Relationsip between IGF-II gene polymorphism and some performance traits in brown swiss

This study was carried out in Brown Swiss cattle reared in the Experimental Station of Agriculture Faculty in Ataturk Universty and in a private enterprise found in region Ilıca of Erzurum city. In the study, genotypic structures were examined in terms of IGF-II gene locus, and the distribution of genotypes and allele frequencies of the cattle in relation to the genes were determined. The identified IGF II genotypes were associated with milk yield traits such as actual milk yield, 305 day milk yield, lactation period and daily milk yield. The blood samples were taken from 114 Brown Swiss cattle raised on both farms for the examination of genotypic structures for IGF-II gene locus. IGF-II genotypes were determined by using PCR-RFLP method. When IGF-II genotypes were associated with milk yields, only milk yield records in in a private enterprise found in region Ilıca of Erzurum city. were used. In the study, it was observed that the distribution of genotype frequencies was stable (P> 0.05) according to the Hardy-Weinberg genetic equilibrium test of bovine population examined. The CC, CT and TT genotype frequencies of the IGF-II gene found in the population were 41 (34%), 65 (54%) and 14 (12%) respectively and the frequency of the C allele was found to be 0.61 and the frequency of the T allele was found to be 0.39. The general averages of actual true milk yield, 305 day milk yield, lactation time and daily milk yield were 4317 ± 272.9 kg, 5277 ± 240.7 kg, 238 ± 15.5 days and 18 ± 09 kg, respectively, while CC, CT and TT genotypes 4168 ± 515.8, 3756 ± 321.7 and 5382 ± 600.3 kg, respectively; The 305-day milk yield averages 5420 ± 454.9, 4898 ± 283.6 and 5632 ± 529.3 kg; Lactation periods were 221 ± 29.2, 225 ± 18.2 and 281 ± 34.0 days, respectively, and mean daily milk yields were found as 19 ± 1.7, 17 ± 1.1 and 19 ± 2.0 kg respectively. According to the statistical analysis, the effect of genotype, genotype x lactation order and genotype x season of calving interaction were nonsignificant for averages of actual milk yield, milk yield adjustment to 305 day, lactation period and day milk yield. The effect of genotype x age interaction were significant (P<0.05) for average milk yield adjustment to 305 day and day milk yield. The effect of genotype x age interaction on the actual milk yield was found to be highly significant (P<0.01). As a result, correctly identified IGF-II genotypes were detected by using the PCR-RFLP method in the blood samples obtained from Brown Swiss cattle. Genotype and allele frequencies determined for IGF-II gene polymorphism can be considered sufficient to demonstrate the genotype diversity of the race. In the analysis of the association, relationships between IGF-II genotypes and performance characteristics examined were not significant