Genetic determination of milk albumen genotypes cappa-casein and beta-lactoglobulin for breeding value estimation of milk performance in cattle
2000
Flak, J | Chrenek, P. | Bulla, J. | Vasicek, D. (Research Institute of Animal Production Nitra, (Slovak Republic))
The problem of genetic determination of milk albumen genotypes was observed in the experiments of genotyping of k-casein and b-lactoglobulin of daughters of five sires from each breed as follows: Slovak Pinzgau, Slovak spotted and Holstein breed at 2nd lactation. Cows of Slovak Pinzgau breed produced 2750.25 kg milk with 3.94% fat content and 3.28% milk protein and Slovak spotted breed 5002.97 kg milk with 4.01% fat milk and 3.32% milk protein. The highest milk production was observed in Holstein cows 7361.90 kg, with the lowest milk fat content 3.87% and with 3.29% of milk protein. Statistical significant differences between milk albumen genotypes were observed only for protein content of k - casein genotypes in Slovak spotted breed. The significant variability between sires was observed only for fat and protein contents both milk albumen genotypes in Slovak spotted breed and for all milk production and milk quality traits of both albumen genotypes of Holstein breed. The association between milk albumen genotypes and sire genotypes derived from significant interaction term of both factors was observed only in milk protein content for b-lactoglobulin genotypes. The small sample sizes of daughter groups of sires caused a very variable estimate of interclass sire correlations. Results from our experiments showed the need of planned sampling designs from statistically and genetically point of view for future simultaneous estimation of breeding values based on markers and polygenic variation of milk traits
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