Relationship Between the CYP21 Marker and some Productive and Physiological Traits of Holstein-Friesian Cows

Abstract

There was a difference in the genetic profiles of the CYP21 genotype, it showed three genetic polymorphisms: 250/240, 260/251 and 270/261 bp, and their distribution ratios were 51.72, 29.31, and 18.96%, respectively. The percentages showed highly significant differences (P≤0.01), and the total of the studied alleles was 116. The study showed that there were no significant differences in the production of total milk and its components between the genetic polymorphisms, as well as in the rate of milk flow. There were significant differences (P≤0.05) between the different genetic polymorphisms of cows in the heat endurance factor, as the cows carrying the genotype 250/240, 260/251 bp outperformed the genotypes 270/261 bp so the value of the thermal endurance factor was 99.73 for the genotype 270/261 bp, as for the genotypes 250/240, 260/251 bp, the coefficient of heat endurance was 101.82 and 102.43, respectively. There were a significant differences (P≤0.05) between the genotypes for the California test for mastitis, cows carrying the genotype 250/240, 270/261 bp outperformed the genotype 260/251 bp. The test values were 1.77 and 1.00 for genotypes 270/261, 250/240 bp respectively, and the value of the California test for genotype 260/251 bp was 2.45.