Contradictory temperature effects on reproductive success in mammals pose a dilemma, with cooler temperatures causing increased milk output, but slower development in young and higher temperatures having the opposite effect. In light of a changing climate, researchers at the University of Veterinary Medicine, Vienna, are studying the effects of temperature on females when raising young.
"It is possible that climate change and global warming may make it even harder for females to perform during lactation and to produce viable young", says Dr Teresa Valencak, who leads the research team.
Lactating female golden hamsters were exposed to three different ambient temperatures (5°C, 22°C, 28°C) to see how temperature affects female energy intake and milk production as well as growth rates of pups.
The researchers found that daily energy expenditure in females at 5°C was significantly higher than in females at 22°C. In fact, mothers housed at 22°C produced less milk than those housed at 5°C ambient temperature. On the other hand, pups housed at 5°C showed much slower development despite the higher milk intake, since they need to expend more energy to keep warm at the lower temperature.
"At 28°C ambient temperature the exact opposite happens, meaning that mothers are heat limited in their milk production while their pups benefit from the warmer ambient temperature in their development. Right now, we are collecting data from females raising young at 28° and first results already showed that food intake was about 53% lower around peak lactation at 28 than at 22. So it is feasible that females can transfer less energy to their young at these conditions", says Valencak.