Effect of chronic heat load during pregnancy on birth weight, behaviour and body composition of Australian feral goat kids

Abstract

Six feral does maintained at elevated ambient temperatures (27.2 degrees - 34.8 degrees) for the last half of pregnancy had rectal temperatures (Tr) elevated by 0.4 degrees above 10 unstressed does. Heat-stressed twin-bearers were 0.15 degrees hotter than single-bearers and bore lighter kids (1.70 kg), than unstressed does (2.24 kg) while singles were less affected (2.22 kg versus 2.28 kg). Birth weight was more highly correlated (P less than 0.001) with the daily minimum Tr of the dam than with the mean or maximum Tr. Kids from heated does stood and began sucking as quickly as control kids but during the first six hours scored significantly (P less than 0.01) lower on a scale of general activity. There were no significant differences in body content of nitrogen, fat and ash or, when birth weight was considered, weight of hide, CNS and liver.

Influence of sex, reproductive status and foetal number on erythrocyte osmotic fragility, haematological and physiologic parameters in goats during the hot-dry season

“…The fact that there was a significant increase in PR in twin compared to single pregnancies during the afternoon hours may suggest that the attempt to dissipate heat increase in proportion to foetal number.The rectal temperatures of goats with twin pregnancies were higher by 0.10 °C and 0.33 °C compared to goats with a single pregnancy in the morning and afternoon, respectively. This finding is similar to that of Holmes et al (1986) where the temperature of heat-stressed twin-bearing goats was 0.15 °C higher than single-bearing goats. Similarly, the significantly elevated PR in Figure 4.…”

Thermal Environment and Human Birth Weight

“…Reduced birth weight following heat stress during pregnancy has been reported in mice (Ashoub, 1958), rats (Benson & Morris, 1971), guinea pigs (Jonson et al, 1976), rabbits (Leduc, 1972), goats (Holmes et al, 1986), sheep (Yeates, 1953;Bell et al, 1987;Ross et al, 1996;Galan et al, 1999), and cattle (Collier et al, 1982;Wolfenson et al, 1988). Growth retardation occurs in the presence of chronic, moderate heat stress.…”