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Maintaining Boar Productivity in Hot Weather

by 5m Editor
22 August 2005, at 12:00am

By Murray Tong, Ontario Pork - Pork producers and breeders need to ensure they keep boars cool during the hot summer months, according to a new University of Guelph study, that found that the high temperatures of summer lower boar semen quality, sometimes permanently.

Information provided courtesy Ontario Pork Ontario Pork Logo

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The results are decisive and surprising, says Prof. Mary Buhr, Department of Animal and Poultry Science, who led the study. All the boars exposed to higher temperatures she studied showed at least some negative changes in semen quality.

The effects were wide-ranging between individual animals, but the overall message was clear: heat hurts boar semen.

"We hope this research will inform the producers and the industry about the effects of hot summers and high temperatures on boar semen quality," she says.

Buhr and her graduate student Deborah Sibblies studied boars that were kept at 30 to 34 C temperatures for 10 days, to mimic the conditions of a hot, humid summer heat wave in non-air conditioned pens, using animals in 20 to 25 C temperatures as controls. From there, the researchers monitored the boar semen quality for another six weeks, housing all the boars at 20 to 25 C.

The effects of the increased temperature on the semen included poorer sperm quality, decreased interest in mating and lower sperm counts. Many of the animals recovered, but some never regained the same semen quality or sperm count they had before the trial.

"Six weeks is enough time for sperm to recover, so non-recovery over an entire six-week period means we're probably looking at permanent damage," says Buhr. "If a producer has a lot of money invested in those particular boars, that's important to know."

While air conditioning in barns is often prohibitively expensive for pork producers, Buhr suggests that breeding boars with desired genetic traits be kept in cooler pens during the summer to preserve semen quality and quantity - especially with some meteorological studies showing average summer temperatures on the rise.

"For important animals, if you want to keep their genetics, you'll keep the temperature down to ensure the quality of the semen," she says.

This research was sponsored by Ontario Pork and the Jamaican government.

Source: Ontario Pork - August 2005

Murray Tong is a former writer with SPARK, the University of Guelph’s student writing program.