Influence of the Casein Composite Genotype on Milk Quality and Coagulation Properties in the Endangered Agerolese Cattle Breed

SIMPLE SUMMARY: Characterization of variants in casein genes allows breeders and researchers to select the most suitable cows for milk production within the same breed. It has been observed that milk from different cattle breeds with the same casein composite genotype shows different chemical and coagulation properties. The aim of this work was to characterize CSN1S1, CSN2 and CSN3 gene variants in Agerolese cattle, an Italian autochthonous breed, milk of which is used to produce “Provolone del Monaco”, a PDO cheese with a relevant economic interest for the Lattari Mountains area and the Sorrento Peninsula (Naples, Italy). According to the results, Agerolese cattle population shows a low genetic variability and a high prevalence of the A(2) allele of CSN2. As regard chemical composition and coagulation properties, BBA(1)A(2)AB, BBA(2)A(2)BB and BBA(2)A(2)AB composite genotypes showed the best parameters. These results will be used to promote the genetic value of Agerolese cattle and to help breeders to improve their breeding practice. ABSTRACT: The aim of this study was the characterization of CSN1S1, CSN2 and CSN3 genetic variability in Agerolese cattle, and the investigation of the effect of casein composite genotypes (CSN1S1, CSN2 and CSN3) on quality and coagulation traits of the corresponding milk. To these purposes, blood and milk from 84 cows were sampled and analysed. Allele frequencies at CSN2 and CSN3 revealed no Hardy–Weinberg equilibrium in the population with a prevalence of allele A(2) for CSN2 and allele B for CSN3. BBA(1)A(2)AB and BBA(2)A(2)AB composite genotypes were the most common in the population. BBA(1)A(2)AB showed a higher total solids and fat content (12.70 ± 0.16 and 3.93 ± 0.10, respectively), while BBA(2)A(2)BB showed the best coagulation properties (RCT 12.62 ± 0.81; k(20) 5.84 ± 0.37; a(30) 23.72 ± 1.10). Interestingly, the A(2) allele of CSN2 was very widespread in the population; thus, it will be intriguing to verify if A(2)A(2) Agerolese cattle milk and the derived cheese may have better nutraceutical characteristics.