Recent studies expand knowledge on shade and nutritional supplementation’s impact on heat stress


The dog days of summer are just a few turns of the calendar way. Documentation of heat stress in livestock, especially in feed yards, is nothing new. Significant research has been conducted in the High Plains and major cattle feeding areas documenting the effects of heat stress. Two newer studies looked at heat stress and shade on replacement cattle, and how a feed additive can reduce heat stress.

Researchers at the North Florida Research and Education Center (NFREC) Beef Research Unit conducted a study providing artificial shade for replacement heifers grazing bahiagrass pastures through the summer and determined replacement cattle are very much impacted by shade. Sixty black-hided, bred replacement heifers that averaged 920 pounds were separated into two treatments: artificial shade vs. no shade from July 17 to September 2, 2017. The heifers included both Angus and Brangus cattle, with equal numbers of each in the research groups.

At the beginning and end of the study, heifers were weighed on two consecutive days to reduce the effect of gut fill on average daily gain. A total of 12 pens were used in the study: 6 with shade and 6 without.

During 47 days of the shade study, a difference of 0.47lbs/day in weight gain was observed in the heifers that had shade in their pens, versus heifers in pens without shade. Those with shade had an average daily gain of 0.43lbs, where as those without shade lost 0.04lbs on average per day.

Researchers commented while the overall results were not surprising, the magnitude of the drop in ADG was. Additional data collected in the study will compare the amount of time spent in the shade vs. grazing, as well as the effects on animal temperature each day.

Another recent study looked at how a feed  additive could help reduce heat stress in livestock. RumeNext-Beef from ADM Animal Nutrition is comprised of specially selected plant extracts that are standardized and protected in a micro-encapsulated matrix. Although early work with the product was for rumen fermentation for efficiency and performance, research discovered the feed additive provided beneficial effects on heat stress.

A study conducted in Nebraska during the summer looked at 600 head of feeder cattle in dry lots. The study compared cattle supplemented with RumeNext-Beef and Rumensin versus only Rumensin. The study showed a positive effect on ADG during the heat stressed portion of the feeding period of 4.06 lbs/day with both products, compared to 3.75 with Rumensin alone.

ADM Beef Field Nutritionist Brian Fieser, Ph.D. said the RumeNext- Beef acts as a vasodilator, expanding the blood vessels to help cattle dissipate heat. The supplement can be used in a feed yard setting as part of a ration or
can be included in a free choice range mineral.

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