Effect of heat stress on age in conception of holstein heifers

Abstract

The aim of the study was to evaluate the effect of heat stress on conception of Holstein cattle heifers. The experiment was carried out at the Mendel University farm in Žabčice. The data was collected between May 2017 and August 2017. 48 heifers of Holstein cattle weighing 400-450 kg and ages 16 to 18 months were included in the experiment. The results of our study showed that heifers at 17 months of age (88 %) and 18 months of age (100 %) conceived best in the temperature range of 15-19.9 oC. Heifers at the age of 16 months (100 %) conceived best in the temperature range of 10-14.9 oC, with a moderately lower success rate (71 %) in the temperature range of 15-19.9 oC. At elevated ambient temperatures (range 15-19.9 oC), a 29 % drop in the level of conception was recorded in the heifers in this age category.