Submitted to: American Dairy Science Association Discover Conference
Publication Type: Abstract Only
Publication Acceptance Date: October 26, 2009
Publication Date: November 5, 2009
Citation: Brown Brandl, T.M. 2009. Overview of the Progress in Reducing Environmental Effects on Cattle. In: Proceedings American Dairy Science Association 18th Discover Conference, 2-5 Nov 2009, Nashville, IN. Technical Abstract: Hot weather can have negative impacts on feedlot cattle by reducing animal performance and compromising animal well-being. In most circumstances, animals adapt with amazing ease – balancing their heat production (maintenance energy, production levels, feed intake and activity) with their ability to lose heat through sensible and latent means (changing the behavior, shifting blood flow, and increasing respiration rate to maximize heat losses). However, impacts of this excess heat load can range from little or no effect to death of vulnerable animals during an extreme heat event. Several severe heat waves have occurred in the Midwestern USA in the previous 10 years that have caused the death of thousands of feedlot cattle and loss of millions of dollars in revenue to the cattle industry, both in direct animal losses and indirect performance losses. Heat stress can be defined using three components: the environmental conditions, how susceptible the animal is to heat stress, and the management strategies employed. Environmental conditions are difficult to summarize because many factors need to be included. Factors include current environmental conditions (temperature, humidity, wind speed, and solar radiation), along with other factors including overnight lows, length of extreme hot weather. In addition, there are several factors which affect the microclimate of the feedlot including saturated soils, irrigation of surrounding fields, and wind breaks. An individual animal’s susceptibility to heat stress is influenced by several factors including species, color, condition score or finish, temperament, sex, coat thickness, and previous exposure. Some of the management options have included diet changes, feeding times, shade, sprinkling the animals, and wetting the soil surface. While the past and current production systems have functioned on a cost/return basis, times are changing in animal care with increased pressure from animal welfare groups. The question arises, "Is there a better method of managing feedlot cattle to improve animal well-being and reduce stress (and in the worst case situations reduce the likelihood of death losses), while maintaining an economically viable system?” Future management schemes will need to use our knowledge of all three components of animal heat stress (environmental conditions, animal susceptibility, and management schemes) in an integrated management approach.