bluuebunny/crossref_metadata_2025 huggingface dataset:
95 Temporal patterns of enteric gas production from cattle in response to ruminal infusions of synthetic bromoform
Authors: Muizelaar Wouter , Nichols Kelly , Taweel Hassan Z , van Laar Harmen , Dijkstra Jan , Martín-Tereso Javier
Published: September 2024

This dataset describes the temporal patterns of enteric gas production from cattle in response to ruminal infusions of synthetic bromoform (CHBr3). Four non-lactating, non-pregnant, rumen-fistulated Holstein-Friesian cows (12 yr of age, 781 ± 33 kg body weight) were infused via the rumen fistula with 592 mg CHBr3/d in an aqueous solution for 14 d. The daily dose was divided into 3 equal portions and infused every 8 h over a 24-h period (0545, 1345, and 2145 h). The 7 d following the infusion period served as a recovery period to describe the dynamics of enteric gas production after cessation of infusion. The Greenfeed system was used for enteric gas measurements. Animals had ad libitum access to grass hay and were supplemented with concentrate through the Greenfeed system for the infusion and recovery periods and for the 14-d adaptation period before the infusions. A two-way ANOVA was performed with phase (pre- and post-infusion) as fixed effect and animal as random effect to assess average differences. Preliminary results show a decrease in methane (CH4) production from on average 371 g/d before the infusions to 5 g/d after 14 d of infusions (P < 0.01). Hydrogen (H2) production increased from on average 0.6 g/d before the infusions to 9.0 g/d after 14 d of infusions (P < 0.01). Dry matter intake (DMI) decreased to on average 12.8 kg/d after 14 d of infusions compared with 16.9 kg/d before the infusions (P < 0.01). A four-parameter logistic model was fitted for the response of CH4 (CH4-inf) and H2 (H2-inf) production in the 14 d after the first infusion, and separately for the response of CH4 (CH4-rec) and H2 (H2-rec) production in the 7 d after the last infusion (Table 1). Preliminary results indicate a 95% decrease in CH4-inf from the A-asymptote (small values of x) is reached after approximately 63 h, and a 95% increase in H2-inf from the B-asymptote (large values of x) is reached after approximately 49 h. After the last infusion, the 95% increase in CH4-rec from the B-asymptote is reached after approximately 109 h, and the 95% decrease in H2-rec from the A-asymptote is reached after approximately 112 h. When comparing the respective inflection points (xmid), the recovery of CH4 production took approximately 3 times longer than the decrease. In addition, after 7 d of recovery, CH4 production did not return to the initial levels before the infusion began. The reduced DMI can partially explain this difference in CH4 recovery; however, other factors cannot be excluded. In conclusion, our data suggest that ruminal infusion of 592 mg CHBr3/d for 14 d reduces CH4 production by >95% and the recovery of CH4 production to pre-infusion levels might take longer than 7 d.
96 Using greenhouse gas flux to estimate forage dry matter intake in ad libitum fed replacement heifers
Authors: Briggs Emma A , Foote Andrew P , Beck Paul A , Reuter Ryan R , Rolf Megan M , Lalman David L
Published: September 2024

An accurate estimate of feed intake is a critical component in determining individual animal feed efficiency. However, existing feed intake measurement systems are not designed for unprocessed, dry forage diets. Open-circuit gas flux technology measures enteric gas emissions for cattle in a pasture-based setting. If a significant relationship exists between feed intake and gas emissions, this system could be used to rank grazing cattle for forage intake and forage utilization efficiency. Our objective was to develop prediction equations to estimate forage dry matter intake using gas flux and performance data. Angus and Angus x Hereford heifers [n = 71; initial body weight (BW) 329.5 ± 31.1 kg] were used over 3 yr to measure intake, gain, and gas flux. All heifers were subject to a 21-d adaptation and 71-d intake test using individual intake technology (SmartFeed; C-Lock Rapid City, SD) with a stocking rate of 3.3 heifers per feeder. Throughout the study, heifers were fed a long-stem, unprocessed, grass hay diet (≥ 10.8% CP, 2.0 Mcal ME, and 56% TDN) with ad libitum access to a salt/mineral supplement. The GreenFeed system (C-Lock Rapid City, SD) was used to monitor oxygen (O2) consumption (means ± SD; 3364.4 ± 374.8 g/d), methane (CH4; 181.4 ± 24.3 g/d) and carbon dioxide (CO2) production (4,965.3 ± 494.5 g/d). Body weights were collected every 14 d, and average daily gain (ADG) was calculated by regressing BW on day of study. The phenotypic correlations of forage DMI with CO2, CH4, O2, and heat production (HP) were 0.72, 0.66, 0.74, and 0.74, respectively. Average daily gain and midpoint metabolic BW combined with the estimate of daily HP, O2, or CO2 accounted for 60% of the variation in forage DMI. These results suggest that forage intake can be predicted using performance data in conjunction with the GreenFeed gas quantification system.
131 Effects of biochar type and inclusion level on in vitro gas production dynamics
Authors: Adams Jordan M , Gonzalez Daisy , Lee Eunsung , Brady Jeff A , Tedeschi Luis O
Published: September 2024

Biochar has been studied as a soil amendment for the storage of stable carbon in the soil, contributing to carbon capture and mitigation of greenhouse gas emissions. There may be potential for biochar use as a feed additive to reduce enteric methane (CH4) emissions from growing beef cattle, but it may be dependent on several factors, including biomass source, production methodology, biochar particle size, and several others. Thus, our objective was to determine the effects of 3 different biochars and their level of inclusion on in vitro gas production dynamics of bermudagrass (Cynodon dactylon) hay. Biochars included yellow pine wood (W, Waste to Energy Inc., Slocomb, AL), yellow pine wood modified with calcium hydroxide (CW), and dairy cattle manure (M, Ecochar, Heehugowaard, Netherlands). Air-dried bermudagrass hay with or without biochars was incubated for 48 h with fresh rumen inoculum collected from 4 ruminally cannulated steers. Biochars were investigated at 3 inclusion levels (IL; IL.5 = 0.5%, IL1 = 1.0%, and IL2 = 2.0% of DM). Four incubations were performed. Incubations were performed in an unbalanced, incomplete randomized block design as inclusion levels differed among incubations, with IL.5 only included in the first two incubations (Group1) and IL2 only included in the last two incubations (Group2), but IL1 was included in all four incubations, and it was used to scale the IL.5 and IL2 variables linearly. Enumeration of CH4 production was performed for all samples. Statistical analyses were performed using PROC GLIMMIX of SAS version 9.4 (SAS Institute Inc., Cary, NC). Data were evaluated by group, with biochar, IL, and biochar × IL included in the model, and incubation included as a random variable. There were no effects of biochar, IL, or biochar × IL for either group on any of the fermentation dynamics (P ≥ 0.05), including total gas production, fractional rate of gas production, and lag time before initiation of gas production, for either the exponential or log 2-pool functions. Additionally, there were no differences in grams of CH4 production (P ≥ 0.12) for either group. To compare biochars at all IL, relative CH4 production was explored after adjusting values for IL1 and IL2 in the last two incubations based on the difference in CH4 produced at IL1 in the first two incubations. In terms of relative CH4 production, the M biochar produced approximately 16 and 28% less CH4 than W and CW, respectively, at IL1. Our results indicate that M biochar may allow for reduced CH4 production from beef cattle, but several factors, including biomass source, production methodology, and particle size, should be considered to understand the differences better. Ultimately, further research is warranted to evaluate biochar in greater depth as a feed additive for growing beef cattle.
128 Bromoform metabolites from Asparagopsis taxiformis: Formation and impact on in vitro rumen fermentation parameters and microbial composition dynamics
Authors: Muizelaar Wouter , Sloth Jens J , Fromberg Arvid , Brask Maike J , Bruneel Brecht , Visker Marleen H P W , Dijkstra Jan
Published: September 2024

The aim of the experiment was to study the formation and impact of bromoform metabolites from Asparagopsis taxiformis on in vitro rumen fermentation parameters and microbial composition over time. Rumen fluid from three rumen fistulated lactating Holstein-Friesian dairy cows was collected and after buffering used as inoculum. Cows were fed a total mixed ration of grass silage, corn silage and concentrate. In total 0.5 g dry matter (DM) of substrate was incubated, consisting of either 0.3 g DM grass silage and 0.2 g DM corn silage (Control) or 0.295 g DM grass silage, 0.195 g DM corn silage and 0.01 g DM A. taxiformis (ASP). Substrates were incubated for 72 h. Total gas production (TGP) was measured continuously and methane (CH4) at 0, 1, 2, 4, 8, 12, 24, 36, 48, 60 and 72 h. After 72 h, volatile fatty acids (VFA), ammonia (NH3), and pH were determined. Substrates (Table 1) and contents of additional bottles at specific timepoints were analyzed for bromoform (CHBr3), dibromomethane (CH2Br2), bromomethane (CH3Br), dibromochloromethane (CHBr2Cl), arsenic (As), bromine (Br) and iodine (I). RNA was isolated and sequenced with specific primers for bacteria, archaea and protozoa. Data were averaged per inoculum and analyzed with an ANOVA to test for differences between treatments. Preliminary results revealed no difference between Control and ASP in TGP (mL/g organic matter; OM) after 72 h (P = 0.102), whereas CH4 (mL/g OM) was 78% less in ASP than in Control (P = 0.005). Total VFA (tVFA) did not differ between Control and ASP (P = 0.435). Acetate (% tVFA) was lower in ASP (49.2 vs 56.6; P = 0.011), and branched VFA (% tVFA) greater in ASP than in Control (5.8 vs 3.8; P = 0.001). At 72 h, NH3 (mg/L) and pH did not differ between ASP and Control (P = 0.183 and 0.519, respectively). After 1 h of incubation CHBr3 concentration was 118 ng/mL, rapidly decreasing below detection limit by 8 h of incubation. At 1 h of incubation CH2Br2 concentration was 22 ng/mL, reaching 40 ng/mL at 4 h of incubation and remained relatively stable thereafter. At any timepoint, CH3Br concentration was below detection limit. At 12 h of incubation CHBr2Cl concentration was 3.7 ng/mL and remained relatively stable. Mineral concentrations (As, I, Br) were constant throughout incubation. Addition of 2% DM A. taxiformis effectively reduced CH4 production without negative effects on TGP and tVFA in vitro. While CHBr3 disappeared quickly and CH2Br2 concentration increased, substantial formation of CH3Br in hydrogenation reactions by methanogens seemed absent. Levels of Br did not change, suggesting no substantial Br vaporization through secondary metabolites. Microbial composition data are pending analyses and will be presented at the symposium.
188 Prediction of individual grazing beef cattle dry matter intake
Authors: Blake Nathan , Walker Matthew , ArunKumar K E , Mata-Padrino Domingo , Holaskova Ida , Wilson Matthew E
Published: September 2024

Estimation of individual dry matter intake (DMI) of pastured beef cattle is critical to grassland management, genetic improvement of efficiency, and increasing the sustainability of animal agriculture. Currently, the only way to measure individual DMI of grazing cattle is through expensive, labor intensive, and spatially demanding research protocol. Very few options for assessment of individual DMI of grazing animals exist for cattle producers. We have developed a machine learning approach to predicting individual DMI of pastured beef cattle that requires only body weight (BW), water intake, and open-source climate variables. Training data were collected in Wardensville, WV at the West Virginia University Research, Outreach, and Education Center. Crossbred steers (n = 32) were phenotyped for Residual Feed Intake (RFI) in the barn. Animals were split into four groups of two low RFI and two high RFI. After a grazing acclimation period, animal groups were rotationally grazed concurrently through 0.05 ha plots for 7 d. Daily BW and water intake data were collected throughout the experiment using an RFID-equipped front-end scale and metered waterers. Beginning on d 2, animals were provided a bolus of Cr2O3 (10 g) at 0700 and 1900 h. Beginning on d 5, fecal samples were collected from each animal at 0700 and 1900 h. Samples were analyzed for Cr2O3 content and used in conjunction with forage digestibility from paired clipped samples to generate individual intakes. These data were used as ground truth data to assess model performance. We used our Repeated Measures Random Forest (RMRF) model to predict individual DMI of animals using daily BW, water intake, and climate variables. Intakes estimated by RMRF were compared with intakes estimated by NASEM equations. Our model outperformed NASEM predictions by 70%, indicating that our method achieves better results than the current most efficient approach. Though iterative model improvements will be made (collection of more training data, collection of more diverse training data, and use of first-differenced, moving average, and seasonally adjusted variables), our work demonstrates a novel, efficient method for researchers and producers to more accurately estimate DMI of individual pastured beef cattle.
190 Implementation of an updated beef energetics and body composition model in the Crop Livestock Enterprise Model (CLEM)
Authors: Dougherty James C H , Keogh Thomas , Liedloff Adam C , Thomas Dean T
Published: September 2024

The Crop Livestock Enterprise Model (CLEM) is a whole-farm bioeconomic model designed to simulate and explore ruminant performance across a wide range of production systems and management strategies. The model features a flexible, component-based structure that allows users to simulate multiple types of livestock production within the same system. Animals in the model are represented on an individual basis, allowing users to explore the effects of between-animal variation on a wide range of performance metrics at the animal and farm system levels. Recently, two new features were introduced to improve ability of CLEM to represent ruminant production systems: a user-defined timestep, and a new energetics model (based on the Australian ruminant feeding standards) that adds the ability to model changes in body composition in addition to existing predictions of body weight gain and feed intake. The change in timestep from monthly to daily was required to implement the new energetics model and allows for greater ability to compare CLEM results against field data, but other timesteps (e.g., weekly) can also be used depending on user preference. The Australian ruminant feeding standards were integrated with the existing CLEM modelling framework to create a revised energetics model for CLEM capable of predicting body composition, with additional updates to prediction of relative feed intake and the effect of diet type on feed quality. The energetics model was then evaluated for prediction of feed intake (DMI), final empty body weight (EBW), and fat and protein gain (Table 1) in feedlot cattle. The evaluation dataset consisted of treatment means (n = 29) from studies of Angus or British cross steers whose body composition (fat and protein) had been measured by serial slaughter. The updated model performed well for predicting final EBW, underpredicting by 2.35 kg on average (0.55% of the observed mean). Dry matter intake was underpredicted for 80% of treatments, with mean bias averaging 1.7 kg/d across all treatments and a root mean square prediction error (RMSPE, % of the observed mean) of 25%. Data on fat and protein gain was more variable than for EBW, and the model overpredicted protein gain and underpredicted fat gain in general, with mean bias of -51 g/d (RMSPE 42%) for protein and 270 g/d (RMSPE 58%) for fat. The addition of a daily timestep and a revised energetics model add to utility of CLEM by allowing for more in-depth exploration of the effects of feeding and management over time on intake, body weight gain, and body composition. The current version of CLEM can be downloaded from the APSIM Initiative website; and an upcoming update with additional options for prediction of intake and performance for both feedlot and grazing cattle will be made available.
251 Effect of diets containing soybean co-products formulated for developing heifers on reproductive efficiency
Authors: Midkiff Kirsten A , Kegley Elizabeth B , Cheek Robin A , Galloway Doug L , Reynolds Jana L , Harness Alexis , Looney Charles R , Littlejohn Brittni P , Powell Jeremy G
Published: September 2024

The objectives of this study were to determine the effects of including soybean oil in supplemental diets for developing heifers on reproductive tract scores, time of puberty and cyclicity, and successful artificial insemination. Angus crossbred heifers [n = 80; body weight (BW) = 248 ± 21 kg) were sorted randomly into one of eight pastures (n = 10 heifers/pasture) and pastures were assigned randomly to one of two treatment groups (n = 4 pastures/treatment), being: 1) control group fed an isonitrogenous and isocaloric grain supplement with no soy product (CON); and 2) treated group fed grain supplemented with soybean oil at 2% of estimated total diet dry matter intake (SBO). Heifers grazed 2.4 ha mixed grass pastures and when forage was limited heifers were offered bermudagrass hay for ad libitum intake. Supplements were offered beginning approximately 30 d after weaning and continued through the breeding season. Body weights, hair coat scores, and body condition scores (BCS) were recorded monthly. When heifers weighed > 295 kg, rectal palpation was performed and an ultrasound used to determine ovary size, dominant follicle size (> 10 mm), and follicular structures on the ovary (presence or absence of corpus luteum), and the tone and diameter of the uterine horns were determined (reproductive tract score; RTS). At 7-d intervals beginning on d 56, blood samples were collected via jugular venipuncture. Samples were used to measure serum progesterone concentrations to determine the percentage of heifers pubertal and cyclic. Heifers were classified as pubertal when serum progesterone concentrations were greater than 1 ng/mL. Heifers that maintained progesterone concentrations greater than 1 ng/mL for two consecutive samples were classified as cyclic. Cyclic heifers were not sampled further. Heifers were bred by artificial insemination (AI) at approximately 14 mo of age. Statistical analyses were performed using the MIXED and GLIMMIX procedures of SAS 9.4 (Cary, NC) to assess treatment effects. Treatment had no effect on hair coat shedding scores (P = 0.87), BCS (P = 0.13), and RTS (P = 0.27). Pubertal (P = 0.39) and cyclicity (P = 0.34) status were not affected by treatment. The percentage of females pubertal and cyclic by d 147 were numerically greater for the CON treatment (89.3% vs. 90.1%) than on the SBO treatment (80.5% and 75.2%). Heifers supplemented with SBO had numerically greater AI conception compared with CON supplemented heifers (52.6% vs. 42.5 %, respectively), but were not statistically different (P = 0.38). Further research is being performed to gather additional data for AI and overall pregnancy rates, effects of soybean co-product inclusion in supplements on uterine blood flow and corpus luteum perfusion, and resulting calf performance to AI-bred females.
255 Awardee Talk: Nutritional management to optimize cow-calf production in Southeast
Authors: Izquierdo Vinicius S , Vendramini Joao M B , Moriel Philipe
Published: September 2024

Nearly one-half of beef cows in the United States are located in southern states where cow-calf operations predominate. Grazing management in cow-calf systems can be affected by environmental and seasonal conditions, often leading to nutrient deficiency, particularly during late gestation of beef females. Maternal nutrition during the last trimester of gestation can influence offspring development and health, and can be explored to optimize maternal and progeny performance. The objective of this presentation is to share nutritional and management strategies for pregnant beef cows and their long-term effects on offspring growth and physiology. Study 1 investigated the effects of timing of maternal protein supplementation during all last trimester of gestation (LATE84), only the first 42 d of last trimester of gestation (LATE42), or no prepartum supplementation (NOSUP) on offspring pre- and post-weaning performance. At weaning, LATE84 calves were the heaviest, followed by LATE42, and NOSUP (P ≤ 0.05). Steer serum parainfluenza-3 titers were greater (P = 0.03) for LATE42 vs. NOSUP and tended to be greater for LATE84 (P = 0.10) vs. NOSUP steers. Marbling and the proportion of steers grading choice were greater (P ≤ 0.04) for LATE42 vs. NOSUP, and intermediate for LATE84. Study 2 evaluated the effects of frequency of maternal protein supplementation on offspring pre-weaning growth. Cows received the same weekly amount of supplement (7 kg·cow⁻¹·wk⁻¹) but with different frequencies: once a week (1X), three times per week (3X), every day (7X), or no prepartum supplementation (NOSUP) during the last 80 d of gestation. At weaning, calves born from 7X cows were the heaviest (P ≤ 0.05), followed by 3X and 1X, which did not differ between them (P = 0.54), and NOSUP calves were the lightest (P ≤ 0.05). Study 3 evaluated the use of monensin supplementation during the last 77 d of gestation and its impacts on offspring performance. Treatments consisted of no prepartum supplementation (NOSUP), supplementation of dried distillers grains at 1 kg·cow⁻¹·d⁻¹ added with 0 (SUP) or 200 mg/d of monensin (SUPMO). At weaning, SUPMO calves were the heaviest (P ≤ 0.05), SUP intermediate, and NOSUP were the lightest. Experiment 4 consisted of pregnant heifers receiving the supplementation of 1 kg/d of soybean hulls dry matter added (BAC) or not (CON) with a Bacillus-based DFM mixture during late gestation (d 0 to 139) and early lactation (d 139 to 242). Post-weaning body weight gain and indicators of humoral immune response post-vaccination were greater for BAC vs. CON calves (P ≤ 0.05). Therefore, changing the time and frequency of supplementation, and the use of additives and probiotics during late gestation of beef females are effective alternatives to improve offspring pre- and post-weaning growth and immune response.
249 Effects of sorghum silage kernel processing on growth performance and blood metabolites of beef heifers
Authors: Podversich Federico , Abdelhadi Leandro O , Sanchez Federico , Angeli Emmanuel , Hein Gustavo J , Ortega Hugo H , DiLorenzo Nicolas
Published: September 2024

Our previous studies suggested that using a shredlage (SHRD) processor or a conventional (CONV) sorghum kernel processor leads to similar apparent total tract nutrient digestibility of whole plant sorghum silage (WPSS). This study evaluated the effects of feeding WPSS harvested using different kernel processors (CONV vs. SHRD), on growth performance of beef heifers. Grain sorghum (ADV2450IG; Advanta Seeds, Argentina) was harvested at the hard-dough stage with a Class Jaguar 950 (Harsewinkel, Germany), switching the kernel processor to generate the forage material for the two treatments: CONV and SHRD. The material was bagged in two 2.7 m diameter bags and allowed to ferment for 3 mo. Black Angus heifers [n = 96; body weight (BW) = 15 ± 1 mo, 249.6 ± 28.6 kg] were blocked by initial BW, and randomly assigned to pens (8 heifers/pen, 6 pens/treatment). Diets consisted, all in DM basis, of WPSS of each respective type (SHRD or CONV) at 90.5%, expeller soybean meal at 7.0%, and a vitamin-mineral-NNP concentrate at 2.5%. The experiment consisted of a 14-d adaptation period, followed by a 56-d growing period; and feed was offered once daily. Data were analyzed as a randomized complete block design, using pen as the experimental unit, with the fixed effect of treatment and the random effect of block. No differences were observed (P > 0.10) for final BW, dry matter intake, and residual feed intake. However, CONV fed heifers tended to gain more BW per day (ADG, 0.83 vs. 0.77 kg/d; P = 0.07) and had greater gain to feed ratio (GF, 0.083 vs. 0.075 kg/kg; P = 0.05) and greater Kleiber ratio (KR, 12.1 vs 11.2 g/kg; P = 0.05) as compared with SHRD fed heifers. Furthermore, performance calculated dietary Net Energy of gain (NEg) in CONV fed heifers tended to be greater than that for SHRD (0.70 vs. 0.65 Mcal/kg of diet DM, respectively; P = 0.06). Moreover, blood serum from CONV fed heifers had 16% greater total bilirubin (P = 0.04), 12% greater cholesterol (P = 0.02), and slightly greater non esterified fatty acids (P = 0.03) concentrations. Noteworthy, serum concentrations of total bilirubin were correlated (P ≤ 0.03) with ADG, GF, KR and NEg. In conclusion, the type of kernel processor utilized for the harvest of sorghum silage may have an impact on feed efficiency of beef cattle. These differences could be related to changes on the site of utilization of nutrients, particularly starch; what could also explain the differences on blood metabolites. However, further research is needed to help explain these findings.
245 The influence of deferment and season of use on beef cattle diet quality and composition following a rangeland wildfire
Authors: Kluth Janessa A , Davis Noah G , Wyffels Samuel , Marlow Clayton , Vermeire Lance , Van Emon Megan L , Nack Makae , Sitz Taylre , Hamilton Thomas , Peterson Jeremiah , DelCurto Timothy
Published: September 2024

Research has shown that forage quality increases after a fire. Greater crude protein content in forage can be beneficial for livestock, and even attract herbivores to recently burned areas. However, there has been little research into how forage quality changes within the first 2 yr after a fire and how it affects livestock diet quality or composition. Therefore, this project was conducted within a burn area of an August 2020 wildfire to evaluate the effect of seasonal deferment and annual rest on diet quality, botanical composition, and foraging efficiency of beef cattle grazing burned rangeland. A randomized complete block design was used comparing June grazing versus September grazing with cow/calf pairs, and no deferment versus a 1 yr deferment of grazing. Sixteen 4-hectare pastures were used, with eight being grazed in 2021 and 2022, and eight only grazed in 2022. Pastures were grazed in either June or September by cow-calf pairs for 2 d at a time. In June, 20 cow/calf pairs were used, and 16 pairs were used in September to account for calf growth/intake. Cattle diet composition and masticate samples were collected during 20-min bite-count periods using six ruminally cannulated cows in each pasture prior to and after 2 d grazing periods. Composition of diets upon pasture entry differed among treatments (P < 0.01) with June diets in greater proportions of forbs than September diets. In addition, June diets with no deferment had greater forb composition than June diets with 1 yr deferment (P < 0.01). Crude protein in June diets were substantially greater than September diets (P < 0.01) and within the June grazing period, greatest for the non-deferred treatment (P < 0.01). June diets had decreased neutral detergent fiber (NDF) concentrations than September diets (P < 0.01) and within the June grazing treatments, the first year after burning was least in NDF content (P < 0.01). There was no difference in ash concentration for all treatments and years (P ≥ 0.07) averaging 16.46% ash content. There was no effect of grazing treatment on grams per bite (P ≥ 0.34) averaging 1.36 grams per bite for pre- and post-grazing treatments. In summary, season of use and timing of grazing following a wildfire has an impact on cattle diet composition and quality with the greatest impact in the spring following a wildfire.
362 Nutrikinetic evaluation and modeling of 25-hydroxyvitamin D3 in beef cattle
Authors: Weigand Macie C , Duncan Zach M , Schwandt Erin , Ellis William , Weir Colton , Levy April , Gott Paige , Martinez Stephanie E , Tarpoff Anthony J , Blasi Dale A
Published: September 2024

The objective of this study was to evaluate serum 25-hydroxyvitamin D3 [25(OH)D3] status in beef cattle when 1) fed diets with supplemental 25(OH)D3 or calcidiol (HyD, dsm-firmenich, Plainsboro, NJ), and 2.) a single dose of calcidiol was administered to cannulated heifers on nutrikinetic evaluation and predictive modeling simulations. In experiment 1, crossbred heifer calves [n = 96, initial body weight (BW) = 222 ± 12.4 kg] were assembled from auction markets near Dickson, TN and transported ~1,069 km to Manhattan, KS. Heifers (n = 12 per pen) were stratified by BW and randomly allocated to a corn-based receiving diet with one of four dietary treatments: 1) No supplemental D3 or calcidiol (CON, n = 24), 2) 3,000 IU supplemental D3·heifer⁻¹·d⁻¹ (D3, n = 24), 3.) 0.5 mg calcidiol/h/d (Hy D Low, n = 24), or 4.) 1.0 mg calcidiol·heifer⁻¹·d⁻¹ (Hy D High, n = 24) for 60 d. Blood samples were collected from each heifer prior to transport (d -1), on arrival (d 0) and on d 14, 31, and 60 of dietary treatment period. Data were analyzed using the GLIMMIX procedure of SAS using animal as experimental unit and treatment as fixed effect. HyD High calves had greater (P < 0.001) serum 25(OH)D3 concentrations than HyD Low at d 14 and 31 (Figure 1 and 2). At d 14, 31 and 60, HyD High and HyD Low calves had greater (P < 0.001) serum 25(OH)D3 concentrations than CON or D3 treatments. In experiment 2, cannulated crossbred heifers (n = 8, initial BW = 289 ± 44.9 kg were randomly assigned to one of two treatments: 1.) 3 mg/272 kg BW calcidiol, or 2.) 5 mg/272 kg BW calcidiol in a single dose administered via rumen cannula at h 0. Serial blood samples were collected at baseline out to 70 d post-dose. Serum 25(OH)D3 concentrations were analyzed via HPLC coupled with tandem MS (dsm-firmenich, Belvidere, NJ). Predictive modeling simulations of serum 25(OH)D3 concentrations used non-parametric superposition (Certara Phoenix WinNonlin 64, St. Louis, MO) from applying non-compartmental analysis with the assumptions of linearity, independent calcidiol dose response, and the rate of absorption and the average systemic clearance were consistent for each calcidiol dosing interval. The elimination half-life (t1/2) of calcidiol was determined to be an average of 7.1 d and area under change in concentration-time curve time 0 to the last time point that measured above baseline concentration post dose (AUC0-last) averaged of 32.6 d (Table 1). Non-parametric dosing simulations using nutrikinetic parameters from experiment 2 suggest that administration of two 5 mg oral doses of calcidiol with daily feeding of 1 mg would result in a rapid and sustained increase in serum 25(OH)D3. However, simulations should be confirmed in vivo before implementation.
356 Exploring the manganese requirement of feedlot steers
Authors: Smerchek Dathan T , Eekohff Marissa K , Rients Emma L , McLaughlin Amy M , Henderson Jacob A , Ortner Brock M , McGill Jodi , Thornton-Kurth Kara J , Hansen Stephanie L
Published: September 2024

Angus-cross steers [n = 144; body weight (BW) = 359 kg ± 13.4] were used to assess the effect of dietary Mn and steroidal implants on trace mineral (TM) status, and liver and serum metabolites related to N metabolism. Steers (n = 6/pen) were stratified by BW in a 3 × 2 factorial. GrowSafe bunks recorded individual feed intake (experimental unit = steer; n = 24/treatment). Dietary treatments included (MANG; 8 pens per treatment; Mn as MnSO4): 1) no supplemental Mn (analyzed 14 mg Mn/kg DM; Mn0); 2) 20 mg supplemental Mn/kg DM (Mn20); 3) 50 mg supplemental Mn/kg DM (Mn50). Within MANG, steers received a steroidal implant treatment (IMP) on d 0: 1) no implant; NO; or 2) combination implant (Revalor-200; REV). Liver biopsies for TM analysis and qPCR, and blood for serum urea-N (SUN) analysis were collected on d 0, 20, 40, and 77. Liver TM, serum metabolite, enzyme activity, and gene expression data were analyzed as repeated measures using PROC MIXED of SAS 9.4. The Correlation Procedure of SAS 9.4 was utilized to assess correlations between liver arginase activity, SUN concentrations, and liver Mn concentrations. No MANG × IMP effects were noted (P ≥ 0.12) for growth or carcass measures. Steroidal implants increased final BW (FBW), overall average daily gain (ADG), and gain to feed (G:F; P ≤ 0.01). Dietary Mn did not influence FBW, overall ADG, or overall G:F (P ≥ 0.14). Liver Mn concentration increased with supplemental Mn (P = 0.01). An IMP × DAY effect was noted for liver Mn (P = 0.01) where NO and REV were similar on d 0 but NO cattle increased liver Mn from d 0 to 20 while REV liver Mn decreased. Relative expression of liver Mn transporter ZnT10 tended to be least (MANG; P = 0.10) in Mn20 while Mn0 and Mn100 were similar. Relative expression of liver Mn transporter ZIP8 was not influenced by MANG, IMP, or MANG × IMP (P ≥ 0.23). Liver arginase activity was not influenced by MANG, IMP, MANG × DAY, IMP × DAY, or MANG × IMP (P ≥ 0.15) but tended to decrease over time (DAY; P = 0.10). On d 0, 20, and 40, arginase activity was correlated (r ≤ 0.33; P ≤ 0.01) with SUN and liver Mn. Relative expression of MnSOD in the liver was greater in REV (P = 0.03) compared with NO and within a MANG × IMP effect (P = 0.01) REV increased liver MnSOD activity. This study indicates current NASEM Mn recommendations are adequate to meet demands of finishing beef cattle given a steroidal implant. This study also reveals how implants and supplemental Mn influence liver enzyme activity and genes related to arginine metabolism, urea synthesis, antioxidant capacity, and TM homeostasis.
361 Evaluating the effect of liver copper concentration on lubabegron fumarate-induced performance and carcass characteristics of finishing steers
Authors: Henderson Jacob A , McGill Jodi , Hansen Stephanie L
Published: September 2024

The objective of this study was to evaluate the effect of copper (Cu) status on response to lubabegron fumarate (Experior, Elanco, Greenfield, IN). Angus crossbred steers [n = 48; body weight (BW) = 469 ± 31 kg] were enrolled in a 77-d finishing study, housed in pens of 6, with a GrowSafe bunk (GrowSafe Systems, Ltd, Airdire, AB, Canada) in each pen and implanted (Revalor-200, Merck Animal Health, Madison, NJ; 200 mg TBA + 20 mg E2) on d 0. A 2 × 2 factorial arrangement was applied to Cu status (deficient, DEF, no supplemental Cu; or adequate, ADE, 10 mg supplemental Cu/kg DM as CuSO4) and Experior (36 mg·steer⁻¹·d⁻¹, EXP; or no Experior, NOEXP). A prior trial resulted in steers with distinct liver Cu (DEF and ADE were 42 ± 21 and 193 ± 31 mg Cu/kg DM, respectively). Experior was fed from d 37 to d 73, and cattle harvested on d 78. Body weights were collected on d -1, 0, 37, 55 (mid-Experior), 76 and 77. Blood was collected on d 0, 37, 55, and 76 for serum urea nitrogen (SUN), non-esterified fatty acids (NEFA), glucose, and insulin. Data were analyzed in Proc Mixed of SAS as a factorial design, with steer as the experimental unit (n = 12 per treatment). From d 0-37, DEF daily gain and feed efficiency (G:F) were greater than ADE (P < 0.01), while dry matter intake (DMI) did not differ (P = 0.36). Overall DMI was greater in ADE than DEF (P = 0.04) and not affected by Experior (P = 0.13). Carcass-adjusted average daily gain was not affected by Cu or Experior (P ≥ 0.21). Deficient steers had greater carcass-adjusted G:F than ADE (P = 0.02). Hot carcass weight was greater in EXP (P = 0.04), but post-hoc analysis of the Cu x Experior effect (P = 0.2) reveals this was driven by DEF-EXP (15 kg over DEF-NOEXP) rather than ADE-EXP (4 kg over ADE-NOEXP). Marbling tended to be greater in ADE (P = 0.06) and was unaffected by Experior (P = 0.14). The revised quantitative insulin sensitivity check index displayed an EXP x Day effect (P < 0.01) where NOEXP was consistent across days and EXP had greater insulin sensitivity during the Experior period. Serum urea nitrogen was affected by Cu × Experior × Day (P = 0.01), where DEF-NOEXP had lesser d 0 SUN than all others, and EXP decreased on d 55 while NOEXP increased steadily during the finishing phase; by d 76 DEF-EXP remain lesser than NOEXP treatments with ADE-EXP being similar to all others. These data suggest Cu concentration influences steer response to lubabegron fumarate, and more research is needed to determine the cause of this.
401 Effect of protein and starch supplementation level on intake and digestibility by steers consuming low-quality forage: I. Bos taurus
Authors: Cox Jodi R , Wickersham Tryon A
Published: September 2024

A deficiency of ruminally available N (RAN) caused by a basal diet of low-quality forage depresses forage utilization. Supplemental protein improves forage utilization by increasing RAN, resulting in increased intake and potentially improving digestion. Addition of starch to a supplement can increase total digestible organic matter (OM) intake (TDOMI); however, too much starch decreases RAN and pH potentially decreasing forage utilization. Our objective was to determine the effect of starch supplementation on intake and digestion in Bos taurus indicus steers. Accordingly, five ruminally cannulated Brahman steers [body weight (BW) = 420 ± 55 kg) were used in a 4 × 4 Latin square to evaluate the effect of decreasing supplemental starch when consuming King Ranch Bluestem hay (3.5% CP, 73% NDF). Steers received four isonitrogenous (130 mg N/ kg BW) supplements providing increasing levels of starch (2% starch = 100% soybean meal; 20% starch = 26.3% corn, 73% soybean meal, 0.7% urea; 38% starch = 51.6% corn, 47% soybean meal, 1.4% urea; 56% starch = 78.6% corn, 19% soybean meal, 2.4% urea). Five 14-d periods were conducted, consisting of 9 d adaptation and 4 d to measure intake and digestion, and 1 d for ruminal fermentation. As designed, supplement OM intake (SOMI) increased linearly (P < 0.01) as starch level increased. Other measures of intake, including forage OM intake (FOMI), total OM intake (TOMI), and total neutral detergent fiber intake (TNDFI) decreased in a cubic manner in response to increasing starch (P ≤ 0.04). Forage OMI also responded with a cubic decrease (72.2, 68.9, and 69.5 g/kg BW0.75) when the protein supplement contained 2, 20, and 38% starch, respectively, but decreased to 61.2 g/kg BW0.75 when the 56% starch supplement was provided. Similarly, TOMI decreased 5.3% when starch inclusion increased from 38 to 56%. Total tract OM digestion and NDF digestion were not significantly affected (P ≥ 0.86) by starch level in the supplement; therefore, despite TOMI and TNDFI decreasing, there was no effect on total digestible OM intake and (TDOMI) and total digestible NDF intake (TDNDFI). In conclusion, providing supplemental starch over 38% decreased forage utilization. Decreases in FOMI with starch inclusion may be attributed to competition for RAN between fiber fermenting and starch fermenting bacteria.
155 Modulating silage fermentation with microbial inoculants
Authors: Ferraretto Luiz
Published: September 2024

Silage is a vital feed ingredient for beef and dairy cattle diets in many areas worldwide. Even though ensiling is a well-established method of forage preservation, producers face a myriad of challenges to produce, harvest, and store forages optimally. Challenging circumstances like these create difficulties for proper silage fermentation, increase dry matter (DM) losses and silage contamination with mycotoxins, and reduce the nutritive value of ensiled forages. Losses of DM and nutrients occur during production, fermentation, and feeding of silage. Although some losses are unavoidable, poor management may increase DM losses up to 60% which may eventually lead to decreased feed efficiency, as each percentage-unit lost as DM is a percentage-unit of feed that cannot be converted into animal products. Loss of DM during forage production and preservation is estimated to cost beyond a billion dollars worldwide. Even in well-managed silages, yeasts and molds that survive anaerobic fermentation may grow rapidly and reduce aerobic stability after silo opening, and mold count in silage is positively related to DM loss. The use of silage microbial inoculants is a key strategy to modulate silage fermentation and preserve forage successfully. This presentation will discuss microbial inoculant strategies to optimize silage fermentation and minimize silage losses. Homofermentative bacterial inoculants, which contain bacteria that almost exclusively produce lactic acid, have been shown to effectively reduce silage pH and improve DM recovery. The use of homofermentative microbial inoculants have been shown to attenuate DM loss during ensiling and to increase dry matter intake and hence lactation performance by dairy cows. Heterofermentative bacterial inoculants, which contain bacteria capable of producing both lactic and acetic acids, reduce mold and yeast counts and improve silage aerobic stability.
Exploring a novel direct-fed microbial for ruminants to mitigate in vitro Salmonella invasion and infection
Authors: Copani Giuseppe , Knudsen Tine Thorup Moeller , Capern Lena Catrine , Gresse Raphaele , Cappellozza Bruno Ieda
Published: September 2024

Managing bacterial infections is of great importance in cattle production, particularly those caused by Salmonella enterica serovars Typhimurium or Dublin, which can impact both animal health and human food safety. Direct-fed microbial (DFM) can support gastrointestinal health and alleviate potential bacterial infections. In the present study, the capacity of a bacteria-based DFM product [BOVAMINE DEFEND Plus; BDP; Novonesis, Denmark (BDP)] containing Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus licheniformis, and B. subtilis to reduce Salmonella Typhimurium ATCC14028 invasion was investigated using the HT29-MTX cell line (Exp. 1) and also to evaluate the possible antagonistic effect against S. Dublin using an in vitro agar well diffusion method (Exp. 2). Briefly, in Exp. 1, after a 30 min pre-incubation with 1.0 ×108 CFU of BDP and/or 2.5 × 106 CFU of S. Typhimurium were added to each transwell. The quantity of S. Typhimurium invading the cells was measured after 90 min of co-incubation using CFU counts. As a control, the viability of the total S. Typhimurium was assessed to confirm the mode of action of BDP targets the pathogen invasion properties. In Exp. 2, the antagonistic efficacy of BDP against S. Dublin CHCC41286, isolated from cattle, was tested by adding BDP to wells in CLED agar plates casted with the pathogen above, zones of inhibition measured after 48 h incubation. In Exp. 1, BDP significantly (P < 0.05) reduced by 80.6 % the invasion of S. typhimurium into HT-29-MTX cells as well as from 16 % the viability of the pathogen. The antagonistic properties of BDP towards S. Dublin were confirmed by clear inhibition zones (8.6 mm). These two in vitro findings set the stage for exploring the potential benefits of using a novel DFM as a promising tool and strategy to mitigate Salmonella infections in ruminants and improve animal health, food safety, and public health. Further in vivo confirmation needs to be developed to validate these preliminary in vitro results.
178 Programing the rumen microbiome to optimize microbial efficiency in high forage diets
Authors: McAllister Tim A , Gruninger Robert J , Terry Stephanie A , Badhan Ajay , Wang Yue , Guan Leluo
Published: September 2024

As the majority of energy and protein supplied to cattle arises as a result of ruminal fermentation, the rumen microbiome has an integral role in determining host feed efficiency. Counterintuitively, current evidence suggests that a less diverse rumen microbiome is associated with improved feed efficiency, possibly as a result of greater metabolic precision and avoidance of energy spilling fermentative pathways. The composition of the rumen microbiome is mainly determined by diet, but host traits such as rumen volume, rate of passage, rumination and immunity also have influence. Although less microbial diversity may improve feed efficiency in cattle fed a specific diet, reduced diversity may impair the ability of cattle to adapt to frequent changes in diet and the environment. Hydrogen exchange and capture is the energetic foundation of the rumen microbiome and considerable capital has been invested to develop additives that redirect hydrogen flow away from the reduction of CO2 to CH4 towards alternative sinks. These additives have been shown to reduce enteric CH4 emissions by 30 to 80%, but improvements in feed efficiency have been less than stoichiometric predictions. Approaches to improve the feed efficiency of cattle need to be multifaceted with consideration for host genetics, functional efficiency of the rumen microbiome, and the structure and composition of feed. Likewise, reductions in carbon emissions need to be broader than just CH4, with an appreciation of the role that cattle have within a circular bioeconomy to promote upcycling of nutrients and reductions in emissions from farming systems. Strategies to improve the efficiency of cattle production are a prerequisite for the sustainable intensification needed to ensure that the social license for milk and meat production from cattle is retained.
210 Maternal dietary organic selenium improves selenium status in neonatal lambs compared with single maternal or neonatal injection of inorganic selenium
Authors: Hasan Daniella , Ford Hunter , Bionaz Massimo
Published: September 2024

The objective of this study was to compare the efficiency of three industry standard practices for improving the selenium (Se) status in neonatal lambs. Pregnant Polypay ewes (n = 27) at around 40 d pre-partum were enrolled in the study. The ewes were fed with grass silage and grain and, at 40 d from expected lambing, randomly allocated to one of three groups: 1) a single injection of 25 g sodium selenate as BO-SE/kg body weight (BW) at 4 wk before expected parturition (Inj-E) and not injection in the lambs; 2) no injection of BO-SE in the ewe but injection of 4.38 mg sodium selenite as BO-SE at 3 d of life of the lambs (Inj-L); and 3) no injection of BO-SE to the ewes or lambs but the ewes were fed 3.6 mg Se/day as Se-yeast (Yst-E) through the duration of the study (40 d prepartum + 30 d postpartum). Lambs were nursed by their own dams for 30 d without access to other feed (i.e., only milk). Blood was collected from the lambs at d 3 and 10 of life to measure 14 minerals, including Se, using ICP-MS. Glutathione peroxidase activity (GPx) was measured using a commercial kit. Data were analyzed using a GLIMMIX of SAS with an ARH covariance with treatment and time as the main effect, with lambs nested in ewe as a random effect. The number of lambs/ewes was used as a covariate. The injection of BO-SE in the ewes did not affect concentrations of Se in the lambs at birth, as there were no differences in whole blood Se between lambs in Inj-E and lambs in Inj-L at 3 d of life (i.e., before Inj-L received the BO-SE). The injection of BO-SE did not affect the level of Se in the whole blood of lambs 7 d after the injection compared with baseline (i.e., 3 d of life). Consequently, there was no difference in whole blood Se between lambs in Inj-E and Inj-L groups (177 vs. 167 ng/mL, respectively). However, injection of Se in pre-parturient dams did improve GPx activity in offspring (P = 0.04). Lambs in Yst-E had significantly greater concentrations of Se in whole blood compared with the other two groups at both 3 and 10 d of life (281 ng/mL; P < 0.001). Our data demonstrate that the typical industry standard approach of injecting inorganic Se in prepartum ewes or neonatal lambs is ineffective while feeding Se-yeast to dams was effective in improving Se status in lambs.