March 16, 2016

Bentley Lecture focuses on heat stress

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By Chloe Mitchell, ASAS/ASAP communications intern

March 15, 2016 – The Bentley Lecture at the 2016 Midwest Meeting was given by Dr. Frank Dunshea from the University of Melbourne, Australia. Dr. Dunshea’s presentation was entitled “Dietary strategies to ameliorate the physiological effects of heat stress in livestock.”

Over 200 people attended the lecture and lunch, where Dr. Dunshea spoke on the use of antioxidants, chromium, betaine, and grain treatments to alleviate the effects of heat stress in livestock such as sheep, cattle and pigs. In particular, he focused on the effects of heat stress on gut integrity.

When given at levels above normal requirements, vitamin E and selenium may improve animal health and production during times of heat stress, as they reverse the effects of heat stress on the gut. These antioxidants were shown to prevent an increase of reactive oxygen species in lambs, thus preventing oxidative damage during heat stress, as well as reducing respiratory rate and rectal temperature without reducing feed intake.

Chromium treatment in pigs resulted in increased blood flow to the skin to assist in heat loss during times of heat stress, as well as decreasing respiratory rate.

Betaine was shown to decrease the maintenance requirement of pigs and prevent a drop in milk yield in cows in high temperature environments.

Finally, Dr. Dunshea spoke on wheat versus corn as the main grain source in a ruminant diet, explaining a cattle trial in which animals on a wheat diet had higher flank temperature, as wheat ferments faster than corn. Corn-fed sheep were also shown to have lower respiratory rate and rectal temperature than those fed wheat. Therefore, slowing down grain fermentation can protect against heat stress in ruminant species.

For more information on Dr. Dunshea and his research, please visit his website: http://www.findanexpert.unimelb.edu.au/display/person28608#tab-affiliation.

This lecture was sponsored by the Bentley Appreciation Club.

The Bentley Lecture at the Midwest Meeting was established in honor of Dr. Orville Bentley. Bentley’s interest in international research collaborations means that the lecture is given annually by an invited international guest speaker.