DESEMPENHO REPRODUTIVO DE NOVILHAS LEITEIRAS NASCIDAS EM DIFERENTES ESTAÇÕES DO ANO

Abstract

The state of thermal stress (TE) is characterized when the body fails to respond adequately to stimuli, compromising the immune system. Problems that start in cows that suffer ET in late gestation lead their offspring to disadvantages until lactation compared to animals that were in term neutral conditions during their fetal stage. Thus, the objective was to evaluate the effects of the season of the year of birth of Holstein heifers on the reproductive efficiency of heifers. The study was carried out from a database of a commercial farm in the Brazilian Midwest for four years. Heifers born in different seasons of the year showed zootechnical distinctions, confirming the assumption that animals born in the summer are affected by high average temperature and humidity, with lesser weight at puberty in heifers. Thus, this work came to add information on the importance of adopting better thermal comfort and well-being strategies during calf birth, in an attempt to obtain better productive and reproductive performance of rearing animals and avoid damage to the property.