Claw traits in cattle breeding programs: Report of the E.A.A.P. working group “Claw quality in cattle”

Abstract

Claw quality in cattle breeding can be defined by claw measures, which show high genetic correlations to the occurrence of claw disorders and to the economic loss by claw disorders. High claw quality provides the opportunity for increased longevity and lifetime performance. Heritabilities and additive genetic variation of claw disorders and claw measures are high enough to provide scope for selection. The morphological claw measures, length of diagonal from the tip of the toe to the proximal heel, length of dorsal border and length of heel, are the most useful traits for genetic improvement of claw quality in a progeny-testing program. These claw shape measures, recorded at the claws of one front and rear leg, give a selection response of 63% relative to direct selection against claw disorders. Adding leg judgments to the selection index increased the relative selection response by about 20%. Selection of bulls, based on claw measures in a performance test at an age of about 1 year, is a promising approach to improve claw health in daughters. Multiple correlations of claw disorders of daughters with claw measures taken on their sires as young bulls at about 1 year averaged 0.79. Genetic correlations were of moderate size between angle of dorsal border to ground and stay-ability to 72 ( r g=0.15) and 84 months ( r g=0.22). Foot angle contributed 32% to 35% of the type traits in a sire selection index for milk yield and functional type traits. Cows with a shorter diagonal of the claw in the first lactation will stay longer in the herds. Practical implementation of selection on claw traits in artificial insemination breeding programs is recommended. Genetic improvement of claw health can be implemented by a progeny test of first lactating daughters on farm, a progeny test of sons at testing stations and by a performance test of young bulls. Claw measures may be also candidates for inclusion as secondary traits in a nucleus breeding program with Multiple Ovulation and Embryo Transfer (MOET).