An investigation on allele frequency at the CSN1S2 locus and its relationship with milk parameters in the Sarda goat

The aim of the study was to assess allele frequencies at the CSN1S2 locus in the Sarda goat and the effects of the genotype on milk composition. Two hundred twenty Sarda goats from 20 farms were selected. Individual blood and milk samples were collected during the middle of lactation and daily milk yield was registered. Fat, protein and lactose percentage, freezing point, pH, somatic cell count and total mesophilic count were measured. DNA was analysed with different methods based on PCR. Allele frequencies, the Hardy Weinberg (HW) equilibrium and the correlations between milk yield and composition and the genotypes were calculated. F (0.400) and A (0.330) alleles showed the highest frequency. D and 0 alleles were not found. Genotype frequencies were the following: AA, 0.136; AB, 0.009; AC, 0.082; AE, 0.032; AF, 0.264; CC, 0.023; CE, 0.023; CF, 0.250; EF, 0.077; FF, 0.105. The population was in HW disequilibrium. No link between the genotypes and milk yield, chemical, physical and cytological parameters was found.