Location: Livestock Issues Research2011 Annual Report
1a. Objectives (from AD-416)
The long-term objective of this project is to enhance animal well-being and performance in swine and beef industry production environments. Over the next 5 years we will focus on the following objectives: Objective 1: Identify non-antibiotic nutritional supplements that support and/or enhance immune function in weaned pigs and incoming feedlot cattle. Objective 2: Determine the relationships among animal temperament, stress responsiveness, and immune function in cattle as related to livestock management practices, such as weaning and transportation, and utilize this information to develop alternative management practices that enhance immunity, productivity, and overall well-being.
1b. Approach (from AD-416)
Our research will focus on enhancing the performance, health, and overall well-being of beef cattle and swine in production environments. For the swine studies in Objective 1, several experiments will be conducted to evaluate various parameters associated with the health and productivity of swine following dietary inclusion of various nutritional supplements that have the potential to enhance innate immunity. Blood samples will be collected for analysis of hormones associated with the stress response, as well as hormones associated with the proinflammatory response following an endotoxin challenge. For cattle studies in Objective 1, calves will be weaned at approximately 6 months of age and fed various non-antibiotic products as potential modulators of immunity. Calves will be provided either a medicated diet or a non-medicated concentrate ration containing a non-antibiotic supplement for 21 days. Calves will be either inoculated with infectious bovine rhinotracheitis virus (IBRV) to determine if the non-antibiotic supplements provided any immunological protection to a viral challenge, or exposed to endotoxin to evaluate whether or not these non-antibiotic supplements enhance innate immunity. Feed intake and body weight will be routine measurements. Blood samples will be collected for analysis of hormones associated with the stress response, the growth axis, as well as cytokines and acute phase proteins associated with the immune response. For Objective 2, the research will focus on determining the relationships among animal temperament, stress responsiveness, and immune function in cattle as they relate to livestock management practices such as weaning and transportation. This information will be used to develop alternative management practices that enhance immunity, productivity, and overall well-being. Initial studies will determine the effect of animal temperament on the innate immune response following an endotoxin challenge. Subsequent studies will evaluate the effect of temperament on the response to management practices such as transportation. We will also evaluate the effects of weaning strategies on the innate immune system of beef calves. In these studies, weaning-age calves from a single breed will be categorized as to their temperament (temperamental or calm) based upon an objective exit velocity (EV) scoring system. Exit velocities will be obtained by determining the rate at which calves exit the working chute and traverse a fixed distance (1.83 m). In the first studies, we will assess the innate immune response to an endotoxin challenge based upon temperament. Blood samples will be collected and serum analyzed for hormones associated with the stress response, as well as cytokines associated with the acute phase immune response following the endotoxin challenge. In the subsequent studies, we will assess the stress responsiveness following management practices such as transportation and weaning. Body weights, blood samples, and rectal temperatures will be routine parameters measured for these studies. Blood samples will be analyzed for stress hormones, as well as cytokines associated with the immune response.
3. Progress Report
Scientists of the Livestock Issues Research Unit were involved in 5 collaborative research projects associated with our project objectives during FY11. For Sub-objective 1A, a final study was conducted to evaluate the inclusion of orange peel/pulp byproduct alone or in combination with yeast, Saccharomyces cerevisiae boulardii, in weaned pig diets as a means to reduce the detrimental effects associated with exposure to Salmonella Typhimurium immune challenge. Results from this study demonstrated that feeding a diet that contained the combination of citrus pulp and yeast reduced the incidence of fecal shedding of S. Typhimurium. Given the increased demand for, and interest in, removing sub-therapeutic antibiotics from livestock production systems, results from this study, along with studies conducted in previous years, demonstrate that natural alternatives exist that could be used to replace antibiotics in feed should the need arise. All data have been analyzed for studies associated with this sub-objective, and the manuscripts have been submitted for publication in peer-reviewed journals. For Sub-objective 1B, a final study was conducted to evaluate the effect of feeding chromium to high-risk cattle coming into a feedlot. Results from this study demonstrate that supplementing the diet of incoming feedlot cattle with chromium for a period of 55 days improved the performance of the cattle, and altered their febrile and innate immune response to an immune challenge. This study, coupled with our previous research in this area, conclusively demonstrated that providing non-antibiotic alternatives to high risk feedlot cattle can improve performance, health, and overall well-being. Given the public's interest in eliminating feed grade antibiotics from cattle feedlots, this research is a significant step towards identifying potential alternatives that are economically feasible and will provide immune protection. All data have been analyzed for studies associated with this sub-objective, and the manuscripts have been submitted for publication in peer-reviewed journals. For Objective 2, two additional collaborative studies were conducted this year to evaluate the influence of animal temperament on the metabolic responses during an immune challenge, and further delineation of the potential stress associated with transportation. Results from these studies demonstrated that the metabolic responses during an immune challenge are different in high-strung or "wild" cattle as compared to calmer cattle. This information allows us to move closer to developing specific management practices for cattle that are based upon animal temperament, thus allowing a greater economic return for producers. With regard to the transportation study, this final study confirmed that handling and loading cattle is the primary event associated with inducing stress, and that transportation in and of itself is not stressful. This information is extremely important with regard to developing guidelines for the transport of livestock. All data have been analyzed for studies associated with this objective, and the manuscripts have been submitted for publication in peer-reviewed journals.
1. Include chromium in the diet for better performance and health. Even with the use of antibiotics and other medications, suboptimal health and poor growth performance of cattle in U.S. feedlots continue to be a significant economic drain for producers. Economically feasible alternative management practices that improve health and performance are greatly needed. One method that is showing promise is the inclusion of chromium, a mineral known to be involved in the metabolism of carbohydrates, fats, and protein in cattle diets. Scientists from the Livestock Issues Research Unit in Lubbock, Texas, teamed up with scientists from Texas Tech University for a cattle study that showed that adding chromium to the diet of cattle when they first come into a feedlot not only enhances their immune response following an acute infection, but also improves growth performance. The study also suggests that chromium may speed the recovery of stressed and/or sick cattle, thus reducing the production costs. Improving the health of animals within our livestock production systems will also reduce potential health risks for consumers.
2. Metabolism is linked to cattle temperament. Feeding a group of cattle all the same diet assumes that all cattle have the same metabolism and require the same amount of nutritional input. As has been shown with people, this is not the case. We are beginning to understand that naturally occurring differences in animal populations impact both animal performance and production costs. In a collaborative study, scientists from the Livestock Issues Research Unit in Lubbock, Texas, and Texas AgriLife Research revealed that high-strung or "crazy" cattle are metabolically different from calmer cattle. In fact, we found that "crazy" cattle use a different energy source compared with calmer cattle, even when their health is in jeopardy. Understanding and capitalizing on these inherent differences within a population of animals will aid in development of alternative management practices that improve the economic return for producers. Additionally, this information may significantly change how future research is conducted in cattle.
3. Taking a ride may not be that stressful after all. Transporting livestock in confined trailers has long been considered stressful on the animals, even in the absence of conclusive evidence one way or the other. With ever-rising concern from consumers, producers must be able to assure that animal well-being is not overlooked. Therefore, scientists from the Livestock Issues Research Unit in Lubbock, Texas, and Texas AgriLife Research teamed up to evaluate the effects of transportation on feed intake, feeding behavior, and productivity of weaned calves. We found considerable variation in post-weaning feeding behavior in cattle, some of which is directly attributable to breed type. We also found that the decrease in body weight following transportation is primarily due to feed and water withdrawal. Finally, these studies indicate that cattle are most stressed during handling and loading, rather than during transportation itself. Thus, contrary to popular opinion, transportation in and of itself does not appear to negatively impact the health, productivity, and overall well-being of yearling cattle. This information will be extremely valuable in the potential development of any government or industry policies or regulations related to the transport of livestock.
4. Development of a new tool for an old measurement. Obtaining body temperature in livestock over an extended period of time has always been a daunting task for researchers. Traditionally, it has involved repeated manual insertion of a thermometer into the body cavity of an animal by a human. Eventually, this method proves to be less appealing to the human, and can become stressful for the animal. Previously, scientists from the Livestock Issues Research Unit in Lubbock, Texas, developed an indwelling rectal probe for obtaining cattle body temperature over an extended time period in various environments, including individual and group penning. As an extension of this technology, we have developed an indwelling vaginal temperature monitoring device to aid in measuring body temperature in female cattle. Similar to the rectal temperature monitoring device, it allows temperature measurement to be obtained without the potential biases associated with stress responses to handling and/or the presence of humans. The vaginal temperature monitoring device provides researchers with an additional inexpensive tool to study physiology in female cattle.
Ballou, M., Hulbert, L.E., Carroll, J.A. 2011. Effects of intravenous Escherichia coli dose on the pathophysiological response of colostrum-fed Jersey calves. Veterinary Immunology and Immunopathology. 141:76-83.