bluuebunny/crossref_metadata_2025 huggingface dataset:
90 Interconnecting feed efficiency with molecular mechanisms of muscle growth in beef steers
Authors: Ascolese Sophia , Rowan Troy N , Beever Jonathan E , Henniger Madison T , Moisa Sonia J , Ault-Seay Taylor B , Voy Brynn H , Myer Phillip R
Published: March 2024

Feed efficiency is an important factor for improving the sustainability and economic value of beef production. Although feed efficiency is moderately heritable, it is a complex trait affected by numerous factors such as diet, the rumen microbiome, and energy metabolism. Recent work has examined the molecular control of cattle divergent in feed efficiency; however, limited work has focused on the transcriptomic regulation of variation in feed efficiency, specifically, the genes contributing to muscle growth and the variation in feed efficiency in beef production. The hypothesis of this study was that cattle with greater feed efficiency will have increased expression of genes that promote muscle growth and energy metabolism. A total of 100 Angus steers weighing approximately 400 kg were enrolled in 70 d feed efficiency trials to determine residual feed intake (RFI) using the Vytelle GrowSafe 8000 individual feed intake monitoring system. At mid-test, 500-mg of muscle tissue was collected from the wing of the ileum between the axis and transverse processes of the lumbar vertebrae and was punched with a biopsy probe tool. The collected biopsy samples were flash frozen in liquid nitrogen for storage until processing. RNA was extracted and 3’ RNA sequencing was conducted on the Novaseq 6000 to determine the differential skeletal muscle transcriptomes of steers differing in RFI. Differential expression analysis was performed with the DESeq2 R package. To determine connections between the differentially expressed genes identified via transcriptional profiling and RFI, gene expression results were examined for correlations. To visualize the correlation matrices, the Corrplot package in R (version 3.4) was utilized. Varying numbers of differentially expressed gene transcripts were detected between steers divergent in RFI (P < 0.05), and were identified with significant correlations to RFI (P < 0.05). Specifically, the genes identified were related to muscle growth and energy metabolism. These results further define the molecular control of muscle growth with regard to RFI, and the opportunity to improve feed efficiency and muscle growth while meeting the needs for food production and sustainability for the growing population.
97 Use of genomic testing for predicting performance of finishing steers
Authors: De Vries Jacee K , Briggs Emma A , Beck Paul A , Lalman David L , Johnson Chris
Published: March 2024

Genomic testing is a commercially available tool that has the potential to be beneficial in selecting cattle for retained ownership, as well as making management and marketing decisions after finishing. The objectives of this study were to determine if commercially available genomic tests are predictive of differences in finishing performance of steers from sires selected based on divergent growth and milk EPDs. The commercial genomic testing of milk and average daily gain (ADG) scores used in the current experiment were based on Neogen Igenity Beef test results. Two trials were conducted at the OSU Willard Sparks Beef Research Center in Stillwater, Oklahoma. These experiments used two sets of steers from the OSU Range Cow Research Center (400 ± 13 kg, n = 154) from a spring calving cowherd (South Range Unit) and a fall calving cowherd (North Range Unit) of primarily Angus ancestry. Following preconditioning and a wheat pasture stocker program (South Range) or dry lot growing period (North Range), steers were allocated into pens (n = 5 animals/pen) by Igenity ADG Score: low growth (LG) had scores ranging from 1 to 4, medium growth (MG) had scores from 5 to 6, and high (HG) had scores from 7 to 10. Steers were blocked by initial BW and fed a step-up diet for 30 d before being switched to a finishing ration diet (8% prairie hay, 20% Sweet Bran, 62% dry-rolled corn, 5% liquid supplement, and 5% dry supplement [DM basis]). Cattle were fed ractopamine hydrochloride for 30 d before slaughter. The heavy block was on feed for an average of 136 d, while the light block was on feed for an average of 160 d. Data were analyzed as a randomized complete block design using the mixed procedure of SAS (SAS Inst. Inc., Cary NC) with pen as the experimental unit and finishing pen within block as the random statement. During the feeding period, HG steers gained more rapidly than MG or LG steers, with ADG of 2.08, 1.94, and 1.90 kg/d, respectively (P = 0.04). Because gains were greater, BW at slaughter for the HG steers was greater than MG and LG, averaging 690, 669, and 660 kg, respectively (P = 0.04) and hot carcass weights were greater for HG than MG and LG, averaging 438, 426 and 418 kg, respectively (P = 0.02). There were no other differences (P > 0.19) in carcass characteristics among steers. These data suggests that the genomic testing is accurate predictor of performance and can be used by producers can make better marketing decisions in selecting cattle for the retained. Genomic testing could be very beneficial for producers looking to minimize risk and maximize performance in their herd.
79 Dietary buffer comparison and tannins supplementation modulating subacute ruminal acidosis and fermentation in beef cattle
Authors: Lehmann Andres Fernandez , Garcia Liza , Maderal Araceli B , Fernandez-Marenchino Ignacio , Tarnonsky Federico , Podversich Federico , Vargas Juan , Cuervo Wilmer , Gomez Camila , Erazo-Mendes Cristian , Dubeux Georgia , Schulmeister Tessa M , DiLorenzo Nicolas
Published: March 2024

As the demand of nutrients by the population will continue to grow over the years, efficient practices are required in the food chain to satisfy the demand. This practice involves the intensification of production systems. Moreover, intensification can potentially harm the animal or environment if the resources are used to the limit. The latter, product of pushing to the limit the ruminal environment. Dietary buffers and tannins offer a key role addressing issues related to intensification. This study aimed to evaluate the effects of two dietary buffers and tannins. Ruminal fermentation parameters, in vitro methane production, ruminal pH, in vitro organic matter digestibility were measured. Eight ruminally cannulated steers were used in a duplicated 4 x 4 Latin square design. Steers were fed with a basal diet comprised of 35.5% corn silage, 18.7% protein supplement, 21.5% corn grain, 22% bermuda hay, 1% mineral supplement (DM basis). Four treatments were used: BICARB (Basal diet + 1.2% DM Sodium Bicarbonate), BRIC-050 (Basal diet + 1.2% DM BRIC), BRIC-150 (Basal diet + 1.2% DM BRIC + 0.15 % DM Tannins), TAN (Basal diet + 0.15% DM Tannins). Steers were housed in individual pens and received every morning a TMR and water ad libitum. The experiment consisted of 4 periods with 16 days total, composed by 3 d of covariates, 7 d of treatment adaptation, 1 d of 50% feed restriction, 1 d SARA challenge, 4 d of recovery, and 20 d of washout between periods. Two in vitro batch culture were performed in every period at the last day of covariates and last day of recovery, collecting ruminal fluid from each animal. Treatments with BICARB promoted a higher pH than TAN during the adaptation at 4 h after feeding (P = 0.01). Moreover, BRIC-150 showed similar results with a tendency to increase (P = 0.07) when compared with TAN. During the feed restriction BRIC-150 showed a greater pH (P = 0.01) when compared with TAN. While, for BICARB and BRIC-050 pH tended to be greater (P = 0.06) than TAN. During the SARA challenge and the recovery, treatments with buffer tended to have greater pH (P < 0.1). A significant reduction ammonia nitrogen was observed for BICARB and TAN compared with BRIC-050 and BRIC-150 (P < 0.01). Overall, the three buffers tested showed similar results in terms of maintaining a greater pH than treatment without buffer.
93 Red clover as a functional feed: Effects on rumen microbiota of finishing ram lambs
Authors: Ragsdale Macy E , Ely Donald G , Weinert-Nelson Jennifer R , Davis Brittany E , Flythe Michael D , Hamilton Tracy A , Hamilton Matthew C , Jacks W Leann , Davis Sydney
Published: March 2024

Red clover (RC) contains bioactive isoflavones. Supplementing RC as a functional feed (as little as 7.5% of the total diet) has been shown to alter ruminal fermentation and improve feed efficiency in ram lambs fed high-concentrate finishing diets. The objectives of this study were to determine if reduced RC inclusion will produce similar rumen microbiological effects. It was hypothesized that RC supplementation below 7.5% RC will alter rumen microbial community composition during the finishing period. Sixteen individually housed Polypay ram lambs (age; 134 ± 2.5 d; initial body weight: 31 ± 0.53 kg) were used in a complete block design and fed one of four isocaloric and isonitrogenous diets (85:15 concentrate:roughage ratio; n = 4 rams diet1): a control diet in which the roughage component (15.0% wt/wt of total diet) consisted of orchardgrass hay, 2.5%-RC (roughage: 2.5% RC; 12.5% orchardgrass wt/wt), 5.0%-RC (roughage: 5.0% RC; 10% orchardgrass wt/wt), and 7.5%-RC (roughage: 7.5% RC; 7.5% orchardgrass wt/wt). Rumen fluid was collected via oral intubation at 0, 2, 4, 6, and 8 h post-feeding at the end of the adaptation period (14 d; all rams on control diet) and at 21-d intervals during the trial. Rumen functional bacterial guilds, including hyper-ammonia-producing bacteria (HAB), amylolytic, lactate-utilizing (LU), and cellulolytic bacteria were enumerated via serial dilution at 4 h post-feeding. Data were analyzed using PROC MIXED with repeated measures in SAS (v.9.4, SAS inst. Inc., Cary, NC). There were no differences between diets on d 0 for any variable (P > 0.05). At d 21, all RC-containing diets exhibited a 10- to 100-fold reduction in ruminal HAB compared with the control (P < 0.05). While suppression of HAB was no longer apparent by d 42 in 2.5%-RC, HAB had decreased 100-fold (109 to 107) in lambs fed the 5.0%-RC and 7.5%-RC diets (P < 0.01). No differences in amylolytic bacteria were detected on d 21 (P > 0.05), but were 10-fold less in all diets containing RC by d 42 in comparison with control (109 to 108; P = 0.08). In contrast, LU increased by d 21 and were 100-fold greater (106 to 108) by d 42 when compared with the control for all levels of RC supplementation (P < 0.05). Cellulolytic bacteria also increased across the study period in all lambs fed RC diets, with 100-fold greater cellulolytics (106 to 108) by d 42 (P < 0.05). Consistent with the hypothesis, supplementing RC at levels as low as 2.5% wt/wt of the total diet decreased protein-wasting HAB and amylolytic bacteria while coincidingly increasing LU and cellulolytic bacteria in the rumen. These results indicate that adding red clover to finishing diets has the potential to increase lamb growth and feed efficiency through a functional feed action.
103 Goats complement cattle in a woody-plant encroached, diverse Cross Timbers rangeland
Authors: Lippy Brittany A , Sherrill Cooper , Goodman Laura , Reuter Ryan R
Published: March 2024

Our objectives were to 1) determine diet selection of goats and cattle grazing woody plant-encroached tallgrass prairie, and, 2) determine the effect of the presence of goats on cattle diet selection. In 2019, pastures (n = 6) were allocated to 1 of 2 experimental grazing treatments. Pastures (n = 3) grazed by cattle only (crossbred Angus yearling heifers) were moderately grazed year-round at 4.2 ha per heifer. Pastures (n = 3) grazed by cattle (similar heifers) and goats (Boer x Spanish crossbred mature does) were moderately grazed year-round at 4.7 ha per heifer and 2.3 ha per goat simultaneously. Each pasture was burned in 6 patches (2 patches per year) to facilitate range management objectives. Every 35 d from May 2022 until June 2023, fecal samples were collected from all animals and stored frozen and later composited into 2 composites per animal species per pasture. Composites were then analyzed by a commercial lab with DNA barcoding and high-throughput sequencing. For statistical analysis, the top 50 Exact Sequence Variants (ESVs), representing species of forage, across all treatments were used for analysis. Each ESV was georeferenced to eliminate plants that did not grow in the study area, and assigned to a representative functional group: graminoid, forb, legume, and woody plant. Analysis of variance and Tukey’s post-hoc separation of estimated marginal means were performed to assess the effects of season, grazer species, and the interaction. The interaction of season and grazer species was significant (P < 0.01) for the percentage of diet selected from each functional group of plants. As expected, goats selected a greater percentage of their diet as woody plants in summer (57%) and winter (74%) compared with cattle (27%). Cattle selected more grass in winter (34%) than goats (11%). Goats selected more forbs in spring (33%) than cattle (10%). However, goats selected a lesser percentage of their diet as legumes in summer (16%) than cattle (58%), which was unexpected. Overall, these results indicate that both species of grazers select a diverse diet from these diverse pastures, and selection is dynamic over time. Goat presence in a pasture does not seem to drastically alter cattle selection, actually complementing cattle in these pastures where goats can be used to target species cattle do not prefer.
7 Environmental sustainability of livestock systems in the southeastern U.S.: Opportunities and research gaps
Authors: Beck Matthew R , Gunter Stacey , Friend Emalee J , Moffet Corey A
Published: March 2024

According to the Environmental Protection Agency (EPA), enteric methane (CH4) was the second largest source of greenhouse gas emissions from agriculture in 2021 behind nitrous oxide emissions from soil management. Cattle production in the southeastern U.S. represent a significant source of enteric CH4. In 2021, 31.5% of all cattle derived enteric CH4 arose from the southeastern U.S., representing 43.3% of cow-calf, 27.4% of stocker, 23.1% of feedlot, and 12.1% of dairy derived enteric CH4, according to the EPA. Previous work has demonstrated that reducing CH4 emissions represents the most promising means to limit climate change in the short-term, due to the short atmospheric lifespan of CH4. As such, developing enteric CH4 mitigation strategies for southeastern cattle producers is imperative. Enteric CH4 mitigation strategies can be grouped into diet formulations (e.g., lipid additions; feeding more grains; protein source and inclusion), feed management (e.g., grain and forage processing; grazing management; forage species), rumen manipulations [e.g., feed additives (ionophores or inhibitors); secondary plant compounds (tannins, essential oils, saponins)], and breeding strategies (e.g., selecting for low CH4 emitters; selecting for low residual feed intake). Of these options, the direct CH4 inhibitors appear to be the most promising. The largest source of enteric CH4 from the southeastern U.S. is from cow-calf production, representing 71.6% of the total. Furthermore, a 13.6% reduction in enteric CH4 from the southeastern cow-calf herd would offset more emissions than a 100% reduction in the southeastern dairy, stocker, or feedlot sectors. Despite the large gains in emission reductions that could be achieved by focusing on enteric CH4 mitigation strategies from southeastern pastoral systems, there has been relatively little research efforts in this area. For example, there has yet to be any investigation into the mitigation potential of CH4 inhibitors when fed to grazing cattle. This is especially important, because the mitigation potential of inhibitors is likely much greater for grazing than for confined fed cattle. Additionally, there are limited and aging research into grazing management strategies effects on enteric CH4 emissions. There also exists a gap-in-knowledge of how common (e.g., supplementation) or changes in management (e.g., selecting for smaller mature cow sizes) practices could potentially influence enteric CH4 emissions. Future research is still needed to further develop enteric CH4 mitigation strategies, with efforts needed in grazing systems, especially for the southeastern U.S.
8 Opportunities in enteric methane emissions mitigation in beef cattle
Authors: Place Sara E
Published: March 2024

Enteric fermentation is the largest source of methane emissions in the United States, with beef cattle representing 71 percent of total enteric methane emissions in 2021. Approximately 87% of the enteric methane produced from US beef cattle comes from animals not housed in feedlots, thus significantly opportunity lies in development and delivery of mitigation solutions to grazing situations. Mitigating methane emissions can be expressed in two ways: on an emissions intensity basis (i.e., methane per kg of beef) or in absolute terms (i.e., methane emissions from the entire beef system). Mitigation solutions that reduce absolute or total emissions consistently are currently limited or in the case of higher concentrate diets in finishing cattle, already widely used. Genetic selection is a promising solution to mitigate enteric methane emissions; however, standardization of phenotype collection is required, as methane emissions estimates can be influenced by a wide array of measurement errors and methodological choices by investigators. Economically viable, practical, and scalable solutions are needed. Researchers and extension professionals should provide objective guidance to cattle producers and others in the cattle industry on the costs and benefits of the variety of potential enteric methane mitigation solutions.
126 Effects of Tall Fescue Seeds and Quercetin on the Meat Quality of Finishing Lambs
Authors: Wang Yongjie , Ge Jing , Shelby Sarah , Huang Yan , Morse Palika
Published: March 2024

Tall fescue is a major cool-season grass for grazing livestock in North America. However, it is typically infected with endophyte fungus, and the intake of the infected tall fescue was toxic to ruminant animals. Quercetin is one of the natural flavonoids that could increase the anti-inflammatory and antioxidant capacity of an animal. This experiment aims to investigate the effects of infected tall fescue seeds on the carcass characteristics and meat quality of finishing lambs, and also to determine the mitigation effect of quercetin on the toxicity of tall fescue seeds. A total number of 24 lambs were randomly assigned to four groups: 1) Control group (C, n = 6), tall fescue seed group (E+Q-, n = 6, feed with tall fescue seed infected with alkaloid endophyte), tall fescue seed, and quercetin group (E+Q+, n = 6, feed with tall fescue seed infected with alkaloid endophyte), and quercetin group (E-Q+, n = 6, feed with quercetin). All the groups were fed ad libitum for 42 d. The longissimus dorsi muscle of each lamb was collected to analyze the meat quality parameters. The results show that the tall fescue seed decreased the final body weight and the hot carcass weight of finishing lambs (P < 0.05). Intake of tall fescue seed with quercetin increased the meat color parameters (L*, a*, b*, C, and h) significantly (P < 0.05). The tall fescue decreased the intramuscular fat content in the longissimus dorsi muscle and also modulated the fatty acids composition (P < 0.05). In conclusion, infected tall fescue negatively affected the carcass characteristics and intramuscular fat deposition of finishing lambs. However, the quercetin didn’t mitigate the influence of tall fescue seeds on carcass characteristics but increased the meat color characteristics.
125 Relationship of electrical conductivity to color variables (chroma, hue, L*, a*, b*) of fresh beef loins
Authors: Mesquita Carolina S , Richardson Reed , Kerth Christopher , Sudhakaran Pratheesh
Published: March 2024

Appraisal of beef color and overall quality assessment by consumers may be variable. In this study, Prime Grade beef strip loins were used to determine if electrical conductivity measurements (ECM) are correlated with color variables (chroma, hue, L*, a*, and b*) and could be used to improve color quality assessment and evaluation. An experimental design consisting of 6 full strip loins x 6 steaks per loin x 2 locations per steak was used and provided 72 total observations for analysis. Electrical conductivity measurements (ECM) procedures developed in our lab consisted of using emulsified meat samples concealed in silicon vessel connected to copper electrodes leading to a digital multimeter. ECM was measured in microsiemens (µS) over 60 sec with a sampling rate of 2/sec. Color variables were measured using a Varian Cary 50 Series Spectrophotometer following procedures of AMSA to ensure standardization. Data were analyzed using ANOVA and Pearson correlation coefficients. ECM means in microsiemens (µS) were 14.37, 42.52, 34.86, 22.89, 16.05, and 24.70 for the six groups of fresh steaks and were not different (P > 0.05). However, ECM values for cooked steaks differed (P < 0.05). Mean values for chroma, hue, L*, a*, and b* were different (P < 0.05) across fresh loin steaks. Correlations of ECM to all five of the color variables were different and negative (P < 0.05): chroma -0.013, hue -0.050, L* -0.009, a *-0.031, b* -0.110. These data show that ECM provide another analytical procedure that may be used in evaluating the color of fresh beef loins, and in the overall assessment and evaluation of beef products.
169 Hemp as a forage crop: Harvest date effects on yield and nutritive value
Authors: Podder Swarup , Fike John H , Wilson Bain
Published: March 2024

Hemp (Cannabis sativaL.) has been a valuable species for humans throughout history due to its adaptability and diverse uses. Farmers are interested in hemp as a forage and feedstuff due to its unique nutritional properties and rapid summer production. This study examined yield and nutritive value of three hemp cultivars, ‘Grandi’, ‘Joey’, and ‘EcoFibre’ as potential forage crops when harvested at weekly intervals in Blacksburg, VA, USA, during 2021 and 2022. The greatest biomass and TDN yield across all cultivars were 3.17 Mg ha-1 and 2.08 Mg ha-1, respectively, at 2 mo after establishment in 2021. However, biomass and TDN yield were 1.9 Mg ha-1 and 1.03 Mg ha-1, respectively at 2 mo after establishment in 2022. The nutritive value in hemp plant biomass harvested at different times varied by cultivar and harvest time (P < 0.05). Depending on cultivar and harvest time, hemp plant biomass contained 13 to 32% CP, 22 to 45% NDF, 20 to 38% ADF, 4 to 9% lignin, and 52 to 80% TDN (cultivar × time interaction; P < 0.05). Hemp CP and TDN decreased gradually with maturation while ADF, NDF, and lignin increased; however, this decline with maturity did not appear as severe as occurs with many other forages. These preliminary results suggest that hemp has the potential to be used as a forage crop. More research is needed to address hemp management and utilization, including field establishment and production, harvest timing for optimum tonnage and forage quality, and animal intake and performance studies.
164 Effect of distillers grains supplementation and fertilization rate on performance of stocker cattle grazing wheat pasture and stand performance
Authors: Gruber Cody , Johnson Michelle , Hess Tom , Rivera Daniel , Mitchell James , Gadberry Shane
Published: March 2024

Within this study, the objectives were to determine how varied Nitrogen (N) fertilization rates and inclusion of dried distiller’s grains plus solubles (DDGS) impacted stocker and wheat stand performance within a no-till (NT) production system. A total of twenty-four 1.62-ha pastures were split between 3 unsupplemented treatments with urea spread at fixed rates of 50.44, 67.25, 84.06 kg N/ha in autumn and again in spring along with an additional 6 pastures fertilized with 50.44 kg N/ha each growing season plus supplemented with DDGS. From fall of 2021 to Spring of 2023, 576 beef steers (286.62 ± 36.67 kg) were randomly allocated at fixed stocking rates of 2.47 steers/ha (4 steers/pasture) in the fall, and 4.94 steers/ha (8 steers/pasture) in the spring. Steers were weighed upon arrival, at turnout, every 28 d, and when pulled off pasture. Steers were pulled off pasture when forage mass (FM) became insufficient, temperatures became too cold to support regrowth, or forage entered reproductive phase. Sampling dates to determine forage mass and quality coincided with weigh dates, where 20 plate meter readings were taken in every field and were recorded with a 0.25m2 plate meter, and 0.25m2 grass clippings were obtained from 15 fields every sampling date to estimate FM. Pairwise comparisons using the Mixed Model procedure in JMP were used to analyze data, with N rates with and without supplementation as a single fixed categorical variable, and year modeled as a random effect. In the fall, supplemented pastures produced greater ADG than 67.25 and 84.06 kg N/ha pastures (P < 0.05), along with greater total costs of supplemented pastures compared with all unsupplemented treatments (P < 0.0001). In the spring, supplemented pastures produced greater end weights, gain per hectare, forage mass and ADG than all unsupplemented treatments (P < 0.0001), and supplementation provided more grazing days (P < 0.05). While total sale income for supplemented pastures were greater than all unsupplemented treatments (P < 0.05), total costs of supplemented pastures were all increased (P < 0.0001), resulting in less income after variable costs (P < 0.0002). Response changes to supplementation were more pronounced than responses to increased fertilization. In conclusion, these results indicate that DDGS supplementation provided greater performance benefits to stocker cattle grazing wheat pasture than increased N fertilization rate, but the added costs associated with feeding resulted in lower profitability. However, the addition of DDGS supplementation may provide an opportunity to increase stocking rates to potentially improve profitability.
167 Use of plant growth-promoting rhizobacteria in bermudagrass systems of the Southeast US
Authors: Mirahki Isaac , Crabtree Jennifer , Neto Jose D Pereira , Smith Brandon , Adesemoye Tony , Mullenix M Kim , Dillard Sandra L
Published: March 2024

Since the discovery of plant growth-promoting rhizobacteria (PGPR) in the mid-20th century, efforts have focused on utilizing them to reduce synthetic fertilizer usage and to improve the sustainability of agricultural systems. However, research in forage systems is lacking. The objective of the current study was to determine the use of PGPR in bermudagrass (Cynodon dactylon) forage systems in Central Alabama. The study was designed as a split plot and conducted at the E.V. Smith Research and Extension Center (Shorter, AL) and compared four levels of PGPR and five levels of nitrogen fertility rates. The PGPR included a negative control, Paenibacillus riograndensis DH44, Bacillus subtilis DH267, and UrtrishaN (Corteva Agriscience, Indianapolis, IN) were allocated to main plots. The strains of DH44 and DH267 were sprayed during each application at a population of 1-5 × 108 cfu/mL while UtrishaN (Corteva) was sprayed at a population of 3×107 cfu/mL with an activator at the rate of 0.25% vol/vol according to the manufacturer’s recommendations. The nitrogen fertilizer treatments were the subplot and were 25 and 50% of the recommended nitrogen for bermudagrass. The N treatments were as follows: negative control, 25% urea, 25% ammonium sulfate, 50% urea (F4), and 50% ammonium sulfate. Plots were treated with PGPR and N fertilizer starting on 11 May 2023. The forage harvest operation was conducted with at least 4 wk intervals depending on precipitation. After one year of the study, PGPR did not have any significant effect on forage biomass (1,209 kg /ha; P = 0.58). There was also no effect of N fertilizer (1,596 kg/ha; P = 0.35) or PGPR × N fertilizer interaction on forage biomass (1,408 kg/ha; P = 0.56). The lack of differences between positive and negative control plots indicates that growing conditions (i.e., lack of timely rainfall) during the first year of the study limited forage production for all treatments. The results from future years of this study will provide a more accurate conclusion on the use of PGPR with and without N fertilizer for bermudagrass systems.
163 Growth trends in Bos grunniens raised in pasture-based systems in Eastern Kentucky
Authors: Lee Amanda L , Lehmkuhler Jeffrey W , McCarty Mary , Dike Gregory
Published: March 2024

Bos grunniens (yak) are well-adapted to the rugged, high-altitude regions of central Asia where they are utilized for a variety of purposes. While the species is well-researched in its native land, limited research has been conducted in North America. The objective of this on-farm project was to evaluate performance of male and female growing yaks in pasture-based systems over two years. Grazing periods were 138 and 151 d for Yr 1 and Yr 2, respectively. The same plots were grazed both years, and pasture areas were approximately 0.49 ha each with three animals grazing each pasture in Yr 1 and two animals grazing each pasture in Yr 2. Pastures were comprised mostly of cool-season grasses with intermittent legumes and weeds. Yaks were assigned to one of four pastures based on sex with a total of six males (beginning weight 132.8 ± 13.5 kg) and six females (beginning weight 124.3 ± 34.4 kg) being grazed in Yr 1, and four males (beginning weight 157.3 ± 15.0 kg) and four females (beginning weight 160.9 ± 26.4 kg) being grazed in Yr 2. Animals in Yr 1 averaged 432 d of age, and animals in Yr 2 averaged 710 d of age at the start of the respective grazing periods. Pasture samples were collected throughout the study to assess nutritive value; botanical composition, presence of endophyte and concentration of ergovaline were also assessed. Tall fescue (Festuca arundinacea) samples collected at the end of the grazing period in Yr 2 averaged 32.65% infection and 146 ppb ergovaline. Data were analyzed using proc mixed procedure of SAS with sex and year as main effects and pasture as a random effect where α = 0.05. In Yr 1, males gained at a greater rate than females (0.45 kg/d vs. 0.23 kg/d; P = 0.0026). In Yr 2, a similar difference was observed for seasonal gains with males gaining 0.61 kg/d and females gaining 0.25 kg/d (P = 0.0003). A difference was also observed between growth rates of males in Yr 1 compared with males in Yr 2 (0.45 kg/d vs. 0.61 kg/d; P = 0.0024), but this difference was not observed in females. Gender can impact body weight gain in Bos grunniens raised in pasture-based systems with males gaining more rapidly than females.
160 Comparison of native to introduced mixed warm-season grass pastures on heifer weight gain and fecal egg count
Authors: Moss Nate T , Wray Eva M , Tucker Chris , Gadberry Shane
Published: March 2024

The objective of this study was to compare summer body weight gain and fecal egg count change of spring weaned heifers grazing either native grass (NG; predominately big bluestem [Andropogon gerardii)) or mixed warm-season grass (MWS; predominately bermudagrass (Cynodon dactylon) and crabgrass (Digitaria sanguinalis)]. Pastures (n = 3 per treatment and 2.02 ha each) were continuously stocked with 10 heifers each in yr 1 and 2, respectively. All pastures received 56 kg/ha N mid-May. Grazing began at the end of May and all pastures were grazed for 84 d. Heifers were previously treated with an anthelmintic at weaning (benzimidazole in yr 1 and macrocyclic lactone plus benzimidazole in yr 2). Dependent responses were analyzed for the fixed effect of treatment, year, and their interaction and random effect of pasture. Pasture was the experimental unit. Fecal egg counts as eggs per gram were transformed to a log base 10 value (log10:epg). Average daily gain differed between treatments by year (P = 0.05). In yr 1, NG gained 0.22 kg/d more than MWS; whereas, in yr 2, NG gained 0.11 kg/d more than MWS. Heifers grazing NG were 15.9 ± 3.52 kg heavier than MWS by d 84 (P = 0.01). Change in fecal egg count differed by year (P < 0.001) and tended to be less for NG compared with MWS (P = 0.11). Native grass fecal egg count change was 45% of MWS. Impact of forage system on internal parasite load may be attributed to canopy structure. Native grasses averaged 67 and 81 ± 2.3 cm at the beginning of grazing in yr 1 and 2, respectively (P = 0.01). Native grass height in yr 1 and yr 2 was similar (P = 0.68) by wk 12 and averaged 41 ± 3.2 cm. By comparison, grazing in the MWS system would be much closer to the soil surface. Initial forage mass and forage mass change was greater in NG than MWS and differed by year (treatment × year P = 0.02 and 0.05, respectively). While this study demonstrated beneficial responses to grazing NG over MWS during summer months, further information regarding how these summer forage options compare under varied stocking rate and grazing duration is warranted.
132 Effects of supplementing corn silage to fall-calving cows grazing tall fescue on cow and calf performance and physiology
Authors: Banks James , Warner Jason , Fike Karol E , Farney Jaymelynn K
Published: March 2024

The objective was to test the effect of fescue varieties and supplemental feeding of cows grazing fescue pastures during the growing season on cow and calf performance and physiology. Multiparous and primiparous Angus crossbred cows (n= 45) averaging 151 ± 7 d of gestation at trial initiation, were stratified and assigned to pasture treatment based on estimated calving date and parity. Treatment design was a 2 x 2 factorial with two types of fescue pasture (toxin producing or non-toxin producing) and two levels of supplemental corn silage (non-supplemented or supplemented at 1% of BW DM basis). Each treatment replicate (pasture, n = 3 or 4 pastures per treatment) was stocked with 3 cows. There were seven replicates of non-toxin-producing fescue (5 ppm ± 2.50 SEM ergot alkaloids; 38.6% endophyte infection), and eight replicates of toxin producing K31 fescue pastures (507 ppm ± 0.82 SEM ergot alkaloids; 92.5% endophyte infection). Cows were fed corn silage (38% DM, 7.83% CP DM basis) daily in fenceline bunks and feeding amount was adjusted at weigh dates to maintain 1% of BW DM basis. Cows were weighed on two consecutive days at initiation and upon conclusion of the study after being fed similar diets for 4 d to minimize variation in ruminal fill. Body weight (BW), body condition score (BCS), hair score (HS), hair length (HL), and rump fat (RF) measurements were taken at initiation (the middle of the second trimester), trial mid-point (beginning of third trimester), and approximately 2 wk before estimated parturition. Cows remained on experimental pastures through parturition. Data were analyzed as a mixed model with pasture as experimental unit and cows within pasture as subsamples. Initial cow BW and BCS were 558 ± 11 kg (SEM), and 4.9 ± 0.08 (SEM), respectively. For all measures of interest there were no significant interactions observed (P > 0.16). Supplemental feeding tended (P = 0.07) to increase BW gain and rump fat (P = 0.05) regardless of fescue type. Cows grazing toxic fescue tended (P = 0.12) to have a longer hair coat. Likewise, cows grazing toxic fescue had less change in overall HS (P = 0.02). Supplemental feeding of corn silage to cows at 1% of BW DM basis while grazing fescue did not significantly affect gain differences or reduce visible symptoms typical of fescue toxicosis when grazing during the growing season.
133 Effects of supplementing corn silage to fall-calving heifers and cows grazing bermudagrass on cow and calf performance and physiology
Authors: Banks James , Warner Jason , Fike Karol E , Farney Jaymelynn K
Published: March 2024

The objective was to test the effect of supplemental feeding of corn silage to cows grazing bermudagrass pastures on cow and calf performance and physiology. In a completely randomized design, multiparous and primiparous Angus-crossbred cows (n = 24) grazed bermudagrass pastures assigned to one of two levels of supplemental feeding (non-supplemented or supplemented at 1% of BW on a DM basis of corn silage) during the growing season. Each replicate (pasture, n = 4 per treatment) was stocked with 3 cows. Cows averaged 155 ± 14 d of gestation at trial initiation. Cows were fed corn silage (38% DM, 7.83% CP DM basis) daily in fenceline bunks, and supplementation rate was adjusted throughout the trial to maintain 1% of BW. Cows were weighed on two consecutive days at both initiation and conclusion of the trial and cows were maintained on similar diets for 4 d prior to collecting weights to minimize variation in ruminal fill. Body weight (BW), body condition score (BCS), hair score (HS), hair length (HL), and rump fat (RF) measurements were collected at initiation (the middle of the second trimester), trial mid-point (beginning of third trimester), and approximately 2 wk before estimated parturition. Cows were removed from experimental pastures upon trial conclusion and relocated to calving pastures consisting of tame grasses (>65% bermudagrass). Data were analyzed as a mixed model with pasture as experimental unit and cows within pasture as subsamples. Cows began the trial at an average BW of 549 ± 22 kg (SEM) and an average BCS of 5.2 ± 0.17 (SEM). Supplementation of second and third trimester pregnant cows on bermudagrass did not influence BW gain, BCS, HS, or HL (P > 0.27). Rump fat tended (P = 0.15) to be increased with supplemental feeding. Supplemental feeding of corn silage on warm season perennial grass during the growing season did not appear to impact late gestation cow performance at the level fed in this study.
135 Effects of intratesticular injectable zinc as an alternative castration method compared to banding one week post weaning in beef bulls: effects on health, inflammation, behavior, and growth during the backgrounding period
Authors: Solice Lauren K , Sims Reagan N , Kegley Beth B , Gadberry Shane , Powell Jeremy G , Dridi Sami , Greene Elizabeth S
Published: March 2024

Castration is a widely practiced management strategy that results in temporary pain with adverse effects on growth performance. Therefore, humane alternatives must be investigated. Male beef calves (n = 81) were stratified by weaning weight and allocated to 1 of 8 pens. Pens were assigned randomly to treatment: 1) banded (B; n = 42) or 2) a 1 mL intratesticular Zn (100 mg Zn) injection (Z; n = 39). Two pens from each treatment were selected for blood collection (B, n = 22; Z, n = 19); the alternative pens were assigned to behavior measurements (5 calves/pen; B, n = 10; Z, n = 10). Behavior data were collected for 1 wk post-castration using accelerometers (HOBOware Lite software). Blood was collected daily on d 0 through d 7 post-castration, and every 28 d for the remainder of the backgrounding phase for complete blood cell counts, serum haptoglobin (Hp), and serum testosterone. Testicular width and BW were also measured. All blood and growth parameters were analyzed using the MIXED procedures of SAS while GLIMMIX was used for behavioral analysis. Body weights did not differ due to treatment throughout the 140-d backgrounding phase (P ≥ 0.39). Overall ADG was greater for Z calves compared with B calves (P = 0.05). Serum testosterone concentrations were greater in Z calves compared with B calves throughout the 140-d trial (P ≤ 0.02). Testicular width in Z calves peaked numerically on d 3 and declined to baseline measurements by d 113 (P = 0.67). Intratesticular Zn castrated calves spent more time lying flat on their side compared with B calves 1 d post-castration (P = 0.03) until d 3 and 4 where B calves spent more time lying on their side compared with Z calves (P ≤ 0.02). Banded calves spent more time standing the first 2 d post-castration compared with Z calves (P ≤ 0.01). On d 3, 4, 5, and 6, Z calves spent more time standing (P ≤ 0.01) while B calves spent more time laying on their sternum (P ≤ 0.03). Banded calves had decreased Hp concentrations on d 1, 2, 3, 7, and 28 compared with Z calves (P ≤ 0.01). Total white blood cell concentrations, both proportion and concentration of neutrophils, and proportion of lymphocytes were greater in Z calves compared with B calves on d 1, 2, and 3 (P ≤ 0.01). Although growth performance was not hindered by the Zn intratesticular injection castration method, it did cause behaviors indicative of pain and resulted in an acute inflammatory and immune response compared with banded calves. Therefore, castrating with an intratesticular injection of Zn may not be a sufficient alternative to conventional methods.
139 Impact of supplementing rumen-protected methionine during the periconceptional period in the post-weaning period in female calves
Authors: Heredia Daniella C , Tarnonsky Federico , Lopez-Duarte Maria C , Venturini Mauro , Ojeda Oscar A , Luchini Daniel D , Hansen Peter J , Pringle Dean , DiLorenzo Nicolas , Gonella-Diaza Angela M
Published: March 2024

This study aimed to identify the impact of supplementing rumen-protected methionine (RPM) during the periconceptional period on beef cows in their progeny. Evidence suggests that changes in maternal nutrition in the periconceptional period have effects during the postnatal growth phase in cattle. We hypothesized that feeding RPM during the periconceptional period would program bovine gestation to enhance progeny growth. A total of 114 beef cows were fed a roughage-based diet and randomized to receive corn gluten supplemented with 15 g of RPM (Smartamine M, Adisseo) or not (CON) from d -7 to +7 relative to artificial insemination (AI) with female sex-sorted semen. Pregnancy diagnoses were conducted using transrectal ultrasonography 30 and 60 d after AI. Female calves (n = 34) remained with their dams until weaning. A month after weaning, calves were weighed every 14 d during an 8-mo period, and wither height (WH), body length (BL), and heart girth (HG) were measured. Dry matter intake (DMI), average daily gain (ADG), and residual feed intake (RFI) were measured during a 56-d performance test. At the end of the performance test, the 12th rib back fat (BF), ribeye area (REA), intramuscular fat (IMF), and rump fat (RF) were determined via ultrasound. A treatment-by-day interaction tendency (P = 0.10) was observed in HG, having larger HG in the RPM treatment from d 336-adj of age (CON = 154.52 ± 1.46 cm; RPM = 158.36 ± 1.34 cm). During the performance test, animals in the RPM treatment were heavier (CON = 437.25 ± 2.46 kg; RPM = 442.79 ± 2.34 kg; P = 0.01) at the end of the test. However, no treatment difference (P > 0.05) was observed in DMI (CON = 12.06 ± 0.19 kg/d; RPM = 12.14 ± 0.18 kg/d), ADG (CON = 1.50 ± 0.03 kg; RPM = 1.55 ± 0.03 kg) and RFI (CON = -0.12 ± 0.15; RPM = 0.11 ± 0.14). No treatment difference (P > 0.05) was observed in BF, REA, and IMF. However, RF was greater in the control treatment (CON = 1.16 ± 0.07 cm; RPM = 0.91 ± 0.06 cm), and a tendency of having a thicker BF in control was observed (Table 1). In conclusion, supplementing RPM enhanced final body weight during the performance test; furthermore, a treatment-by-day interaction tendency was observed in HG. On the contrary, CON progeny had more RF and a tendency to have a thicker BF.
140 High-resolution characterization of the gut microbiota of neonatal dairy calves using full-length 16S rRNA gene amplicon sequencing
Authors: Hawkins Jalyn G , Carpenter Shelby , Woody Mackenzie , Hardin Colby , Brett Jim , McGee Marcus , Smith Trent , Fan Peixin
Published: March 2024

The gut microbiota has a crucial role in preventing pathogen colonization and training the immune system. An imbalanced gut microbiota tends to induce calf diarrhea, which can lead to dehydration and metabolic acidosis. Therefore, it is urgent to identify critical factors that influence the establishment of gut microbiota in the early stages of development in dairy calves. Most previous research relied on short-read-based partial 16S rRNA gene amplicon sequencing to study calf microbiota, which has limited taxonomic resolution. The aim of our study is to obtain a species-level characterization of calf gut microbiota using long-read based full-length 16S rRNA gene amplicon sequencing and investigate the factors that affect the gut microbiota composition in the early stages of development in dairy calves. We collected fecal samples from the recto-anal junction of 25 Holstein-Angus crossed calves at d 4 and d 14 after birth. The calves were raised in individual outdoor hutches from birth and fed milk replacer twice daily. The gut microbiota was analyzed using full-length 16S rRNA gene amplicon sequencing on an Oxford Nanopore sequencer. The results revealed that the gut microbial diversity measured by Chao 1 (P < 0.001) and Shannon index (P < 0.001) significantly increased from d 4 to d 14. We identified 15 and 36 core bacterial species (prevalence ≥ 80%) in d 4 and d 14 gut microbiota, respectively, and both stages share 7 bacterial species: Bacteroides fragilis, Butyricicoccus pulicaecorum, Enterocloster bolteae, Escherichia coli, Lachnoclostridium sp YL32, Rumiococcus gnavus and Streptococcus equinus. The calf gut microbiota was dominated by Bacteroides fragilis (18%), Escherichia coli (13%), Ruminococcus gnavus (10%) and Butyricicoccus pulicaecorum (6%) species on d 4, and Megamonas rupellensis (18%) and Fusobacterium varium (6%) species (relative abundance > 5%) on d 14. Notably, we found a significant impact of hutch location on the composition of gut microbiota, particularly on d 4, but the impact was reduced on d 14. Moreover, there were 4 dystocia calves among the 25 calves, which had a significantly lower Shannon index (P = 0.046) compared with 4 paired normal calves of similar age and sex, and location balanced. In conclusion, this study provides a species-level resolution of gut microbiota for neonatal dairy calves and indicates a potential impact of dystocia on early microbiota development. Additionally, calf microbiota composition is influenced by environmental factors, likely the soil microbiota where hutches were located, with a more substantial effect on the microbiota at an earlier age.
147 Effects of grazing dairy-beef and native beef crossbred steers on native range with supplementation on growth
Authors: Grote Ally J , Grigsby Zane N , Fanning Tom , Turner Dusty , Beck Paul A
Published: March 2024

Our objective was to evaluate the effects of grazing dairy-beef crossbred and native beef crossbred steers on native range with supplementation on growth. Dairy-beef (DB) steers (n = 75) were acquired and transported 214 km from Buffalo Feeders at Buffalo, OK. Native beef (NB) steers (n = 75) were acquired and transported 647 km from Capitol Land and Livestock at Schwertner, TX. All steers were transported to the Marvin Klemme Range Research Station in Bessie, OK. Steers were rested for 48 h and received ad libtum access to mixed grass hay and water. Steers were allocated by BW and randomly assigned to pasture based on a stocking rate of 2.43 ha/animal. Animals grazed 3 native pastures (pasture 1; n = 39, pasture 2; n = 52, pasture 3; n = 59), and pastures were balanced for breed type (pasture 1; DB = 21; NB = 18, pasture 2; BD = 26; NB = 26, pasture 3; DB = 28; NB = 31). Steers were supplemented with extruded 100% DDGS cubes (MasterHand Milling, Lexington, NE) at 0.45 kg per animal per day for the first 53 d. As forage maturity increased and 53-d body weights (BW) were taken, supplementation increased to 1.13 kg per animal per day. Initial BW was 8 ± 3 kg greater (P = 0.01) in DB steers than the NB steers. Native beef steers weighed 16 ± 4 kg heavier (P < 0.01) on d 60 and weighed 24 ± 5 kg heavier (P < 0.01) at final BW than the DB steers. Average daily gain for NB steers was greater (P < 0.01) by 0.46 ± 0.04 kg in the first 53 d and was greater (P = 0.01) by 0.11 ± 0.04 kg for d 53 to 145 than DB. Native beef steers also had a greater (P < 0.01) overall ADG by 0.22 ± 0.02 kg. There were no differences (P = 0.55) in breed for those treated and re-retreated for issues such as pinkeye, foot rot, and BRD. Based on these results, breed of cattle grazing native rangeland in Southwestern Oklahoma with supplementation had an impact on performance, but no impact on treatment of respiratory and non-respiratory issues.