimated breeding value and genome-wide association study. PhD Diss. Colorado State Univ., Fort Collins, CO.</ref><ref name="culbertson" /><ref name="pauling" /> but also indicating that environment has a considerable influence on PAP measures. Therefore, non-genetic factors (i.e. environment) may result in a high PAP score and unsuitability for high elevation environments. These non-genetic effects could include lung damage from bovine respiratory disease and other factors, PAP measurements taken under extreme cold, and feeding of rations for rapid weight gain among others. <br />
<br />
==Pulmonary Arterial Pressure Measurement Considerations==<br />
Cattle moved from low elevations to high elevations should remain at the altitude for a period of 4 weeks or more to accurately PAP test for adaptation to high altitude. Hypoxic pulmonary changes have been seen immediately in cattle as they have been moved to high altitude. However, to most accurately test those that are to be used for breeding, a longer stay at high altitude is recommended. In practicality, it is important for the rancher to know at what elevation the PAP measurement was performed as it has been shown that the PAP measurement will increase as the animal is moved or travels to higher elevations. It is not uncommon to see clinical PH in animals that have a PAP measurement of greater than 49mmHg. Using repeated measures on the same animal it has been shown that the PAP measurement generally increases 1-2 mmHg per 1,000 feet rise in elevation. For simple guidelines to the rancher and veterinarian, an animal should be tested at an elevation of at least 5,000 feet after 4 weeks if testing for suitability to residing at high elevations. The higher the elevation of the test the more accurate and reliable the outcome.<br />
<br />
The equipment, materials and process needed to perform PAP testing in cattle are listed below:<br />
<br />
* Cattle chute equipped with a squeeze and scissor head catch is best. Other types of head catches tend to bind the head and neck, making passing of the catheter difficult. The animal should be secured within the chute with a moderate amount of squeeze applied to reduce body movement. Monitoring the squeeze is very important, too little squeeze allows too much movement, making measurement difficult. Too much squeeze can increase thoracic pressure and result in a false high PAP measure. The chutes must allow securing the head with a halter and turning of the head to allow for jugular exposure<br />
* Adequate labor for handling cattle efficiently and safely. This is best done by having one person responsible for running the chute, catching the head, and applying a consistent level of squeeze to the animal during the procedure.<br />
* Two people securing the halter (nose tongs cannot be used) and turning the heads. This allows for one person to pull the head to the side while the other tightens the halter safely securing the head into the correct position. <br />
* Movement and animal handling processes should be conducted in a low stress manner. The use of dogs and cattle prods should be limited to those animals in a life threating situation or those that have refused movement. Minimal use of these tools is recommended.<br />
<br />
==PAP Scheduling Considerations==<br />
* No vaccinations should be given in the 2 weeks prior to PAP testing although vaccination can be given at time of PAP test.<br />
* Avoid testing two weeks after weaning to avoid stress on the animal and resulting potential for elevated PAP.<br />
<br />
==PAP Data Recording==<br />
* Name and address of owner/owners<br />
* Test Location and elevation. Note: If other breeders bring animals to the testing location from other nearby ranches then the location of the cattle’s origin and elevation should be recorded.<br />
* Breed of each animal<br />
* Sex of each animal (e.g. steer, bull, heifer and cow)<br />
* Date (to enable calculation of age at PAP test)<br />
* Mean PAP, systolic, and diastolic pressure. <br />
* Sire identification if possible, including the registration number of sire if available. <br />
* If the sire is not known, then this should be noted (may occur under commercial production circumstances in an effort to determine whether an animal should remain/reside at altitude).<br />
<br />
==Inherent risks associated with PULMONARY ARTERIAL PRESSURE Testing==<br />
Complications and accidents are very rare but may include infection at needle site as well as systemic septicemia and/or endocarditis, chute injury, loss of catheter in the vascular system, pulmonary cardiac trauma and emboli, acute cardiac failure, local abscess formation, and death resulting from one of the previous.<br />
<br />
==UTILIZATION OF THE PAP TEST FOR VARING ELEVATION==<br />
===AGE OF ANIMAL BEING TESTED===<br />
When evaluating a PAP score in the context of animals residing at elevation, the age of the animal at the time of testing should always be considered. The PAP test is less predictable as an indicator for disease for animals tested at younger than 10 months of age. An exception to this inconsistency is in those animals that have a high PAP measurement, (> 49mmHg). High scores, even at young ages, suggest an animal should not remain, nor be moved to elevations above 5000 feet. For example, if the animal scores a measurement of 49mmHg or greater there is still a great degree of confidence that this animal is a high-risk candidate for high altitude problems while conversely, animals with low PAP scores may not be indicative of a high-altitude suitability. From the perspective of EPD generation, research continues on the genetic relationship between PAP taken at younger ages and those observations taken after 10 months of age. Recent research indicates that while less predictable at ages less than 10 months, there is a genetic relationship with measures taken after 10 months of age and therefore younger measures are useful for genetic prediction<ref>Zeng, X, R. M. Enns, S. E. Speidel, M. G. Thomas. 2015. Angus Cattle at High Altitude: Relationship Between Age and Pulmonary Arterial Pressure. In: Proc. West. Sec. Am. Soc. Anim. Sci. 66:119–121. </ref><br />
<br />
PAP has been shown to increase with age<ref name="shirley" />(and Speidel, pers. Comm.) and therefore indicate a need for adjusting for age in the context of a genetic evaluation.<br />
<br />
==PHENOTYPIC PAP SCORE EVALUATION==<br />
The following chart has been developed to help the breeder evaluate a PAP measurement on an animal for suitability for residing at high altitudes. This must be viewed in the context of animal survival at elevations. An animal may have a high PAP value for reasons other than genetic predisposition (e.g. lung damage as a result of respiratory disease) and therefore not be adapted to living in high altitude environments. As such the chart reflects recommendations for use at elevation based on phenotypic PAP measures rather than genetic recommendations and should be used only for selecting animals that are likely themselves to survive at the elevations listed. Whereas PAP EPD should be used in the context of genetic improvement and production of progeny likely to survive at higher elevations.<br />
<br />
===PAP Risk Factor Low Elevation Test Chart===<br />
PAP Measurements taken between 3,000- and 4,000-feet elevation<br />
should be considered a screening measurement only<br />
<center><br />
PAP test conducted at elevation < 4,000 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | ModerateRisk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | High Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|}<br />
</center><br />
<br />
===PAP Risk Factor Moderate Elevation Test Chart===<br />
<center><br />
PAP test conducted at elevation 4,000-5,500 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Lw Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | Do Not Use<br />
| style="text-align: center;" | Do Not Use<br />
|}<br />
</center><br />
<br />
===PAP Risk Factor High Elevation Test Chart===<br />
<center><br />
PAP test conducted at elevation 5,500-7,000 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Lw Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low/Moderate Risk<br />
| style="text-align: center;" | Low/Moderate Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | High Risk<br />
|}<br />
</center><br />
===PAP Risk Factor High Elevation Test Chart===<br />
<center><br />
PAP test conducted at elevation 5,500-7,000 ft.<br />
{| class="wikitable"<br />
! style="background-color:#efefef;" | PAP<br />
! style="text-align: center; background-color:#efefef;" | Use at Low Elev<br />
! style="text-align: center; background-color:#efefef;" | Use at Moderate Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at High Elev.<br />
! style="text-align: center; background-color:#efefef;" | Use at Extreme<br />
|-<br />
| style="background-color:#efefef;" | Score<br />
| style="text-align: center; background-color:#efefef;" | < 4,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 4,000-5,000 feet<br />
| style="text-align: center; background-color:#efefef;" | 5,500-7500 feet<br />
| style="text-align: center; background-color:#efefef;" | >7,500 feet<br />
|-<br />
| 34-39<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Lw Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 40-45<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
| style="text-align: center;" | Low Risk<br />
|-<br />
| 46-49<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
|-<br />
| >=50<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | Moderate Risk<br />
| style="text-align: center;" | High Risk<br />
| style="text-align: center;" | High Risk<br />
|}<br />
</center><br />
* Special consideration should be given to the amount of time the animal was exposed to elevation (>5,500 ft) prior to testing. The predictability and repeatability of the PAP measurement improves with longer the exposure to higher elevation (minimum of 4 weeks is required).<br />
* This chart is based on animals greater than 10 months of age. <br />
* Testing of younger animals (<10 months) may result in a greater variability to the predictive ability of the measurement.<br />
* Risk—Defined as the likelihood of an animal developing pulmonary hypertension themselves or being at risk for having a genetic predisposition for the disease.<br />
<br />
==References==</div>Menns