Evaluating a new shade for feedlot cattle performance and heat stress

Authors: HAYES, MORGAN - University Of Kentucky; Brown-Brandl, Tami; EIGENBERG, ROGER - Collaborator; Kuehn, Larry; Thallman, Richard - Mark

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2017
Publication Date: 7/1/2017
Publication URL: https://handle.nal.usda.gov/10113/5801882
Citation: Hayes, M.D., Brown-Brandl, T.M., Eigenberg, R.A., Kuehn, L.A., Thallman, R.M. 2017. Evaluating a new shade for feedlot cattle performance and heat stress. Transactions of the ASABE. 60(4):1301-1311. https://doi.org/10.13031/trans.12104.

Interpretive Summary: Heat stress in cattle can decrease feed intake, weight gain, and in extreme cases can cause death in vulnerable animals. A study was completed to evaluate the impact of providing shade to feedlot cattle. The shade was provided with a novel two-tiered design, which was placed in 7 of 14 pens. The shades were designed to reduce solar radiation by 40 to 60%. The north – south design allowed the shade to move across the pen, thus allowing the dirt surface to dry out. The group used consisted of mixed breed cattle with varied genetics including both Bos taurus and Bos indicus. Production parameters including pen feed usage were measured daily and individual body weights obtained. Daily respiration rates and panting scores were collected. Responsiveness to heat (slope between respiration rate and ambient temperature) was calculated for each individual animal. Air temperature, relative humidity, wind speed, ground temperature, and black globe temperature (black globe is a temperature taken within a black 6” globe -- it combines solar radiation, wind speed, and air temperature) with and without shade were measured. The feedlot surface temperatures and black globe temperatures were reduced under the shade. Cattle in the shade had lower feed efficiencies, but did not have different gain or feed intake. When stress levels were measured panting scores were not significantly lowered; however, responsiveness to heat was found to be significantly lower when the animals had access to shade.

Technical Abstract: Heat stress in cattle results in decreased feed intake, lower daily gain and potentially death in susceptible animals under intense conditions. A study was carried out during the summer of 2013 on the USDA-ARS U.S. Meat Animal Research Center feedlot evaluating the impact of shade on environmental conditions and cattle performance. A novel two-tiered shade was utilized in half of the 14 pens, each holding 30 animals. The shades were designed to reduce solar heat load by 40% to 60% and to provide traveling shade across the pen, providing varied amounts of shade area as well as varied solar reduction potential. The objective of this study was to determine if the shade was effective at improving performance (evaluated as average daily gain, feed intake, and feed to gain ratio) and reducing environmental conditions that cause heat stress. A group of mixed-breed cattle with varied genetics including both Bos taurus and Bos indicus were selected, penned on the basis of sex and were blocked by color. Production parameters of pen feed usage were measured daily and individual body weights were taken monthly. Environmental conditions including air temperature, relative humidity, wind speed, ground temperature, and black globe temperature with and without shade were measured. Solar load on the pens was reduced when shade was provided, with both ground temperature and black globe temperature showing reductions. Cattle showed nominally better performance; however, no significant differences were found with gain or feed intake. Panting scores were not significantly lower with shade provided; slopes of cattle respiration rate versus ambient temperature were significantly lower with shade during the afternoon period.