bluuebunny/crossref_metadata_2025 huggingface dataset:
97 Impact of Regionalized Forage Quality and Quantity and Feed Grain Water Use on the Daily Texas Beef Cattle Water Footprint and Supply Chain Efficiency
Authors: Menendez Hector M , Tedeschi Luis O
Published: November 2020

Livestock water use sustainability is a growing concern in the beef cattle sector. The Water Footprint Assessment (WFA) method has been used to quantify the water footprint (WF) of beef products but does not suggest any specific management strategies to decrease the WF of beef cattle (WFB) within and across the beef supply chain. The WFB is primarily influenced by forage and grain production water uses (m3/t), which are directly linked to dry matter (kg/d) and water intake (L/d) and cattle growth (kg/d). Therefore, the objective of this study was to assess the alteration of forage quality and above-ground biomass production (t/ha) of annual ryegrass (Lolium multiflorum) and bermudagrass (Cynodon dactylon), in addition to published WF estimates for corn (Zea mays) and soybean (Glycine max) production (m3/t) on the daily Texas WFB. A dynamic Texas Beef Water Footprint Model (TXWFB) was developed to predict WFB, using the System Dynamic methodology and equations from the Ruminant Nutrition System (RNS) and Beef Nutrient Requirements (NASEM) models. Results indicated that forage and crop biomass production is a high-leverage solution to offset the daily Texas WFB (%∆ = -55 to 130). The alteration of forage TDN had less of an impact on the Texas WFB (%∆ = -39 to 17). An ANOVA with a Tukey Posthoc test indicated that all WFB scenarios were significantly different (P < 0.05) except for the low versus base TDN under low water use conditions scenario. The variability in the use of green and blue waters for grains indicated that the final WFB, in the feedlot phase, may be lower than the WFB in the cow-calf or stocker stages under certain efficiency conditions. Identification of high and low-leverage solutions may help Texas cattle stakeholders implement systemic strategies that aid in the efforts for sustainable beef water use.
111 Metsulfuron and variable nitrogen application rates on infected tall fescue: effects on stocker performance, forage yield, nutritive value, ergovaline concentration and botanical composition
Authors: Meng Kevin R , Bailey Eric , Zeltwanger Josh , Allen Hannah , Adams Mikaela , Brake Derek
Published: November 2020

Chemical seed-head suppression of endophyte infected tall fescue (Lolium arundinaceum) improves stocker cattle performance but may decrease forage yield. Spring nitrogen application increases tall fescue growth with a concomitant increase in ergot alkaloids, produced by the symbiotic endophyte Epichloë coenophiala. We hypothesized that greater amounts of nitrogen applied to tall fescue would increase forage yield and offset losses in forage production from chemical suppression of seed-heads with metsulfuron without effect on alkaloid concentration. Ninety-six steers (270 ± 20 kg) were randomly assigned to one of sixteen paddocks (1.8 ha) on April 18 and continuously grazed for 57 d. Paddocks were blocked by previous use (n = 4) and randomly assigned to one of four treatments; no metsulfuron, no nitrogen (NEGCON), metsulfuron with 0 (MET0), 67 (MET67), or 134 (MET134) kg/ha of ammonium nitrate, applied March 11. Steers grazing MET0 paddocks were removed 17 d early due to insufficient forage availability. Steer weight, forage yield, forage nutritive value and ergot alkaloids in forage samples were measured monthly. Seed-head frequency and species composition were determined in June. Metsulfuron application reduced (P < 0.01) tall fescue seed-heads by 80%. Metsulfuron decreased (P = 0.03) ergovaline but ergovaline increased (P < 0.01) at each monthly sampling across treatments. Nitrogen had no impact on ergovaline concentration (P = 0.50). Forage yield tended to be least (P = 0.07) for MET0, intermediate for NEGCON and MET67, and tended to be greatest for MET134 (P = 0.08). Steer ADG was not affected by treatment (P < 0.80). Metsulfuron decreased NDF (P=0.02) regardless of fertilization rate. Forage CP increased with fertilization (P < 0.01) and no differences were detected between NEGCON and MET0 (P = 0.45). Species composition was not impacted (P >0.07) by treatment. Metsulfuron decreased seed-head growth and ergovaline concentration in tall fescue. Additional nitrogen fertilizer ameliorated forage yield lost to metsulfuron application but did not impact steer gain.
31 Determination of Optimal Harvest Weight for Mangalica Pigs Using a Serial Harvest Approach to Measure Growth Performance and Carcass Characteristics
Authors: Reeves Maegan A , Charlton Courtney E , Wilkerson Shannon R , Rehm John G , Brandebourg Terry D
Published: November 2020

Mangalica pigs are a popular niche breed given their reputation for superior quality pork. However, growth and carcass parameters for this breed are poorly documented. Our objective was to better characterize optimal harvest weights for the Mangalica breed. To accomplish this, a growth trial was conducted whereby pigs (n=56) were randomly distributed across stratified harvest weights (50, 57, 68, 82, 93, 102, 127 kg) in a completely randomized design. Pigs were fed standard finisher rations with individual daily feed intakes and weekly body weights recorded for all animals. At 24h postmortem, carcasses were split and ribbed with marbling and loin eye area (LEA) measured at the 10th rib. Primal cuts were fabricated and individually weighed. Fat back was separated from the loin and weighed. As expected, live weight significantly increased across weight class (P < 0.0001). ADG was similar across classes up to 82 kg live weight before steadily declining with increasing weight class (P < 0.0025). Likewise, feed efficiency did not differ between classes until weights heavier than 82 kg (P < 0.03). LEA significantly increased by class up to 82 kg and then plateaued as harvest weight increased further (P < 0.003). Marbling score significantly increased with increasing weight class up to 102 kg where they then plateaued (p < 0.04). Fat back dramatically increased across all weight classes (p < 0.0001) despite negligible increases in LEA or marbling after 102 kg. Primal cut weights for the ham (P < 0.0001), loin (P < 0.0001), Boston butt (P < 0.0001), shoulder (P < 0.0001), and belly (P < 0.0001) all significantly increased with increasing live weight. These data suggest an optimal harvest weight occurs between 82 to 102 kg while offering little objective justification for the current practice of harvesting Mangalica pigs at much heavier live weights.
8 Assessment of consistency in quantification of ribonucleic acid across multiple methods
Authors: DeCarlo Andrea N , Parrish Joseph , Bridges William , Pratt Scott
Published: November 2020

Quantification and assessment of quality of ribonucleic acid (RNA) is essential for assays determining gene expression including qRT-PCR, northern blotting, and RNA sequencing. Methods assessing RNA abundance and quality vary in detection range and specificity, in part due to their differences in how quantification is achieved. Agilent chip technology utilizes fluorescent labeling of nucleic acids coupled to electrophoresis to separate RNA based on size. Nanodrop utilizes spectrophotometry assesses quantity nucleic acids based on absorption of light and allows for an estimation of purity using the A260/280 (nucleic acid to protein) ratio. RiboGreen assays utilize a fluorescent intercalating dye that specifically targets single-stranded RNA. The objective of this study was to determine the most accurate method of RNA quantification between these three assays. Male pituitary samples (n = 220) were collected at a local abattoir, anterior lobe isolated, flash frozen in methanol dry-ice bath, and stored at -80°C until further processing. Total RNA was isolated from all samples and samples were subjected to spectrophotometry, Agilent nano chip assay, and Ribogreen assay. Data were analyzed for differences in standard deviation of total yield (mg/g) across all methods and each pair of methods using an O’Brien test for unequal variances. Standard deviation differed due to quantification method (P = 0.0002). Over 5 times greater variability in quantification was observed between Agilent chip technology compared to nanodrop (P = 0.0036), 2 times greater between nanodrop and Ribogreen (P < 0.0001), and 10 times greater variation between Agilent and Ribogreen methods (P = 0.0029). The Ribogreen assay provides the smallest variation in quantification from sample to sample and is the most reliable method out of the three technologies for quantification of RNA; however, it does not address issues of RNA quality.
72 Endocrine and ovarian responses to combined estradiol benzoate-sulpiride in anestrous mares treated with kisspeptin
Authors: Bailey Victoria N , Sones Jennifer L , Camp Caroline M , Oberhaus Erin L
Published: November 2020

The objective of this study was to determine if incorporation of kisspeptin 10 (Kp10) into an estradiol benzoate (EB)-sulpiride treatment would result in greater endocrine responses, and a greater number of mares ovulating within 28 days of treatment compared to EB-sulpiride alone. Eighteen anestrous mares were blocked by horse type (light horse and pony crosses), body condition, and age, then randomly assigned to treatment or control. On day 0, all mares received 50 mg EB. On day 1, mini osmotic pumps containing saline (n = 9) or Kp10 (50 mg/hour; n = 9) were inserted subcutaneously in the neck and remained for 7 days. Serial blood sampling occurred for 24 hours after pump placement. On day 2, all mares received 3 g sulpiride. Serial blood sampling continued for 36 hours and daily for 28 days. Transrectal ultrasounds were performed regularly for detection of ovulation. Plasma was assayed for prolactin, luteinizing hormone (LH) and progesterone. Data were analyzed by ANOVA with repeated measures. Plasma prolactin increased (P < .001) in response to sulpiride in all mares and remained stimulated for 7 days. Prolactin responses tended to be greater (P = .09) in Kp10- treated mares compared to controls. No differences were detected in plasma LH during the first 24 hours after pump placement; however, LH increased in all mares beginning 5 days after sulpiride and were greater (P < .05) in Kp10-mares from day 7 to day 21. Eleven of 18 (61%) mares ovulated within 18 days of sulpiride treatment; however, no differences in ovulation dates were detected between Kp10 treated- and control- mares. No differences were detected in plasma progesterone during the first 5 days post ovulation. In conclusion, incorporation of Kp10 potentiated the prolactin and LH responses to EB-sulpiride, but did not further advance first ovulation in treated-mares.
19 Comparing stress indicators of horses used for therapy in riding activities and groundwork activities
Authors: Abbott Gabrielle , Jogan Kathi , Oberhaus Erin L , Apple Jason , Rosenkrans Charles
Published: November 2020

Equine therapy is used to assist people suffering from various physical and mental disabilities. Equine-assisted activities and therapies (EAAT) include therapeutic riding and hippotherapy. Our objective was to determine the effects of EAAT on horse heart rate, respiration rate, temperature, and serum cortisol. Horses (n = 7) were assigned to activity type (groundwork or riding) in a Latin square design in which all horses performed both activities twice. Heart rate, respiration rate, rectal temperature, and serum cortisol concentrations were determined at 15 minutes before, and 15, 45, and 75 minutes after activity was initiated. Pearson correlations revealed that cortisol was not correlated (r < 0.12; P > 0.22) with heart rate, respiration rate, or rectal temperature. Heart rate was correlated (P < 0.05) with respiration rate (r = 0.77) and body temperature (r = 0.2); and body temperature was correlated with respiration rate (r = 0.21; P < 0.05). Analysis of variance was performed with horse within date as the experimental unit, main effects of activity type, horse, date, experimental time, and interactions. Serum concentrations of cortisol (varied from 2.8 to 89.7 ng/mL) and body temperature (37.4 ± 0.06) were affected (P < 0.01) by an interaction between experimental time and horse. Heart rate (61 ± 2.1) and respiration rate (30 ± 1.4) were affected (P < 0.01) by interactions between experimental time and horse; and experimental time and activity type. Our results demonstrate that equine athletes serving in EAAT programs have altered physiological responses depending on the horse, type of activity, and length of time performing the task. Based on our results, cortisol concentrations are not the best indicator of a horse’s response to EAAT work, and we recommend that trainers monitor horses’ heart and respiration rates as an indicator of horse well-being while working with patients.
173 The role of an intronic single nucleotide polymorphism within the dopamine receptor type-2 gene on pituitary prolactin protein expression in bulls
Authors: DeCarlo Andrea N , McCarty Keelee J , Richey Sarah K , Long Nathan , Pratt Scott
Published: November 2020

Detrimental effects to male reproductive physiology have been observed due to changes in prolactin (PRL) serum concentration. Regulation of PRL by dopamine binding to the dopamine type-2 receptor (DRD2) is well defined and associations between male physiology and single nucleotide polymorphisms (SNPs) within the DRD2 gene have been observed. The objective of the study was to evaluate association of a DRD2 SNP to PRL protein expression in bulls. Testis and epididymis were collected from bulls grazing a forage containing or lacking a dopamine agonist at the end of a 126 d study (n = 14). Bovine pituitaries (n = 587) were collected randomly over 3 mo from a local abattoir which processes cull cows and bulls. Sex of pituitaries was verified (n = 259 males) by duplex PCR for amplification of SRY and b-actin followed by Southern blotting of PCR products for selection of male. Prolactin protein expression was assessed in testis, epididymis, and pituitary by western blotting. Expression of PRL protein was below detection range in reproductive tissues but was present in pituitary, therefore experiments continued in pituitary. Restriction fragment length polymorphism genotyping was performed on pituitaries by amplification of the DRD2 SNP region followed by digestion with a Tfil enzyme. Digested of products produced 3,2, or 1 band (AG, AA, GG, respectively). A subset of male pituitaries was blotted by slot blot manifold and PRL protein expression assessed by immunodetection and densitometry analysis normalized to GAPDH expression. Pituitary genotype distribution was 17.4% AA (n = 16), 63% AG (n = 58), and 19.6% GG (n = 18). Prolactin protein expression in the pituitary was similar across genotype (P = 0.23). These findings indicate that the DRD2 SNP has no genotypic effect on PRL protein expression in bovine pituitary.
13 Changes in Cytokine Profiles in Response to Ergovaline Exposure in Slick vs. Normal Hair Coat in Beef Heifers
Authors: Brown Alecia R , Haimon McKenzie L , Poole Rebecca , Poore Matt H , Poole Daniel H
Published: November 2020

Fescue toxicosis is a syndrome common in cattle grazing fescue containing an endophyte that produces ergot alkaloids. Our lab has previously demonstrated that chronic exposure of ergot alkaloids adversely effects innate immune response. Therefore, the objective of this study was to examine changes in cytokine profiles in heat tolerant heifers exposed to ergot alkaloids from endophyte-infected fescue compared to wildtype controls. Angus X Senepol heifers were blocked by weight and hair coat genotype, Slick (S) or Normal (N) then randomly fed novel endophyte fescue (EN) or endophyte-infected fescue (EI) haylage in a total mixed ration for 63d (n=5 per group). Weekly measurements were collected to monitor physiological responses during exposure to ergot alkaloids. Blood samples were collected for cytokine analysis on d 0, 14, 28 and 56. Cytokine concentrations were quantified using Quantibody® Bovine Cytokine Arrays. Data were analyzed using PROC MIXED of SAS with repeated measures. Statistical significance was determined at P< 0.05 and a tendency at 0.05< P< 0.10. Concentrations of TNF were greater in EN-S heifers (6.57 ng/ml) compared to other heifer groups (P< 0.05; 1.33, 2.34, 3.15 ng/ml for EN-N, EI-S, and EI-N, respectively). Concentrations of IL21 were greater in EN-S heifers (8.15 ng/ml) compared to other heifer groups (P< 0.05; 1.55, 3.43, 3.26 ng/ml for EN-N, EI-S, and EI-N, respectively). Concentrations of IFNA (P=0.0543), IFNG (P=0.0558), IL1F1 (P=0.0587), and IL1F5 (P=0.0738) tended to be greater in in EN-S heifers compared to other heifer groups. Interestingly, concentrations of chemokine CCL4 (953.5 vs. 183.7 pg/mL) and CXCL9 (2.57 vs. 0.69 ng/mL) were significantly greater in S heifers than N heifers (P< 0.05). No differences were observed for IL13 and CXCL10 (P >0.05). In contrast to previous data, exposure to ergovaline via endophyte-infected fescue, did not induce an innate immune response. Rather, cytokine concentrations were elevated in heifers with the slick hair genotype. Overall, developing a better understanding of the interaction between ergot alkaloids and the slick hair genotype will help to improve cattle health management.
35 Differential haptoglobin responsiveness to a Mannheimia haemolytica challenge altered immunologic, physiologic, and behavioral responses in beef steers
Authors: Wottlin Lauren , Carstens Gordon E , Kayser William , Welsh Thomas H , Pinchak William
Published: November 2020

A retrospective analysis of data from a previous study (Kayser et al., J. Anim. Sci. 97:596; 2019) revealed that steers challenged with Mannheimia haemolytica (MH) had divergent serum haptoglobin (HPT) despite having similar leukocyte and temperature responses. In that study, 36 steers (BW 352 ± 23 kg) were fitted with rumen boluses and were fed from electronic bunks to measure DMI and feeding behavior prior to inoculation with saline or MH. Whole blood was collected on days -4, 0, 1, 2, 3, 5, 7, 10 and 14 relative to MH inoculation. The MH steers were retrospectively classified as HPT responsive (RES; n = 9; mean AUC = 62.6 mg/dL/d) or HPT non-responsive (NON; n = 9; mean AUC = 4.5 mg/dL/d). The current objective was to determine if the HPT responsive phenotype altered other immunologic, physiologic, or behavioral responses, compared to saline controls (CON; n = 18). The magnitude of increase in neutrophils (P< 0.01) and total leukocytes (P< 0.05) was greater in RES than NON or CON on day 1. All MH-challenged steers experienced a transient febrile response, but temperature was greater (P< 0.01) in RES on days 0 and 4 compared to NON and CON. Intake was depressed in all three groups d 0, but magnitude of depression in RES was greater (P< 0.01) than NON or CON, and remained lower (P< 0.01) d 1, 2, 3, 6, and 8. Bunk-visit duration was decreased (P< 0.01) in all MH-challenged steers on day 0, but RES were greater (P< 0.02) than NON and CON d 11 and 12. Correspondingly, bunk-visit eating rate of RES was decreased (P< 0.01) from day 2 - 14. Had this not been a sub-clinical challenge model, the greater reduction in intake and increased leukocyte recruitment may have resulted in performance differences between RES and NON steers. These results suggest that differences in HPT responsiveness may be associated with differences in innate immunocompetence.
22 Comparison of vaginal microbiome and concentrations of estradiol at artificial insemination in Brangus heifers
Authors: Messman Riley D , Contreras-Correa Zully , Paz Henry A , Perry George , Lemley Caleb O
Published: November 2020

The knowledge surrounding the bovine vaginal microbiome and its implications on fertility and reproductive traits remains incomplete. The objective of the current study was to characterize the bovine vaginal microbiome and estradiol concentrations at time of artificial insemination (AI). Brangus heifers (n = 78) underwent a 7-d Co-Synch + CIDR estrus synchronization protocol. At AI, a double guarded uterine culture swab was used to sample the anterior vaginal tract. Blood samples were collected by coccygeal venipuncture to determine concentrations of estradiol. Heifers were retrospectively classified as pregnant (n = 29) versus nonpregnant (n = 49) on day 35. Lastly, heifers were classified into low (1.1 - 2.5 pg/ml; n = 21), medium (2.6 - 6.7 pg/ml; n = 30), and high (7.2 - 17.6 pg/ml; n = 27) concentrations of estradiol. The vaginal bacterial community composition was determined through sequencing of the V4-V5 region from the 16S rRNA gene using the Illumina Miseq platform. ANOVA was used to compare the diversity metrics between treatment groups. PERMANOVA was utilized to determine variation in community structure. There were no statistical differences in the Shannon diversity index (alpha diversity; P = 0.336) or principal component analysis (beta diversity; P = 0.744) of pregnant versus nonpregnant animals. The vaginal microbiome of pregnant and nonpregnant animals was similar with the four most abundant phyla being Tenericutes, Proteobacteria, Fusobacteria, and Firmicutes. Overall bacterial community composition in animals with high, medium, or low concentrations of estradiol did not differ (P = 0.512). These results indicate that concentration of estradiol does not impact vaginal microbiome composition. In conclusion, the composition of the bovine vaginal microbiome, although dynamic, may not be directly linked to an animal’s reproductive ability.
69 Effects of supplementing heifers with dietary quercetin during late-gestation
Authors: Hisaw Zachary A , Willis Caleta M , Kipp Kaylee R , Eborn Douglas , Owen Megan P
Published: November 2020

Introduction of antioxidants, such as quercetin, into the diets of livestock species have become a new and revolutionary field of study. The objective was to examine effects of dietary supplementation of quercetin in beef heifers. Assessments were evaluated based on uterine artery hemodynamics and maternal hormone concentrations during late-gestation, as well as calf morphometric parameters. Eleven pregnant, Angus x Brahman heifers were randomly assigned to receive one of two dietary treatments: 1) quercetin (250 mg/day; Liftmode.com, Synaptent LLC, Chicago, IL, USA) supplemented group (QR; n = 6) or 2) no quercetin supplemented group (CON; n = 5). Dietary treatments were applied daily from d 190 of gestation until calving in a Calan System (American Calan, Inc., Northwood, NH) with 3.63 kg of a commodity grain and approximately 8.16 kg of hay per head per day. Both groups were subject to ultrasound scanning via rectal ultrasonography of the uterine artery using Color Doppler on d 190, 220, 250, and 270 of gestation. Blood samples were also collected via coccygeal venipuncture for hormone analysis. Data were analyzed using the ANOVA method within the Proc Mixed procedure of SAS 9.4. Total blood flow was greater (P < 0.05) on d 248 and even greater (P < 0.05) on d 270 of gestation as compared to d 190 and 220. Contralateral Pulsatility Index (PI) was greater (P < 0.05) in QR treated heifers as compared to CON. Additionally, QR heifers yielded a greater serum progesterone concentration (P < 0.05) as compared to CON but no differences (P > 0.05) between treatments regarding serum estrogen concentrations. Calf birth weight was not different (P > 0.05), but calves from quercetin supplemented dams resulted in greater wither and hip height (P < 0.05). Future research with antioxidant supplementation could lead to further fetal programming implications.
106 In Utero Exposure of Ergot Alkaloids does not Impact Heifer Growth and Reproductive Performance
Authors: Haimon McKenzie L , Brown Alecia R , Poore Matt H , Poole Daniel H
Published: November 2020

In utero exposure to toxins can alter fetal development and postnatal performance. The objective of this study was to investigate the effects of in utero exposure of ergot alkaloids via endophyte-infected (EI) fescue diets during gestation on heifer growth, onset of puberty, ovarian characteristics and AI pregnancy rates. Pregnant Angus and SimAngus cows grazed either endophyte-free (EF) or EI pastures on d90-180 of gestation. Assessment of puberty of heifer (n = 40) via measurement of BW, BCS, reproductive tract scores (RTS), pelvic area (PA) and weekly blood sample for progesterone (P4) analysis started at 10 mo of age. At 14 mos of age, all heifers were synchronized using the CoSynch+7d CIDR protocol and inseminated to examine reproductive measurements, follicle mapping and AI pregnancy rate. Data were analyzed using a MIXED procedure of SAS and examined for effects of EI, sire, and age. Statistical significance was determined at P < 0.05 and a tendency at 0.05 < P < 0.10. In utero exposure to EI did not affect ADG, BW, or BCS (P > 0.05) however, there was a sire by treatment interaction for ADG during onset of puberty (P < 0.05). While EI did not affect PA or RTS (P > 0.05), sire significantly influenced RTS and PA (P < 0.05) thus impacting of onset of puberty. Based on P4 concentrations, only 55% of all heifers were cyclic by 14 months of age and there was a sire by treatment interaction for onset of puberty (P < 0.05). No differences were observes in AI pregnancy rate between heifer groups (EF 39.5±7; EI, 43.7±7; P >0.05). While EI did not affect follicle counts or luteal area (P > 0.05), sire significantly influenced the percentage of preselected (2-4mm) and selected (>9mm), but not transitional (5-8mm), ovarian follicles at breeding age (P < 0.05). While consumption of EI fescue during gestation impacts cow performance and onset of puberty in heifers, it has minimal effect on heifer growth and reproductive development and performance.
120 Performance Effects on Weaned Calves using 3 Weaning Strategies and Nutritional Supplementation
Authors: Hendricks Meagan , Eborn Douglas , Kipp Kaylee R , Willis Caleta M , Owen Megan P
Published: November 2020

The objective of this study was to compare nutritional and management strategies on performance of beef calves at weaning. Forty crossbred beef calves were assigned to receive either nutritional supplementation (Drench) 3 wks prior to weaning and again at weaning or nothing (Cntrl). In addition, calves were assigned 1 of 3 weaning treatments: 1) abrupt weaning with complete separation (Abrupt); 2) 4d fence line weaning with cows allowed to interact with calves through a fence for 4 d before removal (4Fence); and 3) 7 d fence line weaning with cows allowed to interact with calves through a fence for 7 d before removal (7Fence). Calves were blocked by sex and BW. Nutritional supplementation consisted of an oral drench (5cc/100 lbs. BW; Cellarator Turbo Drench; ADM Animal Nutrition; Quincy, IL). Calves were weighed at weaning, 7 d after, and 85 d after weaning. At weaning, average age of calves was 213 ± 19 d and average weight 224 ± 30 kg. Average final weight of calves was 279 ± 33 kg. Weight differences between weaning and 7 d after weaning and weaning and 85 d after weaning were analyzed using Proc Mixed with nutritional supplementation, sex, and weaning duration as fixed variables. Calves receiving Drench gained more (P < 0.05) 1 wk after weaning (7.9 vs. 3.7 kg, respectively). Weight gains 85 d after weaning were not different (P > 0.05) 7 d after weaning. Weight gain in calves assigned to 4Fence and 7Fence treatments were not different (P < 0.05) but gained more (P < 0.05) than Abrupt calves (8.5 vs. 7.6 vs. 1.2 kg, respectively). Weight gains 85 d after weaning were not different (P > 0.05) between weaning treatments. In conclusion, nutritional supplementation and fence-line weaning improved calf performance 1 wk after weaning but not after 3 mo.
112 Mineral supplement intake by weaned steers as affected by offering multiple salt sources
Authors: Parish Jane A , Yankey Kalisha C , Durst Libby S
Published: November 2020

Pastured cattle are sometimes offered multiple separate salt (NaCl)-containing nutritional supplements. This study objective was to determine how range meal presence impacts mineral supplement intake when cattle choose between multiple salt source offerings. Weaned Bos taurus crossbred steers (n = 24) (initial BW = 263 ± 4.0 kg) were stratified by BW in a completely randomized design across 4 pens with 2 GrowSafe bunks per pen with ad libitum access to mixed-grass pasture and 1) one bunk supplied with a mineral supplement containing 15.0% salt (Grazer Hi/Se Hi/Cu CTC 2800; Multi-Kare, Inc., Tifton, GA) (MINERAL) or 2) one bunk containing a 2:1 range meal containing 30% salt and 13% CP (HI-GRAIN RANGE MEAL 1–2; Land O’Lakes Purina Feed LLC, Shoreview, MN) and the other bunk containing the mineral supplement (RM2) (Exp. 1). In Exp. 2 the 2:1 range meal was replaced with a 3:1 range meal containing 22.5% salt and 15% CP (HI-GRAIN RANGE MEAL 1–3; Land O’Lakes Purina Feed LLC, Shoreview, MN) (RM3). After a 14-d acclimation period intake was monitored for 42 days for Exp. 1 followed by a 7-d acclimation and Exp. 2 spanning 42 days. Mean daily DMI per steer were 104.6 ± 22.7 g and 525.8 ± 228.0 g of the 2:1 and 3:1 range meal, respectively. In Exp. 1 steer daily DMI was greater (P < 0.01) for MINERAL (31.9 ± 2.2 g) than for the mineral portion (4.3 ± 2.2 g) of RM2. Mean steer daily DMI in Exp. 2 was greater (P < 0.01) for MINERAL (57.2 ± 6.1 g) than the mineral portion (3.4 + 6.1 g) of RM3. Range meal offered separately and simultaneously with a salt-containing mineral supplement decreases mineral supplement consumption by severalfold with implications for potential inadequate daily intake of nutrients and medications mixed in these supplements.
101 Impact of weaning strategy on beef cow and calf weight and body condition
Authors: Moore Mikayla , Cox-O’Neill Jordan , Poore Matt H , Pickworth Carrie L
Published: November 2020

Weaning is one of the largest stressors in an animal’s life and can have long term impacts on the animal. The objective of this study was to investigate the effect of weaning strategy on the weight and body condition of beef cattle. A total of 249 Angus-based pairs at two locations were assigned to one of three treatments: abrupt removal of the calf on d0 (Abrupt, n = 84), fenceline contact for 7 days followed by complete separation on d7 (Fence, n = 85), or late weaning d84 (Late, n = 80). Weaned calves were supplemented 0.23 kg/hd/d of grain as fed while Late were not supplemented. Weights were obtained on d0, 7, 14, 28, 56, 84, 91, and 112. Body condition scores were recorded monthly. Data were analyzed using PROC MIXED of SAS and weights were analyzed with repeated measures. Significance was determined at P < 0.05. During the initial week post-abrupt weaning, Abrupt calves lost weight, Fence maintained weight, and Late calves gained weight (-0.4, 0, and 0.7 kg/d, respectively; P < 0.05). Over the complete weaning period (d0 to 112), Abrupt and Late weaned differed (P < 0.05) in their gains, while Fence was not different (P >0.05) than either treatment (0.58, 0.64, and 0.62 kg/d, respectively). Cow overall ADG was not affected by weaning treatment (1.2, 0.8, and 0.5 kg/d, respectively; P > 0.05). From d28 to 84, lactating Late cows gained less weight than Abrupt and Fence (0.3, 0.8, 0.8 kg/d, respectively; P < 0.0001). This contributed to a -0.1 BCS decrease at d112 for Late compared to a 0.3 and 0.2 BCS gain for Abrupt and Fence, respectively (P < 0.0001). Cows weaning calves after 10 mo of lactation were lighter than cows weaned after 7 mo; however calves remaining with their dam maintained growth rates similar to grain supplemented weaned calves on pasture. While treatments influenced cow measures, all remained within normal values, therefore late weaning may be an option for producers to sell heavier calves without grain supplementation if marketing older calves.
52 Effects of an energy or protein supplement on forage dry matter intake for steers grazing summer native range
Authors: Husz Taylor C , Beck Paul A , Foote Andrew P , Reuter Ryan R
Published: November 2020

The objective of this study was to determine the effects of supplementation level and type on forage intake of steers grazing a high-quality native range. This study was conducted in late May through the end of June. On d 0, steers (n=16, initial BW = 193.7 kg ± 14.3 kg) were randomly assigned to one of 5 dietary treatments, fed once daily in individual stalls for 28 d. Treatments were control (no supplement, n=4), or supplemented with either cottonseed meal or dry rolled corn, each at either 0.45 kg or 1.81 kg as-fed/d (n=3 for each combination). Beginning on d 7, steers were orally administered titanium dioxide boluses (10 g/steer) once daily for 21 d. Fecal samples were collected from the rectum once daily for 14 d, analyzed for Ti concentration via a handheld X-ray fluorescence analyzer, and total fecal output was estimated. Diet digestibility was estimated after a 288-h in situ incubation of forage and fecal samples to determine indigestible NDF. Some steers had orts, therefore actual mean supplement intake was used in analysis. Results were analyzed with regression, with animal as the experimental unit. Mean estimated forage DMI of unsupplemented animals was 1.6% BW. Contrary to expectation, corn supplemented steers exhibited greater forage DMI as a percentage of BW than cottonseed meal supplemented steers (P = 0.01; 1.5 vs. 1.1, respectively).
124 Polyclonal Antibody Preparations from Avian Origin Increased Fiber Digestibility of Beef Cattle Receiving a Backgrounding Diet
Authors: da Silva Gleise Medeiros , Schulmeister Tessa M , Tarnonsky Federico , Podversich Federico , Garcia-Ascolani Mariana Eloisa , DiLorenzo Nicolas
Published: November 2020

This study investigated the effects of feeding an avian-derived polyclonal antibody preparation (PAP; CAMAS, Inc.) against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides (40, 35, and 25% of the preparation, respectively) on plasmatic haptoglobin and glucose concentrations (Exp. 1), and apparent total tract digestibility (Exp. 2) of beef cattle consuming a backgrounding diet. In Exp. 1, Angus crossbreed heifers and steers (n = 90; 373 ± 62 kg BW) were randomly assigned to receive a common ad libitum diet (76% TDN, 15.9% CP, DM basis) with the addition of 1 (PAP1), 3 (PAP3), or 0 g (CON) of PAP daily. Plasmatic concentrations of glucose and haptoglobin were measured on d 0, 14, 28, 42, and 56. In Exp. 2, 25 Angus crossbreed steers (390 ± 65 kg BW) were used in a completely randomized design. Steers were housed in 3 pens to receive the same diet and treatments from Exp. 1. Feed intake was measured using GrowSafe feed bunks, and indigestible neutral detergent fiber was used as the internal marker. In Exp. 1, a day effect was detected for plasmatic haptoglobin and glucose concentrations (P ≤ 0.04). In Exp. 2, no difference in DMI was observed (P = 0.88). Dry matter, organic matter, and acid detergent fiber digestibility in the total tract were reduced (P ≤ 0.05), whereas CP digestibility tended to decrease (P ≤ 0.07) in steers receiving PAP3 vs. CON and PAP1. Apparent total tract starch digestibility was increased (P ≤ 0.02) for PAP1 vs. PAP3. Neutral detergent fiber digestibility was greater (P < 0.01) for PAP1 vs. CON and PAP3. Feeding 1 g/d of a PAP against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides increased fiber digestibility in backgrounding diets; however, further research is needed to understand the impaired responses on nutrient digestibility when greater doses are provided.
157 The effect of sample handling methodology on ruminal redox potential measured in vivo and in vitro
Authors: Rivera Madeline E , Norris Aaron B , Tedeschi Luis O
Published: November 2020

Anaerobic metabolism in a biological system, such as the rumen, depends largely on the reducing power of the bacterial population present. For that reason, it is crucial to understand the relationship between redox potential (Eh) and fermentative activity. The diverse microbial profile is characterized by enzyme systems capable of maintaining a constant, yet ever-evolving rumen environment. Variation in Eh is a result of intrinsic and extrinsic factors, including measurement procedure, diet, temperature, and animal. Because Eh is sensitive to oxygen contamination, the objective of this study was to assess different procedures for post-collection rumen inoculum to determine Eh. Four hours after feeding, ten rumen fistulated steers (267.9 ± 8.4 kg), receiving a grower diet, had rumen inoculum (600 mL per animal) extracted using a vacuum suction device and Eh was measured in vivo simultaneously. One subset of samples was incubated in a 39°C water bath (Procedure 1), while the second subset of samples was placed in an ice bath (Procedure 2). Redox potential and temperature were measured at 5, 15, 30, 60, 120, and 240 minutes for both Procedures. For Procedures 1 and 2, Eh values ranged from -235.4 to -313.1 mV and -198.0 to -293.4 mV, respectively. Data were analyzed using orthogonal contrasts with animal within-day and day as random effects in the statistical model. There was no effect for Procedure × Time (P = 0.273) or Time (P = 0.396), but there were differences between Procedures (P < 0.001). Polynomial contrasts indicated quadratic tendencies for Procedure 1 and the interaction of Procedure x Time (P = 0.051 and P = 0.0776, respectively). This study concluded that Procedure 2 more accurately represents in vivo Eh values, likely due to the reduced rate of fermentation associated with samples preserved on ice.
85 Evaluation of methane concentration sampling methods of gas produced from in vitro fermentation
Authors: D’Souza Genevieve M , Norris Aaron B , Tedeschi Luis O
Published: November 2020

Sampling methods of methane concentration (CH4) of gas produced from in vitro fermentation (IVGP) were evaluated to assess their determination efficacy. The original protocol recommends directly placing fermented bottles on ice (0°C) for 30 minutes to stop fermentation (D). An alternate protocol recommends placing the fermented bottles into the refrigerator (4–6°C) to slow fermentation (S). This experiment evaluated the previous methods against direct sampling of the gas after 48 h of fermentation at 39°C (I). Rumen inoculum was pulled from four rumen cannulated steers and filtered through fiberglass wool. Ground alfalfa was used as the fermentable substrate and total gas production was recorded for 48 h of fermentation. After fermentation, each bottle followed a randomly assigned protocol. The pressure and volume of gas in the bottle were recorded, 12 mL of gas from the headspace was placed into an evacuated exetainer for (CH4) sampling via gas chromatography, and the temperature of the fermented fluid was recorded. Eight bottles from D and eight bottles from S were randomly selected to follow the exetainer protocol, while the remaining bottles had (CH4) directly measured from their headspace. Statistical analysis was completed using a random coefficients model. Methane concentration was higher for I than D (P = 0.0286) and S (P = 0.0070). There was no difference in (CH4) between D and S (P = 0.5286). There was no difference in (CH4) in D exetainers and bottles (P = 0.5744), but there was a difference in (CH4) in S exetainers and bottles (P = 0.0229). Pressure, volume, and temperature were different among all protocols (P ≤ 0.0311). Based upon the data, protocol I provides the best estimate of (CH4). Further research is required to understand the discrepancy of (CH4) among the protocols relative to temperature, pressure, and volume.
108 Influence of Cow Body Weight Changes on Calf Growth during the Summer Grazing Period
Authors: Harrelson Flint W , Fraley Joseph , Harrelson Patricia L
Published: November 2020

In spring calving beef herds, the summer grazing period allows the mature cow to recuperate prior to the next calving season. Cow body weight changes during the summer can vary from minimal to extreme, which may also alter calf growth rates. The objective of this study was to determine the influence of cow body weight changes on calf growth during the summer grazing season. Cows and calves were weighed at the beginning, mid-point and end of the summer grazing season with the end-point being weaning. Based on these weights, cows were categorized into one of four groups: low (LO), medium (MED), high (HI), and extreme (EXT). Groups were determined based on the percent body weight gained across the season with LO being less than 4.99%; 5–9.99% as MED; 10–14.99% as HI, and above 15% as EXT. Data were collected over a 3-yr period utilizing a total of 52 mature Angus cows and 102 Angus calves. Cows were rotationally grazed on mixed grass pastures containing tall fescue and supplemented with corn silage for part of the grazing season. Cows were managed in two groups, but all pastures were grazed by all cows during the season. Calves were provided ad libitum access to creep feed for the entire grazing season. All calves were treated similarly and bulls were left intact until weaning. Data were analyzed in the MIXED procedure of SAS with year and group effects with age of dam as a covariate. Calves had the lowest early ADG in LO cows compared to all other groups (P = 0.01). Overall calf ADG tended to be different between groups as LO cows had slower growing calves compared to EXT or HI dams (P = 0.09). Generally, cows that gained the least amount of weight over the grazing season had slower growing calves.
127 Predicting Dry Matter Intake of Gestating and Lactating Beef Cows
Authors: Gross Megan A , Andresen Claire , Holder Amanda , Moehlenpah Alexi , Goad Carla , Freetly Harvey C , Beck Paul A , DeVuyst Eric A , Lalman David L
Published: November 2020

In 1996, the NASEM beef cattle committee developed and published an equation to estimate cow feed intake using results from studies conducted or published between 1979 and 1993 (Nutrient Requirements of Beef Cattle). The same equation was recommended for use in the most recent version of this publication (2016). The equation is sensitive to cow weight, diet digestibility and milk yield. Our objective was to validate the accuracy of this equation using more recent published and unpublished data. Criteria for inclusion in the validation data set included projects conducted or published within the last ten years, direct measurement of forage intake, adequate protein supply, and pen feeding (no tie stall or metabolism crate data). The validation data set included 29 treatment means for gestating cows and 26 treatment means for lactating cows. Means for the gestating cow data set was 11.4 ± 1.9 kg DMI, 599 ± 77 kg BW, 1.24 ± 0.14 Mcal/kg NEm per kg of feed and lactating cow data set was 14.5 ± 2.0 kg DMI, 532 ± 116.3 kg BW, and 1.26 ± 0.24 Mcal NEm per kg feed, respectively. Non intercept models were used to determine equation accuracy in predicting validation data set DMI. The slope for linear bias in the NASEM gestation equation did not differ from 1 (P = 0.07) with a 3.5% positive bias. However, when the NASEM equation was used to predict DMI in lactating cows, the slope for linear bias significantly differed from 1 (P < 0.001) with a downward bias of 13.7%. Therefore, a new multiple regression equation was developed from the validation data set: DMI= (-4.336 + (0.086427 (BW^.75) + 0.3 (Milk yield)+6.005785(NEm)), (R-squared=0.84). The NASEM equation for gestating beef cows was reasonably accurate while the lactation equation underestimated feed intake.
79 Evaluation of extended release eprinomectin efficacy on multiparous beef cow performance
Authors: Zammit Laine , Powell Jermey G , Cauble Reagan N , Lester Toby D , Lichtenwalter Callan , Herring Ellen , McGuire Clay , Pickett Autumn T , Wray Eva , Tucker Christopher
Published: November 2020

Internal parasitism inevitability prompts economic loss in beef cattle production by decreasing growth performance and reproductive traits. Previous studies have conflicting results on the macrocyclic lactones (ML) efficacy against internal parasitism. The objective of this study was to evaluate the efficacy of milbeymycin and avermectin sub groups of ML on cow performance. Multiparous fall calving, crossbred beef cows (n = 106) were allocated randomly to 1 of 3 anthelmintic treatments: 1) Negative control (CON), in which cows did not receive an anthelmintic, 2) Injectable moxidectin (MOX) and 3) Injectable extended release eprinomectin (ERE). Body weights (BW), body condition scores (BCS), and fecal egg counts (FEC) were taken throughout the duration of the calving season to weaning on d0, d80, d162, and d217, with weaning occurring on d217. Performance data were analyzed using the MIXED procedures of SAS, and pregnancy data were analyzed using the GENMOD procedures of SAS. Significance was fixed at P < 0.05 and tendencies were established from 0.05 ≤ P ≤ 0.10. There was no effect of anthelmintic treatment on cow BW (P ≥ 0.57) or cow BCS (P ≥ 0.22) during the 217 d study; however, CON cows tended to have lower BCS (P = 0.08) throughout the duration of the study. Cows treated with ERE had fewer FEC compared to MOX and CON groups (P ≤ 0.001), and tended to improve pregnancy rates (c2 = 0.0546). Calf weaning weight was similar among treatments averaging 216, 225, and 223 kg regarding CON, MOX, and ERE cow treatments, respectively.
102 Impact of weaning strategy on beef cow-calf behavior and activity
Authors: Alexander Molly , Pickworth Carrie L , Moore Mikayla , Poore Matt H
Published: November 2020

The objective of this study was to investigate the impact of three weaning strategies on cow and calf behavior and activity. Research has shown that weaning imposes stress on both the cow and the calf that can alter behavior, activity, and growth performance. Angus-based cow-calf pairs (n = 147) were randomly assigned to one of three treatment groups, abrupt weaning on d0 (Abrupt, n=50), fence-line contact for 7 days and then relocation of the cow on d7 (Fence, n=50), and late weaning by abrupt separation on d84 (Late, n = 47). Both cow and calf behaviors were observed over 7d prior to weaning and 7d post weaning activity for each treatment group. A single observer recorded activity and vocalizations for each animal twice in morning and evening on observation days. Calf activity was also continuously measured using accelerometers secured to collars worn by five calves per treatment group. Observation and activity data were analyzed using PROC MIXED of SAS. Significance was determined at P < 0.05 and a tendency at 0.05< P ≤0.10. The average activity units per day (AU/d) prior to weaning were similar among treatment groups. On d1 of weaning, Fence calves, who still had a visual contact with their dam, tended to have greater AU/d (P = 0.09) than the Abrupt calves and maintained a higher level of activity through d14 (P < 0.001). Late calves tended to have greater AU/d (P = 0.10) than Abrupt or Fence on d0-1 after their weaning. No difference in vocalizations (P = 0.41) by calves 7d post weaning were observed (1% Abrupt, 0% Fence, and 4% Late). More cows on Fence paced (1%) than Abrupt (0%) or Late (0%) (P < 0.05) in the 7d of fenceline contact. Late cows (2%) vocalized more than Abrupt (1%) or Fence (0%) when their calves were still with them (P < 0.05), but not after (P > 0.05) when no vocalizations were recorded. These results differ from the previous year study; therefore, further investigation of the impact of weaning strategy on cow-calf behavior and activity is warranted.