Effect of season and temperature before and after calving on the future milk production of born heifers

Anotace: The aim of the study was to evaluate the effect of birth season, average maximum temperatures 6 weeks before and after birth of heifers on their first lactation milk yield. In chosen herd, the effect of birth weight, weight gain until weaning on first lactation milk yield was also investigated. Additionally, the effect of the average maximum temperatures before birth, effect of birth season on birth weight were evaluated. The data were collected from the herd “A” in Orava region consisting of Slovak spotted breed (127 records), the herd “B” in Lower Nitra (150 records) and herd “C” in Upper Nitra (116 records) both consisting of black Holstein Friesian cows. Birth season tended to influence the heifers first lactation milk yield in the herd “C” (P <0.06). The maximum average temperatures during the first 6 weeks after birth significantly affected heifers first lactation in the herd “A” (P <0.01). The maximum average temperatures affecting pregnant cows before birth of their heifers did not influence heifers’ milk yield during the first lactation in all herds (P >0.66, herd “A”; P >0.59, herd “B”; P >0.38, herd “C”). In the herd “B” there was insignificant effect of prenatal temperatures, birth season on birth weight of heifers (P >0.97; P >0.74). However, the heifers with the highest weight gains until weaning had numerically higher first lactation milk yield (P >0.20).