Date of Award

12-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Animal and Veterinary Sciences

Committee Member

Dr. Nathan M. Long, Committee Chair

Committee Member

Dr. Scott Pratt

Committee Member

Dr. J. Drew Lanham

Abstract

The primary objective of the cow calf sector of the beef industry is to market live calves after weaning. One component to profitability in this sector is to wean healthy, productive calves with as low of an input a possible. This means not only efficiency of preweaning growth of the calf, but the dam needs to produce a more than adequate supply of milk as it is the primary nutrition of the calf. Production of an animal that can convert the milk supply offered and turn it into pounds of gain efficiently is ideal. The calf, ideally, should be born unassisted and the newborn calf must stand and suckle its dam as soon as possible. Short term, the supply of glucose to the calf from the placenta is removed at birth and must now come from exogenous sources, such as colostrum and gluconeogenesis (Hammon et al., 2013). The calf must, within the first 24 hours of life, begin building the immune system that will protect it from most pathogens. With few exceptions, mammals possess an immune system that is virtually innate and humoral (Beck et al., 1996; Janeway et al., 2001). The calf is born with an innate immunity to pathogens which serve as both physical and chemical barriers to pathogens. The immune system is both innate and adaptive, it can adapt to changing challenges from pathogens. Exposure can come from infection of a pathogen or immunization. Immunization is exposure to either modified forms that mimic a pathogen or a killed version of the pathogen itself. The innate immune system exists to provide early defense against pathogen attack, and to alert the adaptive immune system to the fact that pathogen invasion has begun. In many cases, an adaptive immune response confers lifelong protective immunity to reinfection with the same pathogen (Janeway et al, 2001). Adaptive immunity is further subdivided into either humoral or cell-mediated immunity. Humoral immunity is mediated by B-lymphocytes, which respond to antigens to become antibody producing cells and memory cells and provide defense against extracellular microbial infections. In cell mediated immunity, the T-lymphocytes and associated cytokines (proteins made by cells that affect the behavior of other cells) provide defense against intracellular pathogens and tumor cells (Galyean et al 1999). Antibodies are immunoglobulins made up of several classifications. The immunoglobulin isotypes are: IgM, IgD, IgG, IgA, and IgE (Janeway et al, 2001). The most abundant immunoglobulins found in the plasma are IgG and are the workhorse of the immune system. Immunization occurs actively, either contact with a directly or from being vaccinated. Colostrum has evolved in nature as a nutritional supplement that is fed to the newborn by its mother during a short period after birth. In certain mammals, such as humans, IgG is passed to the fetus through the placenta but in ruminants, via colostrum (Larson et al., 1980). All mammals produce colostrum, but they do not contain the same amount of IgG as in the ruminant. Colostrum contains immunoglobulins for every pathogen the mother had either contracted or been vaccinated against. The bovine transfers large amounts of IgG immunoglobulins from the blood stream across the mammary barrier into colostrum (and milk) by a specific transport mechanism. The passive transfer of immunity to the young is an essential process in mammalian species to provide the neonate protection during the early period in life when its own immune system is being established (Larson et al, 1980). The immunoglobulins from the colostrum are the first step in creating an immune system that will keep the calf healthy and able to combat the morbidity that can hinder its ability to turn milk into muscle and therefore profit. Previous research into supplementation of beef cattle has been primarily concerned with protein and energy and how it relates to Body Condition Score (BCS) of the cow (Alderton et al., 2000; Engel et al., 2008), reproductive performance of the cow (Corah et al., 1975; Bellows & Short, 1978; Marston et al., 1995) and postpartum calf performance (Corah et al., 1975). Fat supplementation in beef cattle has been studied with regard to milk production and energy balance. Supplementation of both fat and specific fatty acids have been directed at beef cows, developing heifers, newly received beef steers and as energy supplementation in feedlot steers on fattening rations. Late gestation supplementation of fat or essential fatty acids to beef cows has primarily focused on cow BCS, reproductive performance and calf performance but lacks research investigations on how it influences the developing calf in utero or the neonatal calf postpartum, a type of developmental programming. Limited research has been performed on rumen protected fatty acid provided during late gestation supplementation in beef cattle. Most research has been performed in dairy cattle, however the importance of an effective neonatal immune system in the beef industry due to the different production goals as to breed differences warrants further studies. The objective of this current study was to determine if late gestation supplementation of rumen protected unsaturated fatty acids (FA): 1) increased unsaturated FA in maternal serum and colostrum during late gestation and 2) increased unsaturated FA in serum of subsequent calves and transfer of IgG in new born calves.

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