Associations between CYP17 gene polymorphisms, temperament and maternal behavior in ewes, and growth in their lambs

Abstract

This study was conducted to determine temperament and maternal care classes, CYP17 gene polymorphisms, and cortisol status of a group of Norduz ewes. Additionally, the relationships between these factors, their effects on lambs survival and growth characteristics were investigated. A total of 72 ewes were subjected to arena and isolation box tests to determine their temperament classes. The distance the ewe retreated from the lamb during tagging was utilized to assess ewe maternal care classes. Ewes were genotyped for CYP17 628 SNP. Blood samples were collected between lambing and weaning to measure cortisol concentrations of ewes. The survival and growth data for the lambs of these ewes were recorded until weaning. Two temperament (low reactive and high reactive) and 2 maternal care classes (strong and moderate) were present. Two CYP 17 SNP 628 alleles (A and G) and 3 genotypes (AA, AG, and GG) were identified. For the distribution of CYP17 genotype frequencies within the population, the temperament or maternal care classes were not different (P > 0.05). The temperament of ewes did not affect maternal care in our flock. Positive partial correlations between cortisol and total cross, distance to stimulus, and sniffing were determined (P < 0.05). CYP17 genotype was an effective factor for some behavioral traits (i.e., total cross) and cortisol release (P < 0.001). Neither temperament (P = 0.636) nor maternal care classes (P = 0.985) differed with cortisol concentrations. CYP17 genotype, cortisol status, temperament or maternal care class of ewes did not affect birth or weaning weight of their lambs (P > 0.05). Although there was no significant relationship among CYP17 genotype, maternal care, and lamb survival and growth, the effect of CYP17 genotype on some behavioral traits and cortisol release was found to be significant. Further studies with larger animal populations are required to elucidate the possible use of CYP17 SNP 628 genotypes as genetic markers for temperament classification.