Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/24/2011
Publication Date: 6/30/2011
Citation: Dikmen, S., Cole, J.B., Null, D.J., Hansen, P.J. 2011. Heritability of rectal temperature and genetic correlations with production and reproduction traits in dairy cattle. Journal of Animal Science 89(E-Suppl. 1)/Journal of Dairy Science 94(E-Suppl. 1):255(abstr. 275).
Technical Abstract: Heat stress affects production and reproduction in dairy cattle. Genetic selection for body temperature might help to decrease the effects of heat stress on those traits. Objectives of the current study were a) to estimate genetic parameters of rectal temperature in dairy cows under heat stress conditions, and b) to determine genetic and phenotypic correlations of rectal temperature with production and fitness traits. Rectal temperature was measured between 1500 and 1700 h in 1,695 lactating Holstein cows sired by 509 bulls during the summer in north central Florida. Genetic parameters were estimated with GIBBS1F90 and breeding values were estimated with MTDFREML. The heritability of rectal temperature was estimated as 0.21. Annual genetic trend for rectal temperature was positive and increased 0.000068 oC/year from birth year 2002 to 2008. Genetic correlations of rectal temperature with other traits were close to zero. However, 305-d actual somatic cell score (SCS) was positively correlated with rectal temperature. On the other hand, productive life (PL), daughter pregnancy rate (DPR) and net merit (NM) traits were negatively correlated with rectal temperature. Phenotypic correlations among rectal temperature and production traits were positive and often significant. In conclusion, rectal temperature during heat stress is moderately heritable and generally does not have strong genetic correlations with economically important traits. Selection for rectal temperature would result an increase in health and fitness traits without an adversely affecting production traits.