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Yearling Weight: Difference between revisions
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=== Adjusted Value === | === Adjusted Value === | ||
Adjusted 365 day weights are used to adjust for age of dam and actual age of calf at weighing. Age of dam is known to have an impact on calf weights and each calf is not going to be exactly a year old when the yearling weight measurement is taken, so an adjustment is used. Age of dam is accounted for in the 205-d Adj WW | Adjusted 365 day weights are used to adjust for age of dam and actual age of calf at weighing. [[Age of Dam|Age of dam]] is known to have an impact on calf weights and each calf is not going to be exactly a year old when the yearling weight measurement is taken, so an adjustment is used. Age of dam is accounted for in the [[Weaning Weight|205-d Adj WW]]. The equation used is shown below. | ||
Adj 365-d YW = (Actual YW-Actual WW)/(# Days Between Weights) x 160+ 205-d Adj WW | Adj 365-d YW = (Actual YW-Actual WW)/(# Days Between Weights) x 160+ 205-d Adj WW | ||
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=== Contemporary Group === | === Contemporary Group === | ||
A contemporary group is a group of cattle that are similar in their age, sex, and breed composition and have been managed similarly. Management includes feeding, health treatments, and environment. When gathering yearling weights, it is important to weigh an entire contemporary group on the same day for accurate results. | A [[Contemporary Groups|contemporary group]] is a group of cattle that are similar in their age, sex, and breed composition and have been managed similarly. Management includes feeding, health treatments, and environment. When gathering yearling weights, it is important to weigh an entire contemporary group on the same day for accurate results. | ||
=== Genetic Evaluation === | === Genetic Evaluation === | ||
The adjusted yearling weight is used to calculate the yearling weight EPD. The YW EPD predicts the amount of yearling growth (lbs) that will be transmitted to offspring. It is a reflection of both pre-weaning and post-weaning growth for that animal. There are not as many yearling weight records as there are weaning weight records because once the animal reaches the feedlot, yearling weights are often not reported. Some breed associations account for missing yearling weights by using a multiple-trait model for the yearling weight EPD. This multiple trait model utilizes genetic correlations between birth, weaning, and yearling weights to calculate yearling weight EPDs. Multiple-trait models help avoid selection bias caused by culling lightweight calves from herds before yearling weights are reported. Yearling weight is also sometimes used as an indicator trait for other EPDs such as Mature Weight. | The adjusted yearling weight is used to calculate the yearling weight [[Expected Progeny Difference|EPD]]. The YW EPD predicts the amount of yearling growth (lbs) that will be transmitted to offspring. It is a reflection of both pre-weaning and post-weaning growth for that animal. There are not as many yearling weight records as there are weaning weight records because once the animal reaches the feedlot, yearling weights are often not reported. Some breed associations account for missing yearling weights by using a [[Best Linear Unbiased Prediction|multiple-trait model]] for the yearling weight EPD. This multiple-trait model utilizes genetic correlations between birth, weaning, and yearling weights to calculate yearling weight EPDs. Multiple-trait models help avoid selection [[Prediction Bias|bias]] caused by culling lightweight calves from herds before yearling weights are reported. Yearling weight is also sometimes used as an indicator trait for other EPDs such as Mature Weight. | ||
=== Usage === | === Usage === | ||
Revision as of 23:09, 8 May 2019
Yearling weight is a measure of post-weaning growth reported in pounds.
Phenotype
Yearling weight measurements should be taken between 320-440 days of age. Suggested time between weaning and yearling weight measurement is 160 days. It is important to not take the yearling weight measurement too closely to the weaning weight to allow for more post-weaning growth and a more accurate measure of the yearling weight trait.
Proper measurement procedures are also important. An accurate scale should always be used when possible. Refrain from rounding or estimating whenever possible. The yearling weight measurement is to be taken and reported in pounds.
Adjusted Value
Adjusted 365 day weights are used to adjust for age of dam and actual age of calf at weighing. Age of dam is known to have an impact on calf weights and each calf is not going to be exactly a year old when the yearling weight measurement is taken, so an adjustment is used. Age of dam is accounted for in the 205-d Adj WW. The equation used is shown below.
Adj 365-d YW = (Actual YW-Actual WW)/(# Days Between Weights) x 160+ 205-d Adj WW
Contemporary Group
A contemporary group is a group of cattle that are similar in their age, sex, and breed composition and have been managed similarly. Management includes feeding, health treatments, and environment. When gathering yearling weights, it is important to weigh an entire contemporary group on the same day for accurate results.
Genetic Evaluation
The adjusted yearling weight is used to calculate the yearling weight EPD. The YW EPD predicts the amount of yearling growth (lbs) that will be transmitted to offspring. It is a reflection of both pre-weaning and post-weaning growth for that animal. There are not as many yearling weight records as there are weaning weight records because once the animal reaches the feedlot, yearling weights are often not reported. Some breed associations account for missing yearling weights by using a multiple-trait model for the yearling weight EPD. This multiple-trait model utilizes genetic correlations between birth, weaning, and yearling weights to calculate yearling weight EPDs. Multiple-trait models help avoid selection bias caused by culling lightweight calves from herds before yearling weights are reported. Yearling weight is also sometimes used as an indicator trait for other EPDs such as Mature Weight.
Usage
Yearling weight is an important trait for producers who plan on retaining ownership and feeding out calves. The greater the YW EPD, the more growth potential that animal has to pass to its offspring. Higher growth rates can mean fewer days on feed and lower input costs to reach market weights. Yearling weight measurements may not be as important for those producers who sell their calves directly after weaning. However, producers who purchase weaned calves may be interested in the genetic growth potential the calves have to offer.
References
1. Bormann, J.M., 2010. Data Collection and Interpretation. Beef Sire Selection Manual. Pages 21-23. http://www.nbcec.org/producers/sire_selection/chapter7.pdf. 16 April 2019.
2. American Angus Association. 2019. Adjusted 365 Day Yearling Weight. https://www.angus.org/Performance/AHIR/PerfLinks.aspx. 16 April 2019.
