J. Juszczak et al., Relations between genetic variants of kappa-casein and beta-lactoglobulin and performance of Black and White and Polish Red cattle, ARCH TIER, 44(3), 2001, pp. 239-249
Performance of 184 cows from 4 herds of Black and White (SR) and 178 cows f
rom 4 herds of Polish Red breed (RP) was compared due to genotype encoding
milk proteins: kappa -casein and beta -lactoglobulin. Frequence of inividua
l genotypes differend significantly both between herds within the breed. St
atistically significant influence of genotype was found in relation to milk
fat content in SR cattle (kappa -CNAA > kappa -CNBB and beta -LG(BB) >beta
- LG(AB) > beta -LG(AA)) and in RP cattle milk protein yield (kappa -CNBB >
kappa -CNAA) and fat content (beta -LG(AA) > beta -LG(AB) and beta -LG(BB)
). The highest protein content and protein yield in milk was found in cows
of both breeds carrying kappa -CNBB genotype (P>0.05). Significant relation
with the age of first calving was stated in SR cows: kappa -CNAA > kappa -
CNAB, in RP cows kappa -CNBB > kappa -CNAB and in SR cows beta -LG(BB) >bet
a -LG(AB). Other traits such as longevity, life-time number of calvings and
lactations, life-time yield were not found significantly related to search
ed genotypes although some trends were observed.