Experiments were performed with the aim of determining the effect of co-administration of vitamins A and C on rectal temperature (RT) fluctuations in pullets during the hot-dry season. RTs of 29 experimental and 20 control Black Harco pullets were measured hourly for three days, three days apart, from 06:00 to 19:00 h with a standard digital clinical thermometer. The experimental pullets were administered individually with vitamins A and C orally at a daily dose of 1,200IU/kg and 50mg/kg, respectively. The control pullets were given only water, without the addition of vitamins A and C. The lowest hourly RT of 40.96±0.03oC was obtained in experimental pullets at 06:00 h, while the highest value of 41.28±0.02oC was recorded at 16:00 h (P < 0.001). In control pullets, the RT rose significantly from 40.97±0.05oC at 06:00 h to the maximum value of 41.61±0.03oC at 15:00 h (P < 0.001). There was a positive and very highly significant (P < 0.001) correlation between hours of the day and RT values obtained both in experimental (r = 0.834) and control (r = 0.884) pullets. The overall RT of pullets administered with vitamins A and C was significantly (P < 0.05) lower than that of control pullets (41.16±0.02oC and 41.39±0.05oC, respectively). The dry-bulb temperature was significantly (P < 0.001) and positively correlated with RT in both experimental (r = 0.936) and control (r = 0.969) pullets. The pullets administered with vitamins A and C had consistently lower RT values than those of control pullets, especially during the hot hours of the day, from 13:00-18:00 h, with mean values fluctuating between 41.19±0.02oC and 41.28±0.02oC. The RT of both experimental and control pullets showed distinct diurnal fluctuations. It is concluded that vitamins A and C, by reducing the RT values, ameliorated the thermally stressful effect of the hot-dry season and this mechanism may be partly involved in the enhancement of poultry productivity and health during the season by antioxidant vitamins.
V.O. Sinkalu and J.O. Ayo, 2008. Diurnal Fluctuations in Rectal Temperature of Black Harco Pullets Administered with Vitamins A and C During the Hot-Dry Season. International Journal of Poultry Science, 7: 1065-1070.