bluuebunny/crossref_metadata_2025 huggingface dataset:
266 Effects of Inflammatory States on Ovarian Biology and Oocyte Competence
Authors: Hernandez Gifford Jennifer A , Ferranti Emily , Forrest Kylee , Gifford Craig A
Published: October 2021

Female fertility is dependent on estradiol concentrations which regulate a multitude of ovarian functions including follicle development and oocyte maturation leading to ovulation of a viable oocyte. Estradiol biosynthesis is regulated by coordinated actions of follicle-stimulating hormone and intra-ovarian control mechanisms including the co-transcription factor beta-catenin. Beta-catenin is a multi-faceted protein recognized for its role in granulosa cell steroid production and is shown to be modulated by lipopolysaccharide (LPS), the endotoxin responsible for stimulation of the immune system in infections caused by Gram-negative bacteria. Beef heifers treated with subacute concentrations of LPS during a synchronized follicular wave demonstrate a decline in serum estradiol concentrations 50 h after CIDR withdrawal, corresponding with dominant follicle maturation and preceding ovulation. The endotoxin exposure also resulted in increased LPS concentration and E2:P4 ratios in follicular fluid suggesting that low dose LPS modulates the intra-follicular hormonal milieu. Additionally, in a granulosa cell line, LPS treatment decreased mRNA expression of aromatase and beta-catenin. These data indicate that LPS alters E2 synthesis by modulating beta-catenin and subsequent steroidogenic enzyme expression. To further explore the contribution of naturally occurring LPS exposure on follicular steroid production and developing oocytes, bovine ovary pairs were collected from local abattoirs. Oocytes were aspirated from small follicles and matured in vitro to evaluate meiotic events related to nuclear maturation and spindle morphology. Small follicles from ovarian pairs were separated by the detectable LPS concentrations into high and low LPS groups. Oocytes matured from low LPS follicles demonstrated an increase in the percent of abnormal maturation events. Data indicate that induced or naturally occurring low doses of LPS can alter circulating and follicular estradiol concentrations impairing oocyte maturation. Perturbation to local ovarian signaling cascades from subclinical inflammatory disease may be an unappreciated factor altering fertility and leading to decreased cow retention.
262 Reproductive Microbiomes as Predicators of Fertility in Beef Cattle
Authors: Poole Rebecca K
Published: October 2021

Over the past decade, a multitude of research has sought to understand the complexity and role of the reproductive microbiome as it pertains to fertility. Previously, the reproductive microbiome was evaluated using culture-dependent methods; however, recent advancements in culture-independent, 16S rRNA gene amplicon community sequencing have vastly expanded our understanding of the reproductive tract microbiome. Early sequencing studies sought to compare the vaginal microbiome of cattle to the vaginal microbiome of healthy women, which predominantly consists of bacteria in the genus Lactobacillus and believed to be an indicator of fertility. In the vagina of beef cattle, however, there are incredibly low abundances of Lactobacillus and a greater diversity of bacterial species present. Beta-diversity, which examine differences in bacterial communities between samples, does not appear to differ in the vagina between unbred, open, or pregnant cattle. In postpartum beef cattle just prior to breeding, there are greater levels of diversity and increased bacterial species richness in the vagina compared to the uterus. Research on bacterial species within the uterus have primarily focused on pathogenic bacteria in postpartum cattle diagnosed with uterine disease. Fewer studies have investigated uterine bacterial species in presumed healthy postpartum beef cattle and the subsequent effects on fertility outcomes (e.g., pregnant vs. open at day 30). When evaluating the uterine microbiome during an industry standard estrus synchronization protocol, bacterial community abundance and diversity reduce over time regardless of resulting fertility outcomes. The greatest difference in uterine bacterial abundance between resulting pregnant and non-pregnant cattle appears to occur just prior to breeding. Numerous mechanisms could be contributing to the fluctuations in the uterine microbiome in beef cattle including circulating hormone concentrations or local immunoregulation. This presentation will focus on recent research investigating potential mechanisms that may alter the reproductive microbiome and ultimately impact fertility.
256 Effects of Transition Period Nutrition on Uterine Health
Authors: Cardoso Felipe
Published: October 2021

The transition from gestation to lactation, also known as the transition period, is a critical time for dairy cows. This phase is typically defined as 3 wk before parturition through 3 wk after parturition. Peak disease incidence (shortly after parturition) corresponds with the time of greatest negative energy balance (NEB), the peak in blood concentrations of nonesterified fatty acids, and the greatest acceleration of milk yield. Decreased fertility in the face of increasing milk production may be attributable to greater severity of postpartal NEB resulting from inadequate transition management or increased rates of disease. The depth and duration of NEB is highly related to dry matter intake. Formulation and delivery of appropriate diets that limit total energy intake to requirements but also provide proper intakes of all other nutrients (including the most limiting amino acids Met and Lys) before calving can help lessen the extent of NEB after calving. Cows that received controlled-energy diets during the last 3 wk prepartum had shorter days to pregnancy than cows that consumed high-energy diets in this time period. Additionally, a fully acidified prepartum diet formulated with a higher Ca concentration improved reproductive performance and uterine immune function in the postpartum period through the decrease of days to first ovulation, a tendency to decrease service per conception rate, improved glandular morphology, a tendency to increase polymorphonuclear neutrophil infiltration, and a tendency to increase the tight-junction protein occludin. Supplementation of rumen-protected methionine during the transition period resulted in improved uterine immune function through improved glandular morphology, increased neutrophil infiltration number after calving, and discovery of neutrophil extracellular trap formation in bovine endometrial tissue. In conclusion, nutritional strategies during the transition impact uterine health and fertility in dairy cows.
265 Awardee Talk: Maternal and Paternal Contributions to Fertility
Authors: Pohler Ky G , Reese Sydney T , Franco-Johannsen Gessica A , de Melo Gabriela Dalmaso , Filho Ramiro Oliveira , Poole Rebecca K
Published: October 2021

Using over 56,000 pregnancy diagnostic records in beef cattle, a meta-analysis was conducted to objectively determine that 28.4 % of embryos will not develop past day 7 of gestation with most embryonic losses occurring before day 4. Furthermore, by day 30 of gestation, 47.9 % of cows submitted to a single insemination at day 0 will not be pregnant and pregnancy loss between days 32 and 100 was 5.8%. Reproductive success, however, is highly variable and influenced by maternal and paternal factors. Maternal characteristics, including subspecies, parity and reproductive tract size, intersect with breeding management decisions regarding estrus expression and detection to influence conception and pregnancy rates. The maternal endocrine environment, from estradiol associated with estrus around fertilization to elevated prostaglandins during the embryonic to fetal transition period, play critical roles in pregnancy success. Despite the numerous maternal factors involved with pregnancy establishment, sire contribution to reproductive failure should not be overlooked. Sires are reported to influence pregnancy loss during the second month of gestation in both beef and dairy herds. These differences in sire field fertility could not be explained by differences in semen characteristics nor differences in sire conception rate (SCR) score. To understand parental contribution to pregnancy development during the second month of gestation we developed parthenogenetic (PA) embryos (embryos lacking paternal genome). We observed that PA conceptus had well developed trophectoderm tissue at day 31 of gestation but no site of embryo attachment to the endometrium. Moreover, conceptus secretion such as pregnancy-associated glycoproteins and interferon-stimulated genes were not found in maternal circulation. These results suggest that paternal genetics is required for post-elongated embryo attachment to endometrium. Further exploring the maternal vs paternal contribution to pregnancy development can help elucidate the mechanism that drives reproductive failure in cattle.
268 Growth Performance of Weaned Angus Bulls Housed in a Compost-bedded Pack Barn
Authors: Harrelson Flint W , Harrelson Patricia L , Branham Courtney , Meyers Anna
Published: October 2021

Compost-bedded pack barns (CBP) are commonly utilized in dairy cattle operations across the United States. Their popularity is the result of improved animal welfare and reduced costs. The crossover of CBP into the beef cattle industry is new and the benefits and downfalls are not yet explored. Through a grant from NRCS, a CBP was built at the Morehead State University Derrickson Agricultural Complex in 2019–2020. In fall of 2020, the pack was established by mixing manure and sawdust shavings to start the aerobic composting process. The objective of our study was to determine the performance of growing bulls utilizing a CBP compared to a fully outdoor pasture housing system and measure the pack development. Growth data from 2 consecutive years of growing bulls were utilized, with calves born in 2019 being used as a control (CON) group and calves born in 2020 being used as the CBP group. Adjusted weaning and yearling weights reported to the American Angus Association were utilized to measure growth performance. Heifers born in both years were also evaluated as an outside standardization mechanism to eliminate genetic bias. Temperature measurements, surface and internal, were collected 3 times weekly to measure pack establishment. Weaning weights for CON and CBP bulls were similar (P = 0.45), though interestingly the corresponding heifer calves weaned with CBP bulls were heavier (P < 0.01) than those weaned with the CON bulls. Bulls housed in the CBP were significantly heavier (P < 0.01) as yearlings compared to the CON bulls (496 kg vs. 425 kg, respectively). Temperature differed (P < 0.02) between day, side of the barn, and measurement location. Our results suggest that utilizing a compost bedded pack barn during the winter growing phase may be beneficial to the producer by increasing growth potential of weaned calves.
285 Effects of Encapsulated Calcium-ammonium Nitrate on Greenhouse Gas Emissions from Manure of Beef Steers Grazing a Mature Mixed-winter Forage
Authors: Henry Darren D , Osorio Andrea M , Mejia-Turcios Sebastian E , Vargas David A , Slaughter Lindsey C , Kohmann Marta , Ciriaco Francine M , Onorino Sarturi Jhones O , DiLorenzo Nicolas
Published: October 2021

A 30-d experiment was conducted to evaluate daily and cumulative gas fluxes of N2O, CH4, and CO2 produced by manure from Angus-crossbred steers grazing mature mixed-winter forage pastures [wheat, triticale, and rye (Triticum aestivum, Triticosecale rimpaui, and Secale cereal, respectively) and receiving N supplementation from two different sources. Steers received the following treatments: 1) mature mixed-winter pasture + ground corn (NCTRL), 2) NCTRL + 328 mg/kg of BW encapsulated calcium-ammonium nitrate (NIT) and 3) NCTRL + 124 mg/kg of BW urea (CTRL). All ground corn was supplemented at 0.3% BW. Treatments NIT and CTRL were isonitrogenous. Feces were collected and composited (1 kg as-is) within treatment, within block (3 blocks; 4 steers/treatment/block; 3 fecal composites/treatment). Gas samples were collected from static chambers previously installed in an area excluded from grazing. After 3 d, composites were deposited on the soil surface inside the chamber. Four subsamples were taken per deployment time per chamber, separated by 10-min intervals (t0, t10, t20 and t30) and injected into an evacuated 125-mL serum vial. Gas samples were collected every other day between 0900 and 1100 h and analyzed using a gas chromatograph. Data were analyzed as a randomized complete block design, with chamber as the experimental unit, using the MIXED procedure of SAS. No treatment × day interaction (P ≥ 0.145), nor treatment (P ≥ 0.622) effect were observed on daily-flux data for N2O, CH4, and CO2; however, a day effect was observed (P ≤ 0.001) where all gases peaked on d 2 post-manure application on the soil. Cumulative emissions were not different among treatments for N2O, CH4, and CO2 (P ≥ 0.663). Although it was expected for encapsulated calcium-ammonium nitrate to increase N2O emissions, such effect was not observed. Therefore, it appears that encapsulated calcium-ammonium nitrate does not affect manure greenhouse gas emissions.
282 Nutritional Monitoring of Prenatally Stressed and Translocated Brahman Heifers
Authors: Tolleson Doug R , Randel Ron D , Perry George A , Diaz Jose M , Starns Heath D , Knight Colt W , Garza Nick E , Beall Sarah L , Neuendorff Don A , Welsh Thomas H
Published: October 2021

One drought mitigation strategy is transporting livestock to non-drought locations. Our objective was to evaluate the effects of prenatal stress and translocation on growing Bos indicus heifers. Twelve heifers born in spring 2019 at Overton, TX (1245 mm annual precipitation) were transported ~700 km to Sonora, TX (610 mm annual precipitation) in April 2020. Six heifers (283±10 kg) were born to dams subjected to transportation stress during mid-gestation (PNS) and 6 (279±17 kg) were born to non-stressed dams (CON). Heifers grazed a series of 24-ha native range pastures (aboveground forage biomass; 1508±390 kg/ha) and were sampled (non-shrunk BW/BCS score, feces) at 2-wk intervals from May through September. Fecal samples were collected from the ground or the rectum of each animal and stored at -20o C until processed for near infrared spectroscopy (NIRS) and prediction of diet crude protein (CP) and digestible organic matter (DOM). Inputs to a grazing animal nutrition model for prediction of BW included diet CP and DOM, age, and weather. Differences between groups for BW and nutritional parameters were determined by analysis of variance or paired t-test. Both groups gained BW (22±4 kg) throughout the study, there were no differences (P > 0.1) due to treatment. Diet CP and DOM were affected by date (P < 0.01) as diet quality declined from spring to fall. Percent diet CP was greater (P < 0.05) in PNS than CON, especially during July and August (6.94±0.10 vs 6.23±0.17, respectively). Corresponding values for diet DOM were (59.53±0.55 vs 59.14±0.43, respectively; P = 0.09). Observed vs model-predicted weight was different (P < 0.05) for both groups when using CP-based outputs, but not when using metabolizable protein-based outputs (P > 0.1). In summary, PNS heifers selected a diet of greater CP than CON, and tended to select a diet greater in DOM.
528 Late-Breaking: Late Gestation Metabolizable Energy Intake Increases Colostrum Yield and Alters Colostrum Composition in Beef Cattle
Authors: Hare Koryn S , Croft Emily , Wood Katharine M , Steele Michael A
Published: October 2021

The objective was to determine how late gestation metabolizable energy (ME) intake impacts beef cow colostrogenesis. Angus-Simmental primiparous (n = 47) and multiparous (n = 109) cattle were blocked by expected calving date and randomly assigned to receive diets that supplied 80% (LME; n = 53), 100% (CME; n = 52), or 120% (HME; n = 51) of the ME requirement. Treatments were balanced by initial BW and fed for 53 d prior to calving. Cow body weight was recorded d -53, -39, -25, -10, and -3 relative to calving and retrospectively conceptus-corrected. Calves were weighed and measured prior to suckling. Colostrum was hand-stripped from all cows for compositional analysis and a subset (n = 16/treatment) was fully milked using a milking machine. Data were analyzed (PROC GLIMMIX) as a randomized block design, including the fixed effects of treatment, parity, and treatment×parity and the random effects of block and cow(block). Day and its interactions were included for repeated measurements. Treatment did not affect (P ≥ 0.73) cow BW or conceptus-corrected BW. Calf chest circumference was lesser (treatment×parity: P = 0.023) for primiparous vs. multiparous calves if their dams consumed LME or CME, but not if their dams consumed HME. Feeding HME rather than LME increased (P = 0.006) colostrum yield. The LME diet increased (P = 0.004) colostrum IgG concentration over HME; however, HME colostrum yielded more (P = 0.005) total IgG. Crude protein and urea-N were elevated (P < 0.001) in LME colostrum, whereas HME colostrum contained more (P = 0.026) lactose. Low ME colostrum fat was greater (P = 0.013) than CME and beta-hydroxybutyrate was increased (P < 0.001) in LME vs. CME and HME colostrum. These data provide insight regarding nutrient partitioning during late gestation and demonstrate that beef cow colostrogenesis is responsive to prepartum ME intake.
522 Late-Breaking: Effects of Corn Processing and Age on Energy Balance, Nutrient Digestion and Rumination in Cattle
Authors: Petzel Emily , Brake Derek
Published: October 2021

Current library values for energy content in whole or dry-rolled corn (DRC) are identical and do not differ for cattle of different age (NASEM, 2016). Calves (295 ± 29 kg) and yearlings (521 ± 29 kg) were fed whole, DRC or steam-flaked corn (SFC) to evaluate library values of energy content in different types of processed corn among cattle of different age. Cattle were fed diets comprised of 75% corn (DM-basis) to 2.5-times maintenance energy requirements using estimates of NEm in corn and SFC (NASEM, 2016). Data were analyzed using the MIXED procedure of SAS. There was no observed interaction of corn processing and cattle age (P ≥ 0.40). Time spent ruminating (min/d) was not different between dietary treatment or age. Total tract starch digestibility was greatest (P = 0.01) for cattle fed SFC (97.5%), intermediate in cattle fed DRC (92.4%) and least in cattle fed whole corn (89.5%). Nitrogen balance was not affected (P ≥ 0.30) by corn processing or age. Digestible and metabolizable energy (Mcal/kg-DMI) were greater (P ≤ 0.05) for cattle fed SFC compared to DRC or whole. A greater proportion of DE was lost to heat production (P = 0.01) in cattle fed whole corn compared to DRC and tended to be greater (P = 0.08) in cattle fed SFC than DRC. Retained energy (Mcal/d) should have been similar if current library values correctly reflect energy content in each type of processed corn. However, retained energy was greater (P < 0.01) for cattle fed DRC compared to whole corn and tended to be greater (P = 0.06) compared to SFC indicating that library values for DRC underestimate energy available to growing cattle. Measures of retained energy for cattle fed DRC indicated that energy available for gain from DRC was 42% greater than library values (NASEM, 2016).
527 Late-Breaking: Objective Assessment of Behaviour, Pain, and Lameness Due to Digital Dermatitis in Beef Cattle
Authors: Thomas Anice D , Orsel Karin , Pajor Edmond
Published: October 2021

Digital dermatitis (DD) is an infectious disease affecting cattle feet causing ulcerative and necrotic skin lesions. Most lesions are painful when palpated, some cause lameness and significantly impact animal welfare and productivity. Our objectives were: to determine if changes in behaviour were associated with DD in cattle, to quantify pain associated with DD lesions, and to determine the relationship between pain sensitivity and lameness, and DD and lesion temperature. In total, 255 animals across three feedlots were enrolled. A subset of 120 animals were fitted with accelerometers to record behaviour. Cattle were scored for lameness (Step-Up Locomotion Scoring System), both hind feet scored for DD (M-stage scoring system), the pressure pain threshold of lesions determined using pressure algometry and lesion temperature using thermal images. Animals and feet were classified as DD absent or present. Further, DD present was divided into active or chronic. Behaviour, 5 to 2 days before DD identification was analyzed. Animals with DD ruminated 3% less daily compared to animals without DD (P < 0.05). Further, animals with active lesions ruminated 5% less daily (P < 0.05). Daily inactivity time was greater in animals with DD and the effect of day depended on type of lesion (P < 0.05). Feet without DD lesions withstood 5.6N more pressure (P < 0.001). Active lesions were most sensitive withstanding 8.1N less pressure and chronic lesions 4.1N less pressure than DD absent feet (P < 0.05). Moderate to severely lame animals withstood 3.1N less pressure than sound animals (P < 0.001). Median maximum temperature (MMT) was higher in feet with DD compared to those without (P < 0.001) with MMT being highest in active lesions (P < 0.05). In conclusion, rumination is depressed, and inactivity increased in DD affected animals. Both active and chronic lesions are painful, lame animals have a lower pain threshold and DD is associated with higher lesion temperatures.
519 Late-Breaking: Evaluation of the 7 & 7 Synch and Bee Synch II protocols for control of the estrous cycle among cows of varying percentage Bos indicus influence
Authors: Andersen Carson M , Holton Matthew P , Fontes Pedro L , Thomas Jordan M , Goncalves Lucas , Burato Samir
Published: October 2021

The 7 & 7 Synch and Bee Synch II protocols for control of the estrous cycle were compared among cows with varying percentages of Bos indicus influence. Angus (n = 48), ⅛ - ¼ Brahman-influenced (n = 90), Brangus (n = 11), and ½ Brahman-influenced (n = 56) cows were blocked based on breed, age, and days postpartum and randomly assigned to treatment. Cows treated with 7 & 7 Synch (n = 104) received prostaglandin F2α (PG; 25 mg dinoprost tromethamine) and insertion of an intravaginal progesterone-releasing insert (CIDR; 1.38g progesterone) on Day -17, gonadotropin-releasing hormone (GnRH; 100 μg gonadorelin) on Day -10, and PG coincident with CIDR removal on Day -3. Cows treated with Bee Synch II (n = 101) received PG coincident with CIDR insertion on Day -8 and PG coincident with CIDR removal on Day -3. Fixed-time artificial insemination was performed on Day 0 at 66 h. Ovarian ultrasound was performed on Day -3 to assess presence of corpora lutea (CL) and diameter of the largest ovarian follicle (LFD), and color Doppler was used on Day 7 to assess CL blood perfusion. A greater proportion of 7 & 7 Synch cows (P < 0.0001) had CL on Day -3 (83%; 86/104) compared with Bee Synch II cows (48%; 48/101). On Day -3, LFD did not differ among Bos indicus-influenced cows treated with Bee Synch II (12.5±0.3 mm), Bos indicus-influenced cows treated with 7 & 7 Synch (12.2±0.3 mm), or Angus cows treated with 7 & 7 Synch (12.1±0.6 mm); however, greater LFD was observed among Angus cows treated with Bee Synch II (15.4±0.8 mm). Brangus cows had greater periphery signal percentages (P = 0.02) when treated with 7 & 7 Synch compared with Bee Synch II. In conclusion, across cow of varying percentage Bos indicus influence, 7 & 7 Synch resulted in a greater proportion of cows with CL on Day -3.
520 Late-Breaking: Effect of Technology on Environmental Emissions from Four Representative U.S. Feedlots and the Beef Production System
Authors: Gilreath Jessica , Rotz Al , Place Sara , Thoma Greg , Wickersham Tryon
Published: October 2021

Our objective was to evaluate effects of technological management strategies on environmental impacts and net returns of feedlot operations in the United States. Feedlot operations were simulated with the Integrated Farm System Model (IFSM 4.6; USDA-ARS, University Park, PA) to quantify baseline environmental impacts of feedlot production and full US beef cattle production systems. Strategies simulated included: ionophore, implant, ractopamine hydrochloride, combined management (ionophore, implant, and ractopamine hydrochloride; I+I+R), lubabegron, reduced mortality rate, and improved fiber digestion. Days on feed were adjusted whenever necessary and according to production practices typical of commercial feedlots. Subsequently, annual number of cattle finished by the operation was adjusted according to days on feed to maintain consistent one-time capacities. Mitigation strategies were individually modeled and simulated in IFSM for each feedlot operation to calculate intensities (expressed per kg gain) for greenhouse gas (GHG) emissions, fossil energy use, blue water consumption, and reactive nitrogen loss. Additionally, net returns to management were estimated for each feedlot operation. Feedlots were then integrated with simulations of cow-calf, stocker, and backgrounding operations to estimate environmental intensities (expressed per kg carcass weight) for the full beef cattle production system. Carbon emission intensity was reduced most using the I+I+R strategy (10%), followed by implant (6%) and ionophore (5%) strategies alone. Similarly, energy use intensity was reduced the greatest by I+I+R (9%), ionophore (5%), and implants (4%). Reductions in water use intensity were also greatest using I+I+R (9%). Net returns increased for all strategies compared to baseline net return with the greatest improvements observed for I+I+R ($114/finished animal) and implants ($66/animal). Consistent results were observed for all strategies simulated across all four environmental intensities when quantified for the full cattle production system. Implementing I+I+R (7%), ractopamine hydrochloride (4%), and lubabegron (4%) in feedlots resulted in the greatest reductions in environmental emissions.
295 Effects of Live Yeast and Ruminal Environment on Beef Cattle Diet Digestibility: An in vitro Approach
Authors: Scaranto Silva Kaliu G , Onorino Sarturi Jhones O , Henry Darren D , Karges Kip , Hinds Jordan K , Tonelli Nardi Kaue T , Fávero Igor Gomes , Saes Yasmin , Rush Camron J
Published: October 2021

The effects of live yeast (Saccharomyces cerevisiae) and ruminal environment on in vitro true digestibility of dry matter, organic matter, and fiber components were evaluated. Ruminally-cannulated beef steers (n = 4; BW = 520 ± 30 kg) were used in a cross-over design to serve as donors of ruminal content. In vitro substrates (6 grower and 6 finisher diets) and individual ingredients (steam-flaked corn, wet corn gluten feed, and old-world bluestem hay) were dehydrated (55o C), ground (1 mm), and incubated using a 2 × 2 factorial arrangement of treatments: a) the presence or not of yeast (8×109 CFU/animal-daily adjusted to a 70 L ruminal content volume), and b) two ruminal inoculums collected from donors fed a grower (50:50) or a finisher (92:08) diet (concentrate:forage). Four incubation batches (experimental unit) were performed, in which the initial two batches were performed followed by another two after animals switched diets and were adapted again during 21d. A Daisy in vitro incubation system was used, and samples incubated for 48h (39°C). The GLIMMIX procedure of SAS was used for the statistical analysis. No 3-way interactions (P ≥ 0.71) or 2-way interactions with substrate were observed (P ≥ 0.25). The in vitro true digestibility of DM, OM, NDF, and hemicellulose increased when yeast was added to the incubator containing a 50:50 ruminal content (Rumen × Yeast; P ≤ 0.02). The ADF digestibility increased (P = 0.02) with yeast addition regardless of ruminal content type (50:50 or 92:08). As expected, finisher substrate diets were more (P < 0.01) digestible than grower diets. The combination of live yeast and a specific ruminal environment seemed to be more important than substrate type, in which live yeast improved in vitro digestion within a 50:50 ruminal inoculum more evidently.
287 Effects of a Novel Rumen-protected Folic Acid Supplement on Feedlot Performance and Carcass Characteristics of Beef Steers
Authors: Deters Erin L , Niedermayer Emma , Genther-Schroeder Olivia N , Blank Christopher , Carmichael Remy , Hartman Sarah , Messersmith Elizabeth M , VanValin Katherine , Branine Mark E , Hansen Stephanie L
Published: October 2021

To assess effects of a novel rumen-protected folic acid (RPFA) supplement, 180 Angus-cross steers (292 ± 18 kg) were blocked by body weight to pens and randomly assigned to dietary treatments (n = 6 pens/treatment): target intake of 0 (CON), 30 (RPFA-30), 60 (RPFA-60), 90 (RPFA-90), 120 (RPFA-120), or 150 (RPFA-150) mg RPFA·steer-1·d-1. Steers were weighed on d -1, 0, 55, 56 (end of growing), 86, 87, 181, and 182. Liver and blood were collected (two steers/pen) before trial initiation and at the end of growing and finishing. Data were analyzed as a randomized complete block design using ProcMixed of SAS (fixed effects of treatment and block; experimental unit of pen). Liver abscess scores were analyzed using ProcGenmod of SAS. Contrast statements evaluated polynomial effects of RPFA and compared CON vs. RPFA-30. At end of growing, RPFA linearly increased plasma folic acid (P < 0.01) and linearly decreased plasma glucose (P = 0.01). Liver folic acid concentrations at end of growing were greatest for CON, RPFA-90, and RPFA-120 (cubic P = 0.01), and growing period (d 0 to 56) average daily gain and gain:feed were greatest for CON and RPFA-120 (cubic P ≤ 0.03). At end of finishing, RPFA linearly increased plasma folic acid concentrations (P < 0.01), and liver folic acid concentrations were lesser for CON vs. RPFA-30 (P = 0.04). Severe liver abscess percentage tended to be greater for CON vs. RPFA-30 (P = 0.09), while dressing percent was lesser for CON vs. RPFA-30 (P = 0.04). Overall (d 0 to 182) carcass-adjusted gain:feed tended to be greater for CON vs. RPFA-30 (P = 0.09). Although RPFA increased plasma folic acid concentrations throughout the study, feedlot performance was not improved, possibly due to low vitamin B12 status (plasma < 200 pg/mL) of steers, regardless of treatment.
301 Milk Replacer Biosalt Supplementation for Neonatal Calves
Authors: Casper David P
Published: October 2021

Neonatal Holstein calves may have limited liver bile production and secretion, which could limit fat digestion and absorption. Eighty 2- to 5-d old Holstein bull calves were randomly assigned to one of 4 treatments using a randomized complete block design. Treatments were: 1) BS0: Control, no biosalt added to milk replacer; 2) BW1/2: BS fed at 0.175 g/d; 3) BS1: BS fed at 0.35 g/d; and 4) BS2: BS fed at 0.70 g/d. Calves were fed 2x/d at 0630 and 1800 h along with free choice water and a 22% CP mini-pelleted calf starter. The MR was fed at 0.567 kg/d for d 1–14, then increased to 0.85 kg/d for d 15–35, and feeding reduced to 1x/d for d 36–42 with weaning after d 42 for the 56 d experimental period. Linear, quadratic and cubic responses were found to be nonsignificant (P > 0.10) body weight (BW), BW gains, average daily gain (ADG) and dry matter intake (DMI). Body weight (59.2, 56.6 58.0 and 58.0 kg for BS0, BS1/2, BS1, and BS2, respectively), BW gains (36.5, 33.1, 33.9, and 34.8 kg), ADG (663.6, 602.0, 616.8, and 633,5 g/d) and DMI (1.25, 1.21, 1.23, and 1.23 kg/d) were similar (P > 0.10) for calves fed all treatments. The number of days (37.4, 38,7, 37.9 and 37.5 d) for calves to achieve 0.90 kg/d CS consumption for 3 consecutive d were similar (P > 0.10) among calves fed all treatments. Feed conversion demonstrated a quadratic response (P < 0.05) with calves fed BS0 demonstrating greater (P < 0.05) feed conversions (0.52, 0.45, 0.49 and 0.50 kg BW gain/kg DMI) compared with calves fed BS1/2 with calves fed BS1 and BS2 being intermediate and similar (P > 0.10). Bile salt supplementation to neonatal Holstein calves fed MR did not enhance growth performance.
300 Effects of Associating Feed Additives on Rumen Ph Dynamics by Feedlot Cattle Fed a High-concentrate Diet
Authors: Niehues Maria B , Perdigão Alexandre , de Carvalho Victor Valério , Acedo Tiago S , Vasconcellos Guilherme S F M , Tamassia Luis M , Martins Cyntia L L , Millen Danilo D , Arrigoni Mário B B
Published: October 2021

Our objective was to evaluate the effects of feed additives on ruminal pH of finishing cattle fed a 90%-concentrate diet. Twenty four 18-mo Angus-Nellore crossbred bulls (IBW, 456 ± 6,5 kg) were allocated in a completely randomized design to three treatments with eight replicates each, as follows: 1) Control (MON) - Sodium Monensin (26 mg/kg DM, Rumensin, Elanco Animal Health); 2) Crina® RumistarTM (CR) - a blend of essential oils, 90 mg/kg DM + exogenous α-amylase, 560 mg/kg DM) and 3) CR + HyD® (25-hydroxy-vitamin-D3 at 1 mg/animal/d, CRD, DSM Nutritional Products). The ruminal pH and temperature was monitored individually for 98 days, using a wireless bolus, (SmaXtec Animal Care, Austria). Data were analyzed using the Mixed procedure of SAS and means comparison evaluated by Tukey test at P< 0.05. During adaptation period (i.e. first 14 days), bulls fed CR and CRD had increased rumen mean pH (6.40 and 6.36 vs. 6.16; P < 0.01) and minimum pH (5.89 and 5.87 vs. 5.57; P < 0.01) than bulls fed MON. In addition, rumen pH from bulls fed CR spent less time below 6.0 than bulls fed MON (256.07 vs. 452.62 min/d; P = 0.05). Regarding the total period, bulls fed MON had lower mean (6.22 vs. 6.51 and 6.42, P < 0.01) and minimum rumen pH (5.60 vs. 5.92 and 5.85, P < 0.01) than bulls fed CR and CRD. Additionally, feeding MON increased time duration of rumen pH (390.79 min/day, P < 0.01) and had a larger area below 6.0 (81.52 min x pH units/day; P < 0.01). Moreover, the addition of monensin increased pH time duration below 5.8 (161.10 vs. 121.13 and 122.56 min/day; P = 0.02) compared with CR and CRD, and increased ruminal temperature (39.60 vs. 39.51 and 39.5 °C; P < 0.01). We conclude that feeding Crina® RumistarTM and Crina® RumistarTM HyD® increased the rumen pH of bulls.
299 Combination of Essential Oils, α-amylase and 25-hydroxy-vitamin-d3 Increases Carcass Production by feedlot Cattle
Authors: Niehues Maria B , Correa Hugo L , de Carvalho Victor Valério , Perdigão Alexandre , Acedo Tiago S , Tamassia Luis M , Martins Cyntia L L , Arrigoni Mário B B
Published: October 2021

Our objective was to evaluate the effects of associating feed additives on feedlot performance of Nellore bulls. One hundred and sixtieth Nellore bulls (iBW, 380± 5.8 kg; age, 18 mo) were allocated in 20 pens (n = 8/pen), in a completely randomized block design, according to the treatments: 1) MON+VM - Sodium Monensin (MON, 25 mg/kg DM, Elanco Animal Health, Indianapolis, IN), + Virginiamycin (VM, 30 mg/kg DM, Phibro Animal Health Corporation, Guarulhos, São Paulo), and 2) CRD - Crina® RumistarTM + HyD® - a blend of essential oils, 90 mg/kg DM + exogenous α-amylase, 560 mg/kg DM + 25-hydroxy-vitamin-D3 at 1 mg/animal/d (DSM Nutritional Products, Basel, Switzerland). The initial BW was utilized as a criterion for block formation. Pens were considered experimental units (10 pens per treatment). Animals were adapted to the diets during 14 days with gradually increasing concentrate level from 70% to 86% of diet DM, and fed for 90 days. Weight assessments were performed at day 0 and 90 after 14h fasting. Data were analyzed using PROC MIXED of SAS and means were separated using the PDIFF statement, adopting P < 0.05. Feeding CRD increased the DMI (12.13 kg vs. 10.52 kg, P < 0.01), ADG (1.86 vs. 1.63 kg/d, P < 0.01) and final BW (542 vs. 521 kg, P < 0.01) compared to animals fed MON+VM. In addition, feeding CRD increased final HCW in 15 kg (311 vs. 296 kg; P < 0.01), carcass ADG in 0,16 kg/d (1.31 vs. 1.15 kg/d; P < 0.01) and dressing percentage in 0.48 percent points (57.34 vs. 56.86%; P < 0.01) compared to MON+VM. The G:F (0.155, P = 0.53) and biological efficiency (137.9 kg DM/15 kg carcass, P = 0.87) were similar among treatments. Therefore, the inclusion of Crina® RumistarTM +HyD® can be used as a tool to increase carcass gain of feedlot finishing cattle.
309 Nutrient Digestibility of Beef Steers Consuming Finishing Diets with an Added Nutritional Packet
Authors: Tonelli Nardi Kaue T , Onorino Sarturi Jhones O , Henry Darren D , Ciriaco Francine M , Huerta-Leidenz Nelson O , Osorio Andrea M , Fávero Igor Gomes , Scaranto Silva Kaliu G , Rush Camron J
Published: October 2021

The effects of a nutritional packet fed to beef steers during the final 64 d of the feedlot finishing phase on apparent total tract nutrient digestibility were evaluated. Angus-crossbred steers (n =120; initial BW = 544 ± 52 kg) were assigned to 30 pens (4 steers/pen; 15 pens/treatment; pen = experimental unit) in a randomized complete block design. A steam-flaked corn-based finishing diet was fed ad libitum and treatments applied as follows: 1) control and 2) 30 g/steer-daily (DM-basis) of the nutritional packet [containing live yeast (Saccharomyces cerevisiae; 8.7 Log CFU/g), vitamin C (5.4 g/kg), vitamin B1 (13.33 g/kg), NaCl (80 g/kg) and KCl (80 g/kg)]. The nutritional packet used ground corn as a carrier and was included at 1% of diet DM. Orts were quantified daily (if any) and subtracted from the total dietary DM offered to calculate DM intake. Fecal samples were collected twice daily (0700 and 1700 h) for 5 consecutive days (d 47 to 51) from at least 3 steers within pen. Feed samples were collected daily at time of feeding (0630 h). Fecal and feed samples were composited to represent the collection period, dried (55oC), ground (1 mm), and analyzed to assess DM, OM, NDF, ADF, and hemicellulose. In situ (288 h) iNDF was used as an internal marker to measure apparent total tract nutrient digestibility. Data were analyzed using the GLIMMIX procedure of SAS. Intake of DM, OM, and fiber components during the digestibility period was not affected (P ≥ 0.44) by treatment. Steers fed the nutritional packet had increased apparent total tract digestibility of OM (P = 0.02), DM (P = 0.01), NDF (P = 0.02), ADF (P = 0.01), and hemicellulose (P = 0.08; tendency). Improved nutrient digestibility without affecting nutrient intake may warrant an enhanced energy deposition in the carcass.
323 Effect of an Acidogenic Diet with Phytogenic Supplementation on in Situ Degradability of Corn and Wheat Grain, and Grass Silage in Dairy Cows
Authors: Rivera-Chacon Raul , Ricci Sara , Reisinger Nicole , Zebeli Qendrim , Castillo-Lopez Ezequias
Published: October 2021

Modern dairy production systems require larger inputs of energy in diets to increase milk yield. Therefore, dairy cows are at risk of experiencing subacute ruminal acidosis (SARA). The objective of this study was to evaluate grains and forage rumen degradability in cows fed different diets supplemented with a phytogenic (PHY) feed additive. The experiment was conducted with nine rumen-cannulated non-lactating Holstein cows blocked in two groups of four and five animals, and were part of a cross-over design. This study consisted in 2 runs separated by a 12-week washout period, in which cows grazed on pasture. Each experimental run had one week of forage (F) feeding, one week of transition to a high grain (HG) diet, and four weeks of HG (65:35 concentrate to forage ratio in dry matter basis). Cows were supplemented with PHY (a blend of menthol and thymol) or a control carrier (CON) from week F. Corn and wheat grain were ground through a 4 mm screen, while grass silage was ground through a 6 mm screen. Sampling for in situ degradability was performed in F and in week four of HG diet. Data were analyzed with SAS with week of feeding and supplementation as fixed effects and cow as random effect. Corn and wheat 24-h dry matter (DM) and organic matter (OM) degradability increased during HG diet compared with F (P < 0.05), grass silage DM and OM 48-h degradability was reduced by HG diet compared to F (P < 0.01). Additionally, wheat grain 24-h OM degradability was higher for PHY compared to CON under F and HG diet conditions (P = 0.05). Overall, diet composition and SARA conditions can influence grains and fiber degradability in the rumen.
505 Late-Breaking: Ruminal Microbiota, Inflammation Cytokines, and Performance of High-yield Dairy Cows Supplemented with Saccharomyces Cerevisiae Culture
Authors: Sun Xiaoge , Zhang Shu , Wang Erdan , Lu Na , Wang Wei , Li Shengli
Published: October 2021

Dramatic increases in milk yields in recent decades have created challenges in terms of rumen pH and microbial health which ultimately impact dairy cow health. The objective of this study was to assess the effects on ruminal pH, Volatile Fatty Acid (VFA), microbiota, inflammation, and performance of high-yield dairy cows by supplementing Saccharomyces cerevisiae culture (SC). Forty Holstein cows were divided into two groups based on their milk yield, days of milk, and parity fed the same basal ration diet that did or did not contain 100 g of SC /cow per day. Individual dry matter intake (DMI) and milk yield were recorded each day. Rumen fluid and milk samples were collected after 2 hours of morning feeding at intervals of 15 days during the experiment period. The data showed that rumen pH was increased by 0.19 (P = 0.09) when SC was supplemented than no SC was provided. SC-supplemented cow consumed 0.28 kg (P < 0.05) extra DM/d. Those supplemented with SC produced 1.36 kg (P < 0.05) more milk/cow per day than did non-supplemented cows. Milk fat percentage was higher (4.11 vs. 3.96%) for cows receiving SC. There were no differences in milk protein percentage. Rumen fluid VFA concentration was not statistically affected by SC but was numerically higher acetic and lower propionic for supplemented cows. The blood of the SC group with lower inflammation cytokines and somatic cell count (SCC). SC-supplemented cows had a greater relative abundance of Prevotellaceae, Succinivibrionaceae, Fibrobacteraceae, Lactobacillaceae, and lower relative abundance of Spirochaetaceae, Methanobacteriaceae, Enterobacteriaceae than the unsupplemented cows. It had greater functions on xylanolysis, fermentation, cellulolysis in the rumen in terms of the KEGG function prediction analysis. This study demonstrated that high-yield lactation cows receiving supplemental SC produced more milk and potentially reduced the inflammation and enhanced rumen cellulolysis bacteria growth.
331 Effects of Dried Distillers’ Grains Cube Supplementation Rate on Voluntary Intake and Digestibility of Bermudagrass Hay Fed to Growing Heifers
Authors: Adams Jordan , Robe Jeff , Grigsby Zane N , Rathert Abigail R , Uzee Nick , Major Mike , Lalman David , Beck Paul A
Published: October 2021

The objective of this study was to evaluate supplementation rates of dried distillers’ grains cubes (DDGS) on voluntary intake (DMI), rate and extent of digestibility, and blood parameters of growing Charolais-cross heifers (BW = 286 ± 28.9 kg) fed ad libitum bermudagrass (Cynodon dactylon) hay. For the 29-d study, heifers were randomly assigned to one of four supplementation treatments: 1) Control, no supplement (n = 6); 2) Low, supplemented 0.90 kg/d (n = 6); 3) Intermediate, supplemented 1.81 kg/d (n = 5); or 4) High, supplemented 3.62 kg/d (n = 6). Heifers were offered supplement each morning in individual stalls. From d 15 to 25, heifers were dosed twice daily with titanium dioxide in gelatin capsules (10 g/d), and fecal samples were collected via rectum at time of dosing from d 22 to 25 to estimate fecal output. Post-dosing, fecal sampling continued over 96-h from d 25 to 29 to determine passage rate (Kp) via titanium dioxide analysis. Blood was collected from each animal on d 26 via jugular venipuncture before supplementation, and 4 and 8-h post-supplementation for analysis of blood urea N (BUN), lactate, and glucose. Samples of feces, hay, and supplement were incubated in rumen-cannulated Holstein steers (n = 4; BW = 281 ± 29.5 kg) for 576-h to estimate digestibility with indigestible neutral detergent fiber as an internal marker. Data were analyzed by ANOVA using the mixed procedure of SAS (SAS Inst. Inc. Cary NC), with treatment least-squares means separated using orthogonal polynomial contrasts. Increasing DDGS linearly (P < 0.01) decreased forage DMI linearly, but linearly increased Kp, total diet DMI, and total diet digestibility. Linear increases (P ≤ 0.02) in glucose, lactate, and BUN were likewise observed with increasing DDGS. Increasing DDGS supplementation to growing calves consuming bermudagrass hay may increase productivity while reducing forage intake.
336 Occurrence of Mycotoxins in 2020 US Pasture Grasses and Harvested Hay Feed Ingredients
Authors: Schwandt Erin , Gott Paige N , Ramirez Shelby M , Hofstetter Ursula , Murugesan Raj
Published: October 2021

Mycotoxins are harmful secondary fungal metabolites which limit animal health and performance through various negative effects such as reduced feed intake, diarrhea, and compromised immune and reproductive function. These metabolites are found in a variety of feedstuffs worldwide. This study monitored mycotoxin occurrence and contamination levels in fresh pasture grasses and harvested dry hay from across the US. Samples were screened for six major mycotoxin groups: aflatoxins, type A trichothecenes (A-Trich), type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN), and ochratoxin A via LC-MS/MS. Samples that were above the limit of detection for each mycotoxin group were analyzed using the GLIMMIX procedure of SAS (SAS 9.4, Cary, NC) to test the effect of harvest year on average contamination level. Results are presented in Table 1. Zearalenone and B-Trich contamination prevalence for fresh grass samples was lower in 2020 compared to the previous two years. A-Trich tested positive in 34% of samples which was greater in 2020 compared to 2018 and 2019. Mean concentration levels (parts per billion, ppb) for B-Trich, ZEN, A-Trich were not different in 2020 compared to the previous two years. Prevalence of mycotoxin contamination for dry harvested hay samples for B-Trich and ZEN decreased in 2020 compared to the previous two years, but 64 and 28% of samples tested positive, respectively. A-Trich prevalence was greater than the last two years and resulted in 17% of samples testing positive compared to 0 and 6% in 2018 and 2019, respectively. Mean B-Trich levels in 2020 were similar to levels seen in 2018 and lower than 2019 (P = 0.005). Mean ZEN and A-Trich concentration levels averaged 1,612 ppb and 796 ppb, respectively. Mycotoxin analysis of pasture grasses and harvested hay forages is warranted to identify potential sources of mycotoxin contamination in ruminant diets.