Journal of Animal Science and Veterinary Medicine

One key genetic determinant of milk quality and yield is the casein protein, specifically β-casein and κ-casein, which is associated with important traits such as milk production, protein content, and digestibility. This study investigates the genetic polymorphisms of β-casein and κ-casein genes in three indigenous Nigerian cattle breeds: White Fulani, Sokoto Gudali, and Red Bororo, using the Restriction Fragment Length Polymorphism - Polymerase Chain Reaction technique. A total of 40 blood samples from each breed were collected, and DNA was extracted for Polymerase Chain Reaction amplification and the nucleotides were measured for variations using SNPs genotyping. The alleles identified for the β-casein gene were A1 and A2, with the A1 allele being more prevalent in White Fulani (63%) compared to Sokoto Gudali (54%) and Red Bororo (41%). For κ-casein, the A and B alleles were observed, with the B allele being more frequent in Red Bororo (56%) than in Sokoto Gudali (47%) and White Fulani (36%). Genotype frequencies showed a higher proportion of the A2A2 genotype in Red Bororo (47%) than in White Fulani (14%). The Shannon Index (H') and Effective Number of Alleles (Ne) were highest in Sokoto Gudali for β-casein (H' = 0.65, Ne = 2.15) and κ-casein (H' = 0.60, Ne = 2.03), indicating greater genetic diversity. Genetic distance analysis revealed significant differentiation between the breeds, with White Fulani and Red Bororo being the most genetically distinct. It was concluded that White Fulani is more inclined towards higher milk yields due to its higher A1 allele frequency, while Red Bororo, with its predominant A2 allele and A2A2 genotype, shows potential for producing healthier milk with beneficial protein-to-fat ratios and Sokoto Gudali on the other hand, exhibited the highest genetic diversity and could serve as a critical breed for maintaining genetic resilience and adaptability in future breeding programmes.