Genetic association of variations in the kappa-casein and β-lactoglobulin genes with milk traits in girolando cattle

Abstract

SUMMARY In dairy farm animals, one the most important goal of the selection is the improvement of milk yield and composition. Several studies have demonstrated that the candidate genes of the kappa-casein (CSN3) and β - lactoglobulin (β-LG) are associated with milk yield, milk quality and health traits in dairy animals. Therefore the aim of this study was to detect polymorphisms in CSN3 and β-LG genes and its association with milk yield in up to 305 days (305MY) and predicted transmission capacity (PTA) for 305MY in Girolando cattle. Totally, 138 bulls and 729 cows (n=867) were sampled. The genotypes of both genes were obtained by the PCR-RFLP method using HinfI and HaeIII enzymes for CSN3 and β-LG genes, respectively. Statistical results revealed two alleles A and B for both genes. The genotypes and alleles more frequents for CSN3 and β-LG genes were respectively: AA (0.7324) and A (0.8558), and AB (0.4827) and A (0.5017). The x2 test revealed that the two loci were at Hardy-Weinberg equilibrium (p<0.001). The allele substitution effects for the variants were not significant on 305MY and PTA for 305MY (p>0.05). The allele variants of β-LG and CSN3 might be more investigated before include them into future breeding schemes designed for Girolando dairy cattle with objective of improving milk traits as milk yield in up to 305 days (305MY) and predicted transmission capacity (PTA) for 305MY..

The Polymorphism in Various Milk Protein Genes in Polish Holstein-Friesian Dairy Cattle

“…Another study that described a population with significantly similar observed and expected genotype frequencies and conformed validity of H-W equilibrium was conducted by Hristov et al [ 7 ]. In the research of Barbosa et al [ 13 ], however, observed frequencies for CSN3 loci differ from Hardy–Weinberg equilibrium (χ 2 = 0.00, p < 0.01), which might suggest that in the past selection during reproduction, that favored one of the genotypes, occurred.…”

“…The study investigated four SNPs in the PAEP gene, out of which one was monomorphic, while three polymorphic SNPs were proven to be in H-W equilibrium ( Table 2 ). Barbosa et al [ 13 ] also reported polymorphism in the PAEP gene (both A and B alleles and resulting genotypes were present in the population). In their study, observed frequencies did not differ significantly from expected ones, suggesting that the population was in Hardy–Weinberg equilibrium (χ 2 = 1.04; α = 0.01).…”

Composite genotypes of progestagen-associated endometrial protein gene and their association with composition and quality of dairy cattle milk

“…Hristov et al [ 12 ] reported that the frequencies of A and B alleles differ according to cattle breed: for Shorthorn Rhodopean cattle breed AA and BB frequencies were low (0.063) and heterozygote frequency was very high (0.88), while in Bulgarian Rhodopean cattle the frequency of AA genotype was higher (0.40) and AB lower (0.58). Also, Barbosa et al [ 9 ] investigated polymorphisms within the PAEP gene revealing two alleles and three genotypes. They reported that within the population of Girolando cows, most common were heterozygotes (0.48) and noted that genotype frequencies were in Hardy-Weinberg equilibrium (chi 2 = 1.04; p<0.01).…”

“…Among the best-known milk protein genes are: 4 casein genes ( CSN1S1 , CSN2 , CS1S2 , and CSN3 ) and β-lactoglobulin gene, also called progestogen-associated endometrial protein gene ( PAEP ) [ 8 ]. Moreover, PAEP has been indicated as a candidate gene that is associated with MY as well as quality of milk [ 9 ]. CattleQTLdb lists a total of 14 traits and 53 QTLs associated with PAEP gene, among which 12 QTLs are associated with milk beta-lactoglobulin content and percentage [ 7 ].…”

Genetic Variants of Milk Protein Genes and Their Association with Milk Components in Holstein Friesian Cattle

“…Zyiad & Fawzi (2014) reported that A and B genotypes were favorable alleles in Palestinian Holstein-Friesian cattle. Similarly, some researchers found that A allele in Holstein-Friesian was as dominant allele in milk protein genes (Volkandari et al 2017;Barbosa et al 2019;Huang et al 2012).…”