Effect of high temperature on growth performance of calves maintained in outdoor hutches

The aim of this work was to evaluate effects of high temperature on the growth, feed intake and health condition of calves kept in individual hutches in southern Slovakia.We tested a hypothesis that the calf performance would be infl uenced by the season at birth, sire lineage and gender.Sixtythree Holstein calves were reared in individual hutches from the second day of life to weaning at the age of 8 weeks.The calves originated from 5 sires.All calves were divided according to the temperature period at birth.The effects of period were determined according to two patterns: in pattern A, a low temperature period 1 (LT1, from April 4 to June 11, 69 days), high temperature period (HT, from June 12 to September 14, 95 days) and low temperature period 2 (from September 15 to November 24, 70 days) were distinguished; in pattern B, the results obtained in the LT1 and LT2 periods were combined and compared with those found in HT period.The same conditions of nutrition were ensured.We recorded 62 summer days and 14 tropical days during HT.Sixty-six days with the THI value above 72.0 and twenty-six with the values higher than 78.0 were found.The calves born during the HT had the lowest body weight from the fi rst week to the weaning in the both patterns (P<0.05).These calves drank up the most of water to the weaning, and had the least intake of starter mixture (P<0.05).