Importance of claw quality in cattle: Review and recommendations to achieve genetic improvement. Report of the E.A.A.P. working group on “claw quality in cattle”

Abstract

The objective of this report is to review results of research and to discuss recommendations to achieve genetic improvement of claw quality. High claw quality is defined as a low susceptibility for claw disorders and a low need for footcare. The economic importance of claw problems is considerable, with about 25% of dairy cows treated per year. Direct effects are costs of trimming, veterinary costs and forced culling (2–3%). Indirect costs are decreased milk production or daily gain, lower fertility, decrease of herd life, and lower salvage value. Lameness problems are mainly localized in the claws and can have a traumatic, systemic or infectious origin. The claw quality is a product of claw shape, characteristics of the horn and anatomy of the inner structure of the claw. Environmental factors like housing systems, management and nutrition give considerable herd effects. Improvement of claw quality in the short term can be achieved by managemental procedures that will reduce foot and leg problems in confinement. Genetic improvement can give a contribution in the long term. Genetic variation in claw traits and claw disorders are recorded between and within breeds. Heritabilities and additive genetic variation for claw shape measurements (e.g. claw length, claw angle) are high enough to obtain genetic change in these traits. Claw measurements are partly symptoms but also predisposition factors for claw disorders like sole ulcers. Shorter and steeper hind leg claws are favourable predispositions. Veterinary records on claw and leg disorders after treatment yield very low heritabilities. Claw judgements should be replaced by more effective measurements because of low h 2 and low correlation to claw disorders. Implementation of genetic improvement based on measurements of claw shape (angle, length) may start with a progeny test of 30–50 daughters in first lactation of the most promising A.I. bulls in milk production. Relationships of claw characteristics of young bulls with those of their parents and daughters is recommended for further analysis.