Application of Milk Proteins Genetic Polymorphism for Selection and Breeding of Dairy Cows in Bulgaria

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

“…Other authors also described results of χ 2 test used to verify any deviation from H-W equilibrium, for instance, Ardicli et al [ 9 ] who investigated polymorphism in CSN1S1, noted that the tested HF population was not in H-W equilibrium (not all genotypes were present in the population, χ 2 was at the level of 0.42, and p -value at 0.52), similarly with CSN1S2 genotypes. Furthermore, Hristov et al [ 7 ] subjected their result to χ 2 test in order to evaluate the validity of H-W equilibrium. They investigated polymorphism in CSN1S1 in Bulgarian Rhodopean Cattle (BRC) and noted that while χ 2 (0.26) and p -value (0.88) suggest that observed and expected frequencies did not vary significantly and the population was in H-W equilibrium, the relatively low frequency of CC genotypes (0.023) might suggest that in the past animals with BB and/or BC genotypes were preferred and used during reproduction in BRC breed.…”

“…The literature describes 12 CSN2 alleles (A1, A2, A3, B, C, D, E, F, H1, H2, I, and G) that can be detected in dairy cattle; however, not all of them are present in all breeds [ 2 ]. Different SNPs contribute to the creation of described CSN2 (e.g., A1-A3, B-G, I) and CSN3 (A-E, G1-I) variants [ 3 , 4 , 5 , 6 , 7 ].…”

“…PAEP is localized on bovine chromosome 11 [ 3 ]. Literature describes many genetic variants of that gene, including A, B, and D presented in the Tables S1–S5 [ 3 , 4 , 5 , 6 , 7 ]. Tables included in the Supplementary Materials present genes variants in relation to alleles discussed in this paper.…”

“…Variant frequencies may differ according to breed and even herd. This may suggest that the variability of different milk protein SNPs should be monitored in dairy cattle herds [ 7 , 8 ]. Through the years, a selection aiming at improving milk performance might have changed genotype frequencies of different SNPs, rendering some of them monomorphic.…”

Evaluation of candidate genotype of leptin gene associated with fertility and production traits in Hardhenu (Bos taurus × Bos indicus) cattle

“…Leptin is a 16 kDa polypeptide hormone synthesized and secreted primarily from the adipose tissues (Forhead & Fowden, 2009; Rambachan et al., 2017). Leptin playing a multifunctional and vital role in regulating adiposity and signalling the nutritional status to the central reproductive axis that can potentially be used in marker assisted selection (Aytekin & Boztepe, 2013; Friedman & Halaas, 1998; Hristov et al., 2012; Kok et al., 2017; Sharifzadeh & Doosti, 2010). Leptin gene has pleiotropic effects on several functional traits such as milk yield (Komisarek et al., 2005), carcass quality (Schenkel et al., 2005), growth (Kulig & Kmiec, 2009; Lagonigro et al., 2003) and fertility (Clempson et al., 2011; Kaplan, 2018).…”