bluuebunny/crossref_metadata_2025 huggingface dataset:
12 Carcass Attributes and Performance of Poultry (Gallus gallus domesticus) fed Olive Pomace
Authors: Conn Benny J , Snokhous Payton , Carter Ethan , Urso Phil , Legako Jerrad F , Kelley Stanley F , Beverly Marcy M , Anderson Mark
Published: November 2020

In livestock production systems, feed is the most expensive production input. The goal of any producer is to find feed that provides a balance of nutrients to meet requirements for maintenance, growth, and performance while efficiently contributing favorable carcass attributes at a low cost. Olive pomace, a by-product of the olive industry, can serve as a source of fat (14%), protein (3.6%), and fiber (44.5%). The objective of this study was to determine adipose tissue content and sensory attributes of chicken breast (Phase I), as well as determine growth of growing chickens fed a mixture of commercial feed and olive pomace (Phase II). In Phase I, mature broilers were fed rations consisting of 25%, 50%, and 75% olive pomace blended with standard poultry feed for 27d. After harvest, a fat sample was taken for fatty acid analysis, and a breast was taken from each bird for sensory analysis. The only difference in fatty acid composition was in the 50% treatment, which had lower amounts of docosahexaenoic acid and higher amounts of decanoic acid. No significant differences were detected between treatment groups in the sensory analysis (P = 0.79). The young chickens (n = 40) were divided into three groups and fed a standard diet (control), or a standard diet with either 25% or 75% replaced with olive pomace. They were fed ad libitum for 35d; total feed consumed was measured daily and bodyweight (BW) was recorded weekly. No difference was detected between control and 25% in BW, but the 75% was lighter (P < 0.01) than the other groups. Additionally, 75% consumed more feed (0.91/lb/bird/d; P < 0.01) than any other group with no difference between control (0.64/lb/bird/d) and 25% (0.71/lb/bird/d). The results show that olive pomace can be utilized in chicken rations and will not affect growth or the quality of the end product.
23 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-day 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.
149 The effect of bunk preference on performance, intake, and efficiency of feedlot steers using an automated individual feeding system
Authors: Pierce Kaitlyn N , Reuter Ryan R , Robison Colton A , Wilson Blake K
Published: November 2020

Automatic feeding systems are being used more frequently to understand individual cattle behavior and intake variation when cattle are group housed. The objective of this experiment was to evaluate if bunk preference exists, and if so, how bunk preference affects performance, intake, or efficiency of feedlot steers. Angus steers (n = 123; initial BW = 293 ± 33.8 kg) were blocked by BW and sire and assigned to 1 of 4 pens, each containing 6 automated feed bunks (Insentec RIC; Hokofarm Group, Marknesse, Netherlands), in a randomized complete block design. Steers were fed a common diet and free to consume feed from any bunk within the pen without restriction. A steer’s preferred bunk was defined as the bunk from which the most feed was consumed. In any week, 80% of steers consumed less than 29% of that week’s total feed intake from the preferred bunk, indicating no strong preference for a specific bunk. The maximum weekly feed intake consumed from a preferred bunk was 57%. Further, the percentage of intake from the preferred bunk did not affect overall ADG, feed intake, or G:F (P > 0.64). These results suggest that a few steers may have a relatively strong preference for a specific feed bunk, however this preference was not associated with performance, intake, or efficiency. Researchers can design experiments (at a stocking density of 5 steers per bunk) that restrict or alter an individual animal’s access to any specific bunk, because such access, or lack of access, does not alter the animal’s performance or feed intake.
168 The effects of fly control strategies on fly abundance, fly avoidance behaviors, and performance in feedlot bulls and steers
Authors: McNeff Courtney , Talley Justin , Robison Colton A , Wilson Blake K
Published: November 2020

The objective of this experiment was to examine the effects of fly control strategies on fly abundance, fly avoidance behaviors, and animal performance in a feedlot setting. Angus bulls (n = 64; BW = 281 ± 36.2 kg) and steers (n = 36; BW = 475 ± 40.4 kg) were blocked by sex and BW and assigned to 1 of 4 experimental treatments in a randomized complete block design (7 pens/treatment; 4 bulls/pen; 3 steers/pen). Treatments included: control (CON; no fly control), abamectin, piperonyl butoxide, and zetacypermethrin insecticide tags (FT; Tri-Zap®, Y-Tex Corporation, Cody, WY), permethrin and piperonyl butoxide pour on (PO; Permectrin® CDS, Bayer Animal Health, Shawnee Mission, KS), or a garlic-powder top dress (GR) administered at 0.28 g •-1 animal •-1d. The experiment was conducted between June and September. Horn and stable fly abundance (FA) and fly avoidance behaviors (FAB; i.e. tail-flicks, stomping, head-tossing) were recorded by trained personnel. Both FA and FAB were recorded once/wk on days with similar temperatures, humidity, wind speed, and without precipitation based on Oklahoma Mesonet data (Stillwater site). There was a tendency for a treatment × time interaction for horn FA with differences in treatments occurring at wk 1, 2, 8, and 14. There was no treatment × time interaction for stable FA or FAB, however both were affected by time (P < 0.001). There were no differences in final BW (P = 0.34), overall ADG (P = 0.30), overall DMI (P = 0.53), or overall G:F (P = 0.39). There was a tendency (P ≤ 0.10) for GR to have decreased BW on d 28 and decreased ADG from d 0 to 28 compared to FT and PO. There was also a tendency (P = 0.09) for decreased DMI from d 0 to 56 for GR compared to CON and FT. Overall FA was less than expected (mean = 1 to 17 flies/animal) throughout the experiment and overall animal performance was unaffected by fly control strategy.
160 The effect on ADG, DMI, and blood metabolites of weaned Katahdin lambs offered chelated mineral with Ascophyllum nodosum on a high forage diet
Authors: Jolly Elizabeth , Boyd Jamie A
Published: November 2020

The objective of this study was to determine the effects of Katahdin wethers supplemented with mineral product including Ascophyllum nodosum seaweed on a 100% forage feedlot diet. Twenty-three Katahdin wethers (24.930.59 kg) post-weaning were divided into a treatment group of 12 wethers and a control group of 11 wethers, in which both were fed an ad libitum diet of mixed Alfalfa-Bermuda forage. The treatment group was supplemented with the chelated mineral with seaweed. The control group was supplemented with a non-chelated Cal Phos product without seaweed. To determine mineral absorption, 4 wethers from each group had blood metabolites analyzed for copper, iron, manganese, molybdenum, selenium and zinc via jugular pulls at weeks 0, 4 and 8 weeks. DMI was determined by group on a daily basis, and ADG was calculated. Forage samples were collected 2x week for dry matter analysis then compiled by week and analyzed for NDF, ADF, EE, and CP. Data were analyzed via SAS using a randomized block design. There were no significant differences in blood mineral levels between the two groups or between weeks; both groups displayed adequate or normal blood metabolite levels. Carcass data were collected after 77 days and is pending analysis. DMI was significantly higher (18.620.11 vs 20.610.11; P < 0.0001) in the treatment group, as was the BW (kg) of the treatment group (29.310.52 vs 31.110.52; P = 0.02). ADG was not significantly different (0.210.009 vs 0.220.009; P = 0.18) and efficiency (ADG/DMI) was not significantly different (0.010.001 vs 0.010.001; P = 0.95). Overall, the increase in ADG and BW in 8-wk feed-out suggests that the lambs in the treatment group had performance benefits from the supplementation of the chelated mineral with seaweed. The shortened finishing time supplementing chelated mineral with seaweed is economical for producers; however, a study using traditional finishing diets is needed to confirm results.
143 Rumen Fluid Metabolites as Potential Biomarkers of Feed Efficiency in Angus Steers
Authors: Clemmons Brooke A , Powers Joshua B , Campagna Shawn R , Ault Taylor B , Embree Mallory M , Myer Phillip R
Published: November 2020

Beef cattle is the most consumed red meat in the United States, and the United States is the largest producer and consumer of beef cattle globally. Feed is one of the largest input costs for the beef cattle industry, accounting for 40–60% of the total input costs. Identifying methods for improving feed efficiency in beef cattle herds could result in decreased cost to both producers and consumers, as well as increased animal protein available for global consumption. Identification of feed efficiency biomarkers could aid in the selection of more feed-efficient animals. To identify potential biomarkers of feed efficiency, rumen fluid was collected from low- (n = 14) and high-RFI (n = 15) Angus steers based on RFI ± 0.5 SD around the mean following a 70-d feed efficiency trial to determine rumen metabolites associated with variations in feed efficiency. Steers were 7 mo of age, weighing 264±2.7 kg. Rumen fluid was collected via gastric tubing, filtered through a 0.22 µM syringe filter, extracted for metabolomic analysis using 0.1% formic acid in acetonitrile:water:methanol (2:2:1), and injected into the Dionex UltiMate 3000 UHPLC system with an Exactive Plus Orbitrap MS. Peaks for known metabolites were identified using MAVEN and analyzed using MetaboAnalyst 4.0 and SAS. Significance was determined using an α ≤ 0.05. Based on fold change (high/low RFI), eight metabolites were greater in low-RFI steers compared to high-RFI steers, including 3,4-dihydroxyphenylacetate, 4-pyridoxate, citraconate, hypoxanthine, succinate/methylmalonate, thymine, uracil, and xylose (P ≤ 0.05), while 12 metabolites differed by ≥ 2-fold. These metabolites were predominantly involved in amino acid and lipid metabolism. Rumen fluid metabolomes differed in steers of varying feed efficiencies. These metabolites may be used as biomarkers of feed efficiency and may provide insight as to factors contributing to differences in feed efficiency that may be exploited to improve feed efficiency in beef cattle herds.
53 Effects of an injectable zinc solution at weaning as an alternative castration method during the backgrounding period in beef bulls
Authors: Cauble Reagan N , Powell Powell G , Kegley Elizabeth , Gadberry Shane , Beck Paul A , Sims Michael , Shelton Cody
Published: November 2020

Castration is a routine management practice performed on an estimated 15 million bull calves each year in the United States. Although castration is a common practice worldwide, the process causes pain and stress that temporarily reduces performance. The objective of our study was to investigate the effects of a novel injectable zinc solution as an alternative castration method on the growth performance, testicular width, and serum testosterone concentrations of weaned beef bulls. Calves (n = 74) were processed at birth and were randomly assigned to 1 of 2 castration methods: 1) negative control, in which calves were surgically castrated at birth, or 2) chemically castrated, in which calves remained intact males until weaning and were chemically castrated with a 1 mL intratesticular injection of zinc solution in each testicle. Data were analyzed using the MIXED procedures of SAS and significance was declared at P < 0.05. Chemically castrated calves were heavier (P < 0.01) throughout the 168-d backgrounding phase compared to steers (285 and 266 kg respectively); however, the overall change in BW (P = 0.73) and ADG (P = 0.81) was similar between castration techniques. Testicular width measurements were greatest on d 28 and returned to baseline weaning measurements by d 56. Testicular width continued to decrease on d 77 and remained constant for the remainder of the backgrounding period (time P < 0.01). Although testicular width decreased, chemically castrating did not affect (time P = 0.17) testosterone concentrations; however, concentrations were numerically lowest on d 28 and 56. Chemically castrating cattle at weaning resulted in greater overall body weights and reduced testicular width during the backgrounding period; however, it did not eliminate testosterone production as compared to surgically castrating at birth. This solution was not effective in bulls at weaning.
36 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 with 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 d1. 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 d0, 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.
57 Effects of Diploid and Tetraploid Annual Ryegrass Cultivars on Cattle Performance, Herbage Mass, and Nutritive Value
Authors: Montgomery Sarah M , Karisch Brandi , Parish Jane A , Morrison Jesse , Baldwin Brian
Published: November 2020

Annual ryegrass (Lolium multiflorum Lam.) can be divided into two cytotypes: diploid (2n = 2x) and tetraploid (2n = 4x). Polyploid versions of a given plant species result in increased seedling vigor, more robust growth and, potentially, greater yield. While most data suggest no difference in yield between diploid and tetraploid cultivars, there is still potential for weight gain advantages thanks to increased non-structural carbohydrates in tetraploid cells. The objectives of this study were to compare weight gain of cattle grazing either diploid or tetraploid cultivars of annual ryegrass. Two diploid annual ryegrass cultivars (Marshall and Tam 90) and two tetraploid cultivars (Jumbo and Nelson) were planted in 0.81-ha pastures, each replicated four times. Four steers (mean initial BW = 214 kg) were randomly assigned to each pasture for an 82-d grazing period. Body weights were recorded starting at d0 then every 28 days throughout the season. Data were analyzed in the GLM procedure of SAS using a significance level of α = 0.05. There were significant differences between cytotypes with respect to seasonal yield with diploids (9547.90 kg/ha) yielding greater than tetraploids (7762.00 kg/ha). As expected, ADF and NDF fractions were significantly less for tetraploids (ADF; 31.39%, NDF; 31.39%) compared to diploids (ADF; 33.75%, NDF; 53.25%). Tetraploids also contained significantly greater crude protein (13.50%) than diploids (12.90%). Cytotype had no effect on final average daily gain (ADG) (P = 0.9427). However, final ADG was significantly impacted by cultivar (P = 0.0134). Final ADG for Tam 90 (1.10 kg/d) was greater than Marshall (0.92 kg/d). Cattle grazing Nelson (1.04 kg/d) and Jumbo (0.99 kg/d) did not differ. Results show that regardless of differences in seasonal yield and nutritive value between cytotypes, there were no advantages in ADG for cattle grazing either cytotype.
180 Using condensed tannins in plant materials more effectively with livestock
Authors: Kronberg Scott L
Published: November 2020

A large variety of plant species contain condensed tannins and a few of these have been developed as improved varieties for grazing or for feeding as long-stem, chopped or pelleted hay or as silage. Extracts of tannin-containing plant materials (e.g. quebracho tannin) and tannin-containing by-products of plant materials (e.g. grape marc) have also been fed to livestock. Interactions between livestock and condensed tannins and associated phenolic compounds are complicated and we have much to learn to understand and manage them better. Although many studies have been done on tannin-livestock interactions, many more are needed and especially studies done in conjunction with tannin chemists. Research to date suggests that very few plant materials have ideal condensed tannins for improving the long-term productivity of ruminant livestock (beyond productivity gains from reduction of internal parasites). Moreover, we know little about nutritional consequences relative to micronutrients such as copper and iron from long-term and frequent intake of condensed tannins. Given that grapes contain condensed tannin and associated phenolic compounds that are important to the wine industry, there is research on these compounds in grapes and wine that may be very useful to livestock scientists and producers who are interested in applying some of their concepts and knowledge to livestock. Some of this information will be discussed in my presentation.
4 Agrochemical Residues, Product Quality, and Safety of Beef Fed Cotton Ginning and Other Byproduct Feeds
Authors: Smith David J
Published: November 2020

Most commodity crops undergo milling, husking, ginning or other processing procedures before use as human food or fiber. Byproduct nutrient density varies with the type of grain or oil seed processed and use typically varies with nutrient needs of specific production situations. Drought or high grain prices may increase the use of byproducts; regionally available, low-cost ingredients such as cotton ginning byproduct may be used extensively by beef producers to replace forage. Doubt associated with the use of such byproducts is not typically related to nutritional value but with uncertainties about the presence of residual pesticides, herbicides, or harvest-aid chemicals. Potential chemical residues in consumer products and the concomitant financial and reputational losses borne by the industry provide an impetus for concern. Negative experiences with contaminated Australian beef established a long-lived suspicion of “cotton trash” that continues to impact the industry today. The purpose of this review is to discuss sources, amounts, and risks of chemical residues associated with byproduct feeds used in the southern United States with cotton ginning byproducts as a major focus. The use patterns of specific crop protection and harvest-aid chemicals will be discussed in context with chemical tolerances established by the U.S. EPA. In addition, U.S. pesticide monitoring programs in beef will be discussed. Although data describing the transmission of chemical residues from byproduct feeds into beef products are limited, the available data suggest some best practices could be adopted to mitigate concerns and minimize possible agrochemical residue contamination of beef.
118 Palatability of Olive Pomace in Mozambique Tilapia (Oreochromis mossambicus)
Authors: Krasue Ethan , Conn Benny J , Kelley Stanley F , Beverly Marcy M , Anderson Mark
Published: November 2020

By-products, such as distillers’ and brewers’ dried grains, are used in livestock rations as a source of important nutrients, cheapen feed costs, and reduce the cost of production. Olive pomace is the by-product from the production and milling of olive oil, and is a possible source of protein and energy for livestock. The objective of this study was to determine if Mozambique tilapia would consume olive pomace when mixed with commercial feed. Sixty tilapia, of similar size were divided into two separate tanks, each with its own aquaponic filtration system. Ammonia, pH, nitrates, nitrites, and chlorine levels were monitored to ensure optimum water environment. Olive pomace, from a two-phase mill, has a slurry-like constancy containing approximately 50% moisture. Due to its high moisture content, the pomace was offered to the fish in a dried state and mixed with a commercial feed at a 1:1 ratio. The dried pomace immediately sank to the bottom of the tank while the commercial feed remained on the water surface and consumed by the fish. The rate of consumption of the dried pomace could not be separated from the tank sediment, and therefore was not measurable. To deter the pomace from sinking, wet pomace was mixed at a 1:1 ratio with the floating commercial feed. The wet pomace, mixed well with the commercial feed and yielded a consistent blend of pomace and feed. The moist pomace:feed blend was molded by hand into 2 ½ centimeter spheres, each weighing approximately 9.1 grams. Four spheres were dropped into each tank allowing multiple fish to feed at once. Although, the wet blended feed mixture did not float, the fish ate the feed spheres as they sank. This preliminary research illustrates the willingness of tilapia to consume olive pomace and its potential use as a feed.
81 Evaluation of feeding immunoglobulin-Y to Holstein feeder cattle for the control of liver abscesses & reduction of macrolide-resistant bacteria dissemination
Authors: Stotz Miranda K
Published: November 2020

Despite the regular use of macrolide-antibiotics in the diets of feedlot cattle, liver abscesses persist representing a financial burden to both pre- and post-mortem sectors of the beef industry. Alternative strategies, which simultaneously address liver infections and reduce the dissemination of antibiotic-resistant bacteria, are needed. An immunoglobulin-Y (IGY) product, developed to target Fusobacterium necrophorum andTrueperella pyogenes, was evaluated for the control of liver abscesses and its effect on macrolide-resistant Enterococcus growth from feces. Sixty-four Holstein steers (Initial BW= 384±13.5kg) consuming a finishing diet (90% concentrate) for 188 d (Final BW= 660±42 kg) were used in a completely randomized design where treatments included: TYL (Tylosin phosphate fed at 90 mg/hd/day; n = 32) or IGY (fed at 2.5g/hd/day; n = 32). Feed intake was recorded daily and BW was recorded every 28 d until slaughter. After 150 d on treatment fecal samples were randomly obtained from each treatment group four times (n = 40) and cultured on bile-esculine agar enriched with 8 μg/mL of erythromycin. Continuous variables of feedlot growth performance, carcass data and bacterial growth were analyzed using the MIXED procedure of SAS with the fixed effect of treatment and random effects of steer or sampling day, respectively. Ordinal carcass data was analyzed using the FREQ procedure of SAS observing the Cochran-Mantel-Haenszel value. Treatment did not affect DMI (P = 0.21), ADG (P = 0.50) or G:F (P = 0.36). Treatment neither affected hot carcass weight (P = 0.37) nor longissimus muscle area (P = 0.25). However, TYL resulted in greater back fat thickness than IGY (0.32 vs. 0.23 in.; P < 0.02) and consequently greater numerical yield grade (P < 0.02). Quality grade was not affected by treatment (P = 0.65). No treatment difference was observed for liver abscesses prevalence (TYL= 63% vs. IGY= 52%; P = 0.40) or severity (P = 0.23). There was a greater proportion of erythromycin-resistant Enterococcus growth for TYL than IGY (42.6 vs. 21.9%; P < 0.04). Specifically formulated IGY feed additives may be viable alternatives to antibiotics in the diets of feedlot cattle.
16 Comparing Natural Vegetation and Food Plot Preference against Supplemental Protein Pellets in Captive White-tailed Deer (Odocoileus virginianus) and Exotic Species
Authors: McQueen Robert W , Beverly Marcy M , Kelley Stanley F , Anderson Mark
Published: November 2020

Supplemental feed is the most expensive input in the captive wildlife industries. This is due to operations utilizing high-energy pellets as supplemental feed. Low fence operations often utilize food plots with high quality vegetation to minimize cost and increase forage availability for wildlife. The objective of this study was to determine forage preference of animals in captivity, and determine the most cost effective method of supplemental feeding. Seven food plots covering 25 acres contained one of three treatments. The treatments were: a commercial blend of soybeans; a commercial blend of soybeans, sunflowers, and milo; native/unplanted. Three utilization cages were set up to inhibit wildlife access to samples within each food plot to act as a control. Height of vegetative samples, inside and outside of the utilization cages, was collected on days 30, 60, and 90 after planting. The 30-day sample showed a preference of native/unplanted vegetation over the commercial treatments, P < 0.05. However, samples taken on days 60 and 90 showed the preference shifted toward the commercial blends, P < 0.05. This browsing preference indicates stage of maturity had an impact on plant selection. Regardless of sample date, the commercial blends showed a difference of P < 0.01, selecting the soybean blend more frequently. With an increased selection of the forages in the food plots, there was a decrease in cost of purchasing feed pellets with a total savings of approximately $5,500.00 from April 5-July 5, 2019. These results suggest that white-tailed deer and exotic species in captivity prefer forages compared to pelleted feed. Supplemental feeding programs that include food plots could allow for natural feeding tendencies, while being more cost effective for operations in the captive wildlife industries.
191 Yield and nutritive quality of summer annual forage mixtures
Authors: Thompson Serena , Dillard Sandra L , Jacobson Alana , Koebernick Jenny , Parks Grey , Mullenix Mary K
Published: November 2020

Summer annual forage mixtures are both high yielding and contain a high nutritive quality. They provide a summer forage option for maintaining stockers, forage-finished beef, and replacement heifers on with little to no external inputs needed. Recently, sugarcane aphid infestations have limited production of sorghum × sudangrass (Sorghum bicolor var. bicolor*bicolor var. sudanese; S). This study investigated mono-, bi-, and tri- cultures of S, cowpea (Vigna unguiculata; C), and crabgrass (Digitaria ciliaris; R). Forage yield, CP, NDF, ADF, ADL, and sugarcane aphid counts were determined for each treatment. Sugarcane aphid counts were conducted on a weekly basis during the study and forage samples were harvested twice during each season. A forage subsample was taken for determination of CP, NDF, ADF, and ADL using wet chemistry. Data were analyzed using Proc Glimmix of SAS 9.4 (SAS inst., Cary, NC). During Year 1, the only difference in yield among treatments was observed in R, which was lower than other plots (949 and 1,259 kg/ha, respectively; P < 0.05). Neutral detergent fiber was greatest (P < 0.0001) in treatments containing S, whereas C and C+R had the least NDF (64.6%, 55.1%, and 56.6%, respectively; P < 0.02). Sugarcane aphids were greater (P < 0.0001) in S+C compared to S+R and SI on July 12 (33.5, 21.1, and 22.4 aphid days/ two leaf sample, respectively). During Year 2, there were no differences in yield among plots (996 kg/ ha, P > 0.9); NDF was greatest in S and lowest in plots containing C and C+R (63%, 46%, and 45.6%, P < 0.0001). While there appeared to be no reduction in sugarcane aphid pressure in the mono- and mixed- cultures of S, C+R showed promise as a summer annual mixture with similar yield and higher quality to that of S and S mixtures.
76 Evaluating Nitrogen Management Strategies to Improve Southern Bermudagrass Grazing Systems
Authors: Burt Justin C , Tucker Jennifer J , Baxter Lisa
Published: November 2020

Bermudagrass (Cynodon dactylon) is one of the most common perennial warm-season forage crops grown in the South. While prominent in the region bermudagrass management requires large amounts of fertility and forage quality is moderate at best. Incorporating a legume into bermudagrass pastures could serve as an alternative to the necessary applications of synthetic N, while also improving the nutritive value of the forage base. A two-year grazing evaluation was conducted from May-Sept. 2018 (Y1) and May-Aug. 2019 (Y2) at the University of Georgia Tifton Campus in Tifton, Georgia, to compare concurring production of alfalfa/bermudagrass mixed pastures (BGA) with bermudagrass monoculture pastures with (BGN) or without (BGZ) the application of synthetic nitrogen. The experimental design was a randomized complete block with three treatments and two replications. All paddocks were evaluated pre and post grazing event for herbage availability, botanical composition, forage species competitiveness, and nutritive value. Paddocks (0.8-ha) were rotationally grazed using put and take management with stocker steers (Y1 BW=195.9±22.9 kg; Y2 BW=228.5±30.0 kg), two testers per treatment. Steers were weighed at initiation, conclusion, and on a 28–30 day interval for calculation of ADG and gain/ha. Statistical analysis was conducted using the PROC MIXED procedure of SAS. Despite significant drought in Y2, year did not affect total gain/ha, however treatment did (P = 0.04), such that BGA was highest (383.6±35.1 kg/ha), and BGN and BGZ were not different (261.2±35.1 kg/ha and 239.0±35.1 kg/ha, respectively). This is likely due to the lower stocking density and inclusion of high-quality volunteer annual grasses in BGZ treatments which allowed for selective grazing. These data suggest that rotationally grazing alfalfa/bermudagrass mixtures can result in a higher gain/ha, than bermudagrass pastures that are supplemented with or without synthetic N in the South.
20 Comparison of native warm-season grasses and bermudagrass for stocker calf grazing in the Black Belt Prairie region
Authors: Parish Jane A , Yankey Kalisha C , Durst Libby S
Published: November 2020

Native grasses are touted for use in drought mitigation strategies for grazing cattle. It is important to determine how these forages compare in specific production environments to more widely used improved grasses such as bermudagrass [Cynodon dactylon (L.) Pers.] that they may replace as pasture. Native warm-season grasses including big bluestem (Andropogon gerardi Vitman), little bluestem (Andropogon scoparius), and indiangrass (Sorghastrum nutans L.) were evaluated against bermudagrass pastures in the Black Belt Prairie region of Mississippi for stocker cattle grazing. Objectives were to compare bermudagrass (BG), indiangrass (IG) and mixed-sward native warm-season grass (mix of big bluestem, little bluestem, and indiangrass) (NGMIX) pasture for forage nutritive value and steer ADG. Crossbred (Bos taurus) steers (n = 36 steers/year) were stratified by initial BW (339.7 ± 4.3 kg) to 2.02-ha pastures (3 replications) during 56-d grazing periods in June and July for 2 yr. Mean forage nutritive values on a DM basis were: BG [8.8% CP, 43.4% ADF, 67.3% NDF, 58.7% TDN, and 77 relative feed value (RFV)], IG (6.7% CP, 39.6% ADF, 68.3% NDF, 58.2% TDN, and 79 RFV) and MIXNG (7.3% CP, 40.5% ADF, 69.5% NDF, 58.1% TDN, and 77 RFV). A forage treatment x day x year effect existed (P < 0.01) for each these nutritive values. There was no effect (P = 0.47) of forage treatment on steer ADG (BG: 0.4 ± 0.1 kg/d; IG: 0.5 ± 0.1 kg/d; NGMIX: 0.5 ± 0.1 kg/d). Thus, no net advantage or disadvantage in steer growth rates was observed due to forage species. Other factors such as forage establishment cost and animal stocking rates supported may be relevant to consider in decisions to replace bermudagrass with warm-season native grasses.
62 Effects of forage allowance and supplementation on performance of steers grazing wheat pasture
Authors: McNeill Kynzie , Reuter Ryan R , Beck Paul A
Published: November 2020

A 72-d trial was conducted to estimate the combined effect of forage allowance and a fiber-based energy supplement in stocker cattle grazing wheat. Eight pastures (2.7 to 5.1 ha) each contained seven test steers (initial BW = 210 ± 36 kg). Weekly, additional steers were stocked in each pasture in a put and take method to achieve forage allowance of either 2.5 or 5.5 kg forage DM / kg steer BW (4 pastures each). Two pastures in each forage allowance were fed daily with a supplement containing 50% wheat midds and 50% soybean hulls at the rate of 1.5 kg per steer. Forage mass was measured twice weekly using a calibrated rising plate meter. Cattle were weighed weekly on calibrated scales. Data were analyzed using linear regression with pasture as the experimental unit. Mean ADG was 1.36 kg/d. One pasture in the high forage allowance, non-supplemented treatment was removed because we were unable to maintain the designed forage allowance. The interaction of forage allowance and supplement was not significant (P = 0.37) for ADG, and supplementation did not affect ADG (P = 0.20), however increased forage allowance tended to improve ADG (P = 0.06, 0.21 kg ADG per kg forage allowance). To further investigate forage DMI, a 14-d trial began on day 36. Three of the seven test steers in each pasture were randomly chosen and administered 7 ± 0.1 g of TiO2 daily at 0700 as an external marker to estimate fecal output. Forage DMI (at an assumed 72% DM digestibility) averaged 2.1% of midpoint BW, below our expectation. Additional forage allowance tended to improve estimated forage DMI (P= 0.06), but supplement had minimal effect (P = 0.30).
65 Effects of grazing cool-season cover crops on forage and animal performance
Authors: Carrell Russell C , Dillard Sandra L , Mullenix Mary K , Gamble Audrey , Muntifering Russ B
Published: November 2020

Utilization of cool-season cover crops has been shown to increase soil health and cash crop performance in minimum tillage cash crop systems. Though evidence that grazing of cover crops can be viable is limited. Our objective was to determine animal and forage performance when grazing a cool-season annual cover-crop. Twelve 1.2 ha pastures were established in a forage mix consisting of black oats (Avena strigose), cereal rye (Secale cereal), crimson clover (Trifolium incarnatum), and T-raptor (Brassica napus × B. rapa) and randomly allocated to be grazed either 0, 30, 60, or 90 days. Three tester steers were randomly placed in each paddock with the exception of control paddocks and allowed ad libitum grazing. Animals were weighed every 30 d for determination ADG and total gain (TG). Forage was harvested bi-weekly and analyzed for NDF and ADF using an ANKOM fiber analyzer (ANKOM Tech, Macedon, NY). All data was analyzed using MIXED procedure of SAS version 9.4 (SAS Inst., Cary, NC). Differences were found in ADG between 90 and 60 days grazed (4.2 ± 0.12 vs. 2.8 ± 0.12 kg/d; P < 0.01) and 90 and 30 days grazed (4.2 ± 0.12 vs 2.7 ± 0.12 kg/d; P < 0.01). Differences in TG were detected between 90 and 60 days grazed (819 ± 13.35 vs. 386.67 ± 13.35 kg; P < 0.01), between 90 and 30 days grazed (819 ± 13.35 vs 261.33 ± 13.35 kg; P < 0.01), and between 60 and 30 days grazed (386.67 ± 13.35 vs 261.33 ± 13.35 kg, P < 0.01). No differences in NDF (44.86%, P = 0.99) or ADF (27.20%, P = 0.92) were detected between treatments. These results indicate that different grazing periods could influence cattle growth and performance without negatively impacting forage quality and production.
34 Developing criteria for forage finished beef in the Southeastern U.S
Authors: Acharya Mohan , Burke Joan M , Wood Erin , Yancey Janeal
Published: November 2020

Demand for forage finished meats continues to increase and creates a market for small farmers in the southeastern United States. Little is known about production efficiency and quality. The objective was to examine breed type and dam age on growth and finishing traits of forage finished steers. Calves were born in February and March in 2014 (n = 47), 2015 (n = 59) and 2016 (n = 42), castrated at birth and weaned in October. Breeds were Angus with Brahman or Romosinuano influence (1/4 to 1/8). Dams were 2 to 13 yr of age at calving. After weaning, steers grazed tall fescue (fall, winter, spring), wheat/rye (spring), or bermudagrass (summer). BW and ultrasound measures were determined every 30–60 d to finishing target of 8.4 mm back fat. Data were analyzed using homogeneity of regression (BW or REA over day of age) or Proc mixed and included age of dam, breed type, and yr in the model, and age as a covariate. After weaning, BW and REA of steers from younger dams were lighter or smaller and nearly caught up with steers from 3- and 4-yr old dams within 12 mo (dam age x day of age, P < 0.001). ADG (weaning to 12 m later) during 2014, 2015, and 2016 were 0.571, 0.602, and 0.860 kg/d, respectively, and were 0.941, 1.192, and 0.860 kg/d, respectively, during spring months. There was no effect of breed or dam age on ADG in 2014 and 2015, and subtle effects of Romosinuano breed type in 2016. Breed affected number of days to reach target finishing only in 2015 (P = 0.005), but not in 2014 and 2016. In 2015 Brahman-influenced steers reached target earlier than others. Shear force of steaks was not influenced by breed or dam (2014, 4.86 ± 0.4 kg; 2015, 5.46 ± 1.2 kg). Cattle genetics appropriate for grass finishing should be considered and calves from 2-yr old dams may be less suitable for grass finishing systems.
68 Effects of Plant Growth-Promoting Rhizobacteria on Fall-Stockpiled Bermudagrass
Authors: Cole Madison , Griffin Megan E , Dillard Sandra L , Mullenix Mary K , Muntifering Russ B , Held David
Published: November 2020

Forage production practices have been greatly affected by the increasing cost of N fertilization. Therefore, supplemental and alternative N sources are needed to ensure the economic viability of these systems. A 2-yr, small plot study was designed to evaluate plant growth-promoting rhizobacteria (PGPR) as an alternative form of N fertilizer for fall-stockpiled bermudagrass (Cynodon dactylon). Eighteen 1-m2 ‘Coastal’ bermudagrass plots were treated with a synthetic N fertilizer, DH44 (PGPR strain), DH44+fertilizer, Blend 20 (PGPR blend), Blend 20+fertilizer, and a control, then stockpiled through the fall. Two PGPR applications were applied in late-August and again 30 d later. Fertilizer and PGPR+fertilizer plots received (NH4)2SO4, at a rate of 56 kg N/ha. One-third of each plot was clipped to 2.5 cm in November, December, and January, respectively. Forage DM yield, CP, NDF, ADF, and ADL were determined via wet chemistry at the Auburn University Ruminant Nutrition Laboratory (Auburn, AL). Data were analyzed using PROC MIXED (SAS 9.4, SAS Inst., Cary, NC) as a completely randomized design. Yield was greatest (P ≤ 0.0318) for Blend 20+fertilizer, but it was not different (P = 0.2552) from that of the synthetic fertilizer (1,914 kg ha-1, 1,768 kg ha-1, respectively). Concentration of CP was least (P ≤ 0.0437) for DH44 and Blend 20 treatments (90 g kg-1 and 92 g kg-1, respectively). Concentrations of NDF for the control were different (P ≤ 0.0045) for all treatments except synthetic fertilizer (P = 0.1092). Concentrations of ADF were not different (P ≥ 0.1613) excluding the control (P ≤ 0.0525; 342.8 g kg-1and 358.0 g kg-1, respectively). In vitro true digestibility (IVTD) was not different (P = 0.0947) among all treatments (463.1 g kg-1). All yield and nutritive value parameters were greater (P ≤ 0.0246) in Year 2. These results indicate that PGPR is a viable option for biofertilization of fall-stockpiled bermudagrass; however, further investigation into the effects of PGPR inoculants at a field scale are needed.
61 Effects of fescue cultivar on performance of beef cow/calf pairs grazed on summer stockpiled tall fescue pastures
Authors: Langford Taylor A , Hardin Keri N , Murray Adam R , Zumbaugh Charles A , Claire Olivia M , Fiske David A , Pent Gabriel J , Wilson Thomas B
Published: November 2020

This 2-year experiment evaluated productivity of wild-type endophyte-infected tall fescue (KY-31) and novel endophyte-infected tall fescue (MaxQ) summer stockpiled (SS) pastures and the performance of fall-calving beef cow/calf pairs grazed on each cultivar. Pregnant Simmental x Angus cows (128 total, 64 each year) were stratified by BW, BCS, and expected calving date, then allotted to 1 of 10 groups. Forage growth was stockpiled from April to initiation of strip-grazing on 31 August of 2017 and 2018. Cows grazed treatment pastures for 52 d from 23 ± 14 d prepartum to 29 ± 14 d postpartum, and calved on treatment pastures. Forage quadrats were clipped from the grazed and ungrazed portions of each pasture to determine weekly forage mass (FM). Total ergot alkaloid (TEA) concentrations were analyzed for all pastures at the beginning of the experiment and every subsequent 2 weeks for KY-31. Cow BW was recorded on 2 consecutive d and BCS determined at the start and end of the experiment. In year 2, ultrasound 12th rib fat thickness (BF) was measured at the beginning and end of the treatment period Milk production was estimated using the weigh-suckle-weigh technique at 29 ± 14 postpartum. In year 1, TEA concentrations for KY-31 pastures did not differ (P < 0.48) over time. Fescue cultivars were not different (P ≥ 0.15) in forage CP, TDN, and grazed or ungrazed FM. Cow BW, BCS, and BF at the beginning and end of grazing were not different (P ≥ 0.41) by treatment. Milk production was higher (P < 0.01) for KY-31 grazed cows. Calving date, calf BW, calf ADG were not different (P ≥ 0.65) by treatment. Neither AI nor overall conception rates differed (P ≥ 0.23) between cultivars. Performance of fall-calving cows pre-exposed to KY-31 was not improved when grazed on MaxQ in a SS system.
75 Epigenetic marks within the swine placenta are differentially expressed due to season
Authors: Cheek Robin , Rempel Lea A , Miles Jeremy
Published: November 2020

The objective of the current project was to validate expression of known chromatin modification genes and assess downstream targets in d45 swine placenta derived from seasonal semen collections and breedings and semen storage. Six treatment groups were developed based upon: season of semen collection (cool or warm), storage of semen (cooled-extended or cryopreserved), and season of breeding (summer or winter) with 8 litters per group as follows: 1) cool/cooled-extended/winter, 2) cool/cryopreserved/winter, 3) warm/cryopreserved/winter, 4) warm/cooled-extended/summer, 5) warm/cooled-extended/summer, and 6) cool/cryopreserved/summer. RNA was extracted from the placenta of a small, medium, and large fetus from each litter, pooled by litter, reverse transcribed, and used for qPCR. Three genes; ATF2, ASH2L, and SMYD3, were validated. Downstream gene targets, ILIB and NANOG, were also tested. Interactions and main effects were tested using the mixed procedure of SAS with boar as a random effect. Placental ASH2L had a tendency for increased expression from summer breedings (P >0.05), similar to previous findings using a different expression platform. Placental expression of ATF2 was greatest (P< 0.05) from placenta derived by summer breedings. A downstream target of ATF2, ILIB, had greater (P< 0.05) placental expression from summer breedings and semen that was cooled-extended as compared to cryopreserved (P< 0.05). Validation of placental expression of SMYD3 was greater from cooled-extended semen in contrast to cryopreserved semen (P< 0.05). These data were unexpected, as previously we determined a difference by breeding season only. However, NANOG, downstream of SMYD3, had greater placental expression from summer breedings (P< 0.05). The current study validated previous results indicating chromatin modification genes were primarily influenced predominantly by breeding season and to a lesser extent, semen storage techniques. Downstream targets were also influenced by breeding season likely influencing prenatal development. These data support that epigenetic modifications persist, even though modern swine systems regulate and control temperature and lighting.