May 31, 2016
By John Hutcheson, Ph.D.
The BRD Report blog has featured several posts on the importance of reducing stress, especially at weaning, to reduce BRD outbreaks. With this post, we begin a two-part series that looks at both health and nutrition considerations to help ensure cattle on arrival are ready to thrive.
The survival of newly arrived stocker or feeder cattle is dependent upon a functional immune system. Disease treatments frequently involve measures to diagnose and reverse immune deficiencies, which requires an understanding of basic immunology.
Stress decreases the responsiveness of the immune system. Stress is defined as a nonspecific response of the body to any demand, and is the environment in which the animal resides. Stress alters the steady state of the body and its management has two major components: 1) management of the environment and 2) management of the effects of stress.
Nutrition and stress interact in at least two different ways: 1) stress can produce, or aggravate, nutrient deficiencies, and 2) nutritional deficiencies can produce a stress response. To understand how to reduce stress, we must first look at the management practices used that contribute to stress.
The major stressors created are deprivation of feed and water, weaning, crowding and exposure to disease. Other stressors encountered, either prior to or on arrival at the feedlot, include transportation, weather changes, castration, dehorning and other processing procedures. All of these stressors may be involved in altering the optimum nutrient requirements and responsiveness of the immune system.
In the next post, we will look at nutritional considerations for calves that may be stressed.