Development and Validation of an Animal Susceptibility Model

Authors: Brown-Brandl, Tami; JONES, DAVID - UNIV NEBRASKA

Submitted to: American Society of Agri Engineers Special Meetings and Conferences Papers
Publication Type: Other
Publication Acceptance Date: 5/18/2007
Publication Date: 6/20/2007
Citation: Brown Brandl, T.M., Jones, D.D. 2007. Development and Validation of an Animal Susceptibility Model. In: Proceedings of 2007 American Society of Agri Engineers Special Meetings and Conferences Papers, June 17-20, 2007, Minneapolis, MN. Paper no. 074081. Available: http://asae.frymulti.com/newresults.asp.

Interpretive Summary: Animal response to heat stress is comprised of the effects of three different areas: the individual animal, weather, and management practices. A model was developed to summarize each individual animal's susceptibility to heat stress. This paper summarizes the development of the model, and the testing of its accuracy. The model was tested using cattle over three summers. The model accurately predicted increasing stress with increased susceptibility. Recommendations for further studies included testing the model using animals of more diversity.

Technical Abstract: An individual animal’s stress level is the summation of stresses from three areas: the environment, animal, and management. A model was developed to predict the susceptibility of an individual animal to heat stress. The model utilizes a hierarchal knowledge-based fuzzy inference system with 11 animal characteristics (color, sex, species, temperament, hair thickness, previous exposure, age, condition score, previous cases of pneumonia, previous other health issues, and current health) to predict susceptibility to heat stress and certainty of the prediction The model was validated using data collected on 192 cattle over a 3-year period. Sixty-four heifers of four different breeds (Angus, Charolais, and two cross-breeds [Marc I and Marc III]) were assigned to one of eight outdoor pens in each of three years (2004, 2005, and 2006). The correlation of susceptibility to growth rate, condition score change, respiration rate, and panting score provided the basis for validation. Respiration rate and panting score were significantly higher in the higher categories of susceptibility than the lower categories of susceptibility. Recommendations for further studies include validating the model using a more varied group of animals.