Exploring genetic polymorphism in exon 1 region of PGLYRP-1 gene and its association with age at first calving and production traits in Sahiwal cattle

Genetic variation in the peptidoglycan recognition protein 1 (PGLYRP-1) gene may influence innate immune function and economically important performance traits in dairy cattle. This study investigated polymorphism in exon 1 of PGLYRP-1 and its association with production and reproductive traits in 100 Sahiwal cattle maintained at an organized herd of Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, India. A 796 bp fragment encompassing exon 1 was amplified by PCR and genotyped using PCR-RFLP with ApaI . Ten representative amplicons were subjected to Sanger sequencing for sequence confirmation. Two genotypes, GG and GC, were detected at frequencies of 0.97 and 0.03, respectively, while CC was not observed. The corresponding allele frequencies were 0.985 for G and 0.015 for C. Sequence alignment with the Bos indicus reference sequence JN085440.1 confirmed the targeted nucleotide substitution. Association analysis of first-lactation 305-day milk yield, total milk yield, peak yield, lactation length, dry period, derived milk-yield efficiency indices, and age at first calving revealed no statistically significant genotype effects. Numerically, GG animals showed shorter lactation length and dry period, higher peak yield and milk-yield efficiency, and earlier age at first calving, whereas GC animals showed higher 305-day milk yield. Because only three animals carried the GC genotype, statistical power was limited. These association patterns should therefore be considered preliminary and require validation in larger, multi-herd Sahiwal populations.