Polymorphism and association study of lactoferrin (LF) gene with milk yield, milk composition, and somatic cell count in Beetal goats

Establishment and Validation of a Method for the Identification of Recessive Mastitis Resistance Genes in Dairy Cows

BACKGROUND/OBJECTIVES

The resistance to occult mastitis in dairy cows is a multifaceted trait influenced by a variety of genetic and environmental factors, posing significant challenges to its prevention and treatment.

METHODS

In this study, a cohort of 389 Holstein dairy cows was selected for investigation. The genes NOD2, CXCR1, SPP1 and LF, which are implicated in resistance to occult mastitis, were genotyped utilizing the efficient and cost-effective Kompetitive Allele-Specific PCR (KASP) technology. Additionally, the study analyzed the association between various single nucleotide polymorphisms (SNPs) and the somatic cell score in Holstein dairy cows. Multi-locus penetrance variance analysis (MPVA) analysis was also conducted to assess the resistance of different genotypic combinations to recessive mastitis in dairy cows. A genotyping kit for occult mastitis resistance was developed. Subsequently, 300 Holstein cows were randomly selected to evaluate the accuracy of the kit's classification and resistance detection.

RESULTS

The findings revealed that the most effective genotype combination was SPP1(AA)-CXCR1(CC)-NOD2(CA)-LF(GA). Upon verification, the genotyping kit for recessive mastitis resistance in dairy cows exhibited an accuracy rate of 100% for individual genotyping and 95.90% for resistance detection.

CONCLUSIONS

From the perspective of disease resistance genetics, this study lays a foundation for the precise management of dairy cow herds. It enables the early identification and removal of individuals susceptible to subclinical mastitis, thereby improving the overall quality of the cattle population.

Association of polymorphism in the promotor area of the caprine BMPR1B gene with litter size and body measurement traits in Damani goats

This study aimed to explore polymorphisms in the promoter region of the caprine BMPR1B (Bone morphogenetic protein receptor 1 beta) gene and its association with body measurement and litter size traits in Damani does. A total of 53 blood samples were collected to analyze the association between the BMPR1B gene polymorphism and 11 phenotypic traits in Damani female goats. The results revealed that three novel SNPs were identified in the promoter region of the caprine BMPR1B gene, including g.67 A > C (SNP1), g.170 G > A(SNP2), and g.501A > T (SNP3), among which the SNP1 and SNP2 were significantly (p < 0.05) associated with litter size and body measurement traits in Damani goats. In SNP1 the AC genotype could be used as a marker for litter size, and the CC genotype for body weight in Damani goats. In SNP2, the genotype GG was significantly (p < 0.05) associated with ear and head length. Therefore, we can conclude from the present study, that genetic variants AC and CC of the caprine BMPR1B gene could be used as genetic markers for economic traits through marker-assisted selection for the breed improvement program of the Damani goat.