Characterization of β‑lactoglobulin and κ‑casein genotypes PCR-RFLP in dairy cattle from Panama.

Sustained profitability in dairy production requires continuous improvements in milk yield and composition, traits that are strongly influenced by underlying genetic factors. Polymorphisms in the milk protein genes β-lactoglobulin (β-Lg) and κ-casein (κ-Cn) have been associated with variation in milk production, composition, and technological properties across dairy breeds. This study applied polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis to characterize β‑Lg and κ‑Cn gene variants in Jersey (JE), crossbred (XX), and Creole (CR) dairy cattle in Panama. Genotypic and allelic variation was evaluated using a convenience sample of 351 blood samples collected between 2014 and 2015 (JE, n = 230; XX, n = 90; CR, n = 26). Although the sampling strategy does not support population‑level inference, it is suitable for assessing the feasibility of PCR‑RFLP and conducting an exploratory characterization of genetic variability. Amplification success was 98.6% for β‑Lg and 76.6% for κ‑Cn. At the β‑Lg locus, allele A predominated in JE (0.55) and CR (0.52) cattle, whereas allele B was more frequent in XX cattle (0.73). At the κ‑Cn locus, allele B predominated across all groups. Overall, PCR‑RFLP proved to be a practical and accessible method for detecting variations in milk protein genes, supporting its application in future population‑based studies under Panamanian production conditions.