Diurnal variation in some physiological parameters in the West African dwarf goats, as influenced by age, sex and pregnancy status

Diurnal variation in physiological parameters

Abstract

Diurnal variation in physiological parameters is an established phenomenon. However, the effects under various allostatic states have not been well established. Therefore, this study was carried out to determine the roles of age, sex and pregnancy status in the diurnal variations in heart rate, rectal temperature, and respiratory and pulse rates in West African Dwarf (WAD) goats. Twenty (20) healthy goats comprising 5 adult males, adult non-gravid females, gravid females and kids (less than 6 months old) were used in this study. The animals were sampled two hourly, at 08:00, 10:00, 12:00, 14:00, 16:00, 18:00 and 20:00 hours. The rectal temperature showed considerable diurnal variation. The values increased steadily until the peak was reached at 8 pm in the WAD goats. However, a significant increase was observed at 10 am in the male goats whereas the increases were not significant until 4 pm in the gravid and non-gravid females as well as in the kids. Significant diurnal changes were also demonstrated in the respiratory rates of the goats. Except for the young goats, the respiratory rate increased from 10 am and peaked at 2 pm before falling to the lowest values at 8 pm. However, the highest respiratory rate in the young goats was observed at 8 am, from where it descended to its lowest value at 8 pm.
This study showed that diurnal variation in the rectal temperature, and respiratory rates may not follow the same sequence in both adult and young goats. The sex of the animal involved is also a source of influence on the diurnal fluctuations of these diameters. At the same time, pregnancy status did not appear to influence diurnal variation in the WAD goats studied.