Characterizing individual animal response to environmental changes

Authors: JONES, DAVID - UNIVERSITY OF NEBRASKA; BROWN-BRANDL, TAMI

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/2/2013
Publication Date: 9/10/2013
Citation: Jones, D., Brown Brandl, T.M. 2013. Characterizing individual animal response to environmental changes. In: Berckmans, D., Vandermeulen, J., editors. Precision Livestock Farming '13, Proceedings of the 6th European Conference on Precision Livestock Farming, September 10-12, 2013, Leuven, Belgium. p. 953-965.

Interpretive Summary: Heat stress in feedlot cattle causes losses in productivity and is an animal well-being concern especially for animals that are housed outside. Not all feedlot animals react the same to hot weather some are more impacted than others. The objective of this research was to describe the response of individual animals to environmental changes. Breathing rate and behavior observations of panting were taken on 384 feedlot heifers over three summertime periods (128 heifers/year). Hot weather was described by using temperature and three heat indices. Temperature humidity index (THI) summarizes temperature and relative humidity. Adjusted THI uses THI and adjusts the value based on the solar load and the wind speed. Heat Load Index describes the heat index by summarizing black globe temperature, relative humidity, and wind speed. Determinations of changes in breathing rate and behavioral observations of panting for each individual animal were developed. The use of the composite measure was determined to be useful in finding the heat tolerance of individual animals.

Technical Abstract: Heat stress in feedlot cattle is a concern. A study was conducted to characterize heat stress in feedlot cattle and to determine the impact of providing shade. To characterize the response to heat stress, linear equations were developed for each of 384 heifers relating 8 different indicators. In unshaded feedlot cattle, it was determined that the lower categories of responsiveness had more lighter colored breeds and the higher categories of responsiveness had more darker colored breeds of cattle. However, it was noted that there were lighter colored animals with high responsiveness and darker breeds with low responsiveness.