ENERGY METABOLISM AND THERMOREGULATION IN THE NEWBORN CALF; EFFECT OF CALVING CONDITIONS

Abstract

Rectal temperature (RT) and heat production (HP) were measured continuously during the first day of life, using indirect calorimetry, in 16 eutocial and 13 dystocial Holstein-Friesian (HF) calves held at 10 °C. Blood parameters were determined 0, 2, 4, 6, 12 and 24 h after birth. Twin eutocial calves, as well as calves born after early surgical removal showed variations in RT, HP, and blood parameters similar to those of single eutocial calves. However, dystocial calves, especially those born after a very difficult and delayed parturition, had severe and prolonged acidosis, with high lactataemia and alaninemia, and lower plasma NEFA, T3, and T4 levels during the first hours of life than did eutocial calves. They were also less physically active and frequently did not shiver. Their HP was, on average, 22% lower than that of eutocial calves 2 h after birth and 14% lower from 13 h of life onwards. The difference was 26–36% in a dystocial calf born after a delayed surgical removal. RT of dystocial calves decreased by 2.9 ± 0.7 °C, on average, and increased slowly. Their appetite was low or nil and immunoglobulin absorption was delayed and reduced, which can explain the high mortality and morbidity rates of dystocial calves during the first week of life. The results are discussed in relation to the effects of hypoxia and acidosis on metabolism. Key words: Calf, newborn, energy metabolism, thermoregulation, calving conditions, dystocia