bluuebunny/crossref_metadata_2025 huggingface dataset:
313 Many farmers want a prediction of future performance, not necessarily breeding potential
Authors: Berry Donagh P
Published: September 2024

High heritability is a characteristic of many performance traits in cattle translating to a relatively strong correlation between an (accurate) estimated breeding value for an animal and its (future) production potential. However, the broad sense heritability (i.e., numerator in the formula includes both additive and non-additive genetic variance) is often larger than the narrow sense heritability (i.e., numerator includes only the additive genetic variance) especially for low heritability traits like reproductive performance. Moreover, the repeatability of a trait can be greater again, the difference between the heritability and repeatability is the inclusion of a permanent environmental variance in the numerator. Accurate and pertinent omic-based animal-level features can contribute to an increase in narrow sense heritability owing to a possible reduction in the residual variance; such data can also provide insights into both non-additive genetic variance and the permanent environmental variance. Even at the level of the contemporary group, omic-level data from the likes of bulk blood/saliva/milk sample, can improve how systematic environmental effects are modeled in the mixed model equations thus also reducing the residual variance. The greater heritability will contribute to a strengthening of the correlation between future phenotypic performance potential and estimated additive genetic merit. Importantly, omic measures for individual animals can help predict the permanent environmental effect of that animal capturing the yet untapped contributor to phenotypic variance. Irrespective, predictions need to be replaced by prescriptions; end users are inundated with data yet crave actionable information. Animal breeders have a lush (pardon the pun!) history of distilling estimates of genetic merit for a plethora of traits into a single value per animal (i.e., breeding indexes); this is the first step in transitioning from predictions to prescriptions. Given the familiarity of end users with breeding indexes, the potential exists to develop production indexes to rank commercial animals on future expected performance taking cognizance of genetic and non-genetic effects. Such production indexes align well with the associated breeding index but where the estimates of genetic merit for the traits in question are replaced by estimates of production merit; these estimated production values are the sum of the additive genetic, non-additive genetic and permanent environmental effects. The weighting factors in the production indexes are more short-term using current costs and prices as opposed to breeding indexes which are longer term. In comparison with the breeding indexes, the production indexes can include ancillary information like gender, age, and month of calving/birth. Like breeding indexes, they are updated in real time. Examples of the application of genome-enabled production indexes are guides for valuing animals for purchase or culling.
273 Toxicokinetic approach to measure the efficacy of a mycotoxin deactivator against aflatoxin B1 and zearalenone in pigs
Authors: Preveraud Damien P , Broekaert Nathan , Devreese Mathias , Croubels Siska
Published: September 2024

Zearalenone (ZEN) and aflatoxin B1 (AFB1) are mycotoxins highly prevalent worldwide and can impair the performance and health of pigs. Preventive solutions such as the use of dietary mycotoxin deactivators (MD) can help in reducing the exposure to ZEN and AFB1 in animals. The aim of this study was to perform a toxicokinetic study in pigs focusing on the plasma concentration-time profiles of these 2 toxins, alone or in combination with a MD. The study was conducted on 12 healthy pigs (6 males/6 females) of 8 wk of age with an initial average body weight (BW) of 13.8 kg (ethical approval n° 2017/106). The acclimatization period was 1 wk (d 1-7). The pigs were randomly allocated into 2 mixed sex treatment groups of 6 pigs per group. On d 8, after fasting for 12 h, the pigs were given an intragastric single bolus of ZEN and AFB1 (group 1: ZEN 0.5 mg/kg BW and AFB1 0.1 mg/kg BW) or the same ZEN and AFB1 challenge with a MD (Unike Plus at 0.1 g/kg BW; group 2). Oral absorption and systemic exposure of ZEN and AFB1 were evaluated by comparing the plasma toxicokinetic parameters of the glucuronide conjugate of ZEN (ZEN-GlcA) and AFB1. For ZEN-GlcA, the area under the instrument response-time curve (AUC0-4h) for group 1 was 616.9 responses*h whereas it decreased to 379.2 response*h with the addition of MD. Therefore, MD reduced the oral bioavailability of ZEN by 38.5%. For AFB1, the area under the plasma concentration-time curve (AUC0-4h) for group 1 was 32.3 ng/mL*h whereas it decreased to 14.3 ng/mL*h with the addition of MD. Therefore, the oral bioavailability of AFB1 with MD is 44.3% compared with group 1. This toxicokinetic model developed for swine has shown a great sensitivity that allows to quantity different levels of mycotoxin exposure. Unike Plus was able to reduce the systemic exposure to ZEN as well as AFB1. This preventive strategy is necessary to limit the appearance of clinical symptoms, and therefore, can help to control the development of infectious diseases and maintain the performance of animals.
274 Evaluation of recombinant Capripoxvirus antigens in the development of indirect enzyme linked immunosorbent assays
Authors: Teffera Mahder , Babiuk Shawn
Published: September 2024

Capripoxvirus is a genus of DNA viruses that includes sheep pox virus, goat pox virus and lumpy skin disease virus (LSDV). These viruses are considered high consequence viruses due to the severe clinical disease leading to economic losses to production and impact on trade. The recent spread of LSDV in Europe and Asia has demonstrated the transboundary nature of LSDV. The vaccines used to control Capripoxvirus infections currently do not have the ability to differentiate infected from vaccinated animals (DIVA) and the enzyme linked immunosorbent assays (ELISA) available for detection of antibodies to Capripoxvirus infections are not ideal. Previous research has been done to evaluate different Capripoxvirus antigens using E. coli expressed antigens; however, there has been no prior evaluation of baculovirus expressed Capripoxvirus antigens for use in ELISA. The objective of the current research was to produce 6 recombinant Capripoxvirus antigens using a baculovirus expression vector system (BEVS) and to evaluate these antigens in ELISAs to test bovine, sheep, and goat serum. The sequences used to produce the recombinant antigens were based on a consensus obtained using reference genomes consisting of all three viruses within the genus. All six antigens were produced and purified in-house using BEVS followed by benchtop or FPLC purification (Figure 1). To date, the antigens have been fully validated for performance in indirect ELISA using sheep sera (Figure 2) and partially using cattle sera, with goat sera validation to follow. The ELISAs were developed and optimized using known reference sera as controls. The performance of the ELISAs developed was assessed in comparison with the only commercially available Capripoxvirus serological test. The results demonstrate that some of the antigens used for the ELISAs completely outperformed the commercial test. Several antigens were found to be useful for ELISAs to detect responses in sheep and cattle sera. The sensitivities and specificities of the different ELISAs for sheep sera ranged from 99.54% to 53.57% sensitivity and 99.54 to 94.95% specificity with likelihood ratios above 10 using receiver operating characteristic curve analysis, while the commercial kit had a 42.85% sensitivity using the same positive sheep serum panel evaluated. The development of these serological assays allows for the simultaneous evaluation of immunogenicity of Capripoxvirus antigens through the testing of serum from experimentally infected animals. This study demonstrates the proof of principle, that sensitive and specific ELISAs can be developed for Capripoxviruses.
332 Selection for moderate and high growth and dam age differentially affect immune and stress responses of beef calves at weaning
Authors: Main Alexis R H , Reddout-Beam Cassidy C , Salak-Johnson Janeen L
Published: September 2024

Pressure for intense genetic selection of important economic traits has impacted several robustness traits in cattle including immune function, which can impact animal health and well-being. Furthermore, maternal traits like age and health status can influence passive immunity and, therefore, progeny immune status. This study aimed to determine the effect of genetic selection for moderate or high growth and dam age on immune phenotype and stress response of beef calves at weaning and 14 d post-weaning. Fall-born calves selected and sired by bulls of either moderate (MG, n = 23) or high (HG, n = 23) growth were used. Body weights and blood samples were taken at weaning (6 to 7 mo of age) and 14 d post-wean (14DPW). Samples were processed and analyzed for cortisol, immunoglobulins (Ig), lymphocyte proliferation, complete blood counts, and cytokines. Dam age was categorized into one of four age classifications: Heifer (2 yr, n = 8), Young (3-4 yr, n = 17), Mid (5-6 yr, n = 11), and Old (7+ yr, n = 12). Data were analyzed using PROC GLM (SAS 9.4). A dam age × growth trait interaction occurred for several measures, including neutrophils (P < 0.01), lymphocytes (P < 0.01), neutrophil-to-lymphocyte ratio (P < 0.001) and several cytokines (P < 0.05). The HG-sired calves from Heifer dams had greater numbers and percentages of neutrophils, less percentage of lymphocytes, and a greater neutrophil-to-lymphocyte ratio than calves from Young and Mid Dams and their MG counterparts. Conversely, pro-inflammatory cytokine concentrations, including IL-6 and IL-17A, were greater in MG-sired calves from heifer dams than those from the other dam ages. Main effects of growth or age on immune measures and body weight were also found. Serum IgG1 (P = 0.0003), IgG2 (P = 0.0031), and total IgG (P = 0.001) concentrations and Concanavalin A-induced lymphocyte proliferative response (P < 0.05) were greater among MG-sired calves than HG ones. At 14DPW, neutrophil-to-lymphocyte ratio was greater (P < 0.01) in HG-sired calves than MG ones, and HG calves were also heavier at weaning and 14DPW (P = 0.0020). Calves born to Old dams were heaviest than calves in all other dam age groups (P = 0.0039). These data infer that not only does genetic selection for high or moderate growth impact calf immune function, but maternal influence of age also differentially affects the immune phenotype.
331 1H Nuclear magnetic resonance-based metabolomics of serum from growing beef steers following a combined viral bacterial respiratory disease challenge
Authors: O’Reilly Keara , Carstens Gordon E , Wottlin Lauren R , Welsh Thomas H , Thomson Jennifer M , Copié Valerie , O’Shea-Stone Galen P
Published: September 2024

Bovine respiratory disease (BRD) contributes to high rates of mortality and morbidity among feedlot animals. Thus, there is a need to discover robust predictive biological indicators of infection status and disease severity in feedlot cattle. This study aimed to explore the use of 1H nuclear magnetic resonance (NMR) based metabolite profiling to characterize serum molecular markers associated with a viral-bacterial respiratory disease challenge in beef cattle. Crossbred beef steers [n = 24; initial body weight (BW) = 293 kg) were inoculated intranasally with bovine herpes virus-1 (2×108 PFU) and intratracheally with Mannheimia haemolytica (MH, 2.15×1010 CFU) on d -3 and 0, respectively (n = 16; MH-challenge), or similarly inoculated with phosphate-buffered saline (n = 8; Control-challenge). Blood was collected via jugular venipuncture on d -3, -1, 0, 2, 3, 5, 7, 10, and 14 relative to MH challenge for complete blood count and haptoglobin analysis, with additional serum samples stored at -80°C for subsequent metabolomic analysis. Continuously recorded variables included rumen temperature, activity, rumination, dry matter intake, and feeding behavior. Wottlin et al. (2020) reported that rumen temperature was increased (P < 0.04) in MH-challenged steers until d 6 post-MH inoculation (40.8 vs 39.3°C in MH-challenged and Control-challenged steers several hours post-MH inoculation). Dry matter intake was reduced (P < 0.01) by 42% in MH-challenged compared with Control-challenged steers during the 14-d post-MH inoculation period. Further, haptoglobin concentrations were increased (P < 0.05) in MH-challenged steers from d 2 to 7 of the post-MH inoculation period. Serum samples underwent small molecule metabolite extraction and untargeted 1H NMR metabolomics. The 1H NMR spectra of serum metabolites were evaluated for this study, resulting in the unambiguous identification and quantification of 64 polar metabolites. Univariate analysis was conducted to examine the effect of the MH challenge on relative metabolite concentrations between d 2 and 5 relative to MH challenge, indicating differences between metabolites of MH-challenge and Control-challenged steers. However, multivariate analysis using unsupervised 2-dimensional principal component analysis (2D-PCA) could not differentiate MH-challenged from Control-challenged steers based on distinct serum metabolite profiles. Results indicate the potential of specific metabolites to indicate BRD infected cattle; however, a larger cohort of cattle and expanded metabolite profile coverage may be required to more fully differentiate between BRD vs healthy cohorts. Opportunities exist to further investigate the role of metabolomics to discover robust early biological indicators that are predictive of the onset of BRD in feedlot cattle.
42 Remodeling intestinal barrier damage and gut microbiome by bioengineered probiotics
Authors: Bhunia Arun K , Gallina Nicholas L F , Martinez Ruth C , Johnson Timothy A
Published: September 2024

Intestinal barrier dysfunction, inflammation, and increased expression of heat shock protein 60 (Hsp60) are features of the dysbiotic gut. Probiotics can alleviate inflammation but are ineffective due to poor adhesion and adaptation to the inflamed bowel. We hypothesized that enhancing probiotic adhesion to intestinal cells may augment the immunomodulatory response, mucosal healing, tight junction restoration, and microbiome remodeling. Listeria adhesion protein (LAP; 94-kDa), also known as alcohol acetaldehyde dehydrogenase, aids Listeria attachment to the epithelial cells by interacting with Hsp60 and was cloned and expressed on Lactobacillus casei (Lbc). This bioengineered probiotic showed strong interaction with epithelial Hsp60, greater immunomodulatory response, and epithelial barrier integrity while reducing inflammation in a chemically (dextran sulfate sodium)-induced damaged, inflamed gut and listeriosis in a mouse model. Microbial community shift showed a favorable disposition to overcome dysbiotic conditions, and improved gut health and overall well-being. Bioengineered feeding ameliorated gut inflammation, thus offering a potential dietary supplement for reducing gut-associated inflammation and enhancing gut health in livestock.
39 Microbiome, metabolomics, epigenetics and beef quality in grass-fed Angus cattle
Authors: Carrillo Jose , Liu Jianan , He Yanghua , Li Robert W , Sonstegard Tad , Richard Kohn , Song Jiuzhou
Published: September 2024

The increasing demand for natural products is reshaping meat consumption, with grass-fed and grass-finished beef emerging as a lucrative option. However, shifting from conventional grain-fed style to grass-fed systems necessitates numerous adjustments in management decision-making and practical operations. To meet the knowledge gap, our study delved into various OMIC data, including growth performance, microbiome, metabolites, and epigenetics in a closed Wye Angus herd. Our findings revealed no difference in meat tenderness between the two treatments (P = 0.25), but significant diet effects on epigenetics with a substantial number of DNA methylation marks, which are of paramount importance. Moreover, we ascertained the microbiome in intestinal and rumen after weaning. Grass-fed cattle exhibited a significantly greater level of microbial diversity. The top 20 essential genera identified with random forest analysis could serve as microbial biomarkers and associate with the components of bile acids. Notably, the metabolomic analysis unveiled changes in glucose availability and utilization, variations in free fatty acids and carnitine-conjugated lipids, and altered β-oxidation, which influence complex lipid hydrolysis, contributing to the accumulation of anti-inflammatory n3 polyunsaturated fatty acids in grass-finished cattle. At the same time, greater concentrations of n6 PUFAs in grain-finished animals could promote inflammation and oxidative stress. With the discovery of low cortisol levels in grass-fed cattle, the cattle have health and welfare benefits in a grass-fed manner. Most importantly, they also provide fresh insights into microbial interactions in the rumen under different feed schemes and their ecophysiological implications, further aiding in developing rumen manipulation strategies to enhance feed conversion ratios and methane emission.
4 Hands-on 2: Environmental evaluation of feeding strategies with agent-based modeling and life cycle assessment: From theory to practice. Sponsored by EAAP
Authors: Garcia-Launay Florence
Published: September 2024

Livestock farming systems (LFS) have detrimental effects on the environment, associated mainly to feed production, enteric methane and emissions from manure. Life Cycle Assessment (LCA) is a standardized internationally recognized methodology to assess the various environmental impacts associated to a product, considering all the processes occurring during its life cycle. Cradle-to-farm-gate LCA is commonly used to assess the environmental impacts of LFS. However, LFS are complex because they are structured by multiple interactions between biological and human-controlled processes, at various organization levels. Their behavior and the extent to which feeding strategies can mitigate this environmental burden is not always easily predictable. Dynamic mechanistic models of LFS can simulate the effects of feeding strategies on both animal performance and the associated excretion of nutrients. These models are useful tools to produce the life cycle inventories needed in life cycle assessment. In the pig-fattening unit, the animal performance with multiphase group feeding depends largely on the variability of growth potential among pigs and the farmer makes decisions that can target either the group of pigs or each individual (e.g., when choosing pigs to deliver to slaughterhouse). Therefore, simulating the growth trajectory of each individual pig and events like deliveries to slaughterhouse makes it possible to estimate the response of the pig population rather than the average pig to feeding strategies. Individual-based models (IBM) are particularly adequate because they make it possible to simulate each individual and to build the response of the population from the aggregation of individuals. Agent-based models are IBM that rely on self-governing agents made of properties, behavioral rules and resources that allow each agent to make decisions upon the occurrence of an event, which can be triggered randomly or not. This hands-on will focus on a specific example that illustrates how and why agent-based models are useful tools to assess the effects of feeding strategies through LCA. To keep it easily tractable, it will focus only on the impacts on climate change and acidification of a pen of fattening pigs according to the feeding strategy applied. In a first step, we will develop a simplified individual-based model of a pig-fattening pen (including pigs and the farmer as agents), which simulates the effects of feeding strategies on animal performance (growth rate, feed conversion ratio, slaughter weight, N excretion). In a second step, we will upgrade this model by introducing a module which makes the calculation of the environmental impacts through LCA. In a third step, we will use the model to simulate the effects of various feeding strategies according to the variability of growth potential among pigs in the pen. For all steps, we will work with Python language using pre-developed Jupyter notebooks.
21 Trace mineral nutrition for grain-fed feedlot cattle
Authors: Loh Huey Yi , Thorndyke Meghan P , Thomas Tyler A , Miller Alexandra , Alves Julia Baroni , Wagner John J , Wagner John J
Published: September 2024

Trace minerals are essential dietary components for feedlot cattle diets. They are integral components for normal carbohydrate, lipid, and protein metabolism and have been shown to be involved in hormone production, immunity, oxidation/reduction reactions, and cellular homeostasis. The functions of trace minerals in metabolic processes are extremely complex. In general, trace minerals function primarily as activators or components of enzymes that assist with enzyme structural integrity and/or substrate binding. Enzymes involved in the protection of cells from oxidative stress, electron transport, oxygen transport, bone metabolism, gene expression, and nutrient metabolism all have been shown to require certain trace elements for proper function. Trace minerals typically supplemented to feedlot cattle diets are cobalt (Co), copper (Cu), iodine (I), manganese (Mn), selenium (Se), and zinc (Zn). Although chromium (Cr) is not considered an essential nutrient in the Nutrient Requirements of Beef Cattle: National Academies of Sciences, Engineering, and Medicine (NASEM, 2016) publication, it is currently being included in some feedlot diets. Absorption of trace minerals from the gastrointestinal tract and tissue distribution of trace minerals are tightly regulated. However, many factors can impact the response of an animal to trace mineral supplementation, such as the dose and duration of supplementation, physiological status of an animal, the absence or presence of dietary antagonists, basal diet trace mineral concentrations, environmental factors, microbial-mineral interactions, and stress. Several research groups have compared the impact of supplementing increased concentrations (greater than the NASEM requirements) of Co, Cu, Mn, Zn, I, Se, and Zn (concurrently) on feedlot cattle performance and carcass characteristics. Results of these experiments have been variable, and caution should be taken when comparing experiments. Increasing trace mineral concentrations above published requirements does not always improve feedlot performance and carcass characteristics but has been reported, in some studies, to increase dry matter intake and average daily gain during certain intervals of the feeding period. The variability in animal numbers, the inclusion or omission of a negative control treatment, dietary ingredients, growth technologies used, and basal diet availability of trace minerals make comparing these types of experiments difficult.
363 Effects of supplementation of vitamin B complex on the performance of beef calves during a 42-d preconditioning program
Authors: Ferri Erica , Rezende Aline , Ramalho Ana Laura , Santos Carlos Eduardo Dos , Ferreira Matheus , Heldt Jeff S , Farmer Chance G , Ranches Juliana
Published: September 2024

The objective of this study was to evaluate the effects of supplementation of vitamin B complex on post-weaning performance of beef calves. The study was conducted during fall of 2023 at Eastern Oregon Agriculture Research Center (EOARC; Burns, OR). At weaning (d 0), 63 calves [Angus × Hereford; body weight (BW) = 252 ± 3.6 kg] were randomly assigned to 1 of 3 treatments: 1) Control, 2) VitB1, or 3) VitB2. Calves assigned to Control treatment served as a negative control and were not supplemented with vitamin B complex. Calves assigned to treatment VitB1 were supplemented at 1g/calf daily, while calves assigned to VitB2 treatment were supplemented at 2g/calf daily of vitamin B complex during the 42 d of preconditioning. Upon weaning processing, calves were allocated to 21 pens (3 calves/pen) and treatments were allocated to each pen (7 pens/treatment). Vitamin B complex [Vivalto, pantothenic acid (B5; 40,000 mg/kg), pyridoxine (B6; 20,000 mg/kg), folic acid (B9; 3,200 mg/kg), biotin (B7; 3,200,000 mcg/kg), cobalamin (B12; 320,000 mcg/kg); Selko USA, Indianapolis, IN] supplementation was offered at pen level beginning on d 1 and until the end of the preconditioning phase (d 42). Vitamin B complex was offered to calves assigned to vitamin B complex treatment mixed with 1.3 kg of dried distiller’s grains. Additionally, calves had free access to chopped alfalfa-grass hay mix and whole corn. Pen intake was recorded daily. On d 0, BW and blood samples were collected from all calves. Additional blood and BW were collected on d 1, 3, 7, 14, 21, 42 post-weaning. Body weights were used to calculate calf average daily gain (ADG) and blood samples were assayed for acute phase proteins (ceruloplasmin and haptoglobin). Additional blood samples will be analyzed for cortisol and vitamin B concentrations. Variables were analyzed considering pen as the experimental unit and pen(treatment) as a random effect. Blood variables were evaluated as repeated measures and effects of treatment, day, and treatment the interactions were analyzed with the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC). Significance was set at P ≤ 0.05. No treatment effects (P = 0.98) were observed for final BW (283, 283, and 284 kg respectively for Control, Vit1, and Vit2) or for ADG (P = 0.53; 0.735, 0.795, and 0.747 kg/d respectively for Control, Vit1, and Vit2). Similarly, no treatment effects were observed for the acute phase proteins analyzed, ceruloplasmin (P = 0.66; 27, 30, and 33 µg/dL respectively for Control, Vit1, and Vit2) and haptoglobin (P = 0.41; 0.55, 0.62, and 0.59 mg/mL, respectively for Control, Vit1, and Vit2). Supplementation of vitamin B complex to beef calves post-weaning does not seem to affect calf performance, regardless of the level of supplementation.
17 Effects of trace mineral source on dry matter digestibility of silage and mineral absorption
Authors: de Leonel Fernando P Paula , De Araujo Davi Brito , Resende Maria Eduarda L , Leitão Guilherme C , Vieira Neto Cícero M , Braga Bruna C , Simões Tiago O , Lacerda e Souza Luis Felipe C , Cação Freitas Luis Eduardo Costa , Correa de Souza Geraldo L
Published: September 2024

Copper, manganese, and zinc when coming from highly soluble sources in the rumen can strongly bind to diet fiber, which reduces it intestinal absorption and DM digestibility. Thus, the objective of this study was to evaluate the digestibility of dry matter and the apparent absorption of Cu, Mn, and Zn depending on different sources of these trace minerals. Four ruminally cannulated crossbred steers [body weight (BW = 560 ± 35 kg)] were used in a 4 × 4 Latin square design and offered corn silage ad libitum, and mineral supplement for four 21-d periods (14-d adaptation and 7-d data collection). Treatments assigned were: 1) Control (No Cu, Mn, and Zn); 2) Cu, Mn, and Zn-sulfate; 3) Cu, Mn, and Zn-organic; and 4) Cu, Mn, and Zn-hydroxychloride. In each period, two dry matter intake measurements and two total feces collections were carried out for 24 h. Thus, the digestibility of dry matter (DMd) and the apparent absorption (aA = trace minerals intake - trace minerals in feces/trace minerals intake) of Cu, Mn, and Zn were calculated. Data were subjected to analysis of variance (P < 0.05), and when significant, a multiple comparison test was performed (SNK test). No treatment x animal x period interactions were observed (P ≥ 0.05). The greatest DM digestibility was in the diets with Cu, Mn, and Zn-hydroxychloride and Cu, Mn, and Zn-organic, and the least DMd were Cu, Mn, and Zn-sulfate and control diet (P < 0.05), respectively 588, 575, 468 e, 449 g/kg (Table 1). Copper apparent absorption was greater (P < 0.05) in steers receiving Cu-hydroxychloride (0.14) and Cu-organic (0.12) and was equal (P ≥ 0.05) between those receiving Cu-sulfate (0.05) and those not receiving (-0.006) supplemental Cu. The sources did not affect (P ≥ 0.05) manganese aA, and the absorption of Mn was greater (P < 0.05) in steers receiving Mn than those not receiving. Diets with Zn-hydroxychloride (0.16) and Zn-organic (0.12) had greater (P < 0.05) aA than diet with Zn-sulfate (0.01), and steers that did not receive supplemental zinc (-0.10) had the least (P < 0.05) zinc aA. Low ruminal solubility trace minerals sources result in greater DM digestibility. Hydroxychloride and organic are more absorbable than Cu and Zn sulfates. Non-supplementation resulted in a net loss of Cu, Mn, and Zn, regardless of the type of trace minerals source.
25 Copper, manganese, and zinc source and concentration in free-choice mineral supplements influence production throughout three cow-calf production cycles
Authors: Farmer Chance G , Engle Terry E , Spears Jerry W , Heldt Jeff S
Published: September 2024

The effects of Cu, Zn, and Mn source and concentration in free-choice mineral supplements on mineral status, reproduction, and performance of grazing beef cows and their offspring were evaluated over 3 production cycles. Treatments targeted: 1) 1X NASEM requirement for Cu, Zn, Mn from sulfate sources (1X SUL), 2) 1X NASEM requirement for Cu, Zn, Mn with hydroxychloride sources (1X HYD), and 3) 0.5X NASEM requirement for Cu, Zn, Mn with hydroxychloride sources (0.5X HYD). Crossbred (Angus and Angus x Hereford; n = 160) beef cows were stratified by expected calving date, body weight (BW), body condition score (BCS), and liver mineral status and randomly assigned to one of eight replicates. Replicates were then assigned to one of the three treatments (n = 20 cows per replicate), resulting in three replicates for 1X SUL and 0.5X HYD and two replicates for 1X HYD in each year of the 3-yr study. Replicates were rotated among pastures approximately every 28 d to minimize pasture effects. Free-choice mineral feeders were used to provide Cu, Zn, and Mn treatments which were formulated into complete mineral supplements with a target intake of 114 g·cow-1·d-1. Elemental S was included in the free-choice mineral supplement at an inclusion rate of 12% S to serve as a potential antagonist to Cu. Additionally, pasture forage concentrations of Mo were > 2 mg Mo/kg DM. Body weights and BCS of the cows were obtained at study initiation and at the end of yr 1, 2, and 3. Liver biopsies were obtained from all of the cows before study initiation, and then a subset of cows (10 cows per replicate) at the end of yr 1, 2, and 3. Over the 3-yr study, mineral supplement intake was approximately 1.5 times the targeted intake for all treatments. Cow BW and BCS were similar (P ≥ 0.91) across treatments over the 3-yr study. Liver Cu, Zn, and Mn concentrations and pregnancy rate to AI were greater (P < 0.05) in cows receiving 1X HYD and 0.5X HYD compared with 1X SUL after yr 2 and 3 of the study. Actual weaning weights were greater (P < 0.05) in 1X HYD and 0.5X HYD supplemented animals compared with 1X SUL after yr 3 of mineral supplementation. Hydroxy Cu, Zn, and Mn supplementation improved Cu, Zn, Mn liver status, pregnancy rate to AI, and actual weaning weights of calves compared with sulfate sources of Cu, Zn, and Mn.
26 Trace minerals to improve bull fertility
Authors: Fontes Pedro
Published: September 2024

Bull fertility is paramount for reproductive success in cow-calf production systems and there are a variety of factors that influence bull fertility. Trace mineral requirements and recommendations have been established for growing and finishing steers, as well as lactating and pregnant cows, yet no specific requirements have been established for young or mature beef bulls. Nonetheless, trace minerals have been shown to have an important role in sexual maturation and semen quality of ruminants. Research performed in rams indicates that zinc deficiency results in reduced testicular development, decreased testicular concentrations of testosterone, and impaired development of seminiferous tubules. Deficiency of Zn has also been reported to negatively impact male fertility in humans, where men diagnosed with infertility responded positively to Zn supplementation. In growing bulls, diets with greater concentrations of organic forms of Zn, Cu, and Mn, tended to result in earlier attainment of puberty compared with control diets containing inorganic minerals. Furthermore, greater liver concentrations of Zn have been negatively correlated with sperm acrosomal damage in growing bulls, based on flow cytometry analyses. More recent research indicates that the use of hydroxichloride-based trace minerals results in greater liver concentrations of Zn and Cu compared with sulfate sources. While evidence indicates that trace mineral status has an important role in bull fertility, further research is required to better understand the contributions of trace minerals to semen quality. In addition, investigating the impact of trace mineral sources with greater bioavailability on semen quality may result in the development of practical recommendations that optimize bull fertility.
52 Differences in body composition measurements for developing Angus heifers
Authors: Phelps Sarah L , Dahlke Garland , Reynolds Mary E , Wall Patrick B , Culbertson Miranda
Published: September 2024

The profitability of beef cow-calf operations relies on the reproductive ability of females to calve at 2 yr of age and provide a calf each subsequent year for her lifetime. The management of replacement heifers could affect her ability to conceive early, calve, and rebreed. Common management practices use heifer body weight (BW) (and body condition score (BCS) as indicators of puberty onset but do not indicate body composition and fat deposition. The objective of this study was to use ultrasound measurements of carcass traits to compare the effect of different diet management practices on muscle development and fat deposition of post-weaning heifers. The heifers placed on a higher energy diet are expected to have greater mean carcass trait measurements than the lower energy diet heifers. A total of 124 purebred Angus heifers from the Iowa State University McNay Memorial Research and Demonstration Farm were used for this study. Two diets were administered in this study. One group of heifers (G1; n = 61) was developed on a low-energy roughage diet to reach a target BW of 55% of mature BW at the time of breeding. The second group (G2; n = 63) was developed on a grain diet to reach the target BW of 65% mature BW at breeding. Body weight and ultrasound measurements for backfat (BFAT), ribeye area (REA), and intramuscular fat (IMF) were collected over three time points (0-d, 55-d, and 123-d) during the study to quantify the development of body composition characteristics. The initial measurements were collected 1 wk post-weaning. Significant mean differences between the two groups were observed for BW, BFAT, and REA at 55-d (P = 0.027, P = 0.008, and P < 0.0001, respectively), and 123-d (P < 0.001). The mean differences for BW, BFAT, and REA at 123-d between G1 and G2 were 30.98 kg, 0.10 cm, and 7.81 cm2, respectively No significant difference was found between the groups for IMF measurements at 55-d (P = 0.927) or 123-d (P = 0.169). This suggests IMF is not significantly influenced by diet during the early, post-weaning heifer developmental stage. Although further research is needed, the results from this study suggest the development of weight, BFAT, and REA in early post-weaning beef heifers is influenced by the energy concentration of the diet.
51 Lean meat yield of Angus, Brahman and Charolais grain fed steers
Authors: Burgess Jillian E M , Imaz Jose A , Gonzalez Luciano A
Published: September 2024

Lean meat yield (LMY) is a key driver of profitability in the beef industry, and it is associated with muscling and feed efficiency (Pethick et al., 2021). No research has studied differences in LMY between British, Continental, and Tropical beef breeds fed for increasing days on feed. The objective of the present study was to compare LMY of Angus, Brahman and Charolais steers with increasing days on feed (DOF). The hypothesis was that Charolais have the greatest LMY throughout the feeding period due to being a later maturing, high muscling breed compared with Angus and Brahman. Angus (n = 30), Brahman (n = 30), and Charolais (n = 29) 12-18 mo-old steers were inducted with a body weight (BW) of 361 ± 5.3 kg, 355 ± 5.3 kg and 317 ± 5.3 kg, respectively. Six animals of each breed were randomly selected for slaughter at 50-d intervals until 200 DOF. Steers were allowed ad libitum access to water and feed (78% rolled barley, 13.76% CP, 12.15 ME MJ/kg DM). Body weight, hot carcass weight (HCW), and LMY were measured at slaughter. All components of the animal were collected, and carcass muscle, fat and bones physically dissected with knives and weighed separately. The LMY as % empty BW (EBW) was calculated as the weight of lean meat separated from the carcass divided by EBW. The LMY as % of HCW was calculated as the weight of lean meat separated from the carcass divided by HCW. Data was analyzed with a model containing the fixed effect of breed, DOF at slaughter, and their interaction. Breed, DOF and their interaction affected LMY expressed as both ratio to EBW and HCW (P < 0.05). Charolais steers had the greatest LMY (% HCW) at 50, 100, and 150 DOF, but similar to Brahman at 0 and 200 DOF (P < 0.05; Figure 1a). Angus steers showed the lowest LMY (% HCW) throughout all DOF (P < 0.05) except at 50 DOF being similar to Brahman (P > 0.05). Furthermore, Charolais had the greatest LMY (% EBW) from 50 to 200 DOF (P < 0.05) but it was similar to Brahman at 0 DOF (Figure 1b; P > 0.05). Angus had the least LMY (% EBW) throughout (P < 0.05) but was not different to Brahman at 50 DOF. Brahman had intermediate LMY (% EBW and % HCW) between Charolais and Angus. Differences between beef breeds suggest that LMY should be considered as another factor to establish an accurate carcass value.
261 Vitamin A administration in pregnant cows or newborn calves: Growth performance and carcass traits
Authors: Ladeira Marcio M , Junior Jose Maria oliveira , Casagrande Daniel R , Salinas Sara , Horta Artur , Souza Marcela , Dias Miguel , Souza Paloma , Vale Rafael
Published: September 2024

This study aimed to evaluate the effects of Vitamin A (VA) injection on the growth performance and carcass traits of Nellore × Angus crossbred steers and heifers. For that, the same sire inseminated Nellore cows from two artificial insemination (AI) groups were randomly assigned to one of three treatments at 250 d of gestation: no VA injection (Control); VA injection in pregnant cows at 250 d of gestation (VAcow; 2,000,000 IU single dose); VA injection in newborn calves at birth and 60 d of age (VAcalf; 200,000 IU each dose). Cow-calf pairs were kept in the same paddock, and calves received creep-feeding supplementation from 90 d of age to weaning. After weaning, steers and heifers [n = 36; body weight (BW) 213 ± 25.7 kg] were stratified by treatment and BW and allotted into 16 pens. After 207 d of feeding (77 d of growing diet + 130 d of finishing diet), steers and heifers were slaughtered at a commercial abattoir. Data were analyzed using the MIXED procedure of SAS 9.4 with fixed effects of VA injection, sex, and VA injection*sex interaction. The random effects were animal, AI group, and cow parity. Average daily gain before weaning (P < 0.01) and final BW in the finishing phase were greater (P = 0.04) in VAcow steers compared with heifers from all treatments (Table 1). Vitamin A had a positive impact on weaning BW of male calves and a negative impact on heifers (P < 0.01). There was no treatment difference (P = 0.35) in feedlot average daily gain (ADG), but steers had greater (P = 0.03) ADG compared with heifers. Moreover, VAcow steers had greater dry matter intake (DMI) in the feedlot (P = 0.04) compared with other treatments, and there was no effect of VA on DMI of heifers. On the other hand, feedlot feed efficiency tended to be greater (P = 0.07) in Control steers compared with other treatments, with no VA effect on heifers too. The ribeye area was greater (P = 0.04) in VAcow steers than in Control steers and heifers from all treatments. Intramuscular fat content was greater (P = 0.04) in VAcow steers than in Control and VAcalf steers. However, there was no effect of VA on heifers and VAcow steers. In addition, VAcow treatment tended (P = 0.08) to increase backfat thickness. In conclusion, VA injection in pregnant cows can be a strategy to improve marbling in steers, but there is no effect on intramuscular fat in heifers. Additionally, VA injection in pregnant cows produced intramuscular content in beef of steers, similar to heifers.
262 Why are some cows skinny? An evaluation of stress and immune factors
Authors: Lindholm-Perry Amanda K , Kuehn Larry A , Freetly Harvey C , Oliver William T , Neville Bryan W , Crouse Matt S , Thorson Jennifer F , Wells Jim E , Keel Brittney N
Published: September 2024

For the mature cow with low body condition scores (BCS), being too thin can accompany health issues, reduced pregnancy rates, more days to rebreeding, and decreased milk production resulting in lighter calves at weaning. In addition, reduced fat insulation in low BCS cows during the winter equates to additional feed requirements for warmth. The hypothesis of this study was that stress and immune factors contribute to low BCS in mature cows. The objective of this study was to determine whether there were differences in hematology parameters, hair cortisol concentrations, and plasma cytokine concentrations among animals with low body condition (BCS ≤ 4). Over a 3 yr study, we collected 62 pairs of cows which included cows with a BCS ≤ 4, and a matched control animal born in the same year with the same or similar breed composition from the same population of animals with a BCS of 5 or higher. Hematology parameters, cytokine concentration, and cortisol concentrations were analyzed using a model with BCS classification and sample year as fixed effects and age in years as a covariate. Hemoglobin, hematocrit, red blood cell and mean platelet volume were all less among the low BCS cows, and neutrophil count was greater (P < 0.05). Platelet, monocyte counts, mean corpuscular volume, and mean corpuscular hemoglobin tended to be greater in low BCS cows (0.05 < P ≤ 0.1), and lymphocyte count tended to be less. Hair cortisol concentrations, a longer-term measure of cortisol, tended to be greater in low BCS cows (P = 0.09). None of the 15 cytokines tested differed with BCS. The combination of reduced RBC parameters with greater neutrophils suggests that low BCS cows were responding to or were the reflection of some type of chronic stressor, such as a subclinical disease state or a physiologic stressor. This was also supported by the tendency for greater cortisol concentrations in low BCS cows. USDA is an equal opportunity provider and employer.
259 Impacts of vaccination or lipopolysaccharide challenge on ruminal and physiological responses in beef cattle
Authors: Cooke Reinaldo F , Pickett Autumn , Mackey Shea , Prado Mykael , Gouvêa Vinicius N
Published: September 2024

This experiment compared feed intake, ruminal forage degradability, and physiological responses in beef cattle receiving a lipopolysaccharide (LPS) challenge or a modified-live vaccine for respiratory disease. Ruminally cannulated Angus-influenced steers [n = 15; initial body weight (BW) = 589 kg ± 45] were housed in individuals pens with free access to hay, water, and a commercial vitamin + mineral mix during the experiment (d -7 to 7). On d 0, steers were ranked by initial BW and allocated to 1 of 3 treatments: 1) i.v. bolus dose (5 mL) of bacterial LPS (0.5 μg/kg of BW; Escherichia coli 0111:B4) + s.c. injection (2 mL) of 0.9% physiological saline (LPS), 2) i.v. dose (5 mL) of 0.9% physiological saline + 2 mL s.c. injection of Bovi-Shield Gold One Shot (VAC), or 3) i.v. bolus dose (5 mL) and s.c. injection (2 mL) of 0.9% physiological saline (CON). Hay intake was evaluated daily from d -5 to 7. Immediately prior to treatment administration on d 0, polyester bags containing 4 g of ground dietary hay [dry matter (DM) basis] were immersed into the rumen of each steer and incubated for 0, 2, 4, 6, 8, 12, 18, 24, 36, 48, and 72 h for DM and neutral detergent fiber (NDF) degradability evaluation. Blood samples were collected at -2, 0, 2, 4, 6, 8, 12, 18, 24, 36, 48, 60, 72, 96, 120, and 144 h relative to treatment administration. Values obtained before treatment administration were used as a covariate within each respective analysis. Steers receiving LPS had less DMI (P < 0.01) on d 0 and 1 compared with CON and VACC steers. Steers receiving LPS had reduced (P ≤ 0.02) ruminal disappearance rate (%/h) and effective degradability (%) of DM and NDF compared with CON and VACC steers. Steers receiving LPS and VACC had greater (P ≤ 0.05) plasma concentrations of haptoglobin (P < 0.01) from 18 to 144 h relative to treatment administration when compared with CON, whereas LPS steers had greater plasma haptoglobin (P ≤ 0.05) concentrations compared with VACC at 48 and 60 h. Overall, administration of LPS and VACC elicited an inflammatory response in cattle with increased levels and plasma haptoglobin. However, only LPS administration reduced DMI and ruminal in situ disappearance parameters including ruminal disappearance rate and effective degradability of DM and NDF.
264 Dakota Feeder Calf Show: Twenty-two years of producer retained ownership at NDSU
Authors: Tobin Colin T , Hoppe Karl F
Published: September 2024

Retained ownership of weaned steers has been limited in North Dakota. With annual reductions to cattle on feed numbers, genetic potential continues to leave the state each fall as North Dakota-born steers are fed across Central and Southern Plains States. In October 2001, the Dakota Feeder Calf Show (DFCS) relocated to the North Dakota State University Carrington Research Extension Center (CREC). The DFCS provides livestock producers the opportunity to consign spring-born steer calves to be fed to finish while receiving performance, carcass, and economic data to make informed management decisions, such as genetic selection. Calves consigned to the DFCS are marketed on a value-based grid and producers are afforded premiums for exceptional carcass qualities. The aim of this analysis is to determine changes in growth performance and carcass characteristics of steers. From Fall 2001 to Spring 2023, 140 consigners delivered 3,913 steers to be backgrounded and finished at the CREC. To identify trends throughout time within the dataset, independent variables, including initial bodyweight (IBW), days on feed (DOF), final bodyweight (FBW), marbling score (MS), hot carcass weight (HCW), rib fat (RF), ribeye area (REA), USDA Yield Grade (YG), total weight gain (TWG), and average daily gain (ADG) were regressed against year and DOF and correlations among independent variables were calculated using the REG and CORR procedures of SAS 9.4. No differences in IBW (P = 0.46), REA (P = 0.70), and ADG (P = 0.69) were detected. Days on feed (P < 0.0001), FBW (P = 0.0012), MS (P = 0.0006), HCW (P = 0.0017), RF (P = 0.0023), YG (P = 0.0007), and TWG (P = 0.0015) have increased linearly throughout the 22-year retained ownership program. The relationship of MS and RF are regressed MS = 263+(373*RF; P < 0.0001). Increasing DOF has resulted in linearly increased FBW (P = 0.012), MS (P = 0.0009), HCW (P = 0.0164), RF (P = 0.0193), YG (P = 0.0042), and TWG (P = 0.007).