Effect of Zinc Sulphate on Diurnal Variations of Cloacal and Body Surface Temperatures in Pullets During the Harmattan (cold-Dry) Season

The pullets were grouped into two: 20 experimental pullets, administered with zinc sulphate; and 20 control pullets. The cloacal and body surface temperatures of the pullets were taken bi-hourly from 7:00 h to 19:00 h on each experimental day using digital clinical thermometer and infrared thermometer, respectively. The experiment was conducted thrice, with five days apart. The dry-bulb temperature, relative humidity and temperature-humidity index inside the pen were determined simultaneously with the cloacal and body surface temperatures of the pullets. The dry-bulb temperature fluctuated between 17.33°C – 32.33°C and temperature-humidity index ranged from 14.93 – 26.93; which were outside the thermoneutral zone for pullets indicating that the harmattan season was thermally stressful to the pullets. The overall cloacal temperature in control pullets (41.64 ± 0.02°C) was significantly (P < 0.01) higher than in experimental pullets (41.36 ± 0.02°C), and the hourly cloacal temperature was significantly (P < 0.01) higher in control than experimental pullets at all hours of recording, particularly at 13:00 h. High values of cloacal temperature occurred for eight hours, from 9:00 h to 17:00 h in control pullets; while in experimental pullets, they were obtained at for three hours 13:00 h – 15:00 h. The highest body surface temperature (38.83 ± 0.20°C) was recorded at 13:00 h on the wing in control pullets. The least correlation coefficient was obtained in experimental pullets between the temperature-humidity index and body surface temperature recorded on the leg (r = - 0.643**, P < 0.01). The back temperature was closely and significantly (r = 0.999, P < 0.001) related with the cloacal temperature in experimental pullets.