Location: Livestock Issues Research2008 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. • Sub-objective 1.A. Identify non-antibiotic nutritional supplements that support and/or enhance the immune response associated with a bacterial challenge in newly weaned pigs. • Sub-objective 1.B. Identify non-antibiotic nutritional supplements that support and/or enhance the immune response associated with a viral challenge in incoming feedlot cattle. Objective 2: Develop an automated monitoring, tracking, and recording system to document behavioral responses to various disease challenges in the young pig. Objective 3: Assess the innate and adaptive immunity of cattle with various temperaments to determine whether temperament can be linked to productivity and well-being.
1b. Approach (from AD-416)
Our research will focus on enhancing well-being and performance in beef and swine during periods of production known to be stressful. For Sub-objective 1A, several experiments will be conducted to evaluate various parameters associated with the well-being and productivity of swine challenged with Salmonella Typhimurium following dietary inclusion of either sub-therapeutic levels of antibiotics or various nutritional supplements. Blood samples will be collected for analysis of hormones associated with the stress response, as well as hormones associated with function of the somatotropic axis. Animals will be videotaped to evaluate various sickness behaviors. For Sub-objective 1B, cross-bred beef 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 inoculated with infectious bovine rhinotracheitis virus (IBRV) to determine if the non-antibiotic supplements provided any immunological protection. Feed intake and body weight will be determined weekly. Blood samples will be collected for analysis of hormones associated with the stress response, the growth response, as well as cytokines and acute phase proteins associated with the immune response. For Objective 2, we will focus initially on validation of an automated tracking system using the 'color' tracking method. Once this validation is complete, the 'color' tracking will be used to document the behavior of individual pigs following a Salmonella Typhimurium challenge. Pigs will be video recorded over a 5-day period to determine if the infected pig’s behavior can be distinguished from that of the non-infected pigs. Subsequent transmission and infection in other pigs will be monitored by testing for the presence of the bacteria in fecal samples. For Objective 3, the research will be divided into two separate studies. The first study will address the potential effect of temperament on the innate immune response, and the second study will address the potential effect of temperament on adaptive immunity. In both studies, weaning-age calves from a single breed type 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 Study 1, 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 LPS challenge. In Study 2, we will assess the adaptive immune response following inoculation with IBRV. Body weights, blood samples, and rectal temperatures will be collected post-challenge. Blood samples will be collected for analysis of hormones associated with the stress response, as well as cytokines associated with the adaptive immune response.
3. Progress Report
Research conducted within the Livestock Issues Research Unit during FY2008 was associated with National Program 101 Component 2: "Enhancing Animal Adaptation, Well-Being and Efficiency in Diverse Production Systems." Six collaborative research projects were conducted this past year associated with our CRIS project objectives 1A, 1B, 2, and 3. Four of these projects were associated with Nation Program 101 Component 2, Problem Statement 2A: Enhance Animal Well-Being and Reduce Stress in Livestock and Poultry Production Systems. The other two studies were associated with Nation Program 101 Component 2, Problem Statement 2C: Improving Efficiency of Nutrient Utilization and Conversion to Animal Products. Specifically, associated with Sub-objective 1A, a collaborative study was conducted to evaluate two different plant extracts on the adaptive immune response of weanling pigs. This allowed us to fully meet our milestone for the year, and provided information to help design subsequent studies. Associated with Sub-objective 1B, a collaborative study was conducted to begin the establishment of a viral challenge model in cattle. Data analysis is forthcoming which will allow us to refine this model for future research projects. By conducting this preliminary study, we exceeded our milestone for the year and should progress in a rapid manner during the upcoming year. For Objective 2, a collaborative study was conducted comparing human observation with an actual water meter to determine drinking behavior in weanling pigs in an attempt to help validate the video tracking of animals. The results from this study indicated that while we have made significant progress on tracking animals, the data obtained may not accurately reflect the behaviors of the animal. Therefore, while we met our milestone for the year, these data will require that we re-evaluate and re-design future studies for Objective 2. With regard to Objective 3, two collaborative studies were conducted that provided significant information pertaining to how we should proceed with the future studies outlined in our CRIS project. The first study demonstrated that weaning age can have a significant impact on the innate immune response of cattle, thus highlighting the need to be very selective in obtaining cattle for future studies designed to evaluate the innate immune system in cattle. Therefore, in the second study, purebred calves of the same age and weaned at the same time were used to evaluate the effects of temperament on the innate immune response to an endotoxin challenge. Data generated from this study clearly demonstrated that temperament can significantly influence an animal's innate immune response to endotoxin exposure. Completion of this study allowed us to exceed the FY2008 milestone outlined for Objective 3. Collectively, these studies allowed us to make significant progress with regard to all of our stated objectives within this CRIS project for the FY2008 period, and provided important information that will be necessary in the implementation of future studies. (NP101, Component 2, Problem Statement 2A and 2C)
1. Evaluation of alternatives to sub-therapeutic antibiotics: Collaborative studies continued with scientists from the Livestock Issues Research Unit in Lubbock, Texas, and industry (Prince Agri Products, Quincy, Illinois) to evaluate non-nutrient additives as potential modulators of the acute phase immune response in weanling pigs following a vaccine challenge. Weanling pigs were supplemented with various blends of two plant extracts for ten days and then vaccinated via an intramuscular dose of mycoplasma vaccine. During the ten days prior to the vaccination, the combined treatment of Yucca and Quillaja increased average daily gain. However, growth performance was not different between treatment groups after the vaccine challenge. The reduction in serum cortisol and the tendency for lower pro-inflammatory cytokine concentrations observed in this study suggest that the non-nutrient additives do indeed alter the stress and immune parameters of the weanling pig following vaccine administration. The lymphocyte and neutrophil data also suggest that these additives alter both basal and stimulated aspects of the immune system. These preliminary data suggest that inclusion of non-nutrient additives in the weaned pig's diet may prove to be viable alternatives to antimicrobials. (NP101, Component 2, Problem Statement 2C)
2. Modeling the acute phase response to a viral challenge in beef cattle: A collaborative study with scientists from the Livestock Issues Research Unit in Lubbock, Texas, and Mississippi State University was conducted to document the acute phase response to an infectious bovine rhinotracheitis viral (IBRV) challenge in beef cattle in order to better understand how prevention strategies may be implemented to improve the health of feedlot cattle. Prior to the immune challenge, cattle were acclimated to halter restraint in metabolism crates. Subsequently, all calves were infected via nasal inoculation with IBRV and data collected on heart rate, rectal temperature, and blood samples were collected for the analysis of stress hormones and pro-inflammatory cytokines associated with activation of the innate immune response. Documenting the acute phase response to this economically important viral disease will provide significant information to scientists working in the area of cattle health and allow scientists with in the Livestock Issues Research Unit to move forward with research planned in Sub-objective 1B in subsequent years. (NP101, Component 2, Problem Statement 2A)
3. Evaluation of the effects of early versus normal weaning in beef cattle: A collaborative study with scientists from the Livestock Issues Research Unit in Lubbock, Texas, and the University of Florida-IFAS, Range Cattle Research and Education Center, Ona, Florida, was conducted to evaluate the effect of early weaning beef calves at 90 days of age compared to normal weaning at 250 days of age. Previous research indicates that early weaning prior to shipment can reduce transportation stress and can increase subsequent performance in the feedlot. These data suggest that the combination of weaning and transport stress may compromise the immune system of calves, thus hindering subsequent performance and health. This study was conducted to determine if the innate immune response of early weaned calves differed from normal weaned calves in response to an immune challenge. Eighteen Brahman x Angus calves were fitted with an indwelling jugular catheters and blood samples for 10 hours to determine serum concentrations of stress hormones, pro-inflammatory cytokines and acute phase proteins. Based upon these data, the innate immune system of early weaned calves appears to be less naïve than that of normal weaned calves, therefore making them more effective at recognizing and eliminating endotoxin from their body. These data suggest that an altered innate immune system may be responsible for the improved feedlot performance previously reported in early weaned calves. (NP101, Component 2, Problem Statement 2C)
4. Evaluation of an indwelling rectal temperature probe for cattle during transport: A collaborative study with scientists from the Livestock Issues Research Unit in Lubbock, Texas, Texas A&M University, Texas AgriLife Research and Extension-Overton, and Mississippi State University was conducted to determine if the indwelling rectal temperature device previously developed by scientists within the Livestock Issues Research Unit could be used to continuously monitor rectal temperature during transportation. For this study, 24 Brahman bull calves from the Texas AgriLife Research and Extension Center in Overton, TX, were equipped with the indwelling rectal probe and shipped 770 km to Lubbock, TX. Results indicated that while the indwelling rectal temperature device was capable of collecting significant information associated with rectal temperature during transport, it also revealed that continued refinement of the device was needed in order to ensure that the devices stayed in place without causing tissue damage on the tails of the calves. Data collected indicated that the primary stress associated with transportation in cattle, as indicated by elevated rectal temperature, occurred within the first two hours of transport. Following the initial increase, rectal temperatures returned to baseline values by three hours after the initiation of transport and remained low throughout the duration of transport. To our knowledge, this is the first data set obtained on continuous evaluation of rectal temperature in cattle during transport and could have a significant impact on future transportation studies, the evaluation and interpretation of previously reported stress responses associated with transportation, and the establishment of new management strategies associate with the transport of livestock. (NP101, Component 2, Problem Statement 2A)
5. Evaluation of drinking behavior in weanling pigs: A collaborative study with scientists from the Livestock Issues Research Unit in Lubbock, Texas, and Iowa State University was conducted to determine if human observation using Observer software was an accurate measure of drinking behavior in weanling pigs. Assimilating accurate behavioral events over a significant period of recorded time can be time consuming. If an automatic device, such as a water meter, could accurately record duration and frequency for a given behavioral event, this would provide a useful tool to the field of ethology. For this study, we utilized eleven gilts to compare the two methods of recording drinking behavior in pigs. Results from the study indicated that the method of observation had a significant impact on the ability to determine the duration and number of visits at the water nipple drinker. The data also indicated that the relationship between methods used to predict time spent at the water nipple drinker and number of visits was weak and that using the Observer software method underestimated the number of visits to the water nipple drinker and overestimated the total duration of drinking behavior for the nursery pig compared to an inline water meter. Given the relationship between methods was weak, it cannot be concluded that one method is as accurate as the other. (NP101, Component 2, Problem Statement 2A)
6. Evaluating the influence of cattle temperament on innate immunity: A collaborative study with scientists from the Livestock Issues Research Unit in Lubbock, Texas, Texas A&M University, Texas AgriLife Research and Extension-Overton and Mississippi State University was conducted to determine if cattle temperament affect the innate immune response to an endotoxin challenge. For this study, we utilized 24 purebred Brahman bull calves from the Texas AgriLife Research and Extension Center in Overton, TX. Calves were selected based on temperament score which is an average of exit velocity and pen score determined at 131 days of age. Calves were ranked into 3 groups: calm, lowest score, intermediate, and temperamental, highest score. All calves were fitted with indwelling jugular catheters and rectal temperature devices. The next day blood samples were collected at 30-min intervals for 10 hours to determine concentrations of stress hormones and pro-inflammatory cytokines, and sickness scores were assigned to each calf. Based on data collected in this study, the temperamental bulls appear to be more resilient to an innate immunological challenge such as that associated with endotoxin exposure while calm bulls appear to be more susceptible. To our knowledge, these are the first data to demonstrate a relationship between temperament and the innate immune response in cattle. This is of significant importance to the beef cattle industry and to scientists working in the fields of stress regulation and immune system activation, especially in livestock species. (NP101, Component 2, Problem Statement 2A)
Daniel, J., Carroll, J.A., Keisler, D., Kojima, C. 2008. Evaluation of immune system function in neonatal pigs born vaginally or by Cesarean section. Domestic Animal Endocrinology. 35(1):81-87.