bluuebunny/crossref_metadata_2025 huggingface dataset:
195 Effect of selection for growth and maternal influence on crossbred Angus heifer development
Authors: Garcia-Ascolani Mariana E , Briggs Emma A , Talley Samuel R , Rolf Megan M , Beck Paul A , Lalman David L
Published: September 2024

This multiyear experiment was designed to determine the effects of sire yearling weight (YW) and maternal influence (MILK) expected progeny differences (EPD) on production and fertility of beef replacement heifers. Sires were classified as moderate (< 50th percentile) or high for YW EPD (122 ± 29; from 79 to 172) and as low (< 50th percentile) or high for MILK EPD (27 ± 8; from 5 to 40). Fall-born (n = 214) and spring-born (n = 207) heifers were enrolled in the study. Birth weight (BW), weaning weight (WW), and YW of the heifers were measured. In addition, reproductive tract score (RTS), dry matter intake (DMI), and average daily gain (ADG) while consuming an unprocessed grass hay diet were determined in a subsample of enrolled heifers. Neogen Igenity Beef scores (NIBS) were also run on this subset. Pregnancy rate and conception rate at fixed timed artificial insemination (FTAI) were also determined. Adjusted BW, WW and YW and RTS were analyzed using the GLIMMIX procedure of SAS (9.4, SAS Institute Inc., Cary, NC), with YW and MILK EPD as fixed effects and year of birth as random effect. Effects of sire YW and MILK classification on the likelihood of pregnancy and successful FTAI were also analyzed using the GLIMMIX procedure of SAS. Pearson correlation coefficients between independent and dependent variables were obtained using the CORR procedure of SAS. Sire MILK EPD had no effect (P ≥ 0.13) on the body weight of fall- or spring-born heifers. However, fall-born heifers were 0.12 kg and 0.34 kg heavier (P = 0.06 and 0.001, respectively) per unit increase in sire YW EPD at weaning and yearling time, respectively. There was no effect of sire YW EPD on fall-born heifer DMI as percentage of body weight (DMI % BOW; P = 0.74) nor ADG (P = 0.90) while consuming the low-energy diet. Spring-born heifers had significantly greater (all, P ≤ 0.001) adjusted BW, WW, and YW (0.02, 0.23 and 0.37 kg per unit increase in sire YW EPD, respectively. Reproductive tract score was strong and negatively correlated (P ≤ 0.001) with DMI % BOW. Heifer YW NIBS were moderate and positively correlated (P < 0.001) with ADG. There was a tendency (P = 0.09) for a weak and negative correlation between residual feed intake genetic scores and DMI % BOW. Sire genetic merit for yearling growth was transmitted to replacement heifers. However, neither ADG, nor unprocessed forage DMI % BOW was influenced by genetic potential for growth during this study. Further research is needed to assess the benefits of using genomic profile of heifers for maternal, performance and carcass traits, alongside sire EPDs, when selecting and developing beef replacement heifers.
399 Effect of feeding palm oil products on finishing cattle performance, carcass characteristics, and methane production
Authors: Kobza Anna M , McDermott Rebecca L , Benton Josh R , Norman Mitch M , Zou Long , MacDonald James C , Erickson Galen E
Published: September 2024

The objectives of this experiment were to evaluate feeding palm oil products on feedlot cattle performance and methane production. Steers (n = 320; 380 ± 14.5 kg) were allocated to 40 pens in a randomized block design and assigned to 1 of 5 treatments consisting of different sources of supplemental fat: 1) No Oil; negative control containing 0.0% supplemental fat, 2) Corn Oil; positive control containing 4.0% supplemental corn oil, 3) Whole Palm; 4.0% supplemental whole palm oil, 4) Olein; 4.0% supplemental palm olein oil, or 5) Stearin; 4.0% supplemental palm stearin oil. Cattle consuming Corn Oil, Olein and Stearin all had greater (P = 0.04) final body weight (BW) and hot carcass weight (HCW) than cattle consuming no oil but were not different (P > 0.11) from each other or from Whole Palm, which was intermediate. Dry matter intake (DMI) of cattle consuming No Oil, Whole Palm and Stearin oil was not different from each other; however, cattle fed Corn Oil had greater intake than Whole Palm (P = 0.03). Corn Oil, Olein, and Stearin all had greater average daily gain (ADG) than cattle consuming No Oil (P = 0.04) but were not different (P > 0.12) from Whole Palm. Adding fat improved feed efficiency (gain to feed; G:F) as all diets including added fat had greater (P < 0.01) G:F than No Oil. Marbling scores were greater (P = 0.01) for Olein and Stearin than Corn and Whole Palm. There were no differences in backfat, ribeye area or liver abscess rate among any treatments (P > 0.74). Gas emissions were evaluated for only the No Oil and Whole Palm treatments. Total methane and methane produced per pound of dry matter intake was less for cattle consuming Whole Palm than No Oil by 14.8% (P < 0.04) while cattle were in the methane chamber. Methane produced per kilogram of ADG for Whole Palm was also reduced (P < 0.01) by 21.4% compared with No Oil. The results of this study indicate feeding palm oil products as a source of supplemental fat in finishing diets increases final BW, ADG, and HCW compared with feeding no supplemental fat, but had minimal impact on DMI resulting in an improvement in G:F. Adding supplemental fat reduced methane emissions in cattle when feeding Whole Palm compared with No Oil. The value of palm oil products in feedlot finishing diets is comparable with feeding corn oil.
177 Awardee Talk: Residual feed intake in beef cattle: Biological basis and effect on response to dietary supplementation of rumen bypass protein
Authors: Idowu Modoluwamu , Ogunade Ibukun M , Sidney Taylor S
Published: September 2024

Using ruminal and plasma metabolomics, as well as 16S rRNA gene sequencing, we aimed to identify differences in host metabolome, rumen metabolome, and microbial community in beef steers with high (positive) or low (negative) residual feed intake (RFI) phenotypes. Our microbiome results revealed a greater relative abundance of Weissella, and Muribaculaceae in low-RFI beef steers, while Methanobrevibacter and Clostridium were reduced. Additionally, pathway enrichment analysis of the metabolome data revealed the enrichment of histidine metabolism, and arginine biosynthesis in the plasma of low-RFI beef steers. Overall, our results showed that selection for divergent RFI phenotype is associated with differences in rumen microbiome and overall animal metabolism, notably amino acid metabolism-related pathways, and therefore may be an important animal-related factor that can affect the response of beef cattle to nutritional interventions such as rumen bypass protein supplements. Feeding rumen-bypass protein to cattle has demonstrated positive impacts on weight gain and feed efficiency, especially in rapidly growing young calves. However, the increasing costs of feed protein and the challenges of excessive nitrogen discharge into the environment underscore the need for sustainable protein supplementation in ruminant diets. Although past research has aimed at enhancing amino acid utilization efficiency and/or reducing nitrogen excretion in ruminants by minimizing dietary protein content, there is a gap; no study has assessed how factors intrinsic to the animal, like feed efficiency status, might influence the response of ruminants to dietary protein supplements. In our follow-up study, we investigated the effects of rumen-bypass protein (RBP) supplements on growth performance, plasma and urinary nitrogen concentration, hepatic mitochondrial protein complexes, and mRNA expression of immune genes in crossbred beef steers with divergent negative or positive RFI phenotypes. We assessed the impact of RBP supplementation on feed efficiency in beef steers. Steers [n = 40; body weight (BW) = 492 ± 36 kg) underwent a 42-d trial in a 2 × 2 factorial arrangement, considering RFI classification and RBP supplementation. Liver tissue samples collected on d 42 were analyzed for mRNA expression of immune genes and mitochondrial protein complexes I to V. Regardless of RFI status, RBP increased blood urea nitrogen (BUN; P = 0.01), with decreased BUN in low-RFI beef steers. Interactions of RBP and RFI were observed (P ≤ 0.05) for mitochondrial activities of complexes IV, V, and mRNA expressions of immune genes (TLR2, TLR3, IL23A). While RBP did not impact growth performance, its effects on immune gene expression and mitochondrial protein complexes varied with RFI status, highlighting the importance of considering RFI status in future studies investigating the effects of dietary protein supplements effects in beef cattle.
189 Association of the liver phosphoproteome with divergent dry matter intake in finishing beef steers
Authors: King Mindy E , Newcomb Carlee M , Rathert-Williams Abigail R , Beck Matthew R , Hagen Darren E , Hartson Steven D , Foote Andrew P
Published: September 2024

As the need for improving the sustainability of the beef industry increases, optimizing feed efficiency is of the utmost importance. The liver has a central role in nutrient metabolism, and for ruminants particularly, it is essential for providing glucose through gluconeogenesis via substrates such as propionate, lactate, and glycerol. Further, through cell signaling and vagal afferent signals, the liver acts to stimulate and inhibit dry matter intake (DMI). Thus, the objective of this study was to investigate alterations in the phosphoproteome of finishing beef steers in relation to divergent DMI to identify changes in the abundance of signaling proteins. Angus steers [n = 57; initial body weight (BW) = 518 ± 27 kg] underwent a 63-d intake trial utilizing an Insentec Roughage Intake Control System (Hokofarm Group, Emmeloord, The Netherlands). Prior to beginning the trial, liver biopsy samples were collected from all steers. Samples from steers with the greatest and least DMI (n = 8 each) were utilized for phosphoproteomic analysis. Liver protein was isolated and labeled with isobaric tandem mass tagging reagents. Samples were enriched for phosphopeptides using immobilized metal affinity chromatography and subsequently analyzed using high-performance liquid chromatography tandem mass spectrometry. Spectral data were searched in the National Center for Biotechnology Information Bos taurus protein database using MaxQuant (version 2.2.0.0; Max Planck Inst., Munich, Germany), and the data were analyzed using Perseus (version 2.0.10.0; Max Planck Inst.). Two sample t-tests were conducted to determine the difference in phosphopeptide abundance between steers with high and low DMI. A total of 16,365 phosphopeptides were identified, and 287 were differentially expressed (False Discovery Rate < 0.05). In addition, 2,777 phosphopeptides were differentially expressed based on an unadjusted P < 0.05 which were used for enrichment analysis of Gene Ontology processes and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways using the Database for Annotation, Visualization, and Integrated Discovery. The background for this analysis was all identified phosphopeptides. Gene ontology terms enriched included processes related to phosphorylation activity, intracellular signal transduction, response to insulin, kinase activity, and signaling protein binding. Enriched KEGG pathways included pathways related to insulin signaling, such as AMPK signaling, mTOR signaling, and MAPK signaling. Further, pathways related to glycolysis and gluconeogenesis, glucagon signaling, insulin resistance, carbon metabolism, and various other signaling pathways were also enriched. These results suggest a link between the liver phosphoproteome and DMI, indicating that divergent DMI is associated with alterations in signaling pathways related to nutrient uptake and metabolic processes.
252 Evaluating the impact of inclusion of field pea (Pisum sativum) on rumen fermentation profile, production parameters, and composition of rumen bacterial community of dairy cattle
Authors: Alizadeh Arezoo , Derakhshani Hooman , Plaizier Jan Cornelis
Published: September 2024

Field peas (FP) are characterized by a crude protein (CP) content ranging from 24% to 28% of dry matter (DM). Approximately 78% of this protein is rumen degradable. Hence, FP can be a viable alternative protein source for livestock. We examined the effect of partially substituting corn-based concentrates with FP on production parameters, rumen fermentation profile, and the composition of the rumen bacterial community in lactating dairy cows. Lactating, non-pregnant Holstein cows (n = 12) were used in a repeated 3 × 3 Latin square with 21-d experimental periods, with the last 7 d used for sample and data collection. Cows were fed a basal TMR (control), or partially mixed diets to which 3.9% (LP), or 7.8% DM (HP) of FP were added. The control diet contained on a DM basis 17.4% CP, 4.5% crude fat, 28.0% starch, and an estimated 1.67 Mcal/kg of net energy for lactation (NEL). The FP contained 22.5% CP, 1.67% crude fat, 44.7% starch, and an estimated 1.81 Mcal NEL/kg. The rumen bacterial composition was analyzed by high-throughput sequencing of the V4 region of the 16S rRNA gene. Cows fed the HP diet had greater (P < 0.05) ruminal ammonia (NH3-N), milk urea nitrogen (MUN), and plasma urea concentrations than those fed control and LP diets. Digestibility of DM was greater (P < 0.05) for cows fed control and LP diets than for cows fed the HP diet. The CP total tract digestibility decreased (P < 0.05) with increasing levels of peas in the diet. Compared with the control, the HP diet tended (P = 0.09) to increase the total ruminal concentration of branched-chain volatile fatty acids. The addition of FP to the diets did not affect the alpha diversity, as indicated by Shannon’s index, and the beta diversity of the rumen bacterial community [p(PERMANOVA) = 0.97]. However, the relative abundances of several bacterial taxa, including amplicon sequence variants (ASVs) belonging to Bacteroidia, Clostridia, and Gammaproteobacteria decreased in response to the addition of FP to the diet. Taken together, our results suggest that up to an inclusion rate of 7.8% DM, FP can be included in corn grain-based diets of lactating dairy cows without adverse effects on milk yield, milk composition, rumen fermentation characteristics, and rumen microbial composition.
250 Effects of corn processing on growth performance, starch digestibility, and blood metabolites in receiving beef steers
Authors: Rients Emma L , Smerchek Dathan T , Hansen Stephanie L
Published: September 2024

Corn is the most common grain ingredient fed to feedlot cattle in the U.S. and most corn goes through some processing to increase the energy availability. This study examined the effects of a novel corn processing method on the growth performance, starch digestibility, and blood metabolites of growing steers compared with traditional corn processing methods. Angus-cross steers [n = 218; body weight (BW) = 230 ± 18.5 kg] were sorted into pens of 6 or 7 steers upon arrival and fed a common receiving diet for 2 d prior to being weighed, processed, and starting dietary treatments (n = 12 pens/treatment) on d 0. Treatments included diets with dry rolled corn (ROLL), steam flaked corn (FLAKE), and high shear dry extruded corn (EXT; High-Gel Insta-Pro International, Grimes, IA). Corn was included at 30% DM of a corn silage and SweetBran-based diet. Due to illness concerns, diets were adjusted to reduce corn in the diet to 25% on d 5; in feed antibiotic was fed d 5 to 9, and all calves were weighed and administered Draxxin (1.1 mL/45.45 kg) on d 17. Final BW were collected on d 37 and 38 and serum (glucose, insulin) and fecal samples (total tract starch digestibility) were collected from one steer per pen. Data were analyzed using the Mixed procedure of SAS 9.4 (Cary, NC) with pen as the experimental unit. Treatment did not affect midpoint (d 17) BW or average daily gain (ADG) from d 0 to 17 (P ≥ 0.31). Final BW, ADG, and dry matter intake were not different between treatments (P ≥ 0.15). Feed efficiency (gain:feed) was greatest in EXT (0.261) compared with ROLL (0.232) with FLAKE (0.259) being intermediate and not different from other treatments (P = 0.007). Total tract starch digestibility was determined using the equations from Zinn et al. (2007) and was increased in EXT and FLAKE compared with ROLL (P = 0.0002). Serum glucose and insulin on d 36 were not affected by treatment (P ≥ 0.19). Overall, a growing diet of 25% high shear dry extruded corn increased feed efficiency and total tract starch digestibility over dry rolled corn and resulted in similar performance to steers fed steam flaked corn.
256 Evaluating the effect limit feeding yearling beef steers for 56 or 86 d of a 140-d finishing period on growth performance and carcass trait responses
Authors: Delver Justin J , Rusche Warren C , Thompson Logan R , Francis Forest L , Francis Becca B Grimes , Leeson Riley J , Ribeiro Thiago L Maia , Olinger Grace H , Ross Cassidy R , Smith Zachary K
Published: September 2024

The objective of this study was to determine the effect of limit feeding yearling beef steers for 56 or 86 d before offering ad libitum feed for the remainder of the 140-d finishing period on growth performance and carcass traits. Black Angus steers [n = 194; initial body weight (SBW) = 410 ± 17.9 kg] were allocated into 24 pens (8 steers/pen). Pens were randomly assigned to one of three treatments in a randomized complete block design; feed offered ad libitum for the entire finishing period (ADLIB), feed offered at 92% of ad libitum for 56 d then ad libitum for the remainder of the finishing period (RES56), and feed offered at 92% of ad libitum for 86 d then ad libitum for the remainder of the finishing period (RES86). Feed restrictions began on d 22 after diet adaptation with RES56 and RES86 pens being offered 92% of the ADLIB pen within the daily feed offering of their block. Bunks were evaluated daily, and refusals were weighed weekly. Data were analyzed using the MIXED procedure of SAS 9.4 with treatment and block as the fixed and random effects, respectively. From d 1 to 21 RES56 had lesser average daily gain (ADG), feed efficiency (gain to feed; G:F), and a lighter SBW than ADLIB and RES86 (P ≤ 0.02), but DMI did not differ (P ≥ 0.31). From d 22 to 107, G:F was similar (P = 0.45), but ADLIB had a greater SBW, ADG, and DMI than RES56 and RES86 (P < 0.01). From d 78 to 107 RES56 were allowed ad libitum feed intake while RES86 was still restricted. The d 108 SBW tended to be greatest in the ADLIB and least in the RES86 group (P = 0.07), and DMI was least in the RES86 group (P < 0.01). RES56 had the greatest ADG, RES86 the least, and ADLIB were intermediate (P < 0.01). RES56 and RES86 also had increased G:F than ADLIB during this period (P < 0.01). From d 108 to 140 all cattle had ad libitum access to feed, and DMI did not differ (P = 0.31). RES86 had greater ADG and G:F than ADLIB and RES56 during this period (P ≥ 0.31). Cumulatively, final SBW, ADG, and G:F did not differ between the treatments (P ≥ 0.13), but the ADLIB group had increased DMI (P < 0.01). Ribeye area and hot carcass weight (HCW) did not differ (P ≥ 0.12), but rib fat thickness (P = 0.05) and marbling were greater for ADLIB (P = 0.03). Limit feeding yearling beef steers for a portion of the finishing period before resuming ad libitum feed intake resulted in less cumulative DMI without affecting ADG, G:F, final shrunk BW, or HCW; but decreased fat and marbling scores.
350 Awardee Talk: Beef cattle mineral nutrition: What do we know and where do we go from here
Authors: Hansen Stephanie L
Published: September 2024

Trace minerals are pivotal in enhancing cattle growth and ensuring profitability in beef production. Historically, supplementation strategies have aimed at preventing deficiencies, significantly improving growth and reproductive performance. However, as cattle breeding has evolved to achieve remarkable growth rates, the challenges related to health and stress during the feeding period have intensified. This presentation explores refined trace mineral recommendations, focusing on zinc’s “stress requirement” for cattle undergoing transit and health challenges, and its impact on performance. The segmented nature of the beef industry, necessitating multiple transports, induces physiological stress and oxidative stress, highlighting the need for tailored mineral supplementation. Further, when recognizing feedlot cattle as the high-performing athletes they are, the potential benefits of adjusted trace mineral concentrations become apparent. Preliminary findings suggest that optimal zinc concentrations may exceed current National Academies of Sciences, Engineering, and Medicine (NASEM) 2016 recommendations, whereas for other minerals like copper and manganese, the existing guidelines remain appropriate. This presentation will explore the differential effects of increasing dietary zinc and copper in conjunction with various growth-promoting technologies. Preliminary data indicates that increasing zinc concentrations can linearly enhance average daily gain (ADG) and hot carcass weight (HCW), especially when using potent anabolic implants, while the response to increased copper concentrations exhibits a more quadratic relationship with performance. Building upon the foundational work of pioneering researchers in the field of mineral nutrition, this presentation advocates for the continuous refinement and optimization of trace mineral supplementation strategies. By integrating cutting-edge technologies and fostering collaborative research efforts, we aim to further enhance the sustainability of the beef industry. A deeper understanding of trace mineral requirements in the face of modern production challenges will pave the way for more precise and effective nutritional strategies.
360 Effect of the administration of a protected source of calcium gluconate on growth, feed efficiency, nutrient digestibility, and health in beef cattle
Authors: Grossi Silvia , van Kuijk Sandra , Vandoni Stefano , Rossi Carlo Angelo Sgoifo
Published: September 2024

The gastrointestinal tract has a central role in production efficiency due to its involvement in the digestive function as well as in immunological, nervous, and metabolic functions. In ruminants, a great deal of attention is placed on ruminal functionality and safety. However, it is now recognized that the hindgut is involved in the onset of some metabolic issues, normally associated with ruminal imbalances, as well as in the digestion efficiency. Thus, the application of nutritional strategies that target the hindgut are gaining interest in cattle nutrition. The study evaluated the effects of a protected source of calcium gluconate on performance, digestibility, and health in beef cattle. Charolaise bulls (n = 241) were randomly divided into two groups: i) Control (n = 120) basal diets + 10g/head/day of a placebo of wheat bran; ii) Treatment (n = 121) basal diets + 10 g·bull⁻¹·d⁻¹of a protected source of calcium gluconate (Lactibute, Selko Trouw Nutrition). The population was further divided into two subgroups: i) “Overall population” (n = 201) housed in pens of 7to 8 animals each; ii) “Beefmonitor population” (n = 40). The latter was housed in two pens (Control and Treatment) with 20 animals each equipped with two automatic scales for BW located at the drinkers, to evaluate the daily growth trends. Growth performance, feed intake (FI), feed conversion ratio (FCR), were evaluated with specific approaches in the two populations. The incidence of diseases was evaluated equally in the two populations. The apparent total tract digestibility (aTTD) was evaluated on 10 representative pens per group using a portable near-infrared system that compares the composition of the diets and the correlated feces. All the data were analyzed statistically using the SAS software and applying specific models. The average daily gain (ADG) was improved by the Treatment (+40 and +43 g·bull⁻¹·d⁻¹compared with the Control group, in the “Overall” and “Beefmonitor” populations; Table 1 and Figure 1; P = 0.0084 and < 0.0001, respectively), and the final BW were also heavier (706.82 and 705.83 vs 699.75 and 697.33 kg in the “Overall” and “Beefmonitor” populations; P = 0.0084 and 0.037, respectively). The treatment improved both, FCR (6.90 and 7.03 vs 7.51 and 7.28 in the “Overall” and “Beefmonitor” populations; P = 0.0008 and < 0.0001 respectively; Table 1 and Figure 1) and the aTTDs of starch (97.05 vs 95.71%; P < 0.0001), cellulose (57.91 vs 52.95%; P < 0.0001) and NDF (52.02 vs 50.02%; P = 0.020). The incidence of lameness was reduced in the Treatment group (0.99 vs 7%; P = 0.0282). Including protected sources of calcium gluconate can be functional to improve production efficiency and animal health, as a consequence of its proactive role on intestinal health, functionality and epithelial integrity.
352 Supplementing bovine satellite cells with anabolic hormones and/or zinc at differentiation impacts abundance of mRNA involved in growth, mineral transport, and oxidative stress
Authors: Alberto Anthony F , Brown Bailee , Crump Zachary C , Okamoto Lillian , Hansen Stephanie L , Thornton-Kurth Kara J
Published: September 2024

Zinc (Zn) is the most utilized metal in biological processes and supports growth through critical roles in protein turnover. The Zn requirements of skeletal muscle may be augmented when growth promoting technologies, such as anabolic hormones are being utilized. Both anabolic hormones and Zn affect protein synthesis and degradation in skeletal muscle. However, the molecular mechanisms through which Zn may interact with anabolic hormones to support skeletal muscle growth remains unknown. The objective of this study was to determine whether trenbolone acetate (TBA), estradiol (E2) and Zn interact to promote differentiation of bovine satellite cell (BSC) cultures by assessing abundance of mRNA involved in growth, mineral transport, differentiation, protein turnover and oxidative stress. To do this, primary BSC cultures were isolated from three different steers and grown to 80% confluency and induced to differentiate in 3% horse serum, at which time a factorial design was employed to assess the impact of Zn (0, 10, 20 or 40 μM) as ZnCl2 and/or the impact of hormone (10 nM TBA,10 nM E2, 10 nM TBA and 10 nM E2). Zinc concentrations represent physiologically relevant plasma Zn concentrations. Total mRNA was isolated from the treated cultures at 4 h, 12 h and 24 h post-treatment. Assays utilizing cultures from each steer were run in duplicate (n = 6). The mRNA abundance of 45 genes were examined and analyzed using the PROC MIXED procedure of SAS with time as a repeated measure to evaluate the fixed effects of hormone, mineral, time, and all interactions. No effects (P ≥ 0.19) of hormone x mineral x time, hormone x time, hormone x mineral or hormone were noted. A mineral x time effect (P ≤ 0.04) was noted for the igf1r, slc39a7, mapk1, mmp2, and G6pd. A mineral effect was found for hormone receptors (ir, ar, esr1, esr2, and gper; P ≤ 0.03), mRNA involved in mineral transport (slc30a10, slc30a7, sod1, sod2, slc2a4, and slc39a8; P ≤ 0.009), and genes related to skeletal muscle differentiation (pax7, myf5, myf6, spry1, myog, mef2a, and myod; P ≤ 0.02) and protein turnover (akt1, fox01, fox04, mstn,fbox32, fox03, mtor, trim63, and CKM; P ≤ 0.03). These differences are generally driven by abundance being increased (P ≤ 0.05) in cultures treated with 40 or 20 μM Zn compared with cultures receiving 0 or 10 μM Zn. These results indicate that while Zn and hormone do not appear to interact to influence gene expression of differentiating primary BSC cultures at the time points measured, increased concentrations of Zn appear to increase mRNA abundance of hormone receptors, mineral transporters, and genes involved in skeletal muscle differentiation and protein turnover.
359 Optimization of calcium inclusion levels in diets fed to growing and finishing beef cattle
Authors: Long Nathan S , Beck Matthew R , Smith Jason K
Published: September 2024

Calcium (Ca) is a mineral that has an essential role in many biochemical pathways and functions of beef cattle. Limestone is the primary supplemental source of Ca in diets fed to growing and finishing cattle in the United States. Preliminary data indicated that inclusion of dietary Ca above the NASEM (2016) requirements as well as mean and modal concentrations reported by the most recent survey of consulting nutritionists may improve average daily gain (ADG) and feed efficiency (gain to feed ration; G:F) of finishing beef cattle. Thus, the objective of this experiment was to determine the optimal concentration of Ca in growing and finishing diets when limestone was the supplemental source of added Ca. A database was constructed containing 89 treatment means from 23 experiments published from 1963 to 2024 where dietary Ca inclusion via limestone represented treatments. Search parameters to construct the database included a combination of Ca, limestone, performance, efficiency, ADG, G:F, feedlot cattle, finishing cattle, growing cattle, and backgrounding cattle. Data were analyzed in JMP Pro 17 using a mixed model to determine linear and quadratic relationships between dietary Ca and ADG, DMI, or G:F with citation as a random effect. An economic sensitivity analysis was conducted to determine variables most influential to the dietary Ca concentration projected to minimize cost of gain using the above models. Concentration of dietary calcium was selected as the explanatory variable for the models rather than limestone because a greater proportion of variation was accounted for in the response variables prior to the citation adjustment (Ca R2 0.05 to 0.25; limestone R2 0.06 to 0.21). Diet Ca concentration and DMI were unrelated (P ≥ 0.75), but diet Ca was related to both ADG (R2 = 0.84; RMSE = 0.36; P ≤ 0.03) and G:F (R2 = 0.74; RMSE = 0.01; P < 0.01) in a quadratic fashion. Maximum ADG occurred when Ca was included at 1.20% of diet DM; approximately 2.6-fold greater than Ca requirements estimated by NASEM (2016). Cost of gain was minimized when Ca was 1.35% of diet DM. Sensitivity analysis revealed Ca concentration to minimize cost of gain was sensitive to changes in DMI, ADG, days on feed, ration cost and cost of yardage. These results provide further evidence that it may be beneficial to feed a greater amount of Ca than currently recommended by the NASEM (2016) for growing and finishing cattle. Future pen-scale feeding trials are warranted to validate the results of this meta-analysis and to determine the dose response of cattle fed graded levels of Ca. Future research should also be conducted to determine the mechanism of action responsible for the observed improvements in animal performance and efficiency resulting from feeding an increased amount of dietary Ca.
358 The effect of increasing dietary limestone concentration on growth performance, gas flux, and carcass characteristics in finishing beef cattle
Authors: Long Nathan S , Proctor Jarret , Foster Ryan C , Gouvêa Vinicius N , Beck Matthew R , Smith Jason K
Published: September 2024

Reducing methane (CH4) emissions from beef cattle is desirable as CH4 is a greenhouse gas that represents an energetic loss from the production system. Limestone is commonly fed to cattle as a source of calcium but may also act as a rumen buffer and decrease CH4 emissions by limiting hydrogen availability for methanogenesis. The objective of this experiment was to determine if diet limestone concentration influences growth performance, gas flux, and carcass characteristics in finishing beef cattle. Yearling steers [n = 16; initial body weight (BW) 619 ± 34 kg] were stratified by BW and randomly assigned to 1 of 2 isocaloric and isonitrogenous dietary treatments in a completely randomized design where limestone was included at 1.3% (1X) or 2.6% (2X) of diet dry matter (DM). Finishing diets were formulated to contain 0.43 or 0.96% DM as Ca and were fed ad libitum using automated cattle feeders (SmartFeed Pro; C-Lock Inc.; Rapid City, SD) in a single pen for the final 37 d of finishing. Body weights were measured on d -1, 0, 36, and 37. An automated head chamber system (GreenFeed; C-Lock Inc.) was used to measure gas flux. Analysis of variance was conducted using JMP Pro 17 to determine the fixed effect of treatment with individual animal as the experimental unit. Statistical significance was defined as P ≤ 0.05 with a tendency defined as 0.05 < P ≤ 0.10. Increasing the dietary limestone concentration from 1.3 to 2.6% of DM did not influence DM intake, but numerically increased final shrunk BW (P = 0.68) and hot carcass weight (P = 0.75) and increased average daily gain (ADG; P = 0.02) and gain to feed ratio (G:F) by approximately 12%. Cattle fed the 2X diet tended to have 6.5% greater ribeye area (P = 0.09), but similar USDA yield grade, backfat thickness, and dressing percentage (P ≥ 0.34) when compared with cattle fed the 1X diet. Daily CO2 and CH4 emissions, daily O2 consumption, CH4 yield, and respiratory quotient were unaffected by treatment (P ≥ 0.47). The improvement in ADG resulted in a tendency for CH4 emission intensity to be decreased by 9.1% (P = 0.09) when the concentration of limestone was 2.6% of dietary DM. While increasing dietary limestone concentration from 1.3 to 2.6% of diet DM did not influence absolute daily CH4 emissions, it increased ADG through an improvement in feed efficiency, which translated to a tendency for a reduction in CH4 emission intensity. These preliminary data suggest that there may be a benefit to feeding limestone or calcium at levels greater than currently recommended by the NASEM (2016). Future research should focus on determining optimum dietary limestone or calcium levels for finishing cattle.
398 Effects of timing of fat supplementation on intake, growth performance, carcass characteristics, and methane emissions of finishing beef cattle
Authors: Foster Ryan C , Beck Matthew R , Proctor Jarret , Long Nathan S , Pennington John , Prado Mykael Bichofi Do , Hernandez Mario , Gouvêa Vinicius N
Published: September 2024

Feeding supplemental fat is a common strategy to increase energy density of finishing diets and mitigate enteric methane (CH4) emissions. Recent increases in cost of supplemental fat sources may warrant reduced inclusion and modified feeding strategies. The objective of this experiment was to evaluate the effects of different fat supplementation strategies on growth performance and CH4 emissions of finishing beef cattle. Crossbred steers (n = 54; initial body weight [BW] = 451 ± 3.86 kg) were housed in 6 pens equipped with electronic gates (American Calan Inc., Northwood, NH) allowing individual measurement of feed intake. The basal diet consisted of (DM basis): 62% steam-flaked corn, 20% Cargill Sweet Bran, 3.4% dried distillers grains, 9% corn stalks, 0.6% urea, and 5% vitamin and mineral supplement. Steers were ranked by paired-day unshrunk BW (d -1 and 1), blocked as light or heavy, and randomly assigned to 1 of 4 dietary treatments: 1) no supplemental fat throughout the finishing phase (d 1 to 119; NoFat); 2) 1.5% supplemental fat throughout the finishing phase (d 1 to 119; TotalFat); 3) 1.5% supplemental fat from d 1 to 58 followed by no supplemental fat from d 59 to 119 (EarlyFat); or 4) no supplemental fat from d 1 to 58 followed by 1.5% supplemental fat from d 59 to 119 (LateFat). For treatment diets containing added fat, 1.5% of steam-flaked corn was replaced with 1.5% of corn oil on a DM basis. Paired-day unshrunk BW was recorded on d -1, 1, 58, 59, 118, and 119 to determine average daily gain (ADG) and feed efficiency (gain to feed; G:F). GreenFeed systems (C-Lock Inc.; Rapid City, SD) measured daily CH4 production (DMP; g CH4∙d-1) which was used to determine CH4 yield (MY; g CH4∙kg DMI-1) and CH4 emission intensity (MI; g CH4∙kg ADG-1). Animals were harvested on d 119 to determine hot carcass weight (HCW), dressing percentage (DP), 12th rib fat thickness (FT), ribeye area (REA), kidney pelvic and heart fat (KPH), and USDA yield grade (YG). Data were analyzed using SAS with steer as the experimental unit, a fixed effect of treatment, and random effects of block and steer(treatment). There was no treatment effect on BW, DMI, ADG, or G:F (P ≥ 0.85). There was no treatment effect on DMP, MY, or MI (P ≥ 0.49). There was no treatment effect on HCW, DP, FT, REA, and KPH (P ≥ 0.19). TotalFat had greater (P < 0.05) YG than EarlyFat, but no other differences in YG were observed (P ≥ 0.05). Supplementing crude corn oil at 1.5% of diet DM does not affect growth performance or reduce CH4 emissions of finishing beef cattle; indicating there may be a minimum threshold of fat inclusion to elicit significant changes.
474 Longitudinal assessment of Salmonella enterica prevalence and concentration throughout the gastrointestinal tract of finishing beef steers with and without liver abscesses
Authors: Dornbach Colten W , Broadway Rand R , Line Dalton J , Hanratty Ashlee Noelle , Childress Kallie D , Thompson-Smith Aubrey , Manahan Jeff L , McDaniel Zach S , Canterbury Landon , Sanchez Nicole C Burdick , Galyean Michael , Hales Kristin E
Published: September 2024

Our objective was to longitudinally assess the presence and quantity of Salmonella enterica throughout the gastrointestinal tract of finishing beef steers with and without liver abscesses (LA). Crossbred steers [n = 225; initial body weight (BW) = 353 ± 39 kg] were used in an observational case-control design with individual steer designated as the experimental unit. Nasal, ruminal fluid, and fecal samples were collected at feedlot arrival, 1 wk after adaptation to the finishing diet, and the day before harvest at a commercial abattoir. Healthy and abscessed liver tissue samples were collected at harvest. Steers were fed a steam-flaked corn-based diet without tylosin phosphate. After harvest, LA prevalence was determined, and steers were sorted into those with and without LA. Data were analyzed using the GLIMMIX procedure of SAS. Overall, LA prevalence was 18.7% (n = 42). Nasal Salmonella prevalence was 34.4% but did not differ between steers with or without LA (P = 0.73), and nasal Salmonella concentrations did not differ between treatments (P = 0.85) or collection day (P = 0.50). Ruminal fluid Salmonella prevalence was 73.7% but did not differ between treatments (P = 0.83). From feedlot arrival to harvest, ruminal fluid Salmonella concentration and prevalence decreased (P < 0.01). Fecal Salmonella prevalence tended (P = 0.09) to be 6.4% greater in steers with LA. Conversely, fecal Salmonella concentration tended (P = 0.07) to be 5.9% greater in steers without LA. Fecal Salmonella prevalence was greatest after transition to the finishing diet (P < 0.01), whereas fecal Salmonella concentration was greatest before harvest (P < 0.01). Liver Salmonella prevalence was 9.8% and 6.5% for steers with and without LA, respectively, but did not differ between treatments (P = 0.47). Similarly, liver Salmonella concentrations did not differ in steers with or without LA (P = 0.18). Overall, these data suggest Salmonella concentration and prevalence were affected by time on feed, but not indicative of LA formation.
473 Evaluation of hematology outcomes as indicators of liver abscess formation in beef × dairy cross steers
Authors: Lawrence Macy T , Broadway Rand R , Sanchez Nicole C Burdick , Lawrence Ty , Nagaraja T G , Amachawadi Raghavendra G , Galyean Michael , Hales Kristin E
Published: September 2024

Our objective was to evaluate hematological measurements that could be indicative of liver abscesses (LA) in weaned beef × dairy cross steers. Beef × dairy cross steers [n = 40; initial body weight (BW) = 120 ± 12 kg] were sourced from a local dairy calf ranch and transported 166 km to the USDA-ARS Livestock Issues Research Unit Liberty Farm near Lubbock, TX (d -16). Calves were initially housed outside in soil-surfaced pens for 16 d with ad libitum access to water and high-forage receiving diet before being moved into individual pens within an environmentally controlled barn (d 0). While housed in the barn, calves were cycled between a high-forage diet (2 d) and a high-concentrate finishing diet (3 d) for 3 cycles. Additionally, calves were administered Fusobacterium necrophorum subsp. necrophorum (4.25 x 106 CFU in 100 mL) and Salmonella enterica serotype Lubbock (1.29 x 106 CFU in 100 mL) intraruminally on d 0, 5, and 10. Following the last inoculation on d 10, calves were fed the high concentrate finishing diet for the remainder of the study. Whole blood samples for measurement of complete blood counts were collected via jugular venipuncture on d 0, 10, 21 and 30. On d 31, calves were harvested to determine LA prevalence. Fifty percent of calves developed at least one LA. Complete blood count analysis revealed day effects (P ≤ 0.03) for all variables, with the exception of basophil percentage (P = 0.06; Table 1). Prevalence of a liver abscess was associated with increased (P < 0.01) neutrophil count, neutrophil:lymphocyte ratio, and neutrophil percentage, concomitant with decreased (P ≤ 0.04) lymphocyte percentage, and monocyte percentage. Additionally, a tendency (P = 0.09) was observed for decreased red blood cells in calves with a LA compared with those without. These data suggest that changes in neutrophil and lymphocyte concentrations within the blood may be indicative of LA prevalence in beef × dairy steer calves and hold potential as predictive markers for LA.
154 Forage intake, digestibility, and ruminal fermentation characteristics of beef cows supplemented with a Bacillus-based probiotic
Authors: Marques Rodrigo , Limede Arnaldo C Cintra , Cruz Vinicius Alves , Ogg Makayla A , Cidrini Iorrano A , de Queiroz Amanda Caroliny Marques de Caroliny Marques , Cidrini Fernando , Farias Iasmin , Rodrigues Aline Naime Naime , motter Alarissa , Cappellozza Bruno Ieda
Published: September 2024

The aim of this study was to evaluate the influence of a Bacillus-based probiotic supplementation on intake, digestibility, and ruminal fermentation parameters of beef cows consuming a low-quality forage diet (7.0% CP, 60% NDF, 39% ADF, DM basis). Ruminally fistulated Angus × Hereford cows [n = 15; age = 6.1 ± 1 yr; body weight (BW) = 655 ± 57] were used in two identical complete randomized designs, housed in individual pens with water, and forage intake monitored daily. Treatments consisted of 1) 500 g of protein supplement (dry distillers grain + mineral mix) without probiotic (CON n = 15), and 2) 500 g of protein supplement + 3 g of a probiotic containing Bacillus licheniformis and B. subtilis (BOV; n = 15; 2.2 ×109 CFU of the mixture/g; Bovacillus, Novonesis, Hørsholm, Denmark). Each experimental period lasted 33 d, consisting of 21 d of adaptation, 12 d of collection, and 30 d of wash-out between periods. From d 22 to 26, fecal samples were collected to determine intake and nutrient digestibility using titanium dioxide as an indigestible marker. On d 27, ruminal fluid was collected at h 0 (before feeding), 4, 8, 12, 16, and 20 post-feeding to evaluate short-chain fatty acid (SCFA) and N-NH3 concentration. From d 28 to 32, hay samples (4 g) were fitted in Dracon bags and incubated in the rumen for 0, 12, 24, 48, 72, 96, and 120 h to determine nutrient digestibility. Cows receiving BOV had greater (P < 0.001) dry matter intake compared with the CON group (Table 1). Also, cows supplemented with BOV had greater (P < 0.02) dry matter and protein digestibility and a tendency (P ≤ 0.07) for greater NDF and ADF forage digestibility compared with CON. A tendency was also detected (P = 0.09) for the degradability of forage dry matter, which was improved in BOV vs. CON. No effects were observed on rumen fermentation characteristics (P ≥ 0.14; Table 2).). In conclusion, adding bacillus-based probiotics enhanced the intake, nutritional digestibility, and degradability of beef cows fed medium-quality forage diets.
157 Microbial inoculant effects on limpograss silage
Authors: Lazarin Joao V L , Vendramini Joao M B , Moriel Philipe , Cappellozza Bruno I , da silva Hiran , Miranda Andre , Sinisicalchi Debora
Published: September 2024

Warm-season perennial grasses are the main forage sources preserved as silage or haylage by livestock producers in subtropical and tropical regions; however, the nutritive value and silage fermentation parameters are often less than desirable. Microbial inoculants have been used to improve grass silage nutritive value and fermentation characteristics with inconsistent results. The objective of this study was to investigate the effects of a microbial inoculant on nutritive value and fermentation parameters of ‘Gibtuck’ limpograss (Hemarthria altissima) silage. Treatments were silage treated with SiloSolve FC (68.1 billion CFU/g, Lactobacillus lactis and Lactobacillus buchneri) or control (no microbial inoculant) distributed in a complete randomized design with 10 replicates. The inoculant level used was 0.5 g/Mg of forage. The experiment was conducted in Ona, FL in May 2023. Twenty 4 × 4 m plots of established limpograss were harvested at 15-cm stubble height with 58-d regrowth interval. The forage was chopped to a particle size ranging from 10 to 18 mm, placed into mini-silos (PVC pipes with rubber), and sealed immediately. The inoculant was applied with a hand sprayer before ensiling. The silos were opened after 60 d for analysis. There was no difference (P > 0.05) between the inoculant and control treatments on DM concentration (25%), DM recovery (96%), NDF (67%), and NFC concentrations (14%); however, silage treated with inoculant had greater CP (8.5 vs. 8.0%; P = 0.03), IVTD (56 vs. 54%; P = 0.01), and NDFD (53 vs. 51%, P = 0.02) and lesser ADF concentrations (38 vs. 40%; P = 0.02) than control. The inoculant did not affect (P > 0.05) silage pH (4.2) and lactic acid concentrations (1.5%) but resulted in greater acetic acid (2.5 vs. 2.0%; P = 0.01), propionic acid (1.6 vs. 1.0%, P < 0.01), and total acid concentrations (5.6 vs. 5.0%; P = 0.04), and decreased butyric acid (0 vs. 0.2%; P < 0.01), isobutyric acid (0.1 vs. 0.4%; P < 0.01), and NH3-N concentrations (4.4 vs. 5.3% N; P < 0.01). Aerobic stability (140 h), mold (1.1 log cfu/g) and yeast (2.2 log cfu/g) count were not affected (P > 0.05) by the inoculant treatment. At the genus level, there was no difference (P > 0.05) in relative abundance of Lactobacillus (85%), Enterobacter (4.0%), Enterococcus (1.8%), and Weissella (0.2%) between inoculant and control, but silage treated with inoculant had less Clostridium (1.0 vs. 2.3%, P = 0.04), Pediococcus (0.2 vs. 0.3%, P = 0.03) and greater relative abundance of Lactococcus (2.8 vs. 0.5%, P < 0.01) and Bacillus (0.2 vs. 0.1%, P = 0.01). At the species level, the inoculant was effective to increase the relative abundance of Lactococcus lactis (from 0.02 to 0.48, P = 0.002) and Lactobacillus buchneri (from 1.4 to 1.9, P = 0.03). SiloSolve FC is a promising microbial inoculant to be used in warm-season grass silage in subtropical and tropical regions.