K-casein Genotypic and Allelic Frequencies in the Tropical Milking Criollo Cattle
The objective of this study was to estimate the genotypic and allelic frequencies of the κ-casein A and B variants and their relationship with milk production and composition of the Tropical Milking Criollo cattle. Blood samples were collected from of 180 females and the DNA obtained. A segment of the κ-casein gen was amplified by PCR–and genotyped by restriction endonuclease digestion. Genotypic and allelic frequencies were .09, .60 and .31 for AA, AB and BB (p≤0.05) and .39 and .61 for A and B variants (p≤0.05). For genotypes AA, AB and BB milk production per day, fat and protein percentages were 3.7±.6, 3.9±.4, 4.1±.5; 3.8±.5, 3.6±.5, 3.7±.5; 3.7±.1, 3.7±.4, 3.7±.1, with no statistical differences (p>0.05). Studies on simultaneous effects of the κ-casein and β-lactoglobulin and/or the complete casein complex on milk production and composition seem guaranteed.
Tropical Criollo Cattle