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Talk:Hoof Tape
This page, and references LaShell et al [2], Parish et al[3], and Pruit et al [5] are focused on relationships between hoof circumference and scale-measured birth weight. Shouldn't we be looking at relationships between hoof circumference and calving ease? What are phenotypic and genetic correlations between hoof circumference and calving ease - is hoof circumference a decent indicator of calving ease?
Toser et al. developed a model to predict calving difficulty, first predicting birth weight from hoof circumference, then predicting dystocia from birth weight and pelvic width. They show hoof circumference increased with calving difficulty score, but standard deviations around the mean circumference for each score overlap. Presumably Ko et al [1] show something similar but I cannot a copy of that paper.
Colburn et al. (1997) found a 0.52 phenotypic correlation between hoof circumference and calving difficulty, slightly weaker than their 0.57 correlation between birth wt and calving difficulty. The correlations are a bit curious - mean birth wt increased with calving difficulty and means were significantly different for each category. Mean hoof size bounced around - hard pulls had the numerically smallest feet, not statistically different from easier pulls or unassisted calves. C-sections and easy pulls had the largest feet, different than unassisted. Sires ranked the same by birth wt EPD and calf foot size (lightest EPD/smallest feet ... heaviest EPD/largest feet). The high birth wt EPD/big foot bull also had the most calving difficulty - incidence, mean score, c-section rate. These results suggest hoof circumference might be a useful indicator, but genetic correlation estimates
