Large or Food Animal and Equine Medicine Commons^™

Avian Influenza And The Approach To Designing An H5n1 Vaccine, Lauren N. Hickey

Honors Program: Senior Projects (Public)

The Avian influenza virus (AIV) H5N1 has been responsible for the culling and deaths of millions of birds since 2022 with concern for wildlife, livestock, and human infections occurring as well. With eggs flying off the shelves in grocery stores, even individuals not involved in the agricultural industry have seen the drastic effects of this disease first-hand. For chickens, this virus works quickly and overpowers the innate immune system before the adaptive immune system has time to properly respond. Therefore, a safe and effective vaccine could reduce the number of poultry deaths and prevent the continuous spread of the infection. …

Comparison Of Spayed Heifer Performance To Intact Heifers Fed Melengestrol Acetate On Feedlot Performance And Carcass Characteristics, Tate S. Johnson, Rebecca L. Mcdermott, Halden J. Clark, Jim C. Macdonald, Jessica L. Sperber

Nebraska Beef Cattle Reports

Summary with Implications

Pregnancy and estrous cycle management are critical considerations when feeding intact heifers in the feedyard. Alternatively, producers can opt to spay heifers, which eliminates hormonal fluctuations associated with the estrous cycle. A proportion of U.S. feedlots have spayed heifers on feed, although there is limited data comparing the performance of spayed heifers to intact heifers. A commercial feedlot experiment was conducted to compare performance between spayed and intact heifers fed melengestrol acetate. Intact heifers had greater ADG and tended to have greater DMI compared to spayed heifers, although no difference in feed conversion was observed. Carcass weight …

Recovery And Characterization Of Moraxella Species From Bovine Specimens, Laura G. Leger

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

The family Moraxellaceae is made up of a diverse group of 24 named species that fall into three phylogenetic groups. While most Moraxella spp. act as commensal respiratory and/or ocular flora of mammals, some are associated with disease. One of these diseases, infectious bovine keratoconjunctivitis (IBK), has significant welfare and economic impacts to both cattle and cattle producers. Moraxella bovis is the only experimentally determined cause of IBK, however, an association of Moraxella bovoculi with disease has been proposed. Currently, available vaccines do not have high levels of efficacy in the field. Culture based methods are the gold standard for …

Environmental Effects On Preweaning Calf Health, Lindsay L. Waechter-Mead

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Neonatal calf health is an important factor in the productivity and profitability in the beef cattle industry, influencing preweaning survival, growth, and long-term performance. The overall objective of this thesis is to characterize risk factors that contribute to health issues in young beef calves. The first objective is to review literature exploring the environmental factors affecting preweaning morbidity and mortality, including hypothermia, precipitation, and wind. Management strategies such as the effect of environmental conditions of calving location, body condition score in dams at parturition, and the impacts of dystocia on calf health will also be discussed. Gaps in current research …

Gonadotropin-Releasing Hormone Ii And Its Receptor: Novel Regulators Of Semen Quality And Follicular Function In Swine, Caitlin Elizabeth Ross

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Pigs are the only mammalian livestock species encoding functional proteins for the second form of gonadotropin-releasing hormone (GnRH-II) and its receptor (GnRHR-II). In the first study, GnRHR-II localized to developing germ cells and the connecting piece of ejaculated spermatozoa. Concurrently, GnRH-II was most abundantly produced in the testis compared with other reproductive tract organs and was present within seminal plasma. Moreover, treatment of extended semen with GnRHR-II analogues altered sperm motility, morphology, and kinematics. For remaining studies, we utilized a swine line with ubiquitous knockdown of GnRHR-II (GnRHR-II KD) developed in our laboratory. The second study demonstrated that circulating GnRH-II …

Methane Mitigation And Its Effects On Energy Utilization In Lactating Dairy Cattle, Shan C. Sherwood

Department of Animal Science: Dissertations, Theses, and Student Research

Improved methane (CH4) mitigation strategies are needed to achieve the greenhouse gas emission goals of the dairy industry. The first experiment was conducted to evaluate the effects of feeding black cumin (Nigella sativa) seed oil and acetate (BCA) on CH4 production and whole-animal energy utilization. Twelve dry Jersey cows were used in a 2-period crossover design study with 28d periods. The BCA treatment was compared to a control diet with corn oil. Both BCA and corn oil were added to the base diet as a top dress. Results from this study did not show any difference in CH4 …

Epidemiological Inferences Of The Impacts Of Winter Ticks On Moose Health, Krishna S. Woerheide

Department of Entomology: Dissertations, Theses, and Student Research

The North American Moose (mooz in Anishinaabemowin, Ojibwe language, Alces alces), a culturally significant subsistence species for the Anishinaabe people, faces population decline due to calf predation, pathogen transmission, and parasitism by the winter tick (Dermacentor albipictus), all exacerbated by climate change. This study explores the impact of winter tick infestations on moose health, with a focus on natural mineral seeps as potential transmission hotspots in moose habitats within the Grand Portage Indian Reservation (Gichi Onigaming), on Isle Royale National Park (Minong), and within the 1854 Ceded Territory (greater northeastern Minnesota) - ancestral and present homelands of …

Stereotypic Behaviors And Physiological Indicators Of Stress Occur In Horses With Restricted Durations Of Turnout, Elizabeth E. Rodgers

Department of Animal Science: Dissertations, Theses, and Student Research

The confinement of horses to stalls with limited or no turnout time restricts their natural roaming behaviors, which potentially increases stress and behavioral stereotypies. This study investigated the impact of turnout duration on behavioral and physiological stress indicators in healthy horses. Adult horses (n = 11) were enrolled in a 3 treatment (0-, 15-, and 60-minute turnout/day) Latin square design, including 3 12 d experimental periods over 6 weeks. Horses were acclimated to turnout (24.38 x 64.01m indoor arena) and stalls (2.74 x 4.87m - 3.66 x 3.66m) stalls prior to data collection on day 1. Experienced handlers managed …

Effect Of Feeding Fenugreek Extract And Encapsulated Lecithin On Finishing Cattle Performance, Carcass Characteristics, And Liver Abscesses, Sofia Suarez Lorences, Rebecca L. Mcdermott, Joshua R. Benton, Robert Bondurant, Willard Lemaster, James C. Macdonald, Galen E. Erickson

Nebraska Beef Cattle Reports

Summary with Implications

A feedlot study was conducted to evaluate the effects of adding fenugreek extract and encapsulated lecithin (Furst-McNess Company, Rockford, Illinois, United States) on finishing cattle performance, carcass characteristics, and liver abscesses. Treatments were applied as a 2×2 factorial that included a control diet with no additive; a diet containing fenugreek extract; a diet containing encapsulated lecithin; and a diet containing both fenugreek extract and encapsulated lecithin. Tylosin was not included in any diets to test natural occurrence of liver abscesses. No interactions were observed between fenugreek extract and encapsulated lecithin treatments but neither feed additive impacted intakes, …

Effects Of Allocation Frequency On Cattle Performance And Forage Utilization When Swath Grazing A Sorghum-Sudangrass Hybrid In Eastern Nebraska, Thomas E. Aquino, Mary E. Drewnoski, Pedro Henrique J. Fernandes

Nebraska Beef Cattle Reports

Summary with Implications

A sorghum-sudangrass hybrid was swath grazed by growing steers (529 ± 18 lb) from November 2023 to January 2024. Treatments were offering new forage once (1X) or twice (2X) per week to determine the effect of allocation frequency on animal performance and forage utilization. Average daily gain was not impacted by treatment (1X = 0.45 ± 0.1 lb/day, 2X = 0.45 ± 0.1 lb/day). Pre-and post-graze biomass samples were collected to estimate forage utilization, which was not different between treatments (1X = 57.1 ± 3.6%, 2X = 61.1 ± 3.6%). However, there was a difference in carrying …

Artificial Insemination Of Beef Heifers With Multi-Sire Semen, Dempster Christenson, Jordan M. Thomas, Daniel J. Kelly, Richard N. Funston

Nebraska Beef Cattle Reports

This study compared pregnancy rates of beef heifers artificially inseminated with multi-sire semen to single-sire semen. It was hypothesized pregnancy rates resulting from multi-sire semen would be increased compared to single-sire semen. Heifers were artificially inseminated with semen from one of three single-sires or semen from a combination of the same three sires. Pregnancy rates did not significantly differ. Paternity testing suggests sire parentage can be unequal when semen is mixed from multiple sires. In summary, producers can expect similar pregnancy rates using single-sire and multi-sire semen, but progeny may have unequal sire representation.

Impact Of Overwinter Gain On Growth And Reproductive Performance In March-Born Heifers, Josie N. Crouch, J. Travis Mulliniks, Jacki A. Musgrave, Kacie L. Mccarthy

Nebraska Beef Cattle Reports

Summary with Implications

Heifers developed to lower rates of overwinter gain may reduce development costs without growth and reproduction impacted. A 3-year study was conducted to evaluate different overwinter rates of gain on heifer growth rates, reproductive, and economic performance. Heifers were managed together and individually supplemented (January-May) with dried distillers grains to achieve either a low (0.75 lb/d) or high (1.50 lb/d) average daily gain. At breeding, high gain heifers were heavier than low gain heifers. Average daily gain and body condition score were similar between treatments. Overwinter treatment did not impact attainment of puberty, pregnancy rates, or the …

Impact Of Pre- And Post-Breeding Supplementation On Performance Of May-Born Heifers, Josie N. Crouch, J. Travis Mulliniks, Jacki A. Musgrave, Kacie L. Mccarthy

Nebraska Beef Cattle Reports

Summary with Implications This 3-year study compared growth, reproductive performance, and economics of May-born yearling heifers that either received 2.00 lb/ heifer/ per d of a dried distillers grain supplement from pre-breeding (July) through breeding (August) or no supplement. Supplementation was offered approximately 24 days before breeding, averaging 55 days total. Heifer body weight was unaffected by supplementation. Supplementation increased average daily gain until pregnancy diagnosis, but no differences were noted after pregnancy diagnosis. Providing dried distillers grain increased the percentage of heifers that were cycling before breeding; however, no differences in pregnancy rates, percent that gave birth in the …

Effect Of Forage Allocation On Steer Performance When Grazing Cereal Rye, Shelby L. Davies-Jenkins, Abigail M. Sartin, Daren D. Redfearn, Mary E. Drewnoski

Nebraska Beef Cattle Reports

Summary with Implications

Cereal rye is the most common cover crop planted today. With its good winter tolerance and rapid spring growth during a gap in perennial pasture productivity, it is an attractive forage source in early spring. Unfortunately, optimum stocking rates and how they are related to forage biomass availability are unknown. The study objective was to understand the effect of forage allowance on steer performance when rotationally grazing fall-planted cereal rye in spring. Stocking rate was negatively correlated with pounds of forage offered. Surprisingly, amount of forage offered related to average daily gain. Growing steers grazing cereal rye …

Strategies Affecting Performance And Profitability Of May-Born Steers, Dempster M. Christenson, Jacki A. Musgrave, Richard N. Funston

Nebraska Beef Cattle Reports

Summary with Implications

This study compared the performance and economic outcomes of differing backgrounding and feedlot systems in May-born yearling steers. We hypothesized reduced supplementation with adequate forage availability while backgrounding weaned steers will yield a similar carcass with greater profitability. It was hypothesized yearling steers backgrounded on pasture before finishing in feedlot would have a more valuable carcass that is more profitable than steers that enter the feedlot immediately. Weaned steer calves were backgrounded with ad libitum hay and 4 lb/d supplement in drylot or on pasture with 1 lb/d supplement. As yearlings, half of each backgrounding group immediately …

Interaction Of Backgrounding System And Implant Use On Growing Calf Performance, Sydney T. Vanderhoff, Braden C. Troyer, Rebecca L. Mcdermott, Mitchell M. Norman, Brandon L. Nuttelman, Galen E. Erickson, Mary E. Drewnoski, James C. Macdonald

Nebraska Beef Cattle Reports

Summary with Implications

A two-year study utilized 480 weaned steers each year targeted to gain either 1 or 2 lb/d during the winter followed by ad libitum forage intake during the summer to determine the effects of winter rate of gain and implant strategy during the winter backgrounding and summer phases on steer performance, forage intake, and compensatory gain. During the winter, steers received a Revalor-G or no implant. In the summer, steers either received a Revalor-IS or no implant. The use of Revalor-G and increased rate of gain during the winter backgrounding phase had additive effects to increase animal …

Quantifying Cereal Rye Pastures Biomass With Image Analysis, Pedro Henrique J. Fernandes, Shelby L. Davies-Jenkins, Biquan Zhao, Wei‑Zhen Liang, Mary E. Drewnoski, Yijie Xiong

Nebraska Beef Cattle Reports

Summary with Implications

By accurately assessing the amount of forage available, producers can estimate the pasture carrying capacity to make informed decisions on management. To provide producers with a feasible and efficient approach to estimate forage mass, this project evaluated performance of two image analysis tools, Crop Canopy Image Analyzer (CCIA) and Canopeo, in estimating forage mass for cereal rye. Forage mass measured by clipping the forage (areas with 5.625 ft²) was correlated with plant cover analyzed by the two tools using photos of the forage taken 37 in above the ground. Results obtained have supported the feasibility …

Impact Of Constant Versus Variable Inclusions Of Modified Distillers Grains Plus Solubles On Feedlot Cattle Performance And Carcass Characteristics, Paige M. Madison, Rebecca L. Mcdermott, Isaque F. Vicci, Joshua R. Benton, James C. Macdonald, Galen E. Erickson

Nebraska Beef Cattle Reports

Summary with Implications

A finishing trial was conducted to evaluate the effects of varying dietary inclusion of modified distillers grains plus solubles compared to a constant inclusion throughout the entire feeding period on finishing cattle performance. Treatments were arranged as a 2 × 2 + 1 factorial with two inclusions of modified distillers grains plus solubles (10% and 25%) that were constant or varying in dietary inclusion, and a corn control (0% modified distillers grains plus solubles). Increasing the inclusion of distillers grains from 0 to 25% increased both DMI and ADG when fed at a constant inclusion of 10 …

Impact Of Full-Fat Wet Distillers Grains Inclusion In Steam-Flaked Corn Based Finishing Diets, Gatlin Hissong, Bill Dicke, Doug Smith, Andrea Watson, Galen E. Erickson

Nebraska Beef Cattle Reports

Summary with Implications

Steam-flaked corn and distillers grains are common feed ingredients in finishing rations, but the interaction between the two is not well understood. A finishing trial at a commercial feedlot using 700 calf-fed heifers was conducted to evaluate cattle performance when fed 18 or 30% (dry matter basis) full-fat wet distillers grains plus solubles in steam-flaked corn based diets with 8% roughage (hay + corn silage). No effects on cattle performance were observed due to distillers grains inclusion in the diet. Final body weight, dry matter intake, average daily gain, feed conversion, and hot carcass weight were not …

Effect Of Feeding Palm Oil On Finishing Cattle Performance, Carcass Characteristics, And Methane Production, Anna M. Kobza, Rebecca L. Mcdermott, Mitchell C. Norman, Joshua R. Benton, Long Zou, James C. Macdonald, Galen E. Erickson

Nebraska Beef Cattle Reports

Summary with Implications

Increased demand for biofuel production has increased demand and price of commonly fed supplemental fat sources in beef operations. This finishing study evaluated the effect of feeding palm oil products on performance, carcass characteristics and methane production of feedlot finishing steers. Dietary treatments were feeding no supplemental fat or feeding one of the following fat sources at 4% of diet dry matter: whole palm oil, palm stearin, palm olein, or corn oil. Feeding supplemental fat, regardless of source, increased final body weight, average daily gain, and hot carcass weight. Feeding supplemental fat had no effect on dry …

Impact Of Feeding Distillers Grains Compared To New Fractionated Distillers Grains (Solbran) On Feedlot Cattle Performance And Enteric Methane, Debora G. Sousa, Rebecca L. Mcdermott, Mitchell M. Norman, James C. Macdonald, Rick Stock, Ryan A. Mass, Galen E. Erickson

Nebraska Beef Cattle Reports

Summary with Implications

This study evaluated feeding wet or dry traditional distillers grains with wet and dry fractionated distillers (Solbran) fed at 40% of diet DM compared to a corn control diet on enteric methane emissions and performance. Compared to the control, there was no difference in carbon dioxide production, but there was an increase in methane production in the steers fed fractionated distillers compared to conventional distillers. Feeding steers traditional or fractionated distillers grains increased consumption, increased gain, but improved conversions only for steers fed WDGS, while steers fed the other distillers grains had worse or the same feed …

Effect Of Feeding Two Different Feed Additives (Optipartum C+ And Prime Force) On Finishing Cattle Performance And Carcass Characteristics, Sofia Suarez-Lorences, Rebecca L. Mcdermott, Joshua R. Benton, Robert Bondurant, Willard Lemaster, James C. Macdonald, Galen E. Erickson

Nebraska Beef Cattle Reports

Summary with Implications

A feedlot study was conducted to evaluate the effects of adding two different natural feed additives, Prime Force and Optipartum C+, on finishing cattle performance and carcass characteristics. Treatments were applied as a 2×2 factorial that included a control diet with no additive; a diet containing Prime Force; a diet containing Optipartum C+; and a diet containing both Prime Force and Optipartum C+ combined. Treatment diets were fed the last 67 d prior to slaughter as designed. Cattle fed Prime Force had greater live final body weight, carcass weight, intake, and average daily gain compared to cattle …

Effects Of Replacing Wet Corn Distillers Grains With A Purefield Distillers Grains® At 15% And 30% (Dm Basis) In Feedlot Diets, Sofia A. Canafoglia, Pablo L. Loza

Nebraska Beef Cattle Reports

Summary with Implications

A 2×2 +1 factorial experiment was performed to evaluate the effects of replacing wet corn distillers grain (WCDGS) with PureField distillers grains, a proprietary blend of wet distillers grains plus wheat middlings (Purefield LLC, Kansas, United States) at 15% or 30% of the diet (DM basis), on finishing performance and carcass characteristics. The inclusion of either byproduct resulted in improved steer performance, and carcass characteristics when compared to the treatment without the byproduct inclusion. No interactions between byproduct and inclusion level were observed for steer performance or carcass characteristics. A tendency for higher average daily gains was …

2025 Beef Cattle Report

Nebraska Beef Cattle Reports

Cow-calf Nutrition, Reproduction, and Management

Artificial Insemination of Beef Heifers with Multi-sire Semen, Dempster M. Christenson, Jordan M. Thomas, Daniel J. Kelly, Rick N. Funston

Impact of Overwinter Gain on Growth and Reproductive Performance in March- born Heifers, Josie N. Crouch, J. Travis Mulliniks, Jacki A. Musgrave, Kacie L. McCarthy

Impact of Pre- and Post-breeding Supplementation on Performance of May-born Heifers, Josie N. Crouch, J. Travis. Mulliniks, Jacki A. Musgrave, Kacie L. McCarthy

Growing Calf and Yearling Management

Effects of Allocation Frequency on Cattle Performance and Forage Utilization when Swath Grazing a Sorghum-Sudangrass Hybrid in Eastern Nebraska, Thomas E. Aquino, …

Effect Of Using Whole Soybeans, Roasted Soybeans, Or Soybean Meal In Finishing Cattle Diets, Melissa K. Bausch, James C. Macdonald, Galen E. Erickson, Pablo L. Loza

Nebraska Beef Cattle Reports

Summary with Implications

A feedlot study compared the effect of using whole or roasted soybeans at two inclusion rates (12% and 16% of diet dry matter), soybean meal, distillers grains, or a dry-rolled corn with urea control in finishing cattle diets. Steers fed the diet with the 16% inclusion of roasted soybeans had better average daily gain, feed conversion, and hot carcass weight. All other diets resulted in similar performance to the dry-rolled corn and distillers grains treatments. Roasted soybeans fed at a 16% inclusion improved F:G over the 12% roasted soybeans as compared to the whole soybeans which were …

Assessing Reproductive Health In Zoo-Managed African Elephant Bulls (Loxodonta Africana), Kaitlyn Marie Campbell

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Populations of zoo-managed African elephant (Loxodonta Africana) exhibit substantial individual- and population-level variation in reproductive success, yet research has largely focused on females, leaving male fertility poorly understood. Subfertility in bulls, characterized by low libido and inconsistent semen quality, poses significant challenges to genetic management and long-term population sustainability. This study a) systematically evaluates semen quality, b) identifies physiological, behavioral, social, and environmental determinants of fertility, and c) advances ex situ conservation through the expansion of the African elephant sperm bank. Between January 2023 and July 2025, 209 semen collection events were conducted from 13 sexually mature bulls …

The Use Of Fourier-Transformed Infrared Spectroscopy With An Infrared Biotyper To Establish Classifiers For Major Serogroups Of Moraxella Bovis Based On Spectral Profiles, Jordyn Bailey Schommer

Honors Program: Senior Projects (Public)

A classifier tool was created to identify major serogroups of Moraxella bovis based on spectral profiles collected from bacterial cells through the use of Fourier transformed infrared spectroscopy. M. bovis strains were selected from a group of previously sequenced and genotyped isolates, which provided the pilin sequence type for each isolate. The obtained spectroscopic profiles were analyzed through artificial neural networks to create a classifier tool that could identify the PilA type for unknown strains. Once a sufficient spectral library was obtained, the isolates were split into a training and a validation group, each containing spectra from isolates of five …

The Impact Of A Pgym Variant On Myophosphorylase Deficiency In Red Angus Composite Cattle And Changes In The Skeletal Muscle Transcriptome Due To The Intramuscular Administration Of Lidocaine In Wether Lambs, Mackenzie Christin Batt

School of Biological Sciences: Dissertations, Theses, and Student Research

Project 1 focused on eight calves in a Nebraska herd (composite Simmental, Red Angus, Gelbvieh) that displayed exercise intolerance during forced activity. Available sire pedigrees contained a paternal ancestor within 2-4 generations in all affected calves. Pedigrees of the calves’ dams were unavailable, however, the cows were ranch-raised and retained from prior breeding seasons, where bulls used for breeding occasionally had a common ancestor. Therefore, it was hypothesized that a de novo autosomal recessive variant was causative of exercise intolerance in these calves. A genome-wide association analysis followed by whole-genome sequencing led to the identification of a variant in the …

Artificial Insemination And Fetal Programming In Beef Production Systems, Dempster Christenson

Department of Animal Science: Dissertations, Theses, and Student Research

Pregnancy to artificial insemination and late gestation fetal programming of the next calf crop are central to genetic development, reproductive longevity, calf crop productivity, and efficiency of cow/calf ranching. The purposes of this research are to find methods to improve pregnancy rate to artificial insemination, the growth and reproductive health of pregnant heifers, and the productivity of their offspring. In the first of four studies we found that extending the period of progesterone administration in an estrus synchronization protocol did not significantly hasten estrus response or increase pregnancy rate to artificial insemination, but timing of estrus within the melengestrol acetate …

Pathology Of Chronic Mycoplasma Ovipneumoniae Carriers In A Declining Bighorn Sheep (Ovis Canadensis) Population, Jennifer L. Malmberg, Samantha E. Allen, Jessica E. Jennings-Gaines, Marguerite Johnson, Katie L. Luukkonen, Kara M. Robbins, Todd E. Cornish, Rachel A. Smiley, Brittany L. Wagler, Zach Gregory, Daryl Lutz, Pat Hnlicka, Kevin L. Monteith, William H. Edwards

United States Department of Agriculture Wildlife Services: Staff Publications

Bighorn sheep (Ovis canadensis) across North America commonly experience populationlimiting epizootics of respiratory disease. Although many cases of bighorn sheep pneumonia are polymicrobial, Mycoplasma ovipneumoniae is most frequently associated with all-age mortality events followed by years of low recruitment. Chronic carriage of M. ovipneumoniae by adult females serves as a source of exposure of naïve juveniles; relatively few ewes may be responsible for maintenance of infection within a herd. Test-and-remove strategies focused on removal of adult females with evidence of persistent or intermittent shedding (hereafter chronic carriers) may reduce prevalence and mitigate mortality. Postmortem confirmation of pneumonia …