Beef Science Commons^™

Behavioral And Physiological Responses Of Heifers With No Prior Exposure And Those Adapted To Grazing Endophyte-Infected Tall Fescue, Tyler A. Purvis

Theses and Dissertations--Animal and Food Sciences

Data from year one of a three-year experiment was used to determine behavioral and physiological responses of heifers adapted to grazing endophyte-infected fescue (E+TF) compared to heifers naïve to grazing E+TF. In May, yearling beef heifers from KY (n=15) and MT (n=30) were stratified by body weight, hair coat score, and disposition into nine pastures and assigned to one of three treatments: KY grazing E+ (KY-E+), MT grazing E+ (MT-E+), or MT grazing endophyte-free tall fescue (E-TF) (MT-E-). Prior to grazing, two heifers per pasture were selected to be outfitted with a RumiWatch® halter (Itin+Hoch GmbH, Liestal, Switzerland) for monitoring …

Comparison Of Sheep And Cattle Rumen Microbiological And Physiological Responses To An Abrupt Transition From A High-Forage To A High-Concentrate Diet, Katherine Purvis

Theses and Dissertations--Animal and Food Sciences

Sheep and cattle are often used interchangeably due to having the same gastrointestinal anatomy; however literature directly comparing the two species is minimal. Previous in vitro studies have pointed towards potential species differences in rumen carbohydrate utilization and acidosis susceptibility. The objective of this study was to evaluate in vivo microbiological and physiological responses of wethers and steers when abruptly transitioned from a high-forage to a high-concentrate diet. We hypothesized there are differences between species in response to abrupt dietary transition with respect to intake, rumen microbiology, and the rumen environment. Individually housed, rumen cannulated purebred Polypay wethers (n = …

Strategic Nutritional Interventions With Probiotics And Their Relationship To Performance, Feeding Behavior, And Reticulorumen Environment In Cows And Calves Under Subacute Ruminal Acidosis Risk, Gustavo Mazon Correa Alves

Theses and Dissertations--Animal and Food Sciences

Subacute ruminal acidosis (SARA) is a digestive disorder in ruminants characterized by extended periods of low reticulorumen pH. This digestive disorder is commonly observed in ruminants fed diets with elevated proportions of non-fibrous carbohydrates. This disorder has been vastly studied in adult dairy cattle and has been associated with losses in milk production, changes in feeding behavior, damage to the gastrointestinal tract, and premature culling. Although vastly studied in adult cattle, there is limited research on the effects of SARA in calves. SARA might be prevented by modifying the reticulorumen environment with probiotic supplements containing lactateutilizing bacteria such as Megasphaera …

Selenium Form-Induced Changes In The Early Luteal Phase Corpus Luteum, The Blood, And The Endometrium During Early Gestation In Beef Cows, Sarah Nancy Carr

Theses and Dissertations--Animal and Food Sciences

Selenium (Se) deficient soils and thus forages are widespread throughout the United States, necessitating supplementation of this trace mineral in the diet of grass-fed cattle to negate detrimental effects of a deficiency on immune function, growth, and fertility. Conventionally, Se is supplemented to cattle in a vitamin-mineral mix as an inorganic form (ISe) although the organic forms (OSe) are available when cattle consumer forage, and OSe has been shown to increase the bioavailability of Se in cattle. Previous research has demonstrated supplementation with 1:1 mixture (MIX) of ISe and OSe compared to ISe alone increases systemic concentrations of progesterone (P4) …

Increasing Efficiency Of Finishing Beef Production: Strategies To Optimize Starch Digestion, Improve Flake Quality, And Reduce Methane Emissions, Ronald J. Trotta

Theses and Dissertations--Animal and Food Sciences

To continue to meet the demands of increasing food production and environmental sustainability, new strategies are needed to enhance the efficiency of finishing cattle production. A review of the literature identified several nutritional and physiological constraints that limit the ability for cattle to digest starch and absorb glucose from the small intestine. Comparative sequencing analyses revealed a missing region of the sucrase-isomaltase protein which could affect the capacity for starch digestion in cattle. Post-flaking sampling and handling recommendations were generated based on a series of experiments to improve estimates of starch availability and flaking consistency for commercial feedlots and laboratories. …

Profiling The Cell Wall Polysaccharides Of Hemp (Cannabis Sativa L.) Inflorescence And Hempseed And Exploring Their Application As Ruminant Feed Ingredients, Miranda Agbana

Theses and Dissertations--Animal and Food Sciences

Hemp (Cannabis sativa L.) is used in the United States as a source of CBD oil, fiber, and grain. While hempseeds are consumed whole or as dehulled hemp hearts, hempseed oil is also a desirable seed oil in human nutrition. The process of collecting hempseed oil leaves behind hempseed cakes that are abundant in protein and fiber. Feeding of hempseed cakes to animals, including ruminants, has only initially been explored. Extraction of CBD from hemp inflorescences generates organic waste that may find a second purpose as a fiber feed for cattle. Little is known about the exact fiber composition …

The Response Of Beef Cattle To Disturbances From Unmanned Aerial Vehicles (Uavs), Gabriel Abdulai

Theses and Dissertations--Biosystems and Agricultural Engineering

Unmanned aerial vehicles (UAVs) are increasingly becoming common in animal agriculture. However, research regarding the impact of UAV disturbance on animal wellbeing is lacking or limited. The goal of this study was to investigate the effect of UAV flights on beef cattle by measuring cattle heart and movement rate when introduced to single or multiple UAV flights. A total of 16 -18 crossbred beef heifers were introduced to different flights patterns at between 5 and 9 m above ground level (AGL) at approximately 1 to 2 m/s horizontal velocity for 4 weeks with flights repeated 3 days per week. Results …

Mechanisms Of Programmed Nutrition In Finishing Cattle In Vivo And Ruminal Parameters Of Amaize Supplementation In Vitro, Amanda Pesqueira Schiff

Theses and Dissertations--Animal and Food Sciences

Programmed Nutrition Beef Program (Alltech Inc.) is a dietary supplement that contains Aspergillus oryzae fermentation extract with α-amylase activity that could reduce the use of feed additives such as monensin and tylosin in conventional feedlot diets. This study examines the changes in rumen fermentation resulting from feeding monensin/tylosin and Programmed Nutrition Beef Finisher. The goal was to determine if these shifts in rumen fermentation contribute to the Programmed Nutrition response observed in vivo. This study also analyzes how different levels of α-amylase (Amaize)supplementation impacts feedstuff degradation and utilization in vitro. In vivo experiment used eight steers in a replicated …

The Effect Of Endophyte-Infected Tall Fescue Seed Consumption On Gut And Satiety Hormones Related To Intake Regulation In Holstein Steers, Mindy Elizabeth King

Theses and Dissertations--Animal and Food Sciences

Cattle consuming endophyte-infected tall fescue (E+) typically experience a syndrome termed fescue toxicosis which is thought to be caused by ergot alkaloids produced by the endophyte. The most abundant alkaloid, and considered the most likely cause of the syndrome, is ergovaline (ERV). During fescue toxicosis, a decrease in ADG is observed which is likely due to the decrease in DMI commonly observed in animals consuming E+ compared to animals consuming non-endophyte-infected tall fescue (E-). However, the cause of the decrease in intake is not well elucidated. Many physiological responses control feed intake including, but not limited to, physical, neural, metabolic, …

Influence Of Dietary Manipulation On The Relationship Between Temperament Measures And Growth In Beef Cattle: Endophyte Exposure, Phytogenic Supplementation, And Controlled Feeding, Paul Shanks

Theses and Dissertations--Animal and Food Sciences

The influence of dietary factors (including endophyte exposure, phytogenic supplementation, and controlled feeding) on relationships between exit velocity (EV), growth performance in grazing and finishing cattle, and carcass characteristics were explored. Two grazing studies were conducted evaluating EV effects on cattle grazing both toxic and nontoxic endophyte-infected tall fescue. Cattle were followed through two subsequent finishing studies and an additional beef cattle finishing beef cattle study was also conducted. Results from these studies agree with many literature reports indicating that EV measures relate to growth performance and associated carcass traits in beef cattle being fed high energy diets in confinement, …

Impact Of Mineral Supplementation On Intake Behavior And Blood Flow In Growing Beef Cattle Exposed To Fescue-Derived Alkaloids, Hannah Marie Herzing

Theses and Dissertations--Animal and Food Sciences

Consumption of endophyte-infected tall fescue by cattle has repeatedly been shown to negatively impact dry matter intake (DMI), growth rate, and circulating prolactin concentrations. The objective of the current study was to determine if a mineral supplementation would mitigate the negative effects of fescue-derived alkaloid consumption on feed intake, circulating prolactin, and the vascular system. Twelve Angus crossbred steers were used in a triplicated Latin square design consisting of three 28 d experimental periods. Treatments consisted of three top-dressed mineral supplements (142 g/head/d): a non-medicated control (CON), commercially available Fescue EMT® Mineral Defense (EMT), and a test prototype (EMT 2). …

Monocyte Abundance And White Blood Cell Expression Of Prolactin And Nf-Kb Pathway Genes In Beef Steers Are Altered By Grazing Toxic Endophyte-Infected Tall Fescue And Lipopolysaccharide Challenge, Cecilia Winfrey

Theses and Dissertations--Animal and Food Sciences

Experiment 1 tested the hypothesis that ad libitum consumption of a 1:1 blend (MIX) of sodium selenite (ISe) and SELPLEX vs solely ISe as selenium (Se) supplements (27 ppm) in a vitamin-mineral mix (V-M) by steers subjected to summer-long grazing of toxic endophyte-infected tall fescue (TE) would ameliorate the negative effects of TE by positively affecting the expression pattern of prolactin (PRL) and NF-kB pathway genes by circulating leukocytes (WBC). Experiment 2 tested the hypothesis that the MIX form of supplemental Se also would ameliorate the negative effects of in vitro blood lipopolysaccharide challenge (LPS) on WBC gene expression. The …

Incorporation Of Summer Annual Mixtures Into Grazing Systems In Kentucky, Kelly Marie Mercier

Theses and Dissertations--Plant and Soil Sciences

Utilizing summer annual grass-legume forage mixtures has the potential to improve forage yield and nutritive characteristics, and/or animal performance during times when cool-season pasture growth is limited by high temperatures. Legumes can utilize atmospheric nitrogen, which can increase crude protein and forage digestibility in mixtures. As nitrogen application generally improves both the yield and nutritive characteristics of summer annual forages, but can have a negative effect on legume competitiveness, nitrogen fertilizer recommendations for legume-containing summer annual mixtures are not well established.

Two experiments were conducted to determine the feasibility of utilizing summer annual mixtures in Kentucky, USA. The first experiment …

Myoglobin Post-Translational Modifications And Fresh Beef Color Stability, Yifei Wang

Theses and Dissertations--Animal and Food Sciences

Surface color of fresh beef is the major trait influencing consumers’ purchase decisions. Fresh beef color is determined by the myoglobin (Mb) redox stability. Post-translational modifications (PTMs) play a critical role in regulating Mb structure and functionality. This thesis focuses on the PTMs in Mb and their impact on fresh beef color stability.

In the first experiment, Mb PTMs in beef longissimus lumborum (LL) muscle during postmortem aging and their influence on fresh beef color stability were examined. Beef LL muscle from nine (n = 9) beef carcasses (24 h postmortem) were subjected to wet-aging for 0, 7, 14 …

Forms Of Supplemental Selenium In Vitamin-Mineral Mixes Differentially Affect Serological And Hepatic Parameters Of Growing Beef Steers Grazing Endophyte-Infected Tall Fescue, Yang Jia

Theses and Dissertations--Animal and Food Sciences

Consumption of endophyte-infected tall fescue results in a syndrome of negatively altered physiological systems, collectively known as fescue toxicosis. Another challenge to endophyte-infected tall fescue -based beef cattle operations is that the soils often are selenium (Se) poor, necessitating the need to provide supplemental Se. To test the general hypothesis that different forms of supplemental Se would ameliorate the negative effects of fescue toxicosis, predominately-Angus steers (BW = 183 ± 34 kg) were randomly selected from herds of fall-calving cows grazing an endophyte-infected tall fescue pasture and consuming vitamin-mineral mixes that contained 35 ppm Se as sodium selenite (ISe), SELPLEX …

Relationships Between Animal Temperament And Systemic Immune Responses In Beef Cattle Exposed To Conditions Associated With Conventional Management, Alexander W. Altman

Theses and Dissertations--Animal and Food Sciences

Measures of temperament have been shown to influence physiological responses. Exit velocity (EV) has been identified as an objective, robust measure of temperament that can be used to predict subsequent performance of cattle. Additionally, previous studies from our lab indicate this measure of temperament may be related to production of interferon-γ (IFN-γ), a cytokine associated with cell-mediated immunity (CMI). Whereas research has investigated effects of EV upon immune responses, the overall goal of these studies was to examine this relationship under a variety of scenarios including human handling, transportation, and exposure to endophyte-infected tall fescue (E+) for determination of its …

Responses Of Bovine Pituitary Transcriptome Profiles To Consumption Of Toxic Tall Fescue And Forms Of Selenium In Vitamin-Mineral Mixes, Qing Li

Theses and Dissertations--Animal and Food Sciences

The first goal of the current research was to determine whether gene expression profiles differed between whole pituitaries of growing beef steers grazing pastures containing high (HE) or low (LE) amounts of toxic endophyte-infected tall fescue. The global (microarray analysis) and selected targeted (RT-PCR) mRNA expression patterns of pituitaries collected from beef steers (BW = 266 ± 15.5 kg) that had been randomly assigned to undergo summer-long grazing (89 to 105 d) of either HE (0.52 ppm ergot alkaloids) or LE (< 0.03 ppm ergot alkaloids) pastures were compared. Gene expression data were subjected to one-way ANOVA. The pituitaries of HE steers had 542 differentially expressed genes, and the pattern of altered gene expression was dependent on treatment. Targeted RT-PCR analysis corroborated these findings, including decreased expression of DRD2, PRL, POU1F1, GAL, and VIP and that of POMC and PCSK1, respectively. Canonical pathway analysis (Integrated Pathway Analysis, IPA) identified HE-dependent alteration in signaling of additional pituitary-derived hormones, including growth hormone and GnRH. In conclusion, consumption of endophyte-infected tall fescue alters the pituitary transcriptome profiles of steers in a manner consistent with their negatively affected physiological parameters. The second goal of this project was to test the hypothesis that sodium selenite (ISe), SEL-PLEX (OSe), vs. a 1:1 blend (MIX) of ISe and OSe in a basal vitamin-mineral (VM) mix would differentially alter pituitary transcriptome profiles in growing beef steers (BW = 183 ± 34 kg) commonly grazing an endophyte-infected tall fescue (HE) pasture. Steers were randomly selected from herds of fall-calving cows grazing HE pasture and consuming VM mixes that contained 35 ppm Se as either ISe, OSe, or MIX forms. Steers were weaned, depleted of Se for 98 d, and subjected to summer-long common grazing of a 10.1 ha HE pasture containing 0.51 ppm ergot alkaloids. Steers were assigned (n = 8) to the same Se-form treatments on which they were raised. Selenium treatments were administered by daily top-dressing 85 g of VM mix onto 0.23 kg soyhulls, using in-pasture Calan gates. Pituitaries were collected at slaughter and changes in global (microarray) and selected (RT-PCR) mRNA expression patterns determined. The effects of Se treatment on relative gene expression were subjected to one-way ANOVA. The form of Se affected the expression of 542 annotated genes. Integrated Pathway Analysis found a canonical pathway network between prolactin and POMC/ACTH/ α-MSH synthesis-related proteins, and that mitochondrial dysfunction was a top-affected canonical pathway. Targeted RT-PCR analysis found that the relative abundance of mRNA encoding prolactin and POMC/ACTH/ α-MSH synthesis-related proteins was affected by the form of Se, as were mitochondrial dysfunction-related proteins OSe steers appeared to have a greater prolactin synthesis capacity vs. ISe steers through decreased dopamine receptor D2 signaling, whereas MIX steers had a greater prolactin synthesis capacity and release potential by increasing TRH concentrations than ISe steers. OSe steers also had a greater ACTH and α-MSH synthesis potential than ISe steers. We conclude that form of Se in VM mixes affected genes responsible for prolactin and POMC/ACTH/α-MSH synthesis, and mitochondrial function in pituitaries of growing beef steers commonly grazing an HE pasture. The third goal was to test the hypothesis that sodium selenite (ISe), SEL-PLEX (OSe), vs. a 1:1 blend (MIX) of ISe and OSe in a basal vitamin-mineral (VM) mix would differentially alter selenoprotein profiles in pituitaries and livers of growing beef steers commonly grazing an endophyte-infected tall fescue (HE) pasture (i.e., the same steers used in Goal 2). The effects of Se treatment on relative gene expression were subjected to one-way ANOVA. The mRNA content of 6 selenoproteins in the pituitary was affected by Se treatments, along with two selenoprotein P receptors, whereas the expression of two selenoproteins was altered in the liver. We conclude that the change in selenoprotein gene expression in pituitaries indicates that OSe steers have a greater potential capacity to manage against oxidative damage, maintain cellular redox balance, and have a better quality control of protein-folding in their pituitaries than ISe steers. The change in selenoprotein gene expression by the liver indicates that MIX steers have a greater redox signaling capacity and capacity to manage oxidative damage than ISe steers.

Behavioral And Physiological Adaptations Associated With Feed Intake During Transitioning Cattle To High-Grain Diets, Amanda M. Mclean

Theses and Dissertations--Animal and Food Sciences

Transitioning cattle from a high-forage to a high-concentrate diet increases the risk for ruminal acidosis and is often related to decreased feed intake, which compromises animal health and performance. Since control of feed intake and rumen motility are closely related, we hypothesized that a reduction in rumen motility may be associated with a reduction in feed intake during this transition. Computer programs were created to analyze feed disappearance and rumen pressure data for feeding behavior as well as identification and characterization of rumen contractions, respectively. This method enabled timely analysis of large datasets and removed subjectivity associated with manual analysis. …

Contractile Response Of Bovine Lateral Saphenous Vein To Ergotamine Tartrate Exposed To Different Concentrations Of Molecularly Imprinted Polymer, Manoj B. Kudupoje, James L. Klotz, Alexandros Yiannikouris, Karl A. Dawson, Kyle R. Mcleod, Eric S. Vanzant

Animal and Food Sciences Faculty Publications

Ergot alkaloids, in their active isomeric form, affect animal health and performance, and adsorbents are used to mitigate toxicities by reducing bioavailability. Adsorbents with high specificity (molecularly imprinted polymers: MIP) adsorb ergot alkaloids in vitro, but require evaluation for biological implications. Using ex vivo myography, synthetic polymers were evaluated for effects on the bioactivity of ergotamine tartrate (ETA). Polymers were first evaluated using isotherms. Lateral saphenous veins were collected from 17 steers for four independent studies: dose response of ETA, adsorbent dose response, validation of pre-myograph incubation conditions and MIP/ non-molecularly imprinted polymer (NIP) comparison. Norepinephrine normalized percent contractile response …