bluuebunny/crossref_metadata_2025 huggingface dataset:
128 Impact of different levels of dark-cutting severity on the retail color and color stability of beef longissimus lumborum steaks
Authors: Harr Keayla M , Scott Madelyn , More Sunil , Mafi Gretchen G , Pfeiffer Morgan , Ramanathan Ranjith
Published: March 2024

Dark-cutting beef is hallmarked by a dark red to almost purple color present within the interface of the ribeye between the 12th and 13th rib of the beef carcass. Yet, the shade or degree of darkness present within the ribeye can vary widely and have a substantial impact on the color and biochemical traits of the steaks. However, limited studies have compared color characteristics of different degrees of dark-cutting during retail display. Therefore, the objective of this study was to evaluate the impact of the visual degree of dark cutting at the time of grading on the retail color and color stability attributes of beef longissimus lumborum steaks. Beef strip loins (IMPS #180) were collected from two different Midwestern beef processors over the course of two collections. Strip loins (n = 8/treatment) were identified based on the degree of dark-cutting present within the ribeye to represent one-half dark, two-thirds dark, full dark, and a control of USDA Choice. At 48 to 60 h postmortem, loins were fabricated from the anterior end into 2.54 cm steaks and randomly assigned to retail display or d 0 lab analysis. Steaks designated for retail display were placed into Styrofoam trays and overwrapped with polyvinyl chloride film, and placed into retail display in coffin style display cases under continuous lighting for 5 d. Steaks designated for d 0 analysis were evaluated for pH, bloom, oxygen consumption, and metmyoglobin reducing activity. All color measurements were taken using a HunterLab MiniScan EZ spectrophotometer. The data were analyzed using the PROC GLIMMIX procedure of SAS at an α < 0.05. Two-thirds and full dark-cutter steaks had a greater (P < 0.05) pH than half and normal steaks on d 0. Moreover, full dark-cutter steaks had a decreased (P < 0.05) bloomed L* value and were darker in color on d 0 than normal and half steaks. Full dark-cutter steaks had a greater (P < 0.05) oxygen consumption and metmyoglobin reducing activity on d 0 than normal and half steaks. Full and two-third steaks had a decreased (P < 0.05) a* value and were less red in color on d 0 of retail display than normal and half steaks. All degrees of dark-cutters had a reduced change in redness than USDA Choice steaks. These results indicate color stability activity can be dependent on the degree of dark-cutting, with full and two-thirds dark-cutters being similar in biochemical activity.
168 Evaluate the digestibility effects of alfalfa-bermudagrass mixtures on beef cattle in the Deep South
Authors: Henson Mason , Zessin Peyton , Dillard Sandra L , Mullenix M Kim , Smith William B
Published: March 2024

In the Deep South, one of the hardest times of year for cattle producers is the summer due to extreme temperatures and low-quality perennial forages. Incorporating a high-quality crop like alfalfa (Medicago sativa) into forage mixtures could be economically advantageous; however, there is not much alfalfa produced in the Deep South. Therefore, our objective was to evaluate the effects of forage type on in vivo digestibility and nutrient balance in beef cattle systems. There was also an interest in differing conserved forage types, so we analyzed digestion dynamics influenced by various conserved forage types. Three treatments including bermudagrass (Cynodon dactylon) hay, alfalfa baleage, and alfalfa-bermudagrass baleage were supplied to four fistulated steers (average 412.34 kg +/- 41.25 kg) with a calculated daily forage allowance based on intake, body weight, and feed refusals. Each diet was allocated to one of three periods in which all four animals received the same diet due to potential feed spoilage. Each period had a 21-d adaptation period followed by a 5-d collection period to analyze total fecal excretion, feed intake, feed refusal, total urine output, and rumen fluid dynamics. Data were analyzed using R Core Team (2023) and the GLIMMIX procedure of SAS version 9.4 (SAS Inst., Cary, NC). There were significant differences in dry matter digestibility (DMD) between diets (P < 0.0015). We found that alfalfa-bermudagrass baleage had a 9% (+/- 0.058, 95% C.I.) less DMD than bermudagrass hay (P < 0.0088) and alfalfa baleage had a 7% (+/- 0.058, 95% C.I.) greater DMD than bermudagrass hay (P < 0.025). Results indicate that alfalfa baleage provides the most nutrient use efficiency when comparing alfalfa-bermudagrass mixtures. There was no significant conserved forage effect potentially due to baleage quality and inadequate fermentation of the alfalfa-bermudagrass baleage. That said, there is still potential for beef cattle producers in the Deep South to diversify feeding strategies by using nutrient-rich forage additives like alfalfa and different conserved forage methods to increase digestibility, thus increasing returns in their operations.
165 Does supplementation of beef cattle impact the agronomy performance of tall fescue and bermudagrass pastures?
Authors: Farney Jaymelynn K , Warner Jason , Banks James , Yasuoka Junior , Pedriera Bruno
Published: March 2024

In forage-based beef cattle systems, bermudagrass [Cynodon dactylon (L.) Pers.] and tall fescue (Festuca arundinacea Schreb.) stand as widely used forage species. The strategic supplementation of animals may reduce forage intake, thereby potentially affecting the agronomic performance of these grasses. Our objective was to evaluate the impact of beef cattle supplemental feeding on forage accumulation, forage mass, and nutritive value in tall fescue and bermudagrass pastures. Two studies were conducted where pregnant beef cows were supplemental fed 1% of BW on DM basis of corn silage daily (SUP) or received no supplemental feeding (free-choice mineral; NON). Trial 1: conducted on bermudagrass pastures (BERM) grazed from late May to early October. Experimental design for BERM was completely randomized design with 4 pastures per treatment (n = 3 cows/pasture; average 5 years of age; 550 ± 72 kg initial BW). Trial 2: conducted on fescue pastures (FES) with an experimental design of a 2 x 2 factorial arrangement. The two factors evaluated were fescue type [TOXIC (507 ppm ± 0.82 SEM ergot alkaloids; 92.5% endophyte infection)] or non-toxin-producing (NT; 5 ppm ± 2.50 SEM ergot alkaloids; 38.6% endophyte infection) and two levels of supplemental feeding (NON or SUP). There were 3 or 4 replications per fescue x supplemental feeding treatment (n = 15 pastures), stocked with 3 cows/pasture (average age 4.75 years; 558 ± 73 kg initial BW) and grazed from early May through November. Forage accumulation (FA) was estimated every 28 d using the paired-cage method (4 exclosure cages/pasture). On each exclusion period, the forage mass (FM) was estimated both inside and outside the cages through destructive sampling method and samples analyzed for forage quality. Pasture was experimental unit and repeated measures were included in analysis. Bermudagrass FM tended to be increased by 31% with SUP (P = 0.09; 774 kg/ha greater). Forage accumulation tended (P = 0.07) to be affected by feeding method x month. There was greater FA in June for SUP; however, there was greater FA for NON in July. SUP pastures had greater ADF (1% more; P = 0.01) and reduced TDN (1.5%; P < 0.01) than NON. Forage mass tended to be 10% greater for TOXIC pastures (P = 0.09; 409 kg/ha more forage mass). Supplemental feeding on fescue did not impact FM (P = 0.74). Forage accumulation was not impacted by fescue type, feeding method, nor the interaction (P > 0.30). Cows generally do not consume as much toxic fescue, thus more forage is available in pastures and supplemental feeding did not alter forage parameters. However, on a warm-season grass that is growing while supplemental feeding, forage availability was increased and maybe useful as method to increase stocking rates or as mitigation tool during drought.
161 Effects of Sericea Lespedeza Supplementation on Steers Grazing Wild-Type Endophyte-Infected Tall Fescue
Authors: Poudel Sanjok , Pent Gabriel J , Fike John H , Harlow Brittany , Zeller Wayne
Published: March 2024

Fescue toxicosis poses a significant challenge to the United States beef industry, resulting in considerable economic losses. This syndrome arises from the consumption of tall fescue (Schedonorus arundinaceous) infected with the wild-type endophyte (WE; Epichloe coenophiala), which produces toxic alkaloids. The most effective solution for mitigating fescue toxicosis is renovating WE tall fescue pastures to novel endophyte-infected (NE) tall fescue. However, pasture renovation is costly and may not be feasible under certain conditions, with the economic profitability taking up to 3 yr. While the potential of condensed tannins (CTs) in specific leguminous forages to reduce the absorption of toxic alkaloids is recognized, their use as supplements remains underexplored. This study aims were to investigate the potential of CT-containing feed supplements, specifically sericea lespedeza (Lespedeza cuneata) pellets, in reducing the post-ingestive effects of fescue toxicosis in steers. Over two summers,12 steers were assigned to either Schedonorus arundinaceous (LES) or LES mixed with polyethylene glycol (LES + PEG) as a positive control for 12 wk. Body weight, hair retention score, rectal and extremities temperatures, cortisol concentrations, and lumen area of caudal arteries were collected at 4-wk intervals. Data were analyzed using a mixed-effect ANOVA test in SAS Studio 3.5. Steers on the LES diet exhibited significantly less (P < 0.05) hair retention scores compared with those on the LES + PEG diet. In 2021, steers on the LES diet showed greater (P = 0.0101) ADG, while in 2022, there was no difference (P = 0.9916) in ADG between the treatments. Steers on the LES diet displayed greater (P = 0.0332) tail skin temperatures and decreased (P < 0.0001) rectal temperatures compared with those on the LES + PEG diet. Hair cortisol concentrations were greater (P < 0.05) in steers on the LES + PEG diet than in those on the LES diet. Additionally, steers supplemented with the LES + PEG diet showed a 21.2% smaller caudal artery lumen area compared with those on the LES diet (P < 0.01). These findings underscore the potential of CTs in reducing the post-ingestive effects of fescue toxicosis. However, further research is needed to explore the complex mechanisms underlying these effects, establish the long-term efficacy of such interventions, and extend the investigation to include a broader range of physiological parameters affecting livestock health and performance.
21 Ancylostoma caninum-derived neutrophil inhibitory factor impairs ovine neutrophil chemotaxis to Haemonchus contortus larval antigen in Suffolk but not St. Croix sheep
Authors: Teddleton Hannah G , Greiner Scott P , Bowdridge Scott A
Published: March 2024

Parasite-resistant St. Croix sheep (STC) generate a potent neutrophilic response to larval stages of Haemonchus contortus (Hc) as demonstrated by abomasal neutrophil infiltration as early as 3 days after infection. This phenomenon is delayed in parasite-susceptible Suffolk sheep (SUF) potentially contributing to larval establishment. An excretory/secretory (E/S) product, common to many helminths, is neutrophil inhibitory factor (NIF) which negatively affects neutrophil migration and activity. Due to differences in neutrophil accumulation between STC and SUF sheep, we hypothesized that Hc-NIF may inhibit migration of SUF and not STC neutrophils. To determine the concentration of NIF to use in subsequent experiments, neutrophils from STC and SUF were cultured with varying concentrations of Ancylostoma caninum-derived NIF (Ac-NIF) before exposure to larval Hc third-stage larval antigen (HcLA). Analysis of migration to stimuli revealed that the Ac-NIF concentration of 0.125 ug/mL yielded the greatest inhibition of migration towards HcLA between SUF and STC (8.70% and 11.64% migration, respectively; P = 0.0004).To test our hypothesis, neutrophils were cultured from STC and SUF sheep in the presence of Ancylostoma caninum-derived NIF (Ac-NIF) and measure chemotaxis to Interleukin-8 (IL-8), HcLA or Hc third-stage excretory/secretory (E/S) products. Neutrophils were isolated then incubated with Ac-NIF (0.125μg/mL) or complete media for 1 h. Neutrophils (1,000,000 cell/mL) were applied to cell migration inserts, and placed into a reservoir containing HcLA (20 μg/mL), E/S (20 μg/mL), IL-8 (50 ng/mL), or complete media. Migration plates were incubated (37°C, 5% CO2) for 24 h, after which, migrating cells were quantified using fluorescence. Ac-NIF inhibited SUF neutrophil migration towards IL-8 compared with STC (6.47% vs 9.95%, respectively; P = 0.0025). In response to HcLA alone, 64.0% of STC neutrophils migrated, while only 40.9% of SUF had the ability to migrate (P < 0.001). Towards HcLA, Ac-NIF inhibited SUF neutrophil migration compared with STC (8.40% vs 13.8%, respectively) (P < 0.001). Even more dramatically, in response to E/S products alone, only 24.3% of SUF neutrophils had the ability to migrate, while 76.4% of STC neutrophils migrated towards E/S (P < 0.001). In response to E/S, only 1.52% of SUF Ac-NIF-treated neutrophils were able to migrate, while 23.27% of STC neutrophils migrated (P < 0.001). Taken together, these data demonstrate that STC neutrophils are resistant to effects of neutrophil inhibition that is artificially applied or derived from HcE/S, which may explain breed differences in neutrophil migration in vivo.
18 Progesterone and insulin concentrations during pregnancy in slick and wild type-haired Holstein cows
Authors: Tirado-Colón Anayra I , Feliciano-Figueroa William D , Sánchez-Rodríguez Héctor L , Negrón-Pérez Veronica M , Jiménez-Cabán Esbal
Published: March 2024

In cattle, the presence of the SLICK gene has been associated with shorter calving intervals when exposed to tropical climates. However, the effects this genotype may have in terms of circulating hormones during pregnancy have not been reported. Therefore, the current study aimed to determine if reproductive hormones concentrations differ during the gestation between slick (SH) and wild type-haired (WT) cattle. Holstein heifers were estrus synchronized and inseminated during Winter (December) and Summer (June). A total of 13 SH and 8 WT Holstein heifers became pregnant and are included in the current study. Beginning on the day of insemination (d 0), blood samples were collected every 28 d. Commercially available ELISA kits were used to determine the plasma concentrations of bovine progesterone and insulin. The effects of hair coat genotype, season, day of pregnancy, and the respective interactions were tested by PROC Mixed in SAS. Day of pregnancy was utilized as a repeated measure for each animal. A significant season x day of pregnancy interaction (P < 0.001) was observed for the plasma concentrations of progesterone. On gestational d 0, 28 and 56, progesterone concentrations were greater for heifers inseminated during the Winter (7.11 ± 0.50, 5.31 ± 0.51, 5.39 ± 0.49 ng/mL, for d 0, 28 and 56 of pregnancy, respectively) when compared with those inseminated during the Summer (3.04 ± 0.45, 3.17 ± 0.45, 3.21 ± 0.45 ng/mL, for d 0, 28 and 56 of pregnancy, respectively). For insulin, also a significant interaction of season x day of pregnancy was observed (P = 0.004). On d 112 of pregnancy, the concentrations of insulin were greater for heifers inseminated during Winter (0.337 ± 0.03 ng/mL) when compared with those inseminated during Summer (0.082 ± 0.08 ng/mL). No other significant interactions were observed. Neither differences in progesterone (P = 0.70; 3.7 ± 0.33 and 3.9 ± 0.25 ng/mL, for WT and SH, respectively) nor insulin (P = 0.46; 0.20 ± 0.02 and 0.18 ± 0.01 ng/mL, for WT and SH, respectively) were observed between genotypes. Further research comparing other hormones during pregnancy may provide useful information between genotypes that may help to explain the better reproductive performance of SH dairy cows.
15 Influence of early progesterone removal on follicular development, estrus expression, and pregnancy rates in presynchronized beef cows
Authors: Burato Samir , Walker Madison B , Goncalves Lucas M , Oosthuizen Nicola , Zoca Saulo M , Ciriaco Francine M , Henry Darren D , Ranches Juliana , Fontes Pedro L P
Published: March 2024

The objective of this study was to evaluate the impact of early progesterone removal on pregnancy rates to fixed-time artificial insemination (FTAI) in presynchronized beef cows. Postpartum beef cows (n = 922; body condition score = 4.9 ± 0.77; days postpartum = 77.3 ± 20.77 d) from 7 locations were enrolled in a completely randomized design. Within location, cows were stratified by parity and days postpartum before being randomly assigned to 1 of 2 treatments: 1) 7&7 Synch: Cows received a controlled internal drug release insert (CIDR) and a 25-mg injection of prostaglandin F2α (PG1; d 0). Cows received 100 μg of GnRH on d 7 and the CIDR was removed 7 d later, concurrently with a second prostaglandin F2α (PG2) injection (d 14). Cows received a second injection of GnRH and were FTAI 60-66 h after PG2 (d 17); 2) 7&6 Synch: Cows received the same treatment as 7&7 Synch cows; however, CIDR removal and PG2 were performed on d 13, and cows were FTAI 60-66 h after CIDR removal. Ovarian ultrasonography was performed to determine follicle diameter and CL presence at PG2 and FTAI in a subset of cows (n = 40). Estrus detection patches were utilized to evaluate estrus expression between PG2 and FTAI. Pregnancy diagnosis was performed 28-35 d after FTAI. Cows exposed to the 7&7 Synch tended to have larger follicle diameter at PG2 compared with 7&6 Synch cows (P = 0.09); however, there were no differences in follicle diameter at FTAI. Cows that expressed estrus tended to have larger follicle diameter at FTAI compared with cows that failed to express estrus (P = 0.10). Follicular growth between PG2 and FTAI, percentage of cows with a corpus luteum at PG2, and ovulation rate were not impacted by treatment (P ≥ 0.56). No differences were determined between treatments for estrus expression (7&7 Synch: 77.1 ± 5.91; 7&6 Synch: 74.6 ± 6.28; P = 0.50) or pregnancy rates to FTAI (7&7 Synch: 60.1 ± 4.32; 7&6 Synch: 58.2 ± 4.26; P = 0.69). In conclusion, early removal of progesterone did not impact pregnancy rates in presynchronized beef cows. Thus, the 7&6 Synch protocol described herein may be used as an alternative to the conventional 7&7 Synch protocol without compromising fertility.
28 Investigating the effects of Chromium Propionate supplementation on reproductive performance of beef cows
Authors: Vidlund Trinity , Craun Hannah , Mitchell Camille , Currin John , Stewart Jamie L , Clark Sherrie , Redifer Tracey , Mercadante Vitor R G
Published: March 2024

The objective of this study was to explore the effects on reproductive performance of beef cows supplemented with Chromium Propionate during the post-partum and breeding periods. A total of 955 multiparous suckled beef cows located at eight locations were enrolled in the study. Within location cows were stratified based on parity, body condition score (BCS), and days postpartum (DPP) and randomly assigned to one of two treatments: 1) Control- supplementation of a mineral product at 113 g animal/d (n = 484 cows; 16 experimental units); or 2) CrP - supplementation of mineral product at 113 g animal/d containing Chromium Propionate (0.4% animal/d, KemTRACE, Kemin Industries; n = 471 cows; 16 experimental units). Mineral supplementation was offered starting at 45 d pre-breeding, during the breeding season, and until weaning for a total of approximately 150 d. Cows were enrolled in a fixed-time artificial insemination (TAI) using the 7-d CO-Synch+CIDR protocol followed by natural service with clean-up bulls 7 d after TAI, for a 70-d total breeding season. Pregnancy diagnosis was performed by ultrasonography 55 d after TAI and again approximately 40 d after the end of the breeding season. Cow body weight (BW) and BCS were recorded at the beginning of the experiment (d -45), at the initiation of the TAI protocol (d -10), at each pregnancy diagnosis (d 55 and 110), and at weaning (d 150). Mineral intake was estimated based on the difference in weight between offered mineral and refusals. Data were analyzed using the GLIMMIX, for binomial data, and MIXED, for continuous data, procedures of SAS. Cow initial BW and DPP were similar (P > 0.10) between treatments (584 ± 198 kg and 78 ± 3 d, respectively). Estimated mineral intake was similar (P = 0.52) between treatments (119.6 ± 10.3 g and 124.5 ± 10.4 g animal/d, for Control and CrP, respectively). Supplementation of CrP did not influence estrus expression (58.3% vs 61.0% ± 2.5 %; P = 0.45), TAI pregnancy rates (63.1% vs 60.1 % ± 2.9 %; P = 0.56), or final breeding season pregnancy rates (94.2% vs 94.7% ± 2.9 %; P = 0.86), for CrP and Control, respectively. Chromium Propionate supplementation did not affect (P > 0.10) final cow BCS and BW (5.2 ± 0.03; 562.9 ± 169.93 kg). In conclusion, Chromium Propionate supplementation delivered via an oral mineral supplement during the pre-breeding and breeding periods did not influence reproductive performance and changes in BW and BCS of beef cows.
137 Impacts of heat stress on the accuracy of an ear-tag sensor for detection of eating and rumination behavior in cattle
Authors: Weinert-Nelson Jennifer R , Werner Jessica , Jacobs Alayna A , Anderson Leslie H , Hamilton Tracy A , Williams Carey A , Davis Brittany E
Published: March 2024

Ear-tag accelerometers are used for precision livestock management, but little is known regarding effects of varying environmental conditions on sensor performance. The objective was to evaluate accuracy of a commercially available ear-tag sensor (CowManager SensOor, Agis Automatisering BV, Harmelen, the Netherlands) in quantifying feeding behaviors under varying temperature-humidity indices (THI). RumiWatch System (RW) noseband sensors (Itin+Hoch GmbH, Liestal, Switzerland) were utilized as a benchmark. Nine Holstein-Angus steers (body weight: 488 ± 9 kg) were fitted with CowManager (CM) sensors and RW halters, with continuous monitoring during two 14-d phases: thermoneutral (TN: 21.0 ˚C, 64.0% humidity, THI = 67) and heat stress (HS: cyclical daily temperatures to mimic diurnal patterns; HS: 23.2 ˚C – 33.6 ˚C, 39.5 – 70.0% humidity, THI = 70.3 – 83.5). Steers were individually-housed (3×3 m) and provided ad libitum access to a mixture of corn silage and dried distillers grains with solubles. Hourly summaries of eating time (ET) recorded by CM were compared with EAT1TIME (head down) and EAT2TIME (head up) parameters from RW (v.7.3.36) as well as total ET (EAT1TIME + EAT2TIME); rumination time (RT) was also compared. Agreement was evaluated (R; v.4.3.1) over the full 24-h day (FULL) and a 6-h period from afternoon to early evening (AFT; 1400 – 2000 h) when HS effects would be most pronounced. Across both 14-d phases, agreement between CM and EAT1TIME was moderate to high (concordance correlation coefficient [CCC] = 0.69 to 0.77), whereas agreement with EAT2TIME and total ET was poor to moderate (CCC = 0.41 – 0.61). Bland-Altman analysis demonstrated significant underestimation of total ET by CM, with biases of -8.98 (-10.88, -7.09) to -6.44 (-7.51, -5.38) min h-1. Agreement for EAT1TIME was high for TN (CCC = 0.74), but only moderate during HS (CCC = 0.69) for the FULL dataset. Similarly, agreement for total ET was moderate for TN but poor for HS over FULL and during AFT, respectively (CCC: TN – 0.53, 0.54; HS – 0.47, 0.41). CowManager significantly underestimated EAT1TIME during HS (bias: FULL = -1.45 [-2.60, -0.30]; AFT = -2.14 [-3.93, -0.35] min h-1), but not TN (bias: FULL = -1.38 [-2.82, 0.06]; AFT = -1.83 [-3.68, 0.02] min h-1). Agreement for RT was high regardless of environmental conditions and time period analyzed (CCC = 0.74 – 0.81). However, during the critical AFT period, CM significantly overestimated RT under HS (bias: 4.42 [2.06, 6.79] min h-1) but not TN conditions (bias: -0.47 [-2.42, 1.47] min h-1). These results indicate that ET reported by CM is more reflective of time eating with the head down than the total time engaged in eating behaviors. Results of this study also suggest accuracy of ear-tag accelerometers may be impaired when cattle are subjected to heat stress.
136 Evaluation of internal parasite burden in grazing beef cattle in North Carolina over a production lifecycle
Authors: Williams Katherine G , Pickworth Carrie L , Weaver Andrew R , Poole Daniel H
Published: March 2024

Gastrointestinal nematode (GIN) parasite infections can be detrimental to not only cattle health and immunity, but also result in economic loss and poor performance. Cattle grazing in the southeast are challenged even further by the favorable environmental conditions for parasite development, especially those animals who have yet to develop an immunity to combat parasitism. To diminish potential economic and performance-based losses, many beef producers treat animals for GIN parasites with anthelmintics on a regular basis without proper diagnosis. Anthelmintic resistance(AR) develops when deworming products are overused and misused. To minimize the development of AR, selective deworming and sustainable management practices should be implemented. However, the severity of parasite burden over the production cycle needs to be better understood in beef cattle herds before recommendations can be made. Thus, the objective was to investigate the rates of GIN parasite infections through fecal egg counts (FEC) and the impact on body weight (BW) and body condition score (BCS). Angus-based cattle (6 mo-13 yr, n = 1,154) on a were utilized from five different research and educational herds across North Carolina. Cattle were categorized based on their age at the start of the project as either calves (n = 446), yearling heifers (n = 205), 2 year old (n = 260), 3-5 year old (n = 501), or 6+ year old (n = 206). Starting in September, FEC, BW, and BCS were collected and analyzed every 90 d at critical production timepoints (calving, breeding, weaning, and 90d post-weaning) to monitor the severity of GIN parasite challenge. Cattle on study were not treated with anthelmintics regardless of parasite load, with the exception of calves at four of the locations at the time of weaning. All data were analyzed using Proc MIXED in SAS with repeated measures. Statistical significance was declared at P ≤ 0.05 and a trend at 0.10 > P > 0.05. Age of cattle had an impact on FEC overall (P < 0.05), however, there was no difference between FEC of mature cattle over 3 yr (4.29 ± 4.9 eggs/gm). Calves had the greatest FEC (120.59 ± 4.2 eggs/gm) while cattle 6+ yr had the least (3.68 ± 4.5 eggs/gm). Cattle age at each location affected BCS and BW (P < 0.05). Between age groups across locations, time had an impact on FEC, BW, and BCS (P < 0.05). There was also a tendency (P = 0.6) for location to impact FEC. Calf sex did not affect (P > 0.05) FEC. Further FEC analysis of cattle under 2 yrof age is required to better understand when a natural immune response to GIN parasite infections develops.
144 Utilizing invasive pigweed (Amaranthus Spinosus) as a novel methane mitigation strategy in beef cattle feed: A sustainable approach
Authors: Cuervo Wilmer , Gomez Camila , Fernandez-Marenchino Ignacio , Maderal Araceli B , Tarnonsky Federico , Erazo-Mendes Cristian , Schulmeister Tessa M , DiLorenzo Nicolas
Published: March 2024

By 2050, the US beef industry must produce an extra 40 million tons of beef to satisfy the global demand, while reducing methane (CH4) emissions. This surplus of cattle will be provided mostly by cow-calf operations, which rely primarily on grazing. Those pastures are often infested with weeds such as pigweed (Amaranthus spinosus), one of the most invasive in the US, known for its increased polyphenols concentration. Despite the known effect of polyphenols on CH4 reduction, few studies have explored pigweed as a feed additive. Our objective was to evaluate the effect of in vitro addition of pigweed on ruminal fermentation, digestibility, and CH4 production. We collected ruminal fluid from three American Aberdeen steers (374 ± 21 kg) receiving a backgrounding diet (80:20% corn silage:cotton gin trash, as fed). We incubated (24 h, 39°C) diet (0.7 g) plus the inclusion of 0, 2.5, 5, or 10% (of diet DM) of roots, stems, leaves, seeds, or the whole pigweed plant (WHO). Volatile fatty acids (VFA), CH4 (mmol g-1 organic matter), ammonia, pH, gas, in vitro dry matter, and organic matter digestibility (IVDMD and IVOMD) were determined. Using the MIXED procedure of SAS, data were analyzed as a randomized complete block design with a 5 × 4 factorial arrangement of treatments with plant part (n = 5) and inclusion level (n = 4) as fixed main factors. Incubation and bottle within incubation were random effects. Polynomial orthogonal contrasts were used to determine linear, quadratic, and cubic effects of inclusion level. Plant × level interactions were detected in acetate, propionate, and butyric molar proportion, total VFA, CH4 production, and IVDMD (P < 0.01). Increasing levels of stems increased acetate concentration (P = 0.03), while those from WHO led to a linear reduction of acetate (P < 0.01). The inclusion of 2.5% of leaves, seeds, and WHO increased propionate concentration (P = 0.05), but greater levels decreased it (P < 0.01). Increasing levels of all parts decreased acetate:propionate proportion (P < 0.001). Increasing levels of WHO resulted in a linear reduction of CH4 production (P < 0.05), while increasing inclusion of roots and stems increased CH4 production (P < 0.01). Quadratic reductions in CH4 production were observed after increasing the addition of leaves, seeds, and WHO (P < 0.001). Increasing levels of leaves and roots decreased ammonia concentration (P < 0.01) while stems increased it (P = 0.01). Except for stems and roots, there was a linear decrease in IVDMD with increasing levels of all parts (P < 0.001). The inclusion of low levels of seeds, leaves, and WHO promoted ruminal changes leading to a reduction of CH4 production without significantly compromising the digestibility.
148 Supplementing Bovacillus to newly weaned beef steers during a 90-d grazing period
Authors: Cooke Reinaldo F , Mackey Shea , Pickett Autumn , Colombo Eduardo , Cappellozza Bruno I , Karisch Brandi B , Harvey Kelsey M
Published: March 2024

This experiment compared performance, health, and physiological responses of high-risk stocker cattle receiving a Bacillus subtilis derivative during a 90-d grazing period. Crossbred steers (n = 120) were obtained from an auction yard and transported to the experimental facility. Steer shrunk body weight (BW) was recorded at arrival (d -1). This value was averaged with BW recorded on d 0 to represent initial BW (236 ± 2 kg). On d 0, steers were ranked by BW and allocated to 1 of 12 pastures (4-ha pastures; 10 steers/pasture). Pastures were randomly assigned to receive daily supplementation with dried distillers’ grains at 1% of BW containing either: 1) Bacillus licheniformis and B. subtilis ingredient (BOV; 2 g/steer daily of Bovacillus, Chr Hansen A/S, Horsholm, Denmark) or 2) no additive (CON). Cattle received treatments from d 0 to 90 while housed in pastures containing stockpiled grass forage, as well as free-choice access to water and a commercial mineral + vitamin mix without ionophores. Steers were assessed for bovine respiratory disease (BRD) signs daily, and shrunk BW recorded on d 91. Blood samples were collected, and BW recorded on d 0, 14, 28, 56, and 90. No treatment differences were detected (P ≥ 0.19) for glucose, non-esterified fatty acids, β-hydroxybutyrate, haptoglobin, or insulin-like growth factor 1, whereas a treatment × day interaction indicated increased cortisol in BOV cattle on d 56 (P < 0.01). A treatment × day interaction was detected for serum concentrations of parainfluenza type 3 antibodies, which was greater in BOV steers on d 90 (P < 0.01). No treatment differences were detected (P ≥ 0.23) for serum concentrations of antibodies against other BRD pathogen. Average daily gain (ADG) tended to be increased (P = 0.09) in BOV compared with CON steers from d 56 to d 90 (0.858 and 0.760 kg/d, respectively, although did not impact overall ADG (P = 0.48). No treatment differences were detected for steer final BW (P = 0.43). Total BW change per pasture was greater in BOV compared with CON (790 vs. 550 kg BW change; P = 0.02). No treatment differences were detected (P = 1.00) for BRD incidence, although steers removed from the experiment for health reasons tended to be increased in CON compared with BOV (P = 0.08). Despite lacking differences in health or physiological responses, B. licheniformis and B. subtilis supplementation increased overall production of BW in high-risk stocker steers during a 90-d grazing period.
2 Number of spot samples required when using the GreenFeed System in grazing beef cows
Authors: Dressler Elizabeth , Bormann Jennifer M , Weaber Robert , Rolf Megan M
Published: March 2024

Methane (CH4) production from beef cattle occurs through a natural digestive process called enteric fermentation. This has increasingly become an area of focus due to environmental and efficiency concerns. There are several techniques to quantify gas fluxes from beef cattle such as an open circuit gas quantification system (OCGQS). The GreenFeed (C-Lock, Inc.) is an OCGQS, which has been validated in previous literature, that is capable of quantifying CH4, carbon dioxide (CO2), and oxygen (O2) from grazing beef cattle. However, few studies have reported the minimum number of spot samples to quantify gas fluxes from an individual animal, particularly in a grazing environment. No recommendations have been made to evaluate the number of spot samples for the calculation of metabolic heat production, using the gas fluxes quantified by an OCGQS. A minimum of 100 spot samples each were collected from 17 grazing animals using an OCGQS. The mean gas fluxes were computed starting from the first 10 visits (forward) and increasing by increments of 10 until 100 visits was reached and also from visit 100 moving back in time in increments of 10 (reverse). Mean gas fluxes were used to calculate individual animal metabolic heat production for each interval with both the forward and reverse approach. Pearson and Spearman correlations were computed between the full 100 visits and each shortened visit interval. Mean forward and reverse gas fluxes and metabolic heat production were also computed starting at 30 visits and increasing by 2 until 40 visits and vice versa. The minimum number of spot samples was determined when correlations with the full 100 visits were greater than 0.95. The minimum number of spot samples needed for accurate quantification of CH4, CO2, O2, and metabolic heat production were 38, 40, 40, and 36, respectively. Simultaneous collection of gas fluxes for the calculation of metabolic heat production would require at least 40 spot samples given the recommendations for gas flux components. Animals had an average of 1.2 visits/day to the OCGQS in this study. Therefore, animals met the required number of spot samples for quantification of metabolic heat production, CH4, CO2, and O2 in 29.5 ± 8.7, 30.5 ± 9.1, 31.8 ± 9.2, and 31.8 ± 9.2 d, respectively. There was large variation in the number of days needed to achieve the recommended number of spot samples. For this reason, protocols for the OCGQS should be based on the total number of spot samples, rather than a test duration. These recommendations can be applied to grazing cattle that typically have more infrequent visits. More research is needed to establish if the minimum number of spot samples would be fewer if animals have more frequent visits, although this is difficult in grazing settings.
4 Utilizing SmartFeed Pro and SuperSmart Feeders for applied beef cattle research
Authors: DelCurto Timothy , Wyffels Sam
Published: March 2024

Designing research for applied beef cattle production systems has always presented challenges for Land Grant University and USDA Scientist. Specifically, creating study designs that have enough replication for statistical inference has often prompted scientists to use designs that do not closely replicate actual production systems. Past research has often used multiple replications (pens/paddocks/pastures) that utilize replication (group averages; 4 – 8 animals) means as the experimental unit. While effective in measuring average treatment responses, these types of study designs do little to describe the actual individual animal behavior and performance in a more practical production environments. Approaches to increasing statistical observations in actual production environments will be discussed in this presentation. Embracing new technologies such as GPS, activity monitors, EID tags, and feed intake monitors (C-Lock Inc, GrowSafe) combined with multiple regression modeling tools can aid in designing and publishing beef cattle production research in actual beef production environments. Research at Montana State University has utilized SmartFeed Pro and SuperSmart Feeders for strategic supplementation research on extensive rangelands and dry-land pastures for the past seven years. Results of these studies have evaluated self-fed (salt-limited; loose, pelleted, and baked molasses blocks) as well as hand-fed supplements where daily intakes are limited by the locking gate on the feeder. This presentation will summarize these studies with a focus on research designs that were successful and/or unsuccessful in respect to characterizing beef cattle performance in production settings. Our goal will be to assist the audience in the application of feed intake technology in designing future applied beef cattle research.
52 Evaluation of linseed meal on ovarian follicular development after synchronization in preovulatory small ruminants during seasonal anestrus
Authors: Poole Cameron A , Meyer Audrey G , Runyan Chase
Published: March 2024

Seasonal estrous of small ruminants can hinder overall reproductive efficiency of holistic management strategies involving sheep and goats. The objective of this study was to quantify the effect of increased melatonin containing feed ingredients on ovarian function during seasonal anestrus. Ovarian follicle number and follicle sizes were evaluated on Spanish × Boer cross does and Rambouillet ewes amounts of lineseed meal in the treatment diet (P30DIET) or an isocoloric and isonitrogenous control diet (CON). The P30DIET contained 2.5% linseed meal which contained increased melatonin (Manchester et al. 2000). At d -18 ewes and does were stratified by age into treatment groups and the P30DIET and CON diets were supplemented (0.91 kg and 0.68 kg per animal per day for sheep and goats, respectively). Synchronization protocols were administered at d 0 for both groups and ovarian ultrasound measures were collected 48 h after the removal of the controlled internal drug release device (CIDR). Mixed model procedures of SAS were used to analyze the number of dominant follicles that were present following the synchronization protocols. The number of dominant follicles observed in the P30DIET goats was significantly greater than the CON consuming goats (P < 0.05). Least Squares Means estimates (LSMEANS) in the P30DIET were 1.5 ± 0.20 as compared with CON goats (0.91 ± .21). These data suggest that flushing small ruminants with greater linseed meal during the seasonal anestrus period can increase the number of dominant follicles therefore implying an improvement in reproductive efficiency in holistic management strategies of small ruminants.
57 Impact of Cache Valley Virus in an Arkansas sheep flock
Authors: Burke Joan M , Wood Erin , Lee Charles , Carpenter Ann , Kojima Noah , Fagre Anna , Calvert Amanda , Thrasher Elisa , Martin Stacey , Staples Erin , Gould Carolyn
Published: March 2024

Cache Valley Virus (CVV) is an arbovirus transmitted between mosquitos and several vertebrate species, including small ruminants. Infections in adult sheep and goats is generally subclinical, but infection during pregnancy is a growing animal welfare issue as it can result in embryo or pregnancy loss, fetal malformation, and dystocia. Diagnosis in fetal tissue or neonates is made using serologic or molecular testing. Serologic diagnosis in the dam can indicate past infection but does not confirm CVV infection in the fetus. ARS first noted clinical signs of possible CVV during the Nov/Dec 2015 lambing; first seropositive dam was identified in Jan 2021. To estimate incidence of CVV infections among ewes bred from 2019-2023 and lambing in Jan/Feb (n = 185), adverse pregnancy outcome such as embryo loss, birth of dead, deformed, or weak lambs, were used as surrogate markers. The relationship of animal BW (ewes at breeding and post-breeding; lambs at birth and ~60 d of age), dam age, lamb outcome, and breeding year were compared by likely CVV infection status. To estimate seroprevalence in ewes and correlate serology results with pregnancy outcomes, serum was collected from ewes (n = 46) exposed to rams in Aug 2022 at 0 (first day of ram exposure) and ~60 d later. Tissue from aborted or dead lambs and serum from live lambs exhibiting signs of CVV (swollen joints, parrot mouth, deformities) were collected. Serum was screened for neutralizing antibodies using a CVV-specific plaque reduction neutralization test using a 50% cut-off (PRNT50). For this preliminary analysis, specimens with PRNT50 antibody titers ≥ 10 were considered positive. Tissue specimens were tested using bunyavirus and CVV RT-PCR. Data were analyzed by GLM (SAS). Using surrogate markers, an estimate of incidence of CVV during pregnancy was 26.5 ± 2.9% without year differences (P = 0.16) or age (yearling vs older ewes, P = 0.44). There was no association between CVV and dam BW (P > 0.10), number of live+dead lambs born, but CVV possibly reduced number of live lambs by 18% (P = 0.02) and those weaned by 27% (P = 0.002). Live litter birth (CVV, P < 0.001) and weaning BW (CVV × year, P = 0.04) were reduced by CVV. Of 42 ewes bred in Aug 2022, 9 (21%) had a positive titer in Aug (pre-pregnancy) indicating possible past infection, 3 (11%) seroconverted in Oct, indicating possible infection during pregnancy. Of those, 2 (6.7%) had adverse pregnancy outcomes, including one stillbirth with deformities that had a positive RT-PCR on kidney tissue. Further studies are needed to determine whether CVV is becoming more widely prevalent in small ruminants, as are new technologies for early detection and prevention.
61 Determining in vivo and in vitro predatory activity of Duddingtonia flagrans and interaction with dietary coccidiostat
Authors: Burke Joan M , Rohila Suman , Petersson Katherine , Kass Elizabeth , Vatta Adriano , Miller James E
Published: March 2024

A nematode trapping fungus, Duddingtonia flagrans (Df), fed to sheep is useful for biocontrol of gastrointestinal nematodes on pasture. The objectives were: 1) validate methods to determine viability of a commercial source of Df before beginning research studies, and 2) examine the interaction between Df and dietary coccidiostat (as decoquinate). Methods: Study 1: In Jan 2023, weaned Katahdin lambs (97.3 ± 1.2 d of age; 19.5 ± 1.3 kg BW; packed cell volume of 26.5 ± 1.4 %), naturally infected with predominantly Haemonchus contortus (89%) and mean fecal egg count (FEC) of 6,860 ± 1,535 eggs/g, were randomly assigned to: 1) no Df (-g)/(FEC-g)×100]. Study 2: In Aug 2023, 7 mo old anthelmintic-treated ram lambs (FEC < 50 egg/s; 51.6 ± 3.9 kg in BW) were fed grain supplement daily with decoquinate (Deccox; +C) or without (-C; n = 3/diet) on d -7 to 1, and, within diet, administered 3 g BioWorma/d in 6 gel capsules (+DF; n = 2/diet) or not (-DF; n = 1) on d -1 and -2. Fecal samples were collected on d 0 (2 g/plate + 300 L3 of H. contortus) and d 1 (6 g/plate + 1000 L3) and placed on water agar plates (n = 3/lamb) at 25°C. Trapping structures were visually assessed after 24, 48, and 144 h (6 d), and cultures Baermannized on d 7 for L3 recovery. Relative reduction was (x̅-DF-C-x̅+DF+C/ x̅-DF-C)×100%. Data for variables collected one time were analyzed by Proc GLM (SAS), and for those collected serially, a Proc Mixed with repeated measures. A 2×2 factorial was used in Study 2 and included treatments, day and interaction in model. Results: Study 1: As expected, L3 recovery was reduced (P = 0.005) in DF lambs by 67-78% relative to control. Study 2: DF formed loops and traps around L3 by d 6 and reduced L3 recovery on both days (P < 0.001) without an interaction by decoquinate (P = 0.69). The L3 reduction relative to -DF-C was between 60.2-73.5%. The coccidiostat, decoquinate, can be added to the diet in the presence of BioWorma without antagonism. In conclusion, the in vitro studies allow detection of adverse issues with viability of Df and can reduce the number of animals needed for research studies.
65 Effect of post-weaning fecal egg count EBV on grazing ewe behavior after weaning
Authors: Vaughan Garrett T , Wright Lee L , Greiner Scott P , Bowdridge Scott A
Published: March 2024

Post weaning fecal egg count (PFEC) estimated breeding value (EBV) has been recently linked with improved immune competence and lamb survival to weaning, thus improving health though selection. Animal movement is also linked to animal health, however little is known about behavior differences in sheep with divergent PFEC EBV. Thirty Katahdin ewes were selected after weaning, from the Southwest Virginia Agricultural Research and Extension Center. Where high PFEC ewes (EBV > 172) and 15 low PFEC (EBV < -84) were selected. Upon placement into pastures, ewes were fitted with Digitanimal GPS collars that measure GPS location every 15 min and store data on a micro SD card. Additional data collection included bi-weekly body weights, FAMACHA scores, body condition scores and fecal egg count. There was no difference in any physiological measurement in these ewes for the duration of this 4-week study. However, significant differences were observed between groups for daily distance traveled. On average, High-PFEC ewes traveled 4.52 km, where low ewes traveled only 4.16 km (P < 0.0001). The average distance traveled between GPS signals (every 15 min) was 48.6 m for high ewes and 47.0 m for Low-PFEC ewes (P < 0.0001). Interestingly, the time of day where maximum activity occurred (1506 h vs 1448 h; High and Low-PFEC respectively) was not different, nor was the distance those ewes traveled in that hour (522.6 vs 519.2 m). These data provide a preliminary snapshot of movement differences that occur between PFEC groups and may inform future studies to evaluate linkage between health and movement in grazing livestock.