A variety of conformational imperfections in the feet and leg structure of beef cattle have been documented over time. While subtle changes in the feet and leg quality from optimum may have little effect on longevity or productivity of beef cattle, significant defects may result in substantial economic loss. In addition to economic losses associated with decreased performance or reproductive rates, these structural defects also contribute to decreased welfare for affected animals. Certainly, feet and leg quality is influenced by a number of environmental effects including nutrition and management. However, previous work in beef and dairy cattle has demonstrated moderate to high levels of genetic control for these traits which offers substantial opportunity for improvement via selection. Heel depth, hoof angle and hock set were associated with differences in longevity in dairy cattle. Feet and leg structural failures among breeding and slaughter cattle is a growing concern for producers.
Researchers in Australia evaluated approximately 8,000 Angus animals with age under 750 days. Six traits measured included front feet angle (FA), front feet claw set (FC), rear feet angle (RA), rear feet claw set (RC), rear leg side view (RS), and rear leg hind view (RH). Heritability describes the proportion of variation observed between individuals in the population that is under genetic control. Data was analyzed using several methods to determine the most appropriate analytical technique to estimate heritabilities and genetic correlations between the traits. The heritabilities were 0.50, 0.46, 0.35, 0.44, 0.32 and 0.22 for FA, FC, RA, RC, RH and RS, respectively. The genetic correlations describe the strength and directionality of the linear relationship between traits. In this data, the genetic correlations ranged from 0.02 to 0.50. Front and rear feet angle had the strongest genetic correlation of 0.50. Results from this study provide strong evidence that feet and leg conformation traits are under genetic control and that breeding value estimates could be generated to provide effective tools for improvement via selection. The magnitude of the heritabilities are as large or larger than many of the growth traits currently under selection in beef cattle and for which dramatic improvements have been made using genetic predictions. Providing selection tools for feet and leg traits has the potential to rapidly improve conformation and, potentially, welfare issues.
Jeyaruban, G., B. Tier, D. Johnston and H. Graser. 2012. Genetic analysis of feet and leg traits of Australian Angus cattle using linear and threshold models. Animal Production Science, 52, 1-10. Link
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