bluuebunny/crossref_metadata_2025 huggingface dataset:
186 Have New Feeding Technologies Revolutionized the Way We Design Grazing Experiments?
Authors: Beck Paul A , Beck Matthew R , Adams Jordan , Lalman David , Reuter Ryan R , Gunter Stacey A A
Published: October 2021

New technologies have enabled autonomous measurement of intake and feeding behavior of pen-fed animals and this has piqued interest in utilizing similar technologies in grazing experiments. Various feeding systems are currently available, but individual supplementation and feeding experiments have been conducted for years using individual feeding stanchions, which are the lowest level of technology for measuring supplement intake. These experiments are laborious as they require animals to be trained and acclimated, gathered at each feeding, and sorted into individual stalls for supplementation—thereby disrupting the animals grazing activities. In the mid-1980s Calan Gate systems (American Calan; Northwood, NH) became popular in pasture supplementation experiments, but still have many of the same disadvantages. Newer, more automated systems, reduce labor and possibly have less disruption of the animal’s grazing behavior, but are reliant on the animal’s willingness to use the system and ability to access it when more dominant peers are present. Individuals also do not always follow the “averages”-based rules we often hold true and behave differently in groups. Recent research with automatic feeders show steers consumed average of 60% of the potential supplement with supplement intake CVs of 50 to 100%. These technologies lead many to question the paradigm of experimental units in experimental designs. The experimental unit is defined as the smallest independently assigned unit to which the treatment is applied. This definition of experimental unit is somewhat limiting when taken to the extreme, but still applies well for experiments utilizing individual animal feeding, regardless of the level of technology involved. In many cases where the aforementioned technologies are used, the individual animal can be both the observational and experimental unit. This symposia presentation will discuss attributes of different feeding options and the implications on study design, experimental power, and the designated experimental unit.
200 A Scoring System for Equine Dental Health
Authors: Fenton Jesse , Gordon Mary Beth , Perry Erin B , Dombek Zach , Jerina Micheal , Jacobs Robert D
Published: October 2021

Scoring systems have been implemented in veterinary practice to indicate the severity of pathologies, such as lameness and gastric ulceration. The need for a scoring system of equine dentition in relation to digestive health has been identified. A scoring system would allow veterinarians, owners, and researchers to more accurately assess dental health and the resulting impact it may have on chewing ability. A proposed system, the Equine Dental Scoring System (EDSS), was developed via collaboration of a team of veterinarians and equine nutritionists familiar with equine dental abnormalities. The EDSS was designed to assign higher scores corresponding to increasing severity of dental abnormalities that would impede proper chewing. The proposed scoring system ranges from 0 to 5 as follows: 0) no sharp enamel points, soft tissue damage, or malocclusion, (1) sharp enamel points, but no soft tissue damage or malocclusion, (2) sharp enamel points and soft tissue damage, but no malocclusion, (3) mild malocclusion with all aligned teeth meeting level (ex. ramps, hooks), (4) moderate malocclusion with all teeth meeting but not level (ex. wave, smile, diagonal, frown), (5) major malocclusion with one or more teeth not meeting or inhibited temporomandibular joint movement (ex. step, shear, retained cap), and/or infection, and/or pain while chewing. The EDSS was validated by assessing agreement via the Cohen’s kappa statistic between four trained professionals scoring ten images of horse dentition. Both the weighted (к = 0.62) and unweighted (к = 0.73) kappa statistics indicated substantial agreement between scorers, signifying reliable repeatability of the EDSS. Presenting dental health in the form of a score would indicate severity of dental pathologies and allow for quantitative and statistical evaluation of dental health in nutrition research and veterinary medicine.
203 Historical Perspectives on the Equine NRC
Authors: Lawrence Laurie
Published: October 2021

The “Nutrient Requirements of Horses” is a publication of the National Research Council (NRC) of the National Academy of Sciences (NAS). The U.S. Congress established NAS in 1863 as a non-profit, non-governmental organization that could examine and report on scientific subjects. The NRC was established in 1916 as the working arm of NAS. About 15 years later the Committee on Animal Nutrition was created in order to oversee publications in the “Nutrient Requirement Series.” The “Recommended Nutrient Allowances for Horses” was released in 1949. The publication was updated and renamed “The Nutrient Requirements of Horses” in 1961 and since then there have been revisions in 1966, 1973, 1978, 1989 and 2007. Each revision was produced by a volunteer committee which was appointed by the Committee on Animal Nutrition until it was disbanded. Over time, both the size of the subcommittee on equine nutrition and the length of the document increased. Funds to support the travel of committee members to working meetings as well as support NRC project staff have been obtained from a variety of sources over the course of the publication. A large portion of the funds for the 2007 edition was from industry sources. Since 1973, the intervals between editions of the publication have been quite long, even though interest in equine nutrition and feeding among industry participants seems to be high. Fortunately, other excellent reference sources on equine nutrition are available. The need for a new revision of the Nutrient Requirements of Horses, as well as the feasibility of funding to support a revision will be explored.
232 Effects of Yarrowia Lipolytica Supplementation on Growth Performance and Apparent Ileal Digestibility of Diets Fed to Nursery Pigs
Authors: Cheng Yi-Chi , Duarte Marcos E , Kim Sung Woo
Published: October 2021

The objective was to evaluate Yarrowia lipolytica (YL) as a lipid supplement fed to nursery pigs for the growth performance and apparent ileal digestibility (AID). Twenty-four pigs weaned at 21 d of age (12 barrows and 12 gilts with initial BW at 7.2 ± 0.6 kg) were allotted to 3 dietary treatments (n = 8) based on the randomized complete block design with sex and BW as blocks. The main effect was the dietary supplementation of YL (0, 1.5, and 3.0%, replacing poultry fat) with nutrients meeting or exceeding the requirements by NRC (2012) and fed to pigs for 21 d based on 2 phases. Feed intake and BW were recorded at d 0, 10, and 21 to calculate ADG, ADFI, and G:F. Fecal scores were recorded at every odd day from d 3 to 19. Pigs were euthanized on d 21 to collect ileal digesta for AID of nutrients in diets. Data were analyzed using Proc Mixed of SAS. There were no differences in growth performance among treatments. Whereas, pigs fed 0 and 1.5% YL had higher (P < 0.05) AID of DM (55.0 and 52.2% to 40.2%, respectively) and GE (62.1 and 60.6% to 49.8%, respectively) than pigs fed 3% YL. There were no differences in AID of DM and GE between the pigs fed 0% and 1.5% YL. In conclusion, 1.5% Yarrowia lipolytica could be supplemented in nursery pig diets reducing 0.8% of poultry fat without affecting growth performance and AID of DM and GE.
228 Standardized Ileal Digestibility of Partially Defatted Black Soldier Fly Larvae Meal in Growing Pig Diets
Authors: Tansil Fiona , Huber Lee-Anne , Kiarie Elijah , Columbus Daniel A , Shoveller Anna-Kate
Published: October 2021

New ingredients need to be characterized both chemically and in vivo, then compared to commonly-used protein ingredients before they can be considered for use in feeds. The objective of the present study was to determine the standardized ileal digestibility (SID, %) of amino acids (AA) of partially defatted black soldier fly larvae meal (BSFLM) (49.7% CP; 14.4% crude fat as fed). Subsequently, these results were compared to the SID AA of common protein ingredients in swine feed, fish meal (FM) and soybean meal (SBM) (NRC 2012), and to published full-fat (FF) BSFLM SID values. Six ileal-cannulated barrows (18.03 ± 0.67 kg BW) were used in a 2x2 Latin square design and fed either a nitrogen-free diet (NFD) or BSFLM-containing diet over two 11-d experimental periods. In each period, barrows were adapted for 7 days to the diet and ileal digesta collection was conducted on day 10 and 11 for 8h per day. Basal endogenous AA losses (EAAL) were calculated from pigs fed the NFD and as expected, the ileal AA content were significantly higher for pigs fed the BSFLM diet than NFD (P < 0.05). SID for AA were then calculated based on the obtained EAAL values following Stein et al., 2007. For essential AA, the SID of BSFLM were all above 82%, the highest being Arg (93.76%), followed by Met (91.32%), and Phe (89.80%). The SID of essential AA were on average 5.0% higher in BSFLM than FM, but 2.7% lower than SBM. When compared to the FF BSFLM, SID of essential AA of BSFLM were 1–5% higher, except for Phe and Thr. These results suggest that partially defatted BSFLM is a promising alternative protein ingredient in growing pig diets, which has a more digestible AA profile than FM, only slightly lower than SBM, and comparable to the FF BSFLM.
240 Beef Heifers with Increased Number of Follicles Have Greater Uterine Luminal Glucose Concentrations
Authors: Snider Alexandria , Crouse Matthew S , Rosasco Shelby , Epperson Kaitlin M , Northrop-Albrecht Emmalee J , Rich Jerica J , Chase Chad , Miles Jeremy R , Summers Adam , Cushman Robert A
Published: October 2021

Increased numbers of antral follicles are associated with greater fertility and a uterine environment that is more supportive of early embryonic development in beef heifers. Glucose is a primary energy source for embryos and glucose concentrations are elevated in uterine luminal fluid (ULF) of pregnant heifers. We hypothesized that ULF glucose concentrations and endometrial transcript abundance for glucose transporters at d16 after insemination would be greater in heifers with increased numbers of antral follicles. Heifers classified with either increased (32 ± 1.1) or diminished (14.7 ± 1.1) antral follicle counts were selected and artificially inseminated following the Select Synch protocol (d0). At d16 after insemination, heifers were sent to the abattoir and reproductive tracts were collected to retrieve conceptuses to determine pregnancy. Uterine luminal fluid was collected, the endometrium was biopsied, total RNA was extracted and glucose transporter transcript abundance was determined. Data were analyzed using the MIXED procedure of SAS with antral follicle group, pregnancy status, and the interaction as fixed effects. Glucose concentrations in ULF were greater (P < 0.05) in heifers with increased antral follicle numbers compared to heifers with diminished numbers (122.65 ± 11.91 vs 84.12 ± 12.42 mg/dL). Glucose ULF concentrations were increased (P < 0.05) in pregnant vs. non-pregnant heifers (124.84 ± 12.81 vs 81.93 ± 11.50 mg/dL). Endometrial glucose transporter 1 (GLUT1) transcript abundance was increased in pregnant heifers (P < 0.01) but was not different due to antral follicle number or the interaction. Therefore, differences in glucose concentrations associated with antral follicle number may be due to differences in GLUT1 transcription before d16 or due to differences in protein abundance or functionality. Taken together, heifers with increased number of antral follicles may have increased energy availability in the uterus for trophoblast proliferation and function. USDA is an equal opportunity provider and employer.
246 Examining Melatonin-induced Changes in Uterine Blood Flow and Vaginal Temperatures in Nutrient Restricted Pregnant Heifers
Authors: Contreras-Correa Zully E , Messman Riley D , Sanchez-Rodriguez Hector , Lemley Caleb O
Published: October 2021

The objectives were to examine melatonin mediated changes in temporal uterine blood flow (UBF) and vaginal temperatures (VT) in 54 Brangus heifers (Fall, n = 29; Summer, n = 25) during compromised pregnancy. At d160 of gestation, heifers were assigned to 1 of 4 groups consisting of adequately fed (ADQ-CON; 100% NRC; n=13), global nutrient restricted (RES-CON; 60% NRC; n = 13), and ADQ or RES supplemented with 20 mg of melatonin (ADQ-MEL, n = 13; RES-MEL, n = 15). In the morning (0500h) and afternoon (1300h) of d220 of gestation, temperature dataloggers (Onset Computer Corporation) attached to progesterone-free CIDRs were used to record VT, while UBF was determined via Doppler ultrasonography. Data were analyzed using repeated measures of ANOVA (SAS). Significant differences were found in UBF and VT between Fall and Summer groups (P< 0.05), therefore seasons were individually analyzed. In Fall, a nutrition by treatment interaction was significant, where the RES-CON heifers exhibited reduced total UBF compared to ADQ-CON (5.67±0.68 vs. 7.97±0.54 L/min; P = 0.012). In Summer, there was not a main effect of nutrition (P = 0.390); nevertheless, the MEL heifers exhibited increased total UBF compared to the CON counterparts (8.16±0.73 vs. 6.00±0.70 L/min; P = 0.048). Moreover, there was a nutrition by treatment by time interaction in VT for Fall and Summer heifers (P < 0.0001). In Fall, all groups had decreased VT in the morning compared to the afternoon (P < 0.0001). Whereas, in Summer, VT increased for ADQ-CON, RES-CON, and ADQ-MEL from morning to afternoon (P < 0.0001), while the RES-MEL remained constant throughout the day (P = 0.649). Furthermore, during the afternoon RES-MEL heifers exhibited decreased VT compared to ADQ-CON (38.91±0.09 vs. 39.26±0.09°C, respectively; P=0.039). In summary, nutrient restriction and melatonin supplementation altered UBF in a season dependent manner. Additionally, with the VT differences observed in Summer, future studies should evaluate the potential of melatonin supplementation for mitigating heat stress in farm animals.
271 Assessment of Efficacy of Deworming Options in Recently Weaned Beef Cattle Utilizing Different Anthelmintic Programs in the Southeast
Authors: Hernandez Shane R , Davis Dylan B , Tucker Jennifer J , Credille Brent , Stewart R Lawton
Published: October 2021

This experiment measured the effect of three different deworming strategies on animal performance and Egg per gram (EPG) reduction during a pre-conditioning phase of beef calves using a completely random block designed with n = 797 calves (Year 1 = 263 ± 39 kg; Year 2 = 257 ± 37 kg) randomly assigned to one of four treatments: orally suspended oxfendazole (1ml/55 kgs; ORAL), transdermal eprinomectin (1ml/10 kgs; POUR), both anthelmintic (BOTH), and no treatment (CONT). Weaned calves at four University of Georgia research stations (Calhoun, Alapaha, Eatonton, JPC) were blocked by weight, age, and sex. Calves were weighed at weaning prior to treatment d 0 and on d 42. Fecal samples were collected on d 0 and d 14 from 40 calves per treatment. Anthelmintic resistance was determined if percent EPG reduction and Upper 95% confidence limit were below 95% and the lower 95% confidence limit were below 90%. The ADG was lowest (P < 0.001) for CONT (0.262 kg/d) compared to POUR, ORAL, and BOTH (0.370, 0.412, and 0.387 kg/d, respectively) Anthelmintic resistance to POUR was detected at Eatonton and Alapaha (47.4% and 15.4% reduction respectively), and deemed inconclusive at JPC and Calhoun (51.1% and 50.3% reduction respectively). Only ORAL and BOTH effectively reduced EPG counts across all four research units (> 97.9% reduction). While the POUR option improved animal performance, it was not effective at reducing EPG within the herd. This study demonstrated that the ORAL and BOTH treatments increased ADG compared to CONT and were effective at reducing EPG counts; however, BOTH costs, on average, $3.00 more than ORAL. Producers must consider the cost of each option when choosing a deworming strategy. Based on these results, using orally suspended oxfendazole is a more economical, and effective options to treat parasites during a pre-conditioning phase.
270 Evaluation of Steer Implant Strategies for Long-season Grazing of Cool-season Annuals
Authors: Garcia Taylor J , Reuter Ryan R , White Frank , Blue Ken , Rivera Daniel
Published: October 2021

The objective of this study was to determine the relative effects of stocker-phase implant strategies on growth and carcass characteristics of beef steers. In each of 2 locations (OK and MS), steers were grazed on cool-season annual pastures in fall 2018 through spring 2019. Steers (n = 300 in MS, n = 240 in OK) were randomly assigned to one of three implant treatments, 1) a single Synovex® One Grass implant at d 0, 2) a single Component® TE-G with Tylan implant at d 0, or 3) a reimplant treatment receiving Component® TE-G with Tylan at d 0 and again at d 82 (OK) or 85 (MS). Steers from each treatment were commingled in 2 (OK) or 3 (MS) pastures for 159 (OK) or 161 d (MS). Following grazing, steers were shipped to a commercial feedyard for finishing, sorted into 3 pens based on BW with each treatment equally represented in each pen, and were managed according to that site’s BMPs. Steers from all treatments were implanted identically in the feedyard. Steers were slaughtered when the pen was visually estimated to be at 1 cm backfat. Carcass data of individuals were collected by camera grading equipment in the packing plant. Data were analyzed as a completely random design with animal as the experimental unit, treatment as a fixed effect, and pasture within location as a random effect. Marbling score tended to be greater in the single Component® TE-G with Tylan (treatment 2) vs. the other 2 treatments (425 vs 408 and 410, P = 0.07). No other production variables, including stocker-phase ADG, approached a significant difference (P > 0.39). No evidence was found to recommend stocker-phase reimplanting even in relatively long stocker phases with high ADG, and producers should consider selecting the most cost-effective implant at grazing initiation.
284 Genetic Selection Through Ecofeed Index Reduces Carbon Footprint in Heifers
Authors: Kebreab Ermias , Johnson Jocelyn R R , Heuer Claas , Deeb Joseph
Published: October 2021

Efficient feed conversion by ruminants has a direct impact on the animal’s carbon footprint. The objective of this study was to determine the effect of using the EcoFeed® index by STgenetics® to reduce methane production. The EcoFeed® index is an integrated approach to genetic selection based on progeny testing of females for residual feed intake to identify animals who consume less feed while maintaining production compared to their herd mates to increase profitability and global sustainability. EcoFeed® is moderately heritable and uncorrelated with traits currently selected for in dairy cows. A dataset containing phenotypic and genomic information on 5,441 heifers was used for the analysis. Heifers were divided into low, medium and high EcoFeed® classes based on ±0.5 SD from the mean. To estimate methane emissions, 17 mathematical models were collated from the literature. All models were subjected to evaluation of performance using an independent dataset containing 458 individual-animal methane production measurements. The model recommended by Intergovernmental Panel for Climate Change had the lowest root mean square prediction error with 1% mean bias and 3.37% slope bias. This model was used to calculate emissions from low and high EcoFeed® heifers. In addition, an average of all model results was computed and used to compare different classes of heifers. Based on dietary information and feed intake, low and high EcoFeed® heifers were estimated to produce 194 and 164 g methane/d, respectively, using the selected model. Using model averages, the estimated methane production was 186 and 162 g methane/d, for low and high EcoFeed® heifers, respectively. The reduction in emission between low and high EcoFeed® classes was 12.6 to 15.4%. If savings from crop production were to be considered, there will be further reductions in the carbon footprint. Therefore, genomic selection is a powerful tool to reduce carbon footprint in ruminants.
280 Descriptive Characteristics of Preweaned Heifer Raising Practices on China Dairy Farms: Colostrum Quality, Passive Transfer Status and Growth Performance
Authors: Liu Shuai , Chen Tianyu , Li Jiaqi , Guo Wenli , Peng Rong , Cao Zhijun
Published: October 2021

Few data are available on the descriptive characteristics of colostrum quality, passive transfer status and growth performance within a national population in China. This study included 110 dairy operations in 23 provinces, and data were obtained from management software, report system and questionnaires from 2015 to 2019. Data were analyzed using SAS (version 9.0, SAS Institute Inc., Cary, NC, USA). The results showed that colostrum quality was measured in 96.4% of farms and colostrum was pasteurized in 91.8% of farms. 83.6% of colostrum was excellent (Brix > 22%). Colostrum could be fed to calves within 1 hour after birth in 86.4% of farms. Besides, calves that experienced failure of passive transfer (serum total protein < 5.2 g/dl) decreased from 2015 to 2019 and accounted for 0.75% of calves in 2019. Most farms (48.8%) feed 400 kg - 600 kg milk during the preweaning period and whole milk was the main type of liquid diet accounting for 70.6% of farms. Meanwhile, 22.0% of farms chose to feed forage before weaning, and 90.1% of these farms fed oat hay. The average birth weight of calves was 37.8 kg and the average daily gain of preweaning calves was 848.3 g/d. For preweaning calves, the proportion of single housing was more than 60%, whereas postweaning calves were mainly raised in groups. The morbidity of preweaning calves in China decreased annually, from 43.3% in 2015 to 25.4% in 2019. Digestive diseases and respiratory diseases were two main diseases, and accounted for 46.0% and 38.4%, respectively. This study provides an overview on dairy calves raising practices in China.
525 Late-Breaking: Late Gestational Nutrient Restriction of Primiparous Beef Heifers Decreases Milk Yield and Pre-weaning Calf Growth
Authors: Meyer Allison M , Redifer Colby A , Wichman Lindsey G , Shangraw Erin M , McFadden Thomas B
Published: October 2021

Fall-calving Hereford-SimAngus heifers (single-sired; BW: 451 ± 28 [SD] kg; BCS: 5.4 ± 0.7) bred to a single sire were individually-fed 100% (control; CON; n = 12) or 70% (nutrient restricted; NR; n = 13) of NASEM net energy and metabolizable protein requirements for maintenance, pregnancy, and growth from d 160 of gestation to calving. Post-calving, all females were limit-fed chopped tall-fescue hay supplemented to meet lactational nutrient requirements in Calan gates to constrain calves’ diets to milk only until d 147. Four-hour milk yields were measured 5 times; calf size was determined every 21 d. Data were analyzed with treatment, calving date, and calf sex (when P < 0.25) as fixed effects; day and day x treatment were included for milk yield. From calving to d 147, CON cows had greater (P ≤ 0.003) BW, BCS, and backfat, but NR cows gained more (P ≤ 0.004) BW, BCS, and backfat. Milk weight and volume was 15% less (main effect; P < 0.04) for NR cows. Calf size did not differ at birth (P ≥ 0.27). From d 42 to 147, calves born to NR dams had lower (P ≤ 0.02) BW. Heart, abdominal, and flank girths were less (P ≤ 0.07) for NR calves through d 147. Calf ribeye area tended to be less (P ≤ 0.11) in NR calves at d 42, 84, and 126. Nutrient restricted calves had less shoulder to rump length (d 63 to 147; P ≤ 0.08), shoulder height (d 63 to 126; P ≤ 0.02), cannon length (d 42 to 105 and 147; P ≤ 0.09), and cannon circumference (d 63 and 105 to 147; P ≤ 0.06). These data indicate that even when dams are fed to meet lactational requirements, milk yield and calf growth are reduced by late gestational nutrient restriction.
521 Late-Breaking: Oral Mineral Drench to Reduce Morbidity and Increace Performance on Remore Summer Pastures
Authors: Sager Bob B
Published: October 2021

Economic losses due to morbidity and mortality associated with bovine respiratory disease (BRD), foot rot, pinkeye, and other health issues in yearling beef cattle are consistently over $2 billion annually. This trial was designed to test the hypothesis that yearling beef cattle individually treated with an oral micromineral drench would be associated with decreased BRD, foot rot, pinkeye, and other issues in the first 60 days with improved weight gains while grazing remote summer pastures. This trial utilized 1150 head of steers, spayed heifers, and intact heifers in areas of Idaho and Montana. Trial cattle had unknown background and nutritional history, with no metaphylaxis treatment upon arrival. Treatment data for BRD, pinkeye, and foot rot, and other abnormalities showed decreased morbidity (from 37.5–61%) in different groups P < 0.234 during the first 60 days of the trial compared to the untreated cattle. Weight gains on treatment steers showed an increase 0f 18.89 lbs. in group 2 and 12.34 lbs. in group 3 (salt only) in 100 days grazing in the treatment cattle compared to the controls. The bred heifer group 1 showed showed slight weight gains of 1% and an increase pregnancy rate of 2% compared to the controls after 100 days grazing. Further trials need to be completed to determine the desired dosage using an oral mineral drench on yearling beef cattle with unknown vaccination and nutritional history.
291 Weaned Holstein Calves Fed an Experimental Botanical Extract Alone or in Combination with an Eubiotic Product
Authors: Casper David P , Officer Michael , Klanderman Keith
Published: October 2021

A botanical extract (BE; garlic oil, anise oil, cinnamaldehyde, rosemary, and thyme blend) has been shown to enhance dry matter intake (DMI) and gut health, while eubiotics (EU; lactobacillus acidophilus fermentation product), has been shown to improve gut health and growth performance of growing Holstein calves. The hypothesis was the combination BE and EU could be synergistic to post-weaning neonatal calf growth performance. Seventy-seven (77) Holstein bull calves from a previous milk replacer trial were randomly assigned to 1 of 4 treatments using a 3 wk experimental period. Treatments were: 1) Control: Calf starter (CS) without BE or EU; 2) BE: CS with 275.6 g/ton of an experimental BE (Adisseo North America, Alpharetta, GA); 3) EU: CS with 0.22% EU (RumaCell DF 5G; Pacer Technology, Murtaugh, ID); and 4) BE&EU: CS with added BE and EU. The 22% crude protein CS was a mini-pellet and fed for ad-libitum consumption with amounts fed and orts recorded daily. Calves fed EU demonstrated greater (P < 0.05) body weight (BW; 81.3, 80.8, 84.8, and 84.2 kg for Control, BE, EU, and BE&EU, respectively) compared with calves fed Control and BE with calves fed BE&EU being intermediate and similar (P > 0.10). Calves fed BE demonstrated greater (P < 0.05) average daily gains (ADG; 965.5, 984.3, 1052.8 and 989.1 g/d) compared with calves fed Control with calves fed BE and BE&EU being intermediate and similar (P > 0.10). The DMI (2.19, 2.18, 2.31, and 2.14 kg/d) and feed conversions (0.45, 0.46, 0.45, and 0.45 kg BW gain/kg DMI) were similar (P > 0.10) among calves fed all treatments. Blood urea nitrogen concentrations (14.7, 14.6, 14.9, and 13.4 mg/dL) were similar (P > 0.10) among calves fed all treatments. Feeding a EU improved BW of weaned growing Holstein bull calves, but the BE and EU combination was not beneficial for enhancing growth performance.
297 The Effects of Chromium Propionate Supplementation to Yearling Steers in a Commercial Feedyard on Growth Performance, Carcass Characteristics and Health
Authors: Trojan Sara J , Hergenreder Jerilyn , Canterbury Landon , Leonhard Tyler , Long John M
Published: October 2021

British crossbred steers [n = 3074; initial body weight (BW) = 358 ± 37 kg] were used to evaluate the effects of chromium propionate supplementation to yearling steers in a commercial feedyard on growth performance, carcass characteristics and health. Steers were blocked by initial BW; pens were assigned randomly to one of two dietary treatments within block. Treatments, replicated in 15 pens/treatment with 75 to 135 head per pen, included: 1) control, 0 mg supplemental Cr/kg dietary dry matter (DM) (CTL); 2) 0.50 mg supplemental Cr/kg diet DM (chromium propionate; KemTRACE® Chromium 0.04%, Kemin Industries, Des Moines, IA) (CR). Final BW (638 vs. 641 kg.), average daily gain, (1.81 vs. 1.82 kg), DM intake (11.02 vs. 11.02 kg) and gain efficiency (0.164 vs 0.165) did not differ between CTL and CR, respectively (P ≥ 0.75). No differences among treatments for hot carcass weight (407 vs. 408 kg., CTL and CR, respectively), dressing percentage, longissimus muscle area, or yield grade were observed (P ≥ 0.15). Twelfth-rib fat thickness tended (P = 0.10) to be greater for CR vs. CTL (1.55 vs 1.29 cm, respectively). A trend (P = 0.10) for marbling score to be higher for CR vs. CTL was detected (452 vs. 440, respectively). Distribution of quality grade was similar between CR and CTL; 1.52% of carcasses graded prime (P =0.68), and 87.2% of carcasses graded choice (P = 0.68). Respiratory morbidity was low (1.93%) and not different among treatments (P = 0.20); likewise, there was no difference in respiratory treatment rates between treatments (P ≥ 0.18). Supplementing Cr to high-performing yearling steers did not alter growth performance, carcass characteristics or health outcomes.
313 Effects of Bismuth Subsalicylate on Ruminal Fermentation of Cattle Consuming a Feedlot Diet
Authors: Madrid Kenneth S , Osorio Andrea M , Ciriaco Francine M , Fávero Igor Gomes , Tonelli Nardi Kaue T , Scaranto Silva Kaliu G , Raudales Angel A , Coello Kymberly D , Onorino Sarturi Jhones O , DiLorenzo Nicolas , Henry Darren D
Published: October 2021

A replicated 3 × 3 Latin square was used to determine the effects of bismuth subsalicylate on ruminal fermentation parameters of beef cattle consuming a feedlot diet. Six ruminally-cannulated Angus-crossbred steers (n = 3; 573 ± 105 kg BW) and heifers (n = 3; 553 ± 77 kg BW) were assigned 1 of 3 treatments: 1) low sulfur (S = 0.27% diet DM; LSUL); 2) high sulfur (S = 0.38% diet DM; HSUL); and 3) HSUL + 0.33% bismuth subsalicylate in diet DM; (BSS). Cattle were adapted to treatments for 14 d followed by 7 d of collections. Ruminal gas cap samples were collected at 0, 4, 8, and 12 h post-feeding on d 14, and ruminal fluid samples were collected on d 15 every 3 h post-feeding for 24 h. Data were analyzed using the MIXED procedure of SAS. Treatment tended (P = 0.099) to affect H2S concentration where BSS and LSUL were 50 and 61% lesser when compared to HSUL, respectively. A tendency (P = 0.061) was also observed for concentration of NH3-N where HSUL and BSS were lesser than CTRL. There was also a tendency for a treatment effect (P = 0.082) where HSUL had a lower pH than LSUL with BSS being intermediate. Furthermore, treatment tended (P = 0.0712) to affect the concentration of acetate where HSUL was lesser than BSS. No effect of treatment (P ≥ 0.124) was observed on total VFA concentration nor concentrations of butyrate, propionate, or valerate (P ≥ 0.138). Treatment tended (P = 0.084) to affect branched chain VFA concentration where BSS decreased concentrations compared to LSUL. Molar proportions of the major VFA were not impacted by treatment (P ≥ 0.100). In conclusion, BSS appears to decrease H2S production in the rumen without having negative effects on the fermentation profile.
315 Feeding Behavior of Beef Steers Consuming Finishing Diets with Added Nutritional Packet
Authors: Fávero Igor Gomes , Onorino Sarturi Jhones O , Tonelli Nardi Kaue T , Henry Daren D , Scaranto Silva Kaliu G , Ciriaco Francine M , Huerta-Leidenz Nelson O , Osorio Andrea M , Rush Camron J
Published: October 2021

The effects of a nutritional packet fed to beef steers during the feedlot finishing phase (final 64 d) on feeding behavior were evaluated. Crossbred-Angus steers (n = 120; initial BW = 544 ± 52 kg) were assigned to 30 pens (4 steers/pen; 15 pens/treatment; pen = experimental unit) in a randomized complete block design. Steers were fed, ad libitum, a steam-flaked corn-based finishing diet and treatments were applied as follows: 1) control and 2) 30 g/steer-daily (DM-basis) of a nutritional packet (containing live yeast [Saccharomyces cerevisiae; 8.7 Log CFU/g], vitamin C [5.4 g/kg], vitamin B1 [13.33 g/kg], NaCl [80 g/kg], and KCl [80 g/kg]). The nutritional packet used ground corn as a carrier and was included at 1% of diet DM. Orts were subtracted from the total dietary DM offered to calculate DM intake. Feeding behavior activities were visually assessed by trained personnel twice (d 27 and d 63) for 24 h, when time spent on each activity was recorded every 5 min. Data were analyzed using the GLIMMIX procedure of SAS. Treatment × period interactions (P ≤ 0.03) were observed for eating time (min/d) and eating rates (min/kg of consumed DM, OM, fiber, and digestible DM, OM, and fiber), in which steers fed the nutritional packet spent less time in such activities on d 27 and more time during the assessment on d 63, compared with control. Regardless of period, steers fed the nutritional packet tended (P = 0.07) to spend less time chewing per kg of digestible ADF. Rumination (P ≥ 0.28), drinking (P ≥ 0.40), active (P ≥ 0.92), and resting (P ≥ 0.53) times were not affected by treatment. The nutritional packet affected eating behavior more intensively during the first 27 d of treatment, and digestible ADF seems to be the main feed-fraction inducing such effect.
503 Late-Breaking: Using Random Regression Models to Estimate Genetic Parameters for Milk Production Traits under Different Levels of Heat Stress in Canadian Holstein Cattle
Authors: Campos Ivan , Baes Christine F , Chud Tatiane , Cánovas Angela , Oliveira Hinayah R , Schenkel Flavio S
Published: October 2021

Genetically selecting animals that are heat tolerant can help to maintain production efficiency of the dairy industry under thermal challenges. During the summer months in Canada, dairy cows could be under thermal stress. For instance, in Ontario, cows are expected to be 105 days under thermal stress. The objective of this study was to estimate genetic parameters for milk production traits under heat stress in Canadian Holstein cows. A total of 604,050 test-day records for milk, fat, and protein yields from 78,516 first-lactation Holstein cows were used in this study. The production data was combined with daily maximum temperature-humidity index (THI; ranging from 30 to 83) calculated based on meteorological records from public weather stations. In total, 58 weather stations were located within a maximum distance of 20 km from each of the 1,284 herds included in this study. Single-trait random regressions on THI, fitting linear splines to describe the random additive genetic and permanent environmental effects, were used in the genetic analyses. Based on preliminary analyses, the knots of the spline functions were set to THI = 70, 57, and 58 for milk, fat, and protein yields, respectively. Therefore, the models assumed a linear effect of heat stress beyond the THI threshold, allowing to estimate the additive genetic effect under thermal comfort and at different levels of heat stress. The genetic correlations estimated between thermal comfort and heat stress were -0.09, -0.33, and -0.21 for milk, fat, and protein yields, respectively. This indicates an antagonistic relationship between level of production and heat tolerance. However, small differences in heritability estimates were observed above the THI thresholds (they ranged from 0.20 to 0.22 for milk, 0.18 to 0.15 for fat, and 0.14 to 0.15 for protein yields). This study demonstrates the possibility of genetically selecting for more heat-tolerant animals in Canada.
359 Intake and Growth Performance of Feedlot Lambs Fed Diets with Hi-a and Low-a Corn Cobs and Bermudagrass Hay
Authors: Quadros Danilo G , Whitney Travis R , Weishuhn Cassie , Xu Wenwei , Tolleson Doug R , Diaz Jose M , Kerth Chris
Published: October 2021

Hi-A™ corn is a unique type of lines and hybrids that were developed by the Texas A&M AgriLife Corn Breeding Program and have high anthocyanin and antioxidants. A completely randomized design trial was used to evaluated effects of Hi-A and low-A (regular) corn cobs and bermudagrass hay (BGH) in feedlot diets fed to female Rambouillet lambs (n = 10/treatment), with initial body weight (BW) of 30.7+1.2 kg, on dry matter intake (DMI), BW, average daily gain (ADG), and growth:feed ratio (G:F). After 14 days of adaptation, lambs were individually fed a total mixed ration with 80% concentrate and 20% of one of the roughages (Hi-A, low-A, or BGH) for 63 days. Hay was chopped, while cobs were ground using a hammermill with a 9.52-mm screen. Data were analyzed using repeated-measures ANOVA. The BW was not affected by the diet but increased (P < 0.001) during the trial. Diet did not influence the ADG. However, the ADG was lower (P < 0.001) in the d-42 (0.12 kg/d) than the rest of the trial (0.22 kg/d), after a period of constant high temperatures. The interaction diet vs. day affected (P < 0.05) DMI. In general, lambs increased (P < 0.05) DMI (g/d) and decreased (P < 0.05) relative DMI (%BW) in the final part of the trial, when the animals were getting closer to the harvesting date. Lambs had lower (P < 0.05) DMI of BGH diets than Hi-A diets from d-42 to d-63 and Low-A diets from d-49 to d-56. The G:F ratio was not affected by the diet but decreased (P < 0.05) from the middle to the end of the trial. Corn cobs are valuable as alternative roughage for feedlot lambs, with intake and growth performance comparable to BGH.
366 Impact of Haemonchus Contortus on Feed Intake in Katahdin Sheep Selected for Parasite Resistance
Authors: Maierle Camren L , Weaver Andrew R , Felton Eugene , Greiner Scott P , Bowdridge Scott A
Published: October 2021

Haemonchus contortous (Hc) infections have decreased profitability of flocks worldwide through loss of production efficiency and in severe cases death. Countless research efforts have been made in order to further understand the extensive impact of this gastrointestinal nematode (GIN). Quantifying the impact feeding behavior after Hc infection may prove vital, in understanding internal effect on growing lambs. The aim of this study was to evaluate Katahdin lambs with extensive genetic evaluation for feed efficiency and behavior utilizing a Growsafe™ system. Katahdin ewes from the Virginia Tech Southwest Agriculture Research and Extension Center in Glade Springs Virginia were divergently selected based on fecal egg count (FEC) EBV and mated to rams (n = 8) of similar genotype. A subset of lambs was selected for feedlot evaluation and transported to West Virginia University. Lambs were fed a complete pellet (16% CP) ad libitum while individual intake was measured in pen-fed groups with a GrowSafe™ system. Half of the lambs from each sire FEC EBV group were infected with 5,000 Hc L3 larvae and observed for 6 weeks alongside uninfected contemporaries. Artificial Hc infection resulted in lambs becoming modestly infected with FEC peaking in week 5 at 324 eggs/g. Infection level was not significant between all 4 groups (P < 0.05). Lambs administered H.C. had observably lower feed intake 2 days after infection. Both infected groups returned to normal intake with their control groups shortly after. Feed intake dropped again at day 10 and remained low until day 16 for LoFEC sired lambs and day 20 for HiFEC sired lambs. Offspring of low FEC rams exhibited an ability to return to normal intake levels earlier than lambs with high FEC EBV sires. Further analysis is needed with greater levels of parasite infection to confirm negative FEC EBV have a shorter duration of lower feed intake.
514 Late-Breaking: Effects of Feeding a High Canola Meal-containing Diet and Multi-carbohydrase Supplementation on Growth Performance and Intestinal Ecology of Piglets
Authors: Holanda Debora , Regassa Alemu , Patterson Robert , Nyachoti Martin
Published: October 2021

The objective was to investigate the effects of a high canola meal-containing diet and multi-carbohydrase supplementation on growth performance and intestinal pH, short-chain fatty acid (SCFA) profile, and microbiome in weaned piglets. Twenty-four piglets (7.46 ± 0.23 kg BW) were individually assigned to 1 of 3 diets in a completely randomized design. Diets were fed for 21 d: SB, corn and soybean meal-based diet; CM, 25% canola meal substituting soybean meal and adjusted to meet energy and nutrient requirements of piglets (NRC, 2012); and CM+E, CM supplemented with multi-carbohydrase (0.01%). Feed disappearance and BW were recorded weekly. On d 21, piglets were euthanized to assess digesta pH, SCFA profile, and gut microbiome. Data were analyzed using the MIXED procedure of SAS using the piglet as the experimental unit. There were no differences (P > 0.10) in growth performance and digesta pH. Piglets fed CM+E tended to (P = 0.051) or had significantly lower (P < 0.05) butyric acid in the cecum than piglets fed CM and SB, respectively. Piglets fed SB had higher (P < 0.05) isobutyric acid in the colon than piglets fed CM+E. Piglets fed SB and CM tended to have higher (P < 0.05) isovaleric acid in the colon than piglets fed CM+E. Piglets fed SB tended to have lower (P < 0.10) proportion of Bifidobacteria, and had lower (P < 0.05) Enterobacteriaceae, Enterococcus, and Lactobacillus than piglets fed CM. Piglets fed CM+E tended to have lower (P < 0.10) Bifidobacteria and higher Clostridium XIVa than piglets fed CM, and had lower (P < 0.05) Enterococcus, but higher (P < 0.05) Lactobacillus than piglets fed CM. In conclusion, feeding 25% of canola meal in substitution to soybean meal with or without multi-carbohydrase supplementation changed the intestinal environment by modifying SCFA profile and relative proportion of microbiome, but without affecting digesta pH or growth performance in nursery piglets.
515 Late-Breaking: Effects of Dietary Phytase with or without Multi-carbohydrase Supplementation on Growth Performance, Nutrient Digestibility, and Bone Traits in Nursery Pigs
Authors: Adeshakin Olumide E , Koo Bonjin , Patterson Robert , Nyachoti Martin
Published: October 2021

The aim was to determine the effects of supplementing increasing doses of phytase (PHY) alone or in combination with multi-carbohydrase (MC) blend to a P-deficient diet for nursery pigs on growth performance, nutrient digestibility, and metacarpal bone characteristics. A total of 192 weaned pigs (7.7 ± 0.05 kg BW) were allotted to 1 of 8 dietary treatments each with 8 replicates in a randomised complete block design based on initial body weight. Diets consisted of a P-deficient negative control (NC), NC + 250 FTU/kg (TRT1), NC + 500 FTU/kg (TRT2), NC + 1,000 FTU/kg (TRT3), NC + 0.2g/kg MC (TRT4), TRT4 + 250 FTU/kg (TRT5), TRT4 + 500 FTU/kg (TRT6), and TRT4 + 1,000 FTU/kg (TRT7). Fecal samples (d 18, 19, and 20) and metacarpal bones (d21) were collected to determine apparent total tract digestibility (ATTD) of energy and nutrients and bone mineralization, respectively. Data were analyzed using the MIXED procedure of SAS with orthogonal polynomial contrast statements with a pen as an experimental unit for growth performance and digestibility and 1 pig per pen for bone traits. During week 2, MC supplementation tended to increase (P = 0.05) body weight whereas by week 3, increasing doses of PHY linearly (P < 0.05) increased average daily gain (ADG). Overall, PHY supplementation had a quadratic effect (P < 0.05) increasing ADG. However, there was an interaction (P < 0.05) whereby PHY and MC in combination acted synergistically to increase percentage of ash and P ATTD. Phytase had linear (P < 0.05) and quadratic (P < 0.05) by increasing fat-free dry weight, ash content, and P in metacarpal bone. In conclusion, increasing levels of PHY quadratically improved growth performance, nutrient digestibility, and bone traits of pigs fed a P-deficient diet.
510 Late-Breaking: Dietary Glycine Supplementation During Growing and Finishing Phases Increases Tissue Concentrations of Total Creatine and Gene Expression of Creatine-synthetic Enzymes in Low-birthweight Pigs
Authors: Posey Erin A , He Wenliang , Wu Guoyao
Published: October 2021

Dietary glycine is required for maximum growth and development in animals by stimulating muscle protein synthesis and as a component of creatine. Creatine is synthesized from glycine, arginine, and S-adenosylmethionine by arginine:glycine amidinotransferase (AGAT) and guanidinoacetate N-methyltransferase (GAMT). Sufficient creatine synthesis for growth requires adequate substrate supply. However, swine diets are deficient in glycine. Additionally, intrauterine growth restricted (IUGR) pigs have reduced glycine synthesis. This results in decreased creatine synthesis and lower total creatine content in tissues, leading to reduced cellular energy metabolism and diminished muscle protein accretion. This study was designed to test the hypothesis that dietary glycine supplementation in corn-and-soybean-meal-based diets would improve overall growth and skeletal muscle accretion in post-weaning IUGR pigs by increasing the expression of creatine-synthetic enzymes and tissue concentrations of total creatine. Fourteen IUGR pigs (birthweight = 0.98±0.03 kg, mean±SEM) and 20 normal birthweight pigs (birthweight = 1.44±0.02 kg, mean±SEM) were obtained at weaning for this study. Pigs from each birthweight group were randomly assigned to 1% glycine + 0.19% corn starch treatment group or 1.19% alanine group (isonitrogenous control) for the study (21 d to 188 d of age); tissues were collected at d 188. Data were analyzed by using 2-way ANOVA and the Duncan multiple comparison test. Glycine-supplemented IUGR pigs had greater tissue concentrations of creatine, creatinine, and creatine phosphate than control IUGR in all tissues measured (P< 0.05). Control IUGR pigs showed diminished activity and mRNA expression of creatine-synthetic enzymes (P < 0.05); this was mitigated by glycine supplementation as glycine supplemented IUGR pigs showed normal levels of enzyme activity and mRNA expression. Overall, results of this study indicate dietary glycine supplementation to IUGR pigs between weaning and market weight effectively restores creatine-synthetic enzyme activities and increase tissue concentrations of total creatine, leading to increased lean tissue growth. (Supported by USDA-NIFA)