Location: Livestock Issues Research
2019 Annual Report
Objectives
Objective 1: Determine management strategies to reduce the incidence and severity of bovine respiratory disease.
• Sub-Objective 1.A. Utilize nutritional prophylactic supplements in dairy calves to mitigate the negative effects of bovine respiratory disease on cattle health and well-being.
• Sub-Objective 1.B. Study the interactive effects of different management systems and vaccine administration protocols on respiratory disease development and severity in beef cattle.
Objective 2: Identify nutritional strategies to mitigate the impacts of pathogen exposure on immunity and overall well-being.
• Sub-Objective 2.A. Utilize prebiotic, probiotic and paraprobiotic supplements to mitigate pathogen colonization, migration, and translocation in pigs to promote overall health and well-being.
• Sub-Objective 2.B. Utilize prebiotic, probiotic and paraprobiotic supplements to mitigate Salmonella pathogenesis and its negative impacts on overall well-being in dairy calves.
Objective 3: Reduce the incidence and severity of liver abscesses in cattle.
• Sub-Objective 3.A. Develop a reliable and repeatable experimental model to study liver abscesses in cattle.
• Sub-Objective 3.B. Utilize prebiotic, probiotic and paraprobiotic supplements as a means to reduce the incidence and severity of liver abscesses in cattle.
Approach
As methods to improve productivity in livestock continue to make progress, efforts associated with improving health and well-being must also continue to be a main objective. In this Project Plan, the term “well-being” is being used as a catch-all term for the absence of sub-clinical disease, reduced indicators of stress and inflammation, and improved thriftiness of the animal. Issues barring the way of progress include understanding the pathogenesis of diseases and how stress influences pathogens/diseases, immunity, and overall well-being. Developing models to study stressors, pathogens/diseases, and viable managerial solutions for combating diseases is essential for improving livestock productivity and well-being. Bovine respiratory disease (BRD) and liver abscesses in cattle and salmonellosis in dairy calves and swine cost producers over $5 billion annually. Objective 1 will address the use of nutritional prophylactic supplements and vaccination strategies to reduce the incidence and severity of BRD in cattle. Novel, non-antibiotic compounds have been developed that may improve productivity and well-being while alleviating the negative impacts of disease without the use of consumer scrutinized pharmaceuticals. Objective 2 will evaluate the potential benefit of non-antibiotic supplements to reduce pathogen colonization, migration, and translocation in pigs and dairy calves. In Objective 3, we will develop a reliable and repeatable “real world” experimental liver abscess model to evaluate intervention strategies to improve animal well-being, and reduce economic losses. Discovery and evaluation of non-antibiotic alternatives that reduce economic losses and the negative impacts of stressors and diseases on overall well-being in livestock will be beneficial for producers, consumers, and the production animals themselves.
Progress Report
Researchers in Lubbock, Texas, have conducted five studies in the second year of the project that continue to evaluate possible solutions to mediate important health concerns in cattle and swine. Two studies were conducted under Sub-objective 1A. The studies evaluated the effect of three different prebiotic and probiotic supplements on the immune response to a pathogenic toxin (endotoxin). These two studies were conducted to follow-up on a previously completed study conducted in the first year of this project in which the supplements demonstrated potential as antibiotic alternatives. Preliminary data from these studies suggest that there was an improved response to the endotoxin challenge when calves were fed a prebiotic or a probiotic supplement for 21 days prior to the challenge. Due to the positive preliminary data, more real-world application studies can now be conducted using the unit’s established Bovine Respiratory Disease model. Further progress was also made on Sub-objective 1B. Specifically, a trial was conducted that compared how calves respond to three different Mannheimia haemolytica vaccines, which is a bacteria commonly associated with Bovine Respiratory Disease. Interestingly, while the three vaccines differed significantly in bacterial endotoxin concentration, there were few differences observed in acute immune parameters measured during the first three days following vaccination. Data analysis continues on this project, and follow-up studies are being planned. For Sub-objective 2A, scientists analyzed preliminary data collected in the first year of the project. Based on this data, and newly-acquired access to a neutralizing antibody product, we have moved in a different direction with this project. Working with an industry partner, data suggests that use of a neutralizing antibody may reduce colonization and resistance associated with bacterial infection. Therefore, researchers are planning a study to determine the influence of supplementing pigs with a neutralizing antibody on reducing bacteria concentrations within the gastrointestinal tract. The use of a neutralizing antibody rather than probiotic products may lead to faster resolution of bacterial infections and provide a new research avenue for antibiotic alternatives in swine. Lastly, initial work began on Sub-objective 3A. Specifically, healthy and abscessed (unhealthy) livers were collected during necropsy from a local cattle feedlot and analyzed to determine whether differences in bacterial populations exist between the healthy and unhealthy livers. Data analysis and model development continues on this initial project based on the data collected from the liver samples.
Accomplishments
1. Bovine Respiratory Disease vaccines and the immune response. Bovine Respiratory Disease continues to be the leading cause of illness in beef cattle, costing cattle producers an estimated $1 billion each year. Vaccination is the primary preventative management tool used to combat Bovine Respiratory Disease. Mannheimia haemolytica is one of the bacteria most commonly associated with the disease. However, following vaccination, producers often report reduced performance and increased depression in calves for several days, possibly associated with the endotoxin in the vaccine. Scientists in Lubbock, Texas, collaborated with an industry partner to determine the effects of three different Mannheimia haemolytica vaccines on the immune response. This study found that while drastic differences existed in the concentration of endotoxin in the three vaccines, there were limited differences in immune parameters measured during a 1-week period after vaccination. Data from this project suggest that endotoxin concentration is not the primary driver for reduced performance and depression observed after Mannheimia haemolytica vaccination, and perhaps proper handling of vaccines and/or the adjuvant component of the vaccines may be of greater importance.
2. Natural yeast fermentation product reduces illness in calves. There continues to be increased pressure on livestock producers to reduce antibiotic usage. Thus, producers are seeking natural supplements and antibiotic alternatives that can maintain or improve animal productivity and health. While there are many commercially available products that make these claims, the true benefit of these products when faced with a pathogen remains largely untested. ARS scientists in Lubbock, Texas, collaborated with an industry partner to evaluate the effects of a natural yeast fermentation supplement on the immune response to a pathogenic toxin (endotoxin). This study observed that supplemented calves had increased body temperature, yet reduced signs of clinical illness and inflammation in response to the toxin. As demand continues to increase for more naturally-produced animal protein, cattle producers that feed over 11.5 million calves in the U.S. each day can utilize natural feed supplements to improve cattle health, and thus improve cattle productivity while continuing to meet consumer needs.
Review Publications
Word, A.B., Broadway, P.R., Sanchez, N.C., Roberts, S.L., Richeson, J.T., Liang, Y.L., Holland, B.P., Cravey, M.D., Corley, J.R., Ballou, M.A., Carroll, J.A. 2019. Immune and metabolic responses of beef heifers supplemented with Saccharomyces cerevisiae to a combined viral-bacterial respiratory disease challenge. Translational Animal Science. 3:135-148.
Littlejohn, B.P., Sanchez, N.C., Carroll, J.A., Price, D.M., Vann, R.C., Welsh, T.H., Randel, R.D. 2019. Influence of prenatal transportation stress on innate immune response to an endotoxin challenge in weaned Brahman bulls calves. Stress: The International Journal on Biology of Stress. 22:2, 236-247. https://doi.org/10.1080/10253890.2018.1523895.
Littlejohn, B.P., Price, D.M., Neuendorff, D.A., Carroll, J.A., Vann, R.C., Riggs, P.K., Riley, D.G., Long, C.R., Welsh, T.H., Randel, R.D. 2018. Prenatal transportation stress alters genome-wide DNA methylation in suckling Brahman bull calves. Journal of Animal Science. 96(12):5075-5099. https://doi.org/10.1093/jas/sky350.
Sanchez, N.C., Carroll, J.A., Corley, J.R., Broadway, P.R., Callaway, T.R. 2019. Changes in the hematological variables in pigs supplemented with yeast cell wall in response to a Salmonella challenge in weaned pigs. Frontiers in Veterinary Science. 6:246.
