By Esslemont, R. J. and Kossaibati, M. A. and Pryce , J. E. and Simm, G. and Thompson, R. and Veerkamp, R. F., Animal Science, 1998
Description
10 569 records of 4642 cows from 33 herds collected from 1988 to 1994 were used to study genetic relationships between health, fertility and production traits. These were used to estimate genetic parameters for mastitis, lameness, somatic cell score (SCS), calving interval, days to first service, conception to first service, 305-day milk, butterfat and protein yields. Heritabilities for these traits were also estimated for the first 3 lactations. (Co)variances were estimated using linear, multitrait Restricted Maximum Likelihood with an animal model. The incidence of mastitis and lameness increased with lactation number, therefore a method was used to fix the within-lactation variance to 1 in all lactations while maintaining the same mean. Estimated heritability of SCS across lactations was 0.15. Heritabilities for other health and fertility traits were low and ranged between 0.013 and 0.047. All genetic correlations of health and fertility traits with production traits were negative. The genetic correlation between SCS and mastitis was 0.65 indicating that indirect selection for improvements in mastitis may be achieved using somatic cell counts as a selection criterion. The potential use of linear type scores as predictors of health traits was investigated by regressing health traits on sire predicted transmitting abilities for type. The results indicated that some type traits may be useful as selection criteria
10 569 records of 4642 cows from 33 herds collected from 1988 to 1994 were used to study genetic relationships between health, fertility and production traits. These were used to estimate genetic parameters for mastitis, lameness, somatic cell score (SCS), calving interval, days to first service, conception to first service, 305-day milk, butterfat and protein yields. Heritabilities for these traits were also estimated for the first 3 lactations. (Co)variances were estimated using linear, multitrait Restricted Maximum Likelihood with an animal model. The incidence of mastitis and lameness increased with lactation number, therefore a method was used to fix the within-lactation variance to 1 in all lactations while maintaining the same mean. Estimated heritability of SCS across lactations was 0.15. Heritabilities for other health and fertility traits were low and ranged between 0.013 and 0.047. All genetic correlations of health and fertility traits with production traits were negative. The genetic correlation between SCS and mastitis was 0.65 indicating that indirect selection for improvements in mastitis may be achieved using somatic cell counts as a selection criterion. The potential use of linear type scores as predictors of health traits was investigated by regressing health traits on sire predicted transmitting abilities for type. The results indicated that some type traits may be useful as selection criteria
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