bluuebunny/crossref_metadata_2025 huggingface dataset:
91 Mealworm and black soldier fly larvae as protein supplements for beef steers consuming forage
Authors: Carrasco Mikael , Drewery Merritt L
Published: March 2024

The global population is projected to increase, indicating there will be greater demand for animal protein to meet the associated food needs. This demand will place additional pressure on livestock systems to increase output while also minimizing natural resource inputs. Insect protein has emerged as a potential environmentally sustainable alternative to conventional protein feeds, such as soybean meal. Further, insect protein does not compete in the human food market as the products of conventional oil crops often do. Mealworm larvae (MWL) has been studied in poultry and swine as an alternative protein feed; however, there is not currently research evaluating MWL for cattle. Black soldier fly larvae (BSFL) has also received attention for its potential use in livestock feed due to its scalability and nutritional value, but research in cattle is limited. The objective of this study was to evaluate the effects of whole dried MWL and defatted BSFL as protein supplements for cattle consuming forage. These procedures were approved by IACUC at Texas State University (#7726). Five ruminally cannulated steers were utilized in a 5×5 Latin square experiment to determine how MWL and BSFL supplementation affect forage utilization. Steers consuming low-quality forage (4.2% crude protein) were provided one of five treatments each period: 1) control with no supplement (CON), 2) soybean meal (CONV), 3) BSFL, 4) MWL, and a 5) 50% BSFL and 50% MWL by-weight (MIX). Supplements were provided at 100 mg N/kg BW. Periods included 8-d for treatment adaptation, 5-d for intake and digestion measurements, and 1-d for ruminal fermentation measures. Dry matter (DM), organic matter (OM), CP, neutral detergent fiber (NDF), and acid detergent fiber (ADF) were determined for diet, ort, and feces. Protein supplementation stimulated forage OM intake (P ≤ 0.01) relative to CON. There was a significant difference in FOMI (P ≤ 0.01) between BSFL and CONV. Steers receiving CONV treatment consumed 4.71 kg FOMI/d, which was significantly greater (P ≤ 0.01) than those receiving BSFL (4.30 kg/d). There were not differences in FOMI between other treatment groups. Total digestible OM intake (TDOMI) was stimulated by protein supplementation (P ≤ 0.01) from 1.94 kg/d for CON to an average of 3.24 kg/d across protein supplements. Organic matter digestibility (OMD) and neutral detergent fiber digestibility (NDFD) were not affected by treatment (P ≥ 0.37), for an average OMD of 66.5% and NDFD of 62.7%. There was also not a treatment effect (P = 0.96) on total volatile fatty acid (VFA) concentrations, although there were some shifts in molar proportions of individual VFAs across treatments. These data indicate that MWL may be more efficacious than BSFL in stimulating forage utilization in beef cattle, but both are viable protein supplements.
78 Assessing nutrient digestibility in boer×spanish castrated male goats feeding varied levels of hempseed meal
Authors: Chaudhary Santosh , Ale Khim B , Abrahamsen Frank W , Gurung Nar K
Published: March 2024

Hempseed meal (HSM) has gained considerable attention as a potential alternative protein source for animal feed in the US, although its FDA approval for this purpose remains pending due to an insufficiency of comprehensive scientific data. The HSM is a byproduct of hemp oil production. Tuskegee University, a ruminant coalition group in the US is assessing this byproduct in meat goats. The present study was designed to investigate the influence of varying HSM inclusion rates on the nutrient digestibility in Boer×Spanish castrated meat goats using a 4×4 Latin square design. Four uniform mature Boer×Spanish castrated goats (14-16 months) were randomly assigned to four treatments. These goats received ad libitum access to experimental diets containing 0%, 10%, 20%, 30% HSM on an as-fed basis. Experimental diets were iso-nitrogenous (crude protein: 16%) and iso-caloric (total digestible nutrients: 64%). The experiment was conducted for 21 d in four phases where 16 d was for diet adjustment and 5 d for sample collection. Feed, feces, and urine were collected during the sample collection period and composited. The feed intake and refusal, fecal and urine outputs were monitored during the sample collection period. The feed, fecal, and urine samples were analyzed for nutrient composition. Nutrient digestibility data were analyzed in SPSS 29 and Microsoft Excel 2021. Our findings revealed no significant differences (P > 0.05) in the digestibility of dry matter, crude protein, crude fat, non-fibrous carbohydrate, neutral detergent fiber, hemicellulose, and ash among experimental groups, except for acid detergent fiber, where a significant difference (P < 0.05) was observed. These results shed light on the potential of hempseed meal in meat-goat diets and emphasize the importance of understanding its impact on specific nutrient digestibility for optimal dietary formulation.
96 The effect of embryo stage and biopsy on embryo viability
Authors: Wells Kenleigh N , Perkins Tommy L
Published: March 2024

The importance of embryo biopsy is running a 50K genomic test will be completed on the DNA biopsy, giving us the ability to collect genetic prediction data before the calf is even born. The objective of this study was to compare the viability of bovine embryos (n = 24) at different stages of embryo maturation, after microblade biopsy and embryo transfer. This process was achieved by taking a small biopsy of each embryo. The results of aspirating oocytes from packing house ovaries and in vitro fertilization (IVF), within a 48 h time period marked d 0. After a 7-d incubation period, the results consisted of 14 blastocysts and 10 early blastocysts. The final sample size, of 24 embryos, differing in stages between early blastocyst (TRT 6) and blastocyst (TRT 7). All the embryos, except for one, was a Grade 1 embryo. On d 7 the embryos were grouped by stage of embryo. Each embryo was washed, and biopsied with a microblade by a single technician. After the biopsy, the embryos were incubated for a 24 h period. Immediately after the incubation period, each embryo was analyzed for viability. On d 8, TRT 7 embryos had a 50% viability rate (n = 7), whereas TRT 6 embryos had a 70% viability rate (n = 7). Data were analyzed using GLIMMIX procedure of SAS 9.4. The viability did not differ between either treatment (P = 0.58). However, the biopsy of each embryo resulted in a significant effect on embryo viability (P < 0.01). In conclusion, using embryo biopsy and the stage of the embryo may affect embryo viability.
87 Functional rumen microbiological survey of triplet-bearing Polypay ewes from parturition to weaning
Authors: Purvis Katherine G , Weinert-Nelson Jennifer R , Ely Donald G , May John , Flythe Michael D , Hamilton Tracy A , Ferrell Jessica L , Davis Brittany E
Published: March 2024

Ewes transitioning from late gestation to early lactation face a number of challenges including physiological stress, dietary changes, and metabolic adaptations, particularly when bearing and rearing multiple offspring. Furthermore, rumen microbial composition and function has been correlated with milk production and nutrient density in transitioning dairy cows. However, limited research has evaluated the rumen microbial community of ewes during early lactation. The objective of this study was to conduct a functional microbiological survey of the ewe rumen from parturition to weaning. We hypothesized that ewes would experience fermentative disturbances post-parturition and that the rumen microbiota, and consequently, circulating metabolites, would recover over time. Nine multiparous Polypay ewes bearing triplets were fed a lactation diet consisting of alfalfa hay and concentrate mix to meet protein and energy requirements. One lamb of each triplet set was randomly selected and placed on milk replacer 24 h after birth. The two lambs remaining on the ewe were weaned at 56 d of age. Blood and rumen samples from ewes were collected via jugular venipuncture and oral intubation, respectively, at 2, 7, and 15 d of lactation in addition to at the time of weaning. Rumen bacterial functional guilds were enumerated via serial dilution. Ruminal short-chain fatty acids (SCFA) were quantified via HPLC and serum metabolites by LC-MS. All data were analyzed using PROC Mixed with repeated measures in SAS (v. 9.4, SAS Inst. Inc., Cary, NC). Total starch-utilizing bacteria remained steady during early lactation but increased 100-fold by weaning (P = 0.03). In contrast, the starch-utilizing guild sub-population lactobacilli increased 10-fold by d 15 of lactation (P < 0.01) and remained constant through weaning (P > 0.05). No differences were found in the viable number of rumen cellulolytic bacteria (P = 0.37) throughout the study. Ruminal propionate concentrations increased 35% (P = 0.04) from d 2 to weaning and serum propionate (36.8 ± 4.42 µM; P = 0.08) and glucose (59.8 ± 2.97 mg dL-1; P < 0.01) peaked on d 15 of lactation. While ruminal acetate did not fluctuate in early lactation, it increased 58% by weaning (P < 0.01) leading to an 88% increase in serum acetate (P < 0.01). Ruminal butyrate increased 49% by d 15 (P = 0.01) and this was reflected in a 7-fold increase in serum butyrate (P = 0.02). However, serum β-hydroxybutyrate did not differ from parturition through weaning (P = 0.51). Results of this experiment demonstrate that rumen bacterial functional guilds, as well as rumen and serum metabolites, were lowest two days post-parturition and increased over the course of lactation. This may suggest that ruminal fermentation is suppressed post-parturition, which could have implications for early lactation management strategies of triplet-bearing ewes.
76 An in-vitro analysis of hemp as feed for beef cattle
Authors: Fruge Greyson , Boyer Hannah , Wagner Nicole , Drewery Merritt L
Published: March 2024

Hemp, Cannabis sativa L., is a versatile crop that has been cultivated for centuries. Cannabis production had been outlawed in the United States due to concerns related to tetrahydrocannabinol (THC) intoxication. However, recent legislation has declassified hemp as a schedule 1 drug under regulated conditions (i.e., THC < 0.3%). Thus, hemp has been reclassified as an agricultural commodity, and its production for fiber, food, and medicine has increased. Hemp cultivation results in by-products that are not utilized for human needs and have potential as livestock feed, especially for ruminants. Current regulations restrict the use of hemp and its by-products in livestock systems due to the presence of cannabinoids. Thus, research on the nutritional value of hemp for cattle is lacking. The objective of this study was to characterize the nutrient concentrations, in-vitro digestibility (IVD), and cannabinoid concentrations of different fractions of the hemp plant. Procedures involving animals were approved by IACUC at Texas State University (#8497). Four replications of hemp plants of the Cherry Soda varietal were cultivated at Texas State University. Samples were air-dried and fractionated into lower (n = 4), leaves (n = 4), stalks (n = 4), and whole plant (n = 4). Dry matter, organic matter (OM), acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude protein (CP) were determined. For IVD, samples were incubated in digestion vessels containing buffers and rumen fluid at 39.5°C for 48 h and subsequently analyzed for NDF. Cannabinoid analysis was conducted via high-performance liquid chromatography (HPLC). The OM was in acceptable ranges for each hemp fraction (69-95%). The NDF and ADF were within normal ranges of conventional livestock feeds and forages for most fractions, except hemp stalk (81% NDF, 69% ADF). There was high variability in CP between fractions, with the least concentrations observed in the stalk (4%) and greatest in the flower (25%). Stalks had an IVD of 21%, whole plant of 67%, flower of 87%, and leaves of 93%. Cannabinoids were present in each fraction and especially concentrated in the flower (14%) and depleted in the stalk (0.06%). Flower had THC of 0.56%, while other fractions were less than the 0.3% legal threshold. Similarly, total cannabidiol (CBD) ranged from 0.05-11.4% with the greatest concentrations in the flower and least in the stalk. Our results indicate there is potential for hemp to be integrated into cattle production, especially the leaves. Despite adequate nutritional value, there are practical limitations with feeding hemp flower to cattle. In-vivo trials are needed to assess digestibility and profile cannabinoid metabolism in various tissues before hemp can be integrated into cattle diets.
77 Assessing abundance of pregnancy markers among fertility-classified beef cows
Authors: Bennett Alexandra , Rocha Cecilia c Constantino , Waheed Abdul , Brown Morgan , De Melo Gabriela Dalmaso , Marcello Rubessa , Chebel Ricardo , Moriel Philipe , Krisher Rebecca , Pohler Ky G , Hansen Peter J , Binelli Mario
Published: March 2024

In beef cattle, for a single pregnancy opportunity, only 60% of cows will remain pregnant. It is possible that uterine dysfunction prevents adequate embryo signaling and subsequent placentation. Our aim was to compare the abundance of molecular markers associated with pregnancy retention among embryo recipients classified for fertility. The hypothesis was that expression of interferon-stimulated genes (ISG15 and RSAD2) in lymphocytes and concentration of pregnancy associated glycoproteins (PAGs) in serum increase according to cow fertility. Cyclic, Bos Indicus-influenced, primiparous cows (n = 50) were submitted to five consecutive rounds of estrus synchronization, embryo transfer (ET), pregnancy termination and recovery. The ET was conducted 7 days after estrus (D7). Each cow received two embryos per transfer from a randomly assigned bull pair (BP) containing one embryo from each bull A, B or C (BP1 = A+B; BP2 = A+C; BP3 = B+C). Pregnancy diagnostic was conducted on D32 and D45 using B-mode ultrasonography. Blood samples were collected on D20 to quantify expression of ISG15 and RSAD2 in peripheral blood mononuclear cells and on D25, D32, and D39 to quantify serum concentration of PAGs. Based on D45 pregnancy outcome (pregnant or open), cows were classified as Fertile (Fert; n = 14), Sub-fertile (SF; n = 16) or Infertile (IF; n = 15) if they were pregnant 3, 2, or 1 out of the 5 experimental rounds, respectively. Five cows that never sustained a pregnancy until D45 were excluded. The overall prevalence of twin-pregnancies was 7.8% (n = 13/166). Expression of ISG15 was increased in Fert compared to IF cows (P = 0.01; 0.0196 ± 0.0042 vs 0.0164 ± 0.0052, respectively). There was no effect of fertility classification on the expression of RSAD2. Serum concentrations of PAGs increased over time (P < 0.0001), regardless of fertility classification (day x fertility classification; P > 0.4). There was an effect of BP on the probability of pregnancy on D32 and D45 (P < 0.05). For D32, BP2 (84%) was 3 times more likely to maintain a pregnancy than BP1 (52%), while BP3 (74%) was not significantly different. On D45, BP2 (80%) was 2.8 times more likely to remain pregnant than BP1 (50%), and BP3 (62%) was not different than either BP1 or BP2. The interaction bull pair by fertility classification on the probability of pregnancy on D45 approached significance (P = 0.1). While pregnancy to BP2 was similar across all fertility classifications (80%), pregnancy to BP1 decreased dramatically as classifications changed from Fert to IF (88% vs. 14%, respectively). In conclusion, IF cows were less able to respond to IFN-t, likely because of a reduced secretion of IFN-t from the elongating conceptus. Also, IF cows are more susceptible to the genetics of the embryo than FERT cows.
83 Effects of cottonseed meal supplementation on growth performance of heifers grazing mature summer forage
Authors: Kern Connor R , Crossland Whitney L , Norris Aaron B , Rathmann Ryan R , Sarturi Jhones O
Published: March 2024

As perennial warm-season grasses mature in late summer, dry matter intake (DMI) of growing heifers may be limited due to low protein (7.2 ± 2.5 %) and increased NDF content (67.5 ± 2.7%), which may compromise growth potential. Cottonseed meal (CSM) supplementation may improve forage digestibility by increasing rumen degradable protein offered, but research regarding the specific effects of CSM supplementation on gain performance and composition of gain in heifers is limited. It was hypothesized that supplementation of CSM to heifers grazing mature forage would have greater growth performance compared with heifers not receiving CSM. Objectives for this experiment were to compare the effects of two CSM supplementation strategies on the growth performance of heifers grazing mature summer forage. In two consecutive summers, commercial Angus cross heifers (n = 63) weighing 266.08 ± 32.74 kg were blocked by BW (light, medium, and heavy) and allocated to 9 paddocks (1.64 ha) of WW-B. Dahl Bluestem (Bothriochloa bladhii) for 67 to 70 d. This was a RCBD with a factorial arrangement of 3 treatments by 3 BW blocks, with paddock and year as random effects. Heifers received one of three supplementation strategies: no cottonseed meal (CON), 454 g/animal of CSM daily (CSM1), or 908 g/animal of CSM every other day (CSM2). Initial and final shrunk BW were measured; ADG and percent of BW gained were calculated. Ultrasound of initial and final longissimus muscle area (LMA), backfat (BF), and intramuscular fat (IMF) were measured; percent gained was calculated, respectively. There were no treatment by block interactions for any measured variable. Heifers receiving CSM1 and CSM2 had greater final BW than heifers receiving CON (317 and 320.8 vs 302.6 kg, respectively; (P = 0.01). Likewise, percent of BW gained was greater (P = 0.02) for CSM1 and CSM2 supplemented heifers compared with CON heifers (19.4 and 20.2 vs 14.6%, respectively). The ADG of CSM1 and CSM2 supplemented heifers was greater (P = 0.01) than CON (0.74 and 0.78 vs 0.54 kg/d, respectively). Treatment did not affect the percent of BF (P = 0.24) or IMF gained (P = 0.39). Heifers receiving CSM1 and CSM2 tended to gain proportionally more LMA than heifers receiving CON (13.58 and 13.77 % vs 7.24%, respectively; P = 0.07). As anticipated, BW block affected final BW (P < 0.001) and percent BW gained (P = 0.02), as well as percent LMA gained (P = 0.02). In conclusion, CSM supplementation significantly affected growth performance of heifers grazing late summer WW-B. Dahl Bluestem forage versus no supplementation. In addition, there was no difference in growth performance between heifers receiving 454 g/d of CSM supplementation or 908 g/animal every other day, indicating flexibility for feeding strategy.
84 Efficacy of Livamol with BioWorma for controlling gastrointestinal nematode in nursing Kiko does raised in pastures
Authors: Dhakal Durga P , Karki Uma , Chaudhary Santoshi , Lamsal Sadikshya
Published: March 2024

Prevalence of gastrointestinal nematodes (GINs) has become a critical issue because of nematode resistance to anthelmintics available in the market. Livamol with BioWorma (hereafter BioWorma), a biological product containing spores of Duddingtonia flagrans, is known to trap GIN larvae and reduce the chance of re-infection in artificially-infested animals. However, the efficacy of this product is not known in pasture-raised nursing does acquiring natural challenges of GIN through contaminated pastures. The objective of this study was to evaluate the effectiveness of BioWorma for controlling GIN in pasture-raised nursing does. The study was conducted for 120 d (March-August 2023). Sixteen nursing Kiko Does and kids (n = 30) were divided into two uniform groups. Each group of animals was assigned to separate sets of grazing plots and rotationally stocked in those plots throughout the study. Animals had free access to clean drinking water, shelters, and mineral mix in each plot. BioWorma at the rate of 1g/d/kg of animal body weight (BW) was fed to one group of animals. BioWorma was mixed with 0.227 kg of whole corn before feeding. Another group (control) was provided with an equivalent amount of corn without BioWorma. Additionally, both groups were supplemented with whole corn at the rate of 0.5% BW. Animal performance data [BW, body condition score (BCS), and FAMACHA score] and fecal samples were taken on d 1, every week during the study, and the last day of the study. Fecal samples were analyzed to determine the egg per gram (EPG). Blood samples were taken on the first day of the study, then every month during the study, and on the last day of the study. Blood samples were analyzed in ProCyte Dx Analyzer for hematological parameters (RBC, hematocrit, hemoglobin, WBC, neutrophil, eosinophil, monocytes, basophil, and platelets) and in Catalyst Dx for biochemical parameters (glucose, creatine, blood urea nitrogen, Ca, P, Na, Cl, and other parameters). Animal performance and blood profile data were analyzed using the GLM procedure and EPG data using the Wilcoxon Rank-Sum test in SAS 9.4. Overall, the treatment group had less EPG (35%; P < 0.05) than the control group. However, the consistent trend of BioWorma reducing EPG was not found when data were analyzed for each observation date. BioWorma had no significant impact on BW, FAMACHA score, BCS, and blood parameters. Results showed that BioWorma was able to reduce the overall GIN EPG in nursing Kiko does raised in pastures. Long-term research on the efficacy of BioWorma in controlling GIN in goats will reveal more useful information.
89 Improving cattle grazing efficiency with multi-functional cover crops
Authors: Suazo Sofia A , Pereira Neto Jose D , Mullenix M Kimberly , Smith W Brandon , Dillard S Leanne
Published: March 2024

Grazing cool-season cover crops provides a sustainable way of extending the grazing season and reducing the impact row-crop farming systems on the environment. Cover crops promote soil health; however, the impacts of grazing cover crops on soil health in the Southeast are not well understood. The objective of the current study was to determine the effects of different cover crop mixtures on a cotton (Gossypium hirsutum)-peanut (Arachis hypogaea) cropping system. The experiment consisted of 18 paddocks, planted in mixtures of grass [‘Coker’ oat (Avena sativa)], grass + legume [‘Dixie’ crimson clover (Trifolium incarnatum)], or grass + legume + brassica [(‘T-raptor’ brassica (Brassica napus × B. rapa)] planted at the Wiregrass Research and Extension Center (Headland, AL). Paddocks were randomly allocated to grazed or not grazed (n = 3). Grazed paddocks were grazed with yearling beef steers (266 ± 44 kg) using the put and take method to maintain a forage alloance of 1 kg DM per kg BW. Forage samples were collected every 2 wk, for biomass, botanical compositions, and nutritive value. Paddocks were grazed from 17 Jan – 22 Mar 2023 (65 d) and steer BW were taken at the beginning and end of the grazing season for calculation of average daily gain Data were analyzed using Proc Glimmix of SAS 9.4 (SAS Institute, Cary, NC) with forage sampling date considered a repeated measure. No difference in steer average daily gain was detected among grazed treatments (1.5 kg/d; P > 0.44). Cover crop (forage) biomass was also not different among all grazed and ungrazed treatments (1,097 kg DM/ha; P = 0.56). According to the results, grazing cool-season annual cover crops may reduce the supplementation required to maintain cattle through the winter months in the Southeast.
98 Using youth hippology contest results as a needs assessment as a framework for a train the trainer program
Authors: Main Sawyer , Ivey Jennie L , Strickland Lew G , Rhinehart Justin D
Published: March 2024

Land-Grant Institutions and Cooperative Extension Services seek to disseminate science-based information to the general public and strive to develop the next generation of agriculturists. Extension agents across Tennessee implement youth and adult educational programs to build the knowledge and skill sets of producers and youth. However, Extension agents differ in areas of expertise, leaving some counties with minimal ability to provide 4-H horse project members with sufficient content knowledge while agents in other counties are more well versed in equine-specific areas. Youth (n = 224) competed in the 2021 regional 4-H Hippology contest across the Eastern (n = 59), Central (n = 93), and Western (n = 72) regions. Youth competed within their age divisions, where junior (grades 4 and 5, k=60 where k represents number of participants within each age division), junior high (grades 6 to 8, k = 100), and senior (grades 9 to 12, k = 100) divisions competed in written exam and slide identification phases. Contest scores from the Tennessee regional and Eastern National 4-H Hippology contests were used to determine areas of knowledge deficiency. Nutrition, tack, selection, health, and breeds were categories identified as areas in which 4th – 12th grade youth lacked adequate knowledge and a training program and new curriculum was developed and delivered to county extension agents. Statistical analysis was conducted using SAS v9.4 (Cary, NC). Differences were found when comparing across question category (P < 0.0001), age group (P < 0.0001), and year (P < 0.0001). Nutrition questions were most often missed by senior and junior high youth (k = 7.8, 51.94%; k = 7.5, 44.22%) whereas junior youth missed training questions most frequently (k = 4.9, 54.14%). Of the 5 deficient topic areas, selection questions were the lowest percentage missed by senior and junior high youth (k =5.9, 36.81%; k = 7.1, 39.53%) whereas junior youth missed health questions least frequently (k = 4, 39.87%). It was found that training status had no significant on scores from year to year (P >0.05). Despite the lack of training effect, these findings still prove valuable when assessing performance upholding the extension mission of delivering science-based information to the next generation of industry professionals.
104 Maternal pre- and post-partum supplementation of Bacillus-based DFM enhanced cow and calf performance
Authors: Izquierdo Vinicius S , Cappellozza Bruno I , Silva João V L , Santos Giovanna C M , Miranda Andre , Bittar João H J , Pickett Autumn , Mackey Shea , Cooke Reinaldo F , Vendramini João M B , Moriel Philipe
Published: March 2024

This study evaluated the effects of maternal supplementation of Bacillus-based direct-fed microbials (DFM) on physiology and growth performance of Bos indicus-influenced cow-calf pairs. On d 0 (~139 d before expected calving date), 72 fall-calving, Brangus crossbred beef heifers (25 to 37.5% Bos indicus; 20 to 22 mo of age) pregnant with their first offspring were stratified by their initial body weight (BW; 431 ± 31 kg) and body condition score (BCS; 6.0 ± 0.36; scale 1 to 9), and randomly allocated into 1 of 12 bahiagrass pastures (1 ha and 6 heifers per pasture). Treatments were randomly assigned to pastures (6 pastures per treatment) and consisted of heifers supplemented with 1 kg/d of soybean hulls dry matter (DM) added (BAC) or not (CON) with a Bacillus-based DFM mixture (BovacillusTM; Chr. Hansen A/S, Hørsholm, Denmark) from d 0 to 242 (139 ± 4 d prepartum to 104 ± 4 d postpartum). Calves were weaned on d 242 (96 ± 30 d of age) and then allocated into 1 of 16 drylot pens and limit-fed the same concentrate at 3.25% of BW until d 319. Maternal treatment effects were not detected (P ≥ 0.29) for herbage allowance, forage nutritive value, and heifer activity on pasture. Heifer BCS on d 39 and 63 tended (P ≤ 0.09) to be greater, whereas heifer BCS on d 91 was greater (P = 0.01) for BAC vs. CON heifers and did not differ (P ≥ 0.20) between treatments on d 179 and 242. Plasma concentrations of glucose did not differ from d 0 to 63 (P ≥ 0.14) but were greater (P = 0.005) on d 179 and tended (P = 0.09) to be greater on d 242 for BAC vs. CON heifers. First offspring BW at birth, ADG from birth to early weaning, and BW weaning did not differ (P ≥ 0.19), but BW at drylot exit (d 319) was greater (P = 0.05) for BAC vs. CON calves. Maternal treatment effects were not detected (P ≥ 0.42) for calf serum concentrations of IgG at birth, and post-vaccination plasma concentrations of glucose, cortisol and haptoglobin. However, serum titers against bovine respiratory syncytial virus (BRSV) were greater (P = 0.04) for BAC vs. CON calves on d 287, whereas seroconversion against parainfluenza 3 virus (PI-3) was greater (P < 0.01) for BAC vs. CON calves on d 271. Thus, maternal supplementation of Bacillus-based DFM increased prepartum BCS gain and postpartum plasma concentrations of glucose of heifers and led to positive carryover effects on post-weaning BW gain and some indicators of humoral immune response to vaccination in their first offspring.
100 Can in vitro or in situ disappearance predict to in vivo digestibility of forages?
Authors: Hines Abbigail R , Rigney Diva N , Underwood Anna G , Bergen Werner G , Mullenix M Kim , Dillard Sandra L , Callaway Todd R , Smith William B
Published: March 2024

Though much effort has been made to characterize the in vivo (IV) and in situ (IS) dry matter digestibility (DMD) of southeastern forages, there is a lack of information identifying methods that best represent the in vivo digestibility of these forages. Thus, the objective of our study was to compare IV and IS methods to determine which technique best represents the in vivo DMD of four bermudagrass (Cynodon dactylon [L.] Pers.) cultivars. In an IV experiment, ruminally fistulated heifers (n = 4) were randomly assigned to one of four bermudagrass cultivars (Coastal [COS], Russell [RUS], Tifton 44 [T44], or Tifton 85 [T85]) for four 30-d in vivo periods (21-d adaptation and 9-d collection) in a Latin square design. On d 28 of each period, rumen fluid was collected 4 h post-feeding for an accompanying IV experiment using a completely randomized design with a 4 × 2 factorial treatment structure. Factors in the IV experiment included bermudagrass cultivar (COS, RUS, T44, and T85) and digestibility method (Tilley and Terry [TT] or Goering and Van Soest [GVS]). On d 31 of in vivo periods 3 and 5, an accompanying IS experiment was conducted as a randomized complete block design with three treatment factors (in vivo diet [previous described], bermudagrass cultivar [previously described], and incubation timepoint [0, 0.25, 0.50, 0.75, 1, 2, 3, 4, 8, 12, 16, 20, 24, 48, 72, 96, 120, 144, and 168 h]). Correlations were computed between in vivo DM disappearance and each of the IV (TT and GVS) and IS (24, 48, and 72 h) methods. Regressions were calculated for each of the individual IV and IS measurements, and a stepwise regression was used to determine the predictive value of linear combinations of the measurements. None of the IV or IS DMD values were correlated with in vivo DMD (P ≥ 0.18). Individual IV and IS DMD values did not yield significant models through linear regression (P ≥ 0.18), though the best model (based on AIC) was TT IVDMD (r2 = 0.09; P = 0.26). Stepwise regression revealed that there was no linear combination of IV or IS DMD that improved prediction beyond single predictor models. While both IV and IS experiments remain viable tools to screen forages and make relative comparisons, results from this experiment are interpreted to mean that neither of these methods is suitable for prediction of in vivo performance.
6 Identifying research gaps and opportunities to enhance sustainable beef production
Authors: Gilreath Jessica
Published: March 2024

Sustainability has evolved and extended its influence across diverse sectors of the economy, including those in the beef supply chain. Public-facing companies predominantly emphasize environmental sustainability, especially climate-associated features, while beef producers continue to prioritize economic sustainability, hoping to to ensure their operation thrives into the next generation. Diversifying revenue and improving productivity are pivotal for safeguarding economic sustainability and fostering resilient production systems. Diversification is not new to beef producers; many have integrated ecosystem services into their operations to generate non-production revenue. The most valuable asset of a beef producer is the productivity of the land. Decision support tools need to be enhanced to allow producers to either capitalize on above average forage production to generate additional income, or to plan for alternative strategies when forage supply is forecast to be reduced. Because downstream beef supply chain participants prioritize environmental sustainability or reduction of scope 3 emissions, an emerging diversification opportunity for beef producers is to address this opportunity. While soil carbon initiatives have received attention, companies with substantial scope 3 emissions from beef production may value greenhouse gas (GHG) emissions from cattle more highly. Incentives for practices that reduce GHG emission from cattle can simultaneously reduce environmental impact associated with beef production and generate an additional revenue stream adjacent to beef production. Current opportunities to participate in these incentive programs are limited. Research can address the creation of functional protocols, and their intrinsic value. Clear targets, for gross emissions or emissions intensity, must be set but are not equivalent. In particular, research on effective/acceptable monitoring, reporting, and verification of emissions claims is imperative to functional markets. Innovation in emissions management and productivity gains can be integrated, so that goals of economic and environmental sustainability among value chain participants can be achieved. Maintaining a comprehensive perspective on sustainability solutions is essential to meeting the needs of humanity.
156 In-situ degradability of hemp (Cannabis sativa L.) plant components in cattle
Authors: Lopez Alyssa , Fukuda Emma , Fruge Greyson , Drewery Merritt L
Published: March 2024

The 2014 and 2018 Farm Bills defined hemp (Cannabis sativa L.) as an agricultural commodity and removed it from the controlled substances list, developing a pathway for commercialization and increasing interest in cultivating hemp in the United States. Demand for therapeutic, cannabinoid-based hemp products is increasing, and, as not all of the plant components are utilized for these products, there will likely be significant quantities of hemp by-products created. As these by-products are cellulosic, they may be marketed as livestock feed, especially for ruminant animals. There have been limited studies into hemp as cattle feed. Accordingly, the objective of this study was to determine the in-situ degradability of different hemp components in beef cattle. We conducted an in-situ trial with three ruminally cannulated steers (IACUC #8497) and 16 unique hemp samples: leaves, flower, stalk, or whole plant cultivated with four different seed inoculants. Samples were incubated in the rumen for 0, 4, 6, 12, 24, 48, and 72 h and replicated across each steer. After samples were removed, they were rinsed and analyzed for partial dry matter (DM), DM, organic matter (OM), and crude protein (CP). Solubility fractions [immediately soluble (IS), potentially soluble (PS), and not soluble [NS]), rate of degradation (kd), and rumen degradability was determined for OM and CP. Rate of passage (kp) was set at 4.7%. As there were not differences across seed inoculant method, data were combined across plant components. For OM, the NS fraction was greatest for hemp stalks (12%) and least for leaves (7%). The PS fraction ranged 72-75% across plant components with the least value for stalks and greatest for leaves. Of the PS fraction, ruminal OM degradability was lowest for stalks (51%) and highest for leaves (72%). For CP, the NS fraction of hemp stalks (16%) was greater than other fractions, which ranged from 6-8%. The PS fraction was approximately 76% for both whole plant and leaves, a vast majority of which (71-73%) was degradable, indicating these plant components provide a good source of rumen degradable protein. The IS fraction was largest (20%) for hemp flower. Although hemp flower may be easily digested by ruminants, it does not have practical value because this plant component competes in the human market as the flower contains an increased percentage of cannabinoids which have therapeutic properties. Ultimately, our data indicate that hemp leaves have nutritional and practical value as feed for beef cattle and that hemp stalks would likely not be well-utilized as a forage source. Before hemp can be integrated into the beef cattle industry as feed, additional research is required to determine the effects of feeding hemp on animal performance and evaluate uptake and retention of cannabinoids in body tissues.
166 Effect of silo type on fermentation characteristics of laboratory-scale silage
Authors: Andrew Lauren M St , Hines Abbigail R , Tarter William P , Espino Berman E , Fernandez Cecelia N Sagastume , Neto Jose D Pereira , da Silva Aghata E Moreira , Dillard Sandra L , Belk Aeriel D , Mullenix M Kim , Smith William B
Published: March 2024

Creating ensiled forage on a laboratory-scale is a tedious and cumbersome process. One must ensure an anaerobic environment for the success of the fermentation while also striving to replicate field-scale conditions. The objective of this experiment was to determine the effect of laboratory-scale silo type on nutritive value and fermentation profiles of grass-legume silage. This experiment was conducted as a generalized complete block design. There was one treatment factor (silo type) with 11 levels: field-scale baleage control (CON), miniature wrapped baleage (MINI), large fermentation bucket (6GAL), small fermentation bucket (2GAL), miniature silo (PVC), pint-sized Mason-type jar with “BurpLid” (BURP), pint-sized Mason-type jar with Ball-brand fermentation lid (BALL), pint-sized Mason-type jar with an airlock lid (LOCK), single-layered vacuum-sealed bag using a chamber-style sealer (CHMB), double-layered vacuum-sealed bag using a chamber-style sealer (HCHMB), single-layered vacuum-sealed bag using a suction-style sealer (FOOD), or double-layered vacuum-sealed bag using a suction-style sealer (HFOOD). Harvest served as the random blocking factor. Forage was harvested from a single alfalfa-bermudagrass pastures at the Wiregrass Research and Extension Center in Headland, AL. Forage was cut 24 h before collection and allowed to sun-cure. After allocation to treatment, samples were allowed to ferment for 56 d. Following fermentation, samples were assayed for NDF, ADF, ADL, CP, pH, mold, and yeast. Dunnett’s test revealed a difference (P < 0.05) from CON for NDF, ADF, and pH. Samples from PVC had 26% greater NDF and 45% greater ADF than CON (58 and 37%, respectively). Samples from BALL were 3 units greater and samples from LOCK were 2 units greater in pH than CON (4.8). When comparing alternative treatments exclusive of CON, there were differences (P ≤ 0.01) in NDF, ADF, ADL, pH, and mold counts among treatments. Results are interpreted to mean that BALL and LOCK are not effective representatives of field-scale silage production due to lack of pH drop, while PVC alters the fiber profiles. All other methods showed promise as prospects for laboratory silage procedures.
162 Nutritive value and dry matter yield of stockpiled tall fescue across plant hardiness zones 7 and 8
Authors: Fancher Malerie E , Mason Katie , Dillard Sandra L
Published: March 2024

Pastures in Tennessee comprise mainly tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.], a cool-season perennial grass. Given that producers in Tennessee feed hay for an average of 143 d per year, there is interest in utilizing the practice of stockpiling to extend the grazing season. Although this practice has been proven to reduce hay needs (Freeman et al., 2019), it is vital to maintain up-to-date recommendations using data from across the southeastern US to inform grazing decisions. The objective of this study was to determine the nutritive value and dry matter yield of stockpiled tall fescue across plant hardiness zones 7 and 8. Fourteen farms across Tennessee and Alabama were identified as sampling sites. In September 2021, three exclusion cages (1.3 m × 1.3 m) were constructed at each site, forage was clipped to a 5-cm height, and plots were fertilized at a rate of 67 kg N/ha. During years 2021-2022 and 2022-2023, samples were clipped at a 5-cm height from a 0.1-m2 quadrat monthly from October through February. Samples were collected from a different location within the plot each month to ensure there was no overlap. Samples were dried and weighed to determine dry matter yield and then ground for NIRS analysis to determine nutritive value. Data were analyzed using PROC GLIMMIX for a completely randomized design. Independent variables were stockpile period length and plant hardiness zone. Results indicate that plant hardiness zone did not have a significant effect on forage yield (P = 0.2098). Dry matter yield increased over the length of the stockpiling period (P < 0.0001) from 2,637 to 4,922 kg DM/ha. Crude protein (CP) and total digestible nutrients (TDN) concentrations decreased (P < 0.0001 and P = 0.0358, respectively) throughout the stockpiling period; however, ranges were still within those needed to support the nutritional needs of a lactating cow with CP ranging from 15 to 17% and TDN ranging from 68 to 70%. As expected, neutral detergent fiber (NDF) and acid detergent fiber (ADF) concentrations increased over the stockpiling period (P = 0.0029 and P = 0.0145, respectively) as plants matures. There were no significant changes in ash and fat concentrations due to stockpiling length. Results from this study conclude that stockpiled tall fescue in plant hardiness zones 7 and 8 can support the nutritional requirements of mature cows at all stages of production through the winter months. Results will be used to inform Extension recommendations to assist producers in making management decisions that increase grazing days and reduce supplemental feed input costs.
9 Randel Lecture: In Vivo investigation of pregnancy Physiology
Authors: Anthony Russell V , Tanner Amelia R , Kennedy Victoria C , Winger Quinton A , Rozance Paul J
Published: March 2024

Pregnancy in any mammal requires the integration of three distinct compartments; the maternal, placental and fetal compartments. Compromised function of any of the three compartments can result in suboptimal pregnancy outcomes, including increased morbidity and mortality at delivery, reduced livestock production efficiency and adult-onset of metabolically-related disease in humans. To accurately understand the progression of both normal and compromised pregnancies, therefore, requires the simultaneous assessment of all three compartments, which for most species is not technically feasible. Consequently, over the past 60 yr the pregnant sheep has been used extensively for in vivo investigation of pregnancy physiology. The ability to place indwelling catheters, within both maternal and fetal vessels, allows the simultaneous steady-state assessment of uterine and umbilical blood flows, hormone secretion, and nutrient uptake and utilization of nutrients by each of the three compartments, under non-stressed and non-anesthetized conditions. This has provided unrivalled insight into the physiology of pregnancy, and the realization that the placenta is a highly metabolic tissue, utilizing the majority of oxygen and glucose taken up by the uterus. However, the deficit in studying pregnant sheep is the lack of genetic models, readily available in rodents, that could help define specific gene function during pregnancy. Consequently, we developed in vivo lentiviral-mediated RNA interference (RNAi) methods to specifically alter the abundance of specific gene transcripts/proteins within the placenta, beginning at 9 d of gestation (dGA). Our lentiviral-mediated approach limits the RNAi to the trophectoderm derivatives of the placenta. Initially we used this approach to determine the importance of PRR15 and LIN28 during the establishment of pregnancies, but turned our efforts towards combining in vivo RNAi with steady-state physiological assessments during late gestation to examine the function of genes involved in placental nutrient transport (SLC2A3) and placenta derived hormones (CSH). By creating a placental deficiency in SLC2A3, not only was the fetus smaller and hypoglycemic at mid-gestation, but by interfering with placental glucose uptake, maternal hormone concentrations were also impacted, yet near-term, a distinctly different phenotype was present. For the placental hormone CSH (a.k.a. placental lactogen), CSH RNAi not only impacts placental and fetal growth, but also reductions in uterine blood flow, nutrient fluxes to the fetus, and produces an altered hormonal environment. Combining these methodological approaches provides new and often unexpected insights into the physiological integration of the maternal, placental and fetal compartments. Supported by NIH-NICHD grants HD093701 and HD094952.
12 Impact of progesterone signaling on tumor necrosis factor-alpha synthesis by luteal macrophages
Authors: Giurgis Mariam , McCann-Deshazer Madison , Gadsby John E , Poole Daniel H
Published: March 2024

Understanding the mechanism in which luteolysis occurs is an important step in improving the reproduction of livestock in the industry. The corpus luteum (CL) is a transient endocrine organ found on the ovary responsible for progesterone secretion. It is well known that prostaglandin F2-alpha (PGF) is responsible for luteal regression, however, the process by which luteal cells (LC) become sensitive to the luteolytic effects of PGF remain unclear. Therefore, the objective of this study was to determine if suppression of progesterone (P4) synthesis or blocking P4 signaling activates tumor necrosis factor (TNF)-alpha production by the luteal macrophages. Ovaries were collected from an abattoir and transported to the laboratory on ice. Ovary status (i.e. approximate days post ovulation), was determined by phenotypic description of ovarian structures. Only ovaries (n = 5) containing midcycle (d 12/13 post ovulation) CL were used in these experiments. Luteal tissue was isolated and dissociated to collect LC and and luteal macrophages (MAC). Isolated cells were incubated independently at 37°C at 5% CO2 for 24 h in 24-well plates. Luteal cells and MACs were then harvested and placed in the following conditions: 1) LC + MAC + DMSO (control), 2) LC + MAC + trilostane (TRIL 1.0mg/mL), 3) LC + MAC + TRIL 1.5 mg/mL, 4) MACS only, 5) MACS +LPS. Supernatant was harvested at 24 h whereas both cells and supernatant were harvested after 48 h, in vitro. Supernatant was immediately frozen for subsequent P4 analysis, via RIA. Data results were analyzed using a MIXED procedure of SAS and evaluated the effects of cell-type, treatment, and culture time. Statistical significance was determined at P < 0.05 and a tendency at 0.05 < P < 0.10. Overall, TRIL treatment reduced supernatant P4 concentration (8.3 and 6.8 ng/mL to 1.0 and 1.5 mg/mL TRIL, respectively) compared with controls (22.8 ng/mL; P = 0.0012); however there was not a difference when comparing the TRIL treated cultures. Progesterone concentrations tended to decrease over time (P = 0.0661). At 24 h in vitro, P4 concentrations were suppressed in 1.0 mg/mL TRIL and 1.5 mg/mL TRIL treated wells (5.3 and 4.2 ng/mL, respectively), compared with controls (16.4 ng/mL; P = 0.0014). Whereas P4 concentrations were reduced in the 1.5 mg/mL TRIL treated wells (1.6 ng/mL) compared with controls (9.95 ng/mL; P = 0.0419) and tended to differ in the1.0 mg/mL TRIL treated wells (2.4 ng/mL; P = 0.0634), at 48 h in vitro. Progesterone concentrations were undetectable in wells containing MAC only. Collectively, TRIL treatment effectively reduced P4 synthesis in LC cultures. Therefore, the greater concentration of TRIL is needed for P4 suppression in longer term culture systems. Additional analyses will be conducted to determine the effect of P4 suppression on macrophage function.