Effect of ambient temperature and diet composition on lactation performance of sows with regard to parity

The effects of ambient temperature (20 vs. 26°C) and dietary nutrient contents on sows’ lactation performance was studied over their first three lactations. The net energy (NE) and lysine contents were 9.7 MJ and 8.5 g per kg, respectively, in diet B, and 10.5 MJ and 9.1 g per kg, respectively, in diet H. Each sow was allocated to the same treatment over its three successive lactations. Animals had free access to feed between the fifth day of lactation and the day before weaning.Ninety-five percent of sows that achieved three lactations came into oestrus within the fourteen days after the first weaning. Average litter size was 10.9 except during the second lactation (9.9). From the first to the third lactation, litter performance increased. Increase of temperature from 20 to 26°C resulted in a decreased feed intake (6.3 and 5.0 kg/d, respectively) and litter’s growth rate (3.09 and 2.70 kg/d, respectively), but the BW loss increased (25 and 31 kg, respectively). Diet composition did not influence significantly body reserves mobilisation but NE intake was higher with diet H (+19% when compared to diet B) as well as piglets’ weaning weight (+400 g). Despite a non significant interaction, negative effect of hot temperature on litter growth rate seemed to be attenuated with diet H when compared to diet B.