By Andersen, B. B. and Madsen, P. and Smedegard, H. H., Beretning fra Statens Husdyrbrugsforsog, 1991
Description
3047 Danish Red, Friesian and Jersey bulls at 2 performance test stations in Denmark were tested for leg and claw quality at 4 and 10 months of age. The data were analysed by Restricted Max. Likelihood. The type of housing differed in the 2 stations. One station (station 1) used the tie-up system and had concrete floors, and in the other (station 2), the floor comprised slippery concrete in the eating area and straw-bedding in the lying area, and animals were housed in groups. Animals in station 2 had a significantly higher frequency of claw disorders, but scored higher for leg quality, than those in station 1. Among bull breeds, Jerseys had dark, hard claws with few disorders, Friesians had light claws, a high frequency of claw disorders, and a third of the animals had high scores for horn hardness, and the Danish Reds had good claw quality and few disorders. Estimates of h2 were high to moderate for cannon bone circumference (0.65), pastern angle (0.51), claw size (0.43), claw colour (0.58) and horn hardness (0.34). The h2 of an index constructed by weighting individual claw disorders according to the risk of lameness was 0.18. The phenotypic correlation of horn colour with horn hardness was 0.2. Indirect traits of legs (cannon bone circumference and pastern angle) and claws (claw symmetry, claw colour and horn hardness) had low to moderate genetic correlations with claw disorders. The correlation of a selection index of claw quality with breeding value was 0.50. It is concluded that selection for claw quality, using the index, would be useful for Friesians, but not for Jerseys. For the Danish Red, slaughter of bulls with extremely low claw indices is recommended
3047 Danish Red, Friesian and Jersey bulls at 2 performance test stations in Denmark were tested for leg and claw quality at 4 and 10 months of age. The data were analysed by Restricted Max. Likelihood. The type of housing differed in the 2 stations. One station (station 1) used the tie-up system and had concrete floors, and in the other (station 2), the floor comprised slippery concrete in the eating area and straw-bedding in the lying area, and animals were housed in groups. Animals in station 2 had a significantly higher frequency of claw disorders, but scored higher for leg quality, than those in station 1. Among bull breeds, Jerseys had dark, hard claws with few disorders, Friesians had light claws, a high frequency of claw disorders, and a third of the animals had high scores for horn hardness, and the Danish Reds had good claw quality and few disorders. Estimates of h2 were high to moderate for cannon bone circumference (0.65), pastern angle (0.51), claw size (0.43), claw colour (0.58) and horn hardness (0.34). The h2 of an index constructed by weighting individual claw disorders according to the risk of lameness was 0.18. The phenotypic correlation of horn colour with horn hardness was 0.2. Indirect traits of legs (cannon bone circumference and pastern angle) and claws (claw symmetry, claw colour and horn hardness) had low to moderate genetic correlations with claw disorders. The correlation of a selection index of claw quality with breeding value was 0.50. It is concluded that selection for claw quality, using the index, would be useful for Friesians, but not for Jerseys. For the Danish Red, slaughter of bulls with extremely low claw indices is recommended
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