Abstract

FARIA, F.J.C. et al. Polimorphism analysis of k -casein gene on Nelore females and effect on weaning weight of the calves. Arq. Bras. Med. Vet. Zootec. [online]. 1999, vol.51, n.4, pp.377-382. ISSN 1678-4162.  https://doi.org/10.1590/S0102-09351999000400015.

Data from a Nelore herd were used after adjustment of the weaning weight for 205 days of age, sex, age of dam, sire and month of weaning resulting two groups of cows that differed in weaning weight of their calves. The least square means (LSM) and standard error (SE) were 163.21±2.18kg and 134.44±2.18kg, for heavy (H) and light (L) groups, with 41 animals each one. These animals were genotyped for DNA polymorphisms of k-casein gene, using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism). The segment analysis of k-casein IV exon identified the genotypes 71AA, 10AB and 1BB, with frequencies of 0.92 and 0.08 for A and B alleles, respectively. The LSM±SE for weaning weight were 147.73±2.38kg and 156.76± 6.35kg for calves of AA and AB genotype cows. Heavy and light groups were similar for the allelic frequencies for this gene. The dam’s genotype did not affect the weaning weight of the calves. This suggests the existence of another genetic or non-genetic factors with major magnitude.

Keywords : Cattle; Nelore; k-casein; genetic polymorphism.