Steve Sachtleben, PhD, PAS – KNG Beef Research and Nutrition
Cattle producers are faced with multiple challenges today when attempting to be profitable, such as high ingredient costs, high fuel prices and seemingly upward feeder calf prices. The environment can be extremely cruel at times when nature throws extremes into the picture. Heat stress, combined with high humidity and no air movement, can be lethal in a matter of hours if management practices cannot correct the situation. Feeding the majority of the diet at night can help the situation as can the use of sprinklers and strategically placed shades. In addition, sparse information has suggested that dairy cows consuming diets with humates (a carbon source in BoVantage®) may stimulate consumption and decrease uneasiness (and death) in animals exposed to high temperatures, humidity and little air movement. Broussard and coworkers (1994) reported that dairy cows under heat stress, when fed humates, were found to graze longer compared to before, and when brought into the milking parlor did not pant as hard or frequently. Regarding milk production, the humate tended to limit the negative effects of heat stress.
It has been reported by Edmonds (KNG, 2008) that during a heat wave poultry that consumed feed with NutriVantage® Technology exhibited significantly lower mortality rates than birds not fed NutriVantage (control). Intakes of the former group were observed to be greater during the stress period when compared to control groups. It seems that the Midwest always has at least one heat wave each summer; each with variable durations, but the end result for livestock can be disastrous. With the poultry trial in mind, one could speculate that similar results might be obtained in feedlot cattle exposed to severe heat and humidity challenges.
Two prospect feedlots (4-5,000 head capacity) were located, one in Sioux county, Iowa (Randy Rosenboom, KNG commercial account manager) and Astoria, Illinois (Chad Horsley, KNG commercial account manager). BoVantage was moved to the local Kent dealer or feedlot ahead of time in order to start feeding it upon the initiation of an extended heat wave. That heat wave hit in late June and early July 2012. Feedlots were requested to provide at least two pens of cattle of equal average pen weights and keep track of dry matter intakes, morbidity and mortality. In addition, a daily temperature log was to be provided by the feedlot during the heat stress phase. BoVantage was fed at the rate of 25-lb per ton of complete feed (as-fed basis, adjusted for moisture).
￼At Black Gold Feedlot (Astoria, IL), four pens of cattle were placed on test on June 28th for a period of nine days. Two pens were randomly chosen to receive the control diet (no BoVantage) and two were chosen to receive BoVantage. Pens were chosen next to one another to eliminate barn location as a variable. Ambient temperatures ranged from 95° to 103°F during the trial period. Humidity was not as high as observed in normal heat waves as the midsection of the U.S. was in the middle of an extended drought. The intake data are summarized in Graph 1. Those cattle assigned to receive BoVantage ate more feed (P < .0001) than the control cattle during this study (24.1 lb dry matter vs. 22.2 lb dry matter). No deaths or sickness were reported during the heat spell, regardless of treatment. However, some cattle deaths were observed within other pens in the barn. Feedlot personnel at Black Gold stated that cattle fed BoVantage showed no distress during the heat wave. They were comfortable and did not show excessive panting with tongues hanging out. Graph 1 Effect of BoVantage on Intake During Heat Stress
At the second location (Sioux county, IA), about 1,360 yearling cattle (1250 lb) were placed into six pens during June 2012. Cattle (3 pens each) were fed a control diet with or without BoVantage. The air temperatures ranged from 78° to 101°F with the majority of days in the mid to upper nineties. Again, humidity was not exceptionally high. The dry matter intake data from these cattle are summarized in Table 1.
Influence of BoVantage on Intakes of Cattle During 3 Weeks of Heat Stress*
|Treatment||Daily Dry Matter Intake, lb|
Cattle fed BoVantage during this heat challenge consumed 2.46 lb additional (10.46%) dry matter per head, daily, compared to controls.
The intake data from these two field trials fully support the feeding of BoVantage to feedlot cattle during heat stress in order to maintain dry matter intakes. Cattle fed BoVantage during heat stress were observed to be calmer with lower respiration rates.
Most summers have one or several heat spells that can be deadly to feedlot animals. If one is forecast to occur, place BoVantage in the diet at least several days prior to the expected heat spike. Do not remove the BoVantage until the spell has dissipated, as the data from these field trials indicate that the effect of BoVantage on intake disappears within 24 hours of its removal from the diet.