An evaluation of corticotropin-releasing hormone and leptin SNPs relative to cattle behaviour

Pugh, K. A., Stookey, J. M. and Buchanan, F. C. 2011. An evaluation of corticotropin-releasing hormone and leptin SNPs relative to cattle behaviour. Can. J. Anim. Sci. 91: 562-572. The purpose of this study was to identify associations between single nucleotide polymorphisms (SNPs) in two genes involved in the hypothalamic-pituitary-adrenal axis and growth, namely corticotropin-releasing hormone (CRH), and leptin (LEP), and measurements of temperament in beef cattle. Four hundred crossbred beef steers were evaluated upon entry into a beef facility using several different measurements of response to handling: subjective score (SS), strain gauge (SG), movement measurement device (MMD) and exit time (ET). The steers were genotyped at the CRH 22C>G, CRH 240C>G and LEP 73C>T SNPs by PCR-RFLP. The SNP genotypes and two-way interactions between LEP and each CRH SNP were analyzed as effects on the various temperament measurements. We found interactions between CRH 22C>G and LEP and CRH 240C>G and LEP with SG. Within this interaction there appears to be a positive effect of one CRH allele (C) within LEP TT animals while in LEP CC the other CRH allele (G) had a positive effect. These interactions, especially between CRH 22C>G and LEP, needs to be confirmed in other populations of beef cattle. It may be possible in the future to select for temperament alongside production goals.