Researching ways for dairy cattle to deal with heat stress
By Jim Massey, Freelancer for UW-Madison Department of Animal & Dairy Sciences
Jimena Laporta, an assistant professor of lactation physiology in the UW-Madison Department of Animal and Dairy Sciences, has been studying heat stress in dairy animals since she began her research and teaching career at the University of Florida in 2015. She was recruited to UW-Madison in 2020 and has continued her focus on trying to find ways to keep dairy animals cool when temperatures rise.
Laporta, originally from Uruguay, says her five years on staff in Florida – “the epicenter of heat stress” – were instrumental in piquing her interest in heat stress biology. She has gone beyond usual heat-stress studies with lactating animals to investigate how heat stress can also affect pre-weaned calves, growing heifers and dry-pregnant cows.
To conduct her most recent study, Laporta resorted to using electric heat blankets – similar to those used to keep horses warm in the winter – to induce heat stress in 56 transition dairy cows for 70 consecutive days through the dry period and into the onset of lactation. The electric blanket contains 12 infrared heating pads making cows uncomfortably warm even when the ambient temperature wasn’t hot.
She worked with a Canadian company that makes electric heat blankets and modified the design slightly so the blankets could stay securely on the animals throughout the study. The electrical outlets in the barn at the UW-Madison Dairy Cattle, where the study was conducted, had to be modified to handle the extra electrical load.
Graduate student Brittney Davidson was instrumental in the implementation of the heat blanket study, which was just completed in December of 2022, Laporta says.
Laporta says she was not the first dairy researcher to use electric heat blankets for a heat-stress study. There had been six prior studies in peer-reviewed journals using the research method – primarily in Iowa – where blankets were originally validated for cattle, but those studies had been for shorter periods of time and with relatively small cow numbers. Yet, as with other heat-stress studies, classical hallmarks of heat stress were successfully induced, including increased respiration frequency and reduced milk production. | READ MORE
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