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Heat Waves Stress Sheep and Koala Fertility

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Western Sydney University researchers have provided an insight into the physiological stress that summer heatwaves place on wildlife and livestock.

In a study published in PLoS ONE, Dr Edward Narayan analysed the physiological stress of Australian merino sheep during an artificial insemination breeding program in Dubbo, and found that the body temperature of the ewes was a significant factor behind reduced embryo survival.

Faecal samples and body temperature measurements were collected from 15 superovulating donor merino ewes during the 2015–16 summer, when ambient temperatures reached up to 40°C. “Ewes that had higher recorded temperatures had a significantly lower percentage of transferable embryos,” Narayan says.

These results suggest a plausible link between heat stress, physiological stress and reduced fertility in merino ewes. “Given that the Australian merino sheep industry is heavily reliant on the breeding efficacy of its ewes in order to maintain a profitable business, further research is required to determine the full extent that hot Australian climates could be impacting reproductive output.”

As part of his work in the Stress Lab, Narayan also investigates the key environmental stresses that are impacting on the mortality rate of Australia’s native fauna, in particular koalas. “Like the merino ewe, koalas also experience chronic...

The full text of this article can be purchased from Informit.