Body Temperature and Haematological Indices of Boars Exposed to Direct Solar Radiation

Abstract

The effects of exposure to direct sun light on body temperature (BT) and blood profile (BP) of boars was studied using Large White and Large White x local F₁ crossbred boars. The experiment involved three treatments: zero exposure (T₁); 45 minutes (T₂) and 60 minutes exposure (T₃). Pigs were exposed between 13:30 and 14:45 hr daily for 4 weeks. Body temperature of control and exposed pigs was measured daily at the end of exposure. Blood samples were collected and analysed for LC, EC, HbC and PCV while MCV, MCH and MCHC were calculated from EC, HbC and PCV values. Ambient temperature (AT) averaged 27.84 ^oC indoors and 40.54 ^oC outdoors over the experimental period. There were significant genotype, treatment and interaction effects on most of the parameters studied. The LW boars were more severely affected by exposure to direct sunlight than the crossbred boars. It was concluded that wallow pits and shades should be provided for extensively managed pigs to enable them cope with the high thermal radiation and heat stress inherent in the tropics. Again, crossbreeding and selection for heat tolerance would ensure improved productivity in future.

Key word: blood profile, body temperature, erythrocyte indices, Large White, local boar, thermoregulation.