The interleukin-8 gene polymorphism and its association with milk production traits in holstein cows

This study proposed to identify a polymorphism in the IL8 gene in Holstein cows and analyze the relationship with milk production traits in Taiwanese Holstein cows. Investigations were done for single nucleotide polymorphism at position 2862 and the impact of IL8-T2862C polymorphism on the milk production traits of 68 Holstein cows was randomly analyzed by fixed effects model. No significant difference was found between genotypes for 305-2X-ME, fat%, protein%, total solid%, and somatic cell counts score (SCS). Significanteffects were observed on daily milk yield (MY), SCC (p<0.05), and lactose% (p<0.01). Cows with the CC genotype had less SCC compared with CT and TT ones. The allelic substitution effect was 0.70 kg daily milk yield for IL8 favorable allele T (p<0.05), and 3.24 x 10 ⁴ cells/mL SCC for IL8favorable allele C (p<0.01). Significant dominance effects of IL8-T2862C on daily milk yield (1.22 kg, p<0.05) and lactose% (+0.07%, p<0.01) were found.