With sweltering heat wreaking havoc on Wisconsin farmers this week, it’s incredibly important to remember to watch for heat stress in livestock. This is especially true when it comes to dairy cattle.
Heat stress is much more than being uncomfortable during scorching temps and early warning signs need to be caught before it’s too late. According to Dr. Jennifer Van Os, Assistant Professor and Extension Specialist in Animal Welfare at UW-Madison’s Department of Dairy Science, “heat stress actually begins when the animal begins experiencing subjective discomfort and begin to show natural signs of attempting to cope with the heat.” As Van Os explains, when these natural attempts made by the cow itself to cope with extreme heat are unsuccessful, that impacts productivity and infertility.
Early signs of heat stress in dairy cattle include sweating and panting, Van Os says. “Once you see panting you know it’s really time to intervene.” Milk production also slips drastically when a cow is experiencing heat stress. “For the cow she’s constantly producing body heat…and ruminant fermentation as part of digestion also produces a lot of body heat,” Van Os says. “With lactation, that’s also a very energy intensive process, so when cows are lactating they produce even more body heat.” The drop in milk production begins with this cascade of events that leads to the cow consuming less feed as she tries to regulate her internal body temperature. From there, milk production drops.
Don’t forget about caring for your calfs as well, says Van Os. “A lot of times people really focus on their lactating animals which makes sense as their your money maker but the calf is the future of the herd.” She further explains that calfs show the same signs of heat stress that a full grown cow does and this is another thing producers need to watch out for.
Stay cool this week and remember, if you are having trouble in the heat, chances are your cows are as well.
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