Diurnally variation of ambient temperature around 24 or 28 deg C: influence on performance and feeding behavior of growing pigs

摘要

The influence of variation of ambient temperature (T) on growth performance was studied in three successive experiments, involving each 192 crossbred gilts and barrows. The T was either kept constant or fluctuated over the day by +- 1.5, +- 3 or +- 4.5 deg C around 24 or 28 deg C. Artificial light was provided between 0700 and 1900. Growth performance were lower at 28 than at 24 deg C whichever the range of variation of T. At the mean T of 24 deg C, the highest average daily gain (ADG) was obtained when the diurnally variation of T was +- 1.5 deg C (903 vs. 881 g/d at the other T); at the mean T of 28 deg C, the lowest ADG was obtained when the variation oft was +- 3 deg C (753 vs. 789 g/d at the other T). Feed consumption was mainly diurnal: 80 percent of total feed intake occurred during the day when T was kept constant at 24 or 28 deg C, this proportion decreased when variation oft was higher than +- 3 deg C (74 percent on average at 24+-4.5 and 28+-4.5 deg C). Such a result is associated with the decrease of feed intake when T increased above 24 (or 28) deg C during the day. Simultaneously, feed intake increased T decreased below 24 (or 28) deg C, especially during the night. However this adaptation did not permit to maintain feed intake level when variation of T exceeded +- 1.5 deg C around 24 deg C. Similarly, a variation of T above +- 1.5 deg C around 28 deg C induced an additional marked reduction in growth performance.