Heat Stress Effects Linger Longer in Dairy Herds
AUSTRALIA - New research has found that the effects of heat stress on dairy cattle last much longer than previously thought.
18 February 2008
1 minute read
The impact on herd fertility lasts for up to five weeks after a hot spell, and tends to be greater in higher producing cows, according to new research from Dr Bill Tranter, from Tableland Veterinary Service, and Dr John Morton, from the University of Queensland.
* "Because heat stress has an effect during the five weeks prior to servicing, there's little to be gained by not inseminating on very hot days" |
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Dr Bill Tranter, Tableland Veterinary Service
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"Because heat stress has an effect during the five weeks prior to servicing, there's little to be gained by not inseminating on very hot days, or by inseminating in the morning, instead of the evening," Dr Tranter said.
Running a bull with the herd during summer will increase submission rates but it won't improve conception rates, the pair found.
The effects can be severe during periods of continuous hot humid weather.
For example the average number of services to achieve one conception is usually about two, but this can increase to four or even six after prolonged periods of heat stress.
"In these situations, it's definitely worth using cheaper semen straws or possibly even running bulls at those times because it will take it will take more inseminations to achieve a pregnancy," Dr Tranter said.
Source: North Queensland Register
