ASSOCIATION OF β-LAKTOGLOBULIN WITH MILK YIELD OF CROATIAN SIMMENTAL II. GENE EFFECT

Istraživanje utjecaj alela β- laktoglobulin lokusa u 195 uzoraka na količinu mlijeka i masti (kg) te sadržaj masti (%) prve laktacije hrvatskog simentalca. Za isti gen lokus procijenjen je udio aditivne u fenotipskoj varijanci. Prosječan efekt supstitucije alela B za A izračunat je gen supstitucijskim modelom. Aditivna genetska varijanca (ơ²ᴀ) istih mliječnih proizvodnih osobina izračunata je formulom ơ²ᴀ =2pqα². Signifikantan prosječan efekt supstitucije alela B za A utvrđen je za količinu mlijeka - 176,648 ± 63,273 (P=0,006), masti - 5,487 ± 2,690 (P=0,043) i sadržaj masti 0,041 ± 0,013 (P = 0,003). Udio aditivne genetske varijance u fonotipskoj varijanci iznosio 4,1% za količinu mlijeka (kg), 2,2% za količinu masti (kg) i 4,9% za sadržaj masti. U ovom radu utvrđena je veća količina mlijeka i masti (kg) za alel A, te viši postotak masti (%) za alel B. Naravno, posebna su daljnja istraživanja koja bi potvrdila dobivene rezultate prije uključivanja β-laktoglobulin alela u selekciju.
Effects of β-lactoglobulin locus on first lactation milk yield, kilograms of fat and fat percentage in milk samples from 195 Croatian Simmental cows were examined by gene substitution models after allele A was set to zero. Additive genetic variance due to β-lactoglobulin locus was calculated by formula ơ²ᴀ =2pq α². The substitution of the B allele for the A allele was associated with decreased mitt yield (P=0,006) and fat yield (P=0,043) but increased fat content (P=0,003). The contribution of B- lactoglobulin locus accounted for 4.1% of phenotypic variance in milk yield, 2.2% in fat yield and 4.9% in fat content. This study found that milk with allele A had higher milk and fat yield but allele B was associated with higher fat content. However, more research is necessary to confirm these findings before B- lactoglobulin alelles are included in selection.