Physiological response of four exotic breeds of boar to humid tropical environment

Abstract

The study was conducted to assess the thermoregulatory response of four exotic breeds of boar to tropical humid environment. Sixteen (16) exotic boars (four boars per breed) imported from the United Kingdom to Nigeria were used for this experiment. The breeds were Duroc, GC 750 (hybrid), Large white (LW) and Landrace (LR). The ambient temperature and the relative humidity of the pen house were recorded. The thermoregulatory response of the pigs was assessed by measuring the rectal temperature (RT) and respiratory rates 3 times daily: Morning, (8:00 and 8:30 am), afternoon (12:30 and 1:00 pm) and evening (3:30 and 4:00 pm). The daily ambient temperature and relative humidity of the pen house were 27.98±1.66⁰C and 84.48±5.99% respectively. The daily rectal temperature recorded for LW (37.14±0.45^oC) was significantly (P<0.05) lower when compared to other breeds. The daily rectal temperature of GC 750 (37.56±0.62⁰C) was the highest while the least was recorded in LW (37.14±0.45). The respiratory rate of the boars ranged between 26.16±3.26 (LW) and 27.07±3.96 bpm (GC 750). The physiological response of the boars to tropical humid environment was found to be different among the breeds. The large white showed the best capacity to tolerate heat among the four breeds. It can be concluded that environmental factors such as ambient temperature in humid tropical environment influenced physiological response of exotic boars.