Submitted to: Extension Reports
Publication Type: Experiment Station
Publication Acceptance Date: September 1, 2012
Publication Date: October 15, 2012
Citation: Sanchez, N.C., Carroll, J.A., Welsh Jr, T.H., Randel, R.D., Vann, R.C. 2013. Metabolic differences in cattle with excitable temperaments can influence productivity. Extension Reports. p.68-78. Interpretive Summary: Two collaborative studies were conducted involving scientists from the Livestock Issues Research Unit, the Texas AgriLife Research and Extension Center-Overton, Texas AgriLife Research-College Station, and Mississippi State University in order to elucidate the differences in metabolism due to temperament in Brahman calves. The data collected from these studies demonstrates that there are clear metabolic differences between cattle that exhibit calm versus more excitable temperaments. Specifically, the data suggest that greater cortisol concentrations observed in the temperamental bulls may make them more resistant to the effects of cortisol, which may have reduced their subsequent responsiveness to glucose and insulin. Decreased glucose concentrations in Brahman calves and the decreased ability to utilize glucose both support the potential for temperamental cattle to utilize an alternate source of energy when glucose concentrations are low. Therefore, data from these studies suggest that it is likely that temperamental cattle utilize free fatty acids, resulting from the continuous break down of adipose tissue, to fuel tissues and organs that can utilize other energy sources rather than glucose. These data imply that the common practice of treating 'all cattle the same' is not the best management system, as alternative management for temperamental cattle (e.g., not implanting due to the likelihood of decreased fat deposition by temperamental cattle) may decrease input costs. Future research by our research team is focused on determining if alternative management strategies for calm versus temperamental cattle can increase profitability through reducing costs. This information will be of interest to both scientists and producers working in the field of beef cattle production with a specific focus on animal behavior, stress, and immune responsiveness.
Technical Abstract: Temperament can negatively affect various production traits, including live weight, ADG, DMI, conception rates, and carcass weight. Three research studies are summarized which indicate the potential influence of temperament on metabolism. In Brahman heifers, (n=12) the 6 most temperamental and 6 most calm were utilized for a glucose tolerance test. Calm heifers were able to clear glucose at a faster rate than temperamental heifers.Additionally, a study in Brahman bulls utilized calm (n=8), intermediate (n=8), and temperamental (n=8), selected based on temperament score, in order to determine their response to an immune challenge (i.e., lipopolysaccharide, LPS). Temperamental bulls had the smallest increase in rectal temperature (i.e., relative to baseline values) compared to calm or intermediate bulls (P < 0.01). Also, the data from this study suggest that temperamental cattle may display limited behavioral signs of illness which may prevent proper medical intervention and increase the risk of transferring pathogens to healthy cattle. Furthermore, blood urea nitrogen and NEFA concentrations in these bulls suggest that temperamental bulls did not have to break down muscle protein in order to provide energy during the immune challenge, as did intermediate and calm bulls. Collectively, these data suggest that temperamental cattle may be utilizing NEFA rather than glucose for energy, which may have influenced their response to the LPS challenge. Thus, collectively, these data suggest that clear metabolic differences exist between calm and temperamental bull calves and that alternative management strategies for temperamental cattle may increase input costs for producers.