Variations in the thermoregulatory response of geese during high temperature – humidity index

Abstract

Geese have a seasonal reproductive pattern governed by environmental fluctuation. Birds must therefore be in homeostasis with their environment for optimum performance and reproductive efficiency. In a 21–day trial, the effects of sex and daytime on the thermoregulatory response of geese during high temperature – humidity index was investigated. Twenty four geese (12 males and 12 females) were allotted into two treatments according to their sexes in a completely randomized design. Their respiratory rate, rectal temperature, pulse rate and panting rate were measured and recorded in the morning, afternoon and evening throughout the entire experimental period. Also, the ambient temperature and relative humidity of the pen were recorded on a daily basis. Results showed that females had significantly (p<0.05) higher respiratory rate and pulse rate than males. However, males had significantly (p<0.05) higher rectal temperature than the females. The panting rate was not significantly different (p>0.05) between the two sexes. The respective mean temperature, humidity and temperature-humidity index values recorded were 26.59oC, 85.65% and 40.69 (morning); 34.16oC, 46.05% and 48.25 (afternoon) and 34.39oC, 47.45% and 47.84 (evening). The rectal temperature in the morning was significantly (p<0.05) lower than in the afternoon and evening and their pulse rate decreased (p<0.05) inversely with daytime. Hence, it can be concluded that sex and daytime independently has effect on the thermoregulatory response of geese.