BPEX: Stressful spring for boars
The hot, dry spring has highlighted the issue of heat stress in pigs which can cause fertility problems in boars as well as sows. To help pig producers avoid this problem, BPEX has published its latest 2TS Action for Productivity fact sheet on preventing and managing heat stress in boars.
BPEX Knowledge Transfer manager Angela Cliff said: “The main concern currently is how heat stress can affect working boars’ fertility rates and render them less fertile for a period as long as eight weeks. If body temperature is raised by as little as 2°C it can interfere with sperm production and lead to a reduced number of sperm.
“The boar’s sperm is kept at temperatures 2 to 4 degrees below its average body temperature of 38.5°C to 39.5°C. Air temperatures above 23°C can cause heat stress so the boar searches for ways to prevent over-heating – and temperatures have already reached 27°C this spring.”
A boar’s scrotum is only two-thirds external and the remaining part is internal which proves a further challenge to regulate sperm temperature.
Measures producers can take reduce the effects of hot weather include:
- Shade and wallows – do the same for the boar as the sow
- Space – allow room for the boars to lie prone and isolated
- Little bedding – provide easier access to cool flooring/dirt etc
- Plenty of water – the minimum requirement for a boar daily is 5-8 litres
- Do not encourage matings in such heats
- Additional air movement – use fans
- Feed in early mornings or evenings when cool
“If you suspect that your DIY AI boars have been heat stressed, then be extra vigilant and monitor their semen quality over an eight-week period,” Angela said. “If chaser boars have been affected by heat then consider using AI as insurance.”
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