Date of Graduation
12-2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Animal Science (PhD)
Degree Level
Graduate
Department
Animal Science
Advisor/Mentor
Powell, Jeremy G.
Committee Member
Kegley, Elizabeth B.
Second Committee Member
Almodovar, Jorge
Third Committee Member
Littlejohn, Brittni P.
Keywords
reproductive efficiency; respiratory disease; soybean co-products
Abstract
Soybeans are a vital commodity for Arkansas and the United States, with co-products such as soybean meal having wide popularity in animal feeds due to high protein content and palatability. Soybean meal primarily is utilized in diets for swine and poultry operations with a small market in the beef cattle industry, likely due to the increased costs that are associated with the product. On the other hand, soybean oil is a product from the production of soybean meal that is not as widely used in the livestock industry as most of the oil produced is used for industrial purposes. Additionally, the cost of soybean oil can be quite high, and producers are looking toward including ingredients in supplements that are not as expensive. However, some research has shown that there are benefits of including soybean co-products in livestock diets, specifically on health, performance, and reproduction. The fatty acid profile of soybean co-products is greatest in omega-6 fatty acids, which are known to be more pro-inflammatory compared to other fatty acid types. The fatty acid composition of different feedstuffs influences production parameters mentioned prior, and this research aims to gain a clearer understanding of the possible effects that soybean meal and soybean oil have in stocker cattle and developing heifer supplements. The following chapters in this dissertation outline the effects of including soybean co-products in ruminant supplements on various aspects of the immune response, overall health and performance, reproductive parameters, and cost projections for different supplements.
Because of the known responses and effects that chronic inflammation can have on the health of cattle, Chapter II describes the initial study to determine if soybean co-products could be supplemented to low-risk cattle without having detrimental effects on cattle health and hemocytology, as well as subjecting these cattle to a lipopolysaccharide challenge to determine any changes in the acute immune response. During the summer growing period, there were no effects of soybean co-products on the growth performance, stress responses, or blood hemocytology measurements that would suggest an overactive immune system in the cattle caused by supplementation strategies. During the lipopolysaccharide challenge, there were influences on stress responses for supplementary treatment groups, as well as interactions with time for hemocytology measurements showing a normal activation of an acute immune response when given the lipopolysaccharide and influences that the supplement including soybean meal may have had on the neutrophil percentage and neutrophil:lymphocyte ratio. Additionally, the cattle that were supplemented with soybean oil had numerically greater rectal temperatures and sickness behavior scores, which in combination with the hemocytology results indicate a more active immune response compared to the control or soybean meal supplemented cattle. Results indicate that soybean co-products could effectively be supplemented to growing cattle without causing detrimental effects to the immune response, and a possible activation of the immune system should an infection be present.
In Chapter III, we aimed to determine how the soybean co-products would affect cattle in a more traditional stocker setting, where respiratory disease remains a driving force for finding new strategies to alleviate negative effects on performance and compromised immunity of high-risk cattle. Additionally, we included an economic analysis to determine the viability of including the co-products in supplements. Our results indicate that there were no differences in the incidence of morbidity and mortality associated with respiratory disease, and eosinophils were the only hemocytology measurement that was affected by supplement treatments with cattle consuming soybean meal having greater percentages of eosinophils on day 14 compared to the soybean oil supplemented cattle. While these differences may be attributed to the increased concentrations of omega-6 fatty acids present in the soybean oil, it is possible that there may be other factors associated with this increase, and there needs to be further investigation into the mechanisms by which this occurred in these cattle. Finally, the costs of the soybean oil supplement were greater compared to the other supplements utilized, but it is important to note that the costs of the feed ingredients were not accounted for when formulating supplements. Also, the net returns for cattle consuming soybean meal were greater than other supplement treatments, indicating that including soybean meal in cattle supplements may be the more cost-effective option when determining what to supplement cattle during the stocker phase. Still, it is important for stocker operations to keep in mind market fluctuations throughout the year and the impacts that uncontrollable conditions can have on commodity markets and prices. Ultimately, the results of this chapter show that there were no decreases in disease incidence or improvements in performance of the high-risk cattle, and that the choice of feed ingredients for supplements lies with the producer’s preferences.
In the cow-calf industry, reproduction and the ability of a female to produce a live calf each year is important to all producers raising cattle. One of the main issues in the industry is early embryonic loss and low conception rates in females. Chapter IV discusses the inclusion of soybean oil as an energy source in supplements for developing heifers on various reproductive parameters like puberty, cyclicity, corpus luteum area, and blood perfusion, artificial insemination conception rates, and overall pregnancy rates, with economic calculations for inclusion of soybean oil in the supplement and projections on potential revenue. We did not find any differences in puberty or cyclicity status but did note that numerically more females were pregnant by artificial insemination and more pregnancies at the final ultrasound for heifers supplemented with soybean oil. The corpus luteum area was greater in females fed the control supplement. Also, the potential revenue captured by the soybean oil treatment compared to the control treatment was greater. In this research, we conclude that soybean oil did not have any negative effects on reproductive efficiency and the numerical increases in conception rates both from artificial insemination and natural services warrant further investigation to determine if there is a positive effect for supplementation with soybean oil on these parameters.
Citation
Midkiff, K. (2024). The Inclusion of Soybean Co-Products in Ruminant Supplements on Health and Reproductive Efficiency. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/5593
