bluuebunny/crossref_metadata_2025 huggingface dataset:
339 Effects of a Blend of Mannan and Glucan on Growth Performance and Immunocompetence of Newly Weaned Beef Steers
Authors: Taiwo Godstime A , Ogunade Ibukun M
Published: October 2021

We examined the effects of dietary supplementation of a blend of mannan and glucan on the growth performance, diet digestibility, and whole-blood immune gene expression of newly weaned beef steers during a 42-d receiving period. Forty-eight newly weaned Angus crossbred steers (2 d post-weaning; 199 ± 13 kg of initial BW) were randomly assigned to 1 of 2 treatments: basal diet with no additive (CON; n = 24) or a basal diet top-dressed with 5 g of a blend of mannan and glucan (MANGLU; n = 24). Average daily gain (ADG) was calculated from weekly BW. Blood samples were collected on days 0, 14, and 42 for measurement of plasma glucose and NEFA. Expression of 84 immune-related genes was analyzed on blood samples collected on day 42. Beginning on days 37 to 42, total mixed ration, refusals, and fecal samples were collected once daily to determine apparent total tract digestibility of DM, CP, NDF, and ADF using indigestible NDF as an internal marker. Immune gene expression data was analyzed using a GeneGlobe Data Analysis Center. All other data were analyzed as a randomized complete block design using the GLIMMIX procedure of SAS. Over the 42-d feeding trial, MANGLU tended to increase final BW (P = 0.07) and ADG (P = 0.06). Compared to CON, beef steers fed supplemental MANGLU had greater DM digestibility (P = 0.03) and tended to have greater NDF digestibility (P = 0.09). No treatment effects (P > 0.10) on plasma glucose and NEFA on d 14 and 42 were detected. Compared with CON, MANGLU increased (P ≤ 0.05) the expression of five immune-related genes involved in recognition of and mounting immune defense against microbial pathogens. In conclusion, this study demonstrated that supplemental MANGLU enhances beef cattle immunocompetence and productivity during feedlot receiving period.
342 Effects of Maternal Nutrient Restriction During Late Gestation on Primiparous Dam Performance and Fetal Growth
Authors: Redifer Colby A , Wichman Lindsey G , Meyer Allison M
Published: October 2021

To determine the effects of late gestational nutrient restriction (NR) on heifer performance, fetal growth, and calving difficulty, single-sired fall-calving Hereford-SimAngus heifers (BW: 451 ± 28 [SD] kg; BCS: 5.4 ± 0.7) bred to a single sire were allocated by fetal sex and expected calving date to either 100% (control; CON; n = 12) or 70% (n = 13) of NASEM net energy and metabolizable protein requirements for maintenance, pregnancy, and growth. Beginning on d 160 of gestation, heifers were individually fed chopped sorghum sudan hay (1.74 Mcal ME, 6.66% CP, 72.0% NDF; DM basis) and based on individual intakes, supplemented to meet targeted nutritional planes. Dam BW, BCS, and backfat (BF) were determined pre-treatment, every 21 d (BW) or 42 d (BCS and BF) during treatments, and post-calving. At birth, calf BW and size (length, heart girth, abdominal girth, flank girth, cannon circumference, cannon length, shoulder height, and ribeye area) were measured. Data were analyzed with treatment, treatment initiation date, and calf sex (when P < 0.25) as fixed effects. Dam BW tended to be less (P = 0.09) and BCS was less (P = 0.04) at d 202 of gestation for NR dams. Dam BW, BCS, and BF were less (P ≤ 0.01) in NR dams for the remainder of gestation. Post-calving, NR dams weighed 64 kg less (P ≤ 0.01) than CON, with a BCS of 3.6 ± 0.1. Nutrient restriction did not affect (P ≥ 0.27) calf gestation length, BW, or size. Calf BW as % post-calving dam BW tended to be greater (P = 0.09) for NR calves. Fetal presentation was normal for all CON births, while 23.1% of NR dams had fetal malpresentation (P = 0.12). In the current study, NR dam BW and BCS were sacrificed during late gestation without altering fetal growth trajectory.
343 The Influence of Weather Variables on Average Daily Gain of Beef Steers
Authors: Yusuf Mustapha , Bauer Marc L , Swanson Kendall C , Hanna Lauren L Hulsman
Published: October 2021

Average daily gain is one of the most important measures producers utilize to measure productivity of beef cattle. The objective was to examine how weather variables influence ADG. Data from 790 beef steers collected using an Insentec feeding system were utilized for this study. Intake data were condensed from daily data into weekly averages (n = 13,739 steer-weeks). The variables considered were ADG (-3.0 to 4.86 kg/d), DMI (2.50 to 21.77kg/d), BW (197.3 to 796.1 kg), dietary energy density (NEm; 1.2 to 2.5 Mcal/kg), average ambient temperature (-23.7 to 21.4 °C), range of temperature (2.8 to 19.4 °C), dew point (-27.8 to 14.3 °C), wind speed (2.08 to 6.49 km/h), solar radiation (30.8 to 297.1 W/m2), and two weeks lag (average of previous two weeks values) and monthly lag (average of previous four weeks values) of each weather variable. Relationship between weather variables were considered while developing the model, including controlling for confounding variables. Residuals of ADG generated after fitting week of year as a fixed effect were used in scatter plots with explanatory variables to identify if non-linear relationships existed. The MIXED procedure of SAS was used to assess the fit and regression parameters of explanatory variables as fixed covariates. Repeated measures were handled using the REPEATED statement and within-individual relationship was accounted for using the Toeplitz covariance structure. Body weight and energy density had linear and quadratic relationships with ADG (Table 1). Two weeks lag of wind speed and monthly lag of solar radiation had positive and negative associations with ADG, respectively, and there were several interactions between weather variables. These data indicate that weather variables influence ADG and should be considered in ADG prediction equations.
341 Meta-analysis of the Performance Responses of Replacement Heifers and Beef Cows to Monensin
Authors: Moore Mikayla F , Gadberry Shane , Lalman David , White Frank , Linneen Sara , Beck Paul A
Published: October 2021

Performance benefits of monensin have been extensively studied in finishing and stocker cattle, but considerably less published work is available evaluating response to monensin supplementation in cow-calf production systems. Feed additives are more difficult to study in cow-calf production systems due to unstable diet characteristics and cow physiological state throughout the production cycle. This meta-analysis investigated the impacts of monensin on performance of extensively raised beef cow-calf and developing replacement heifers. The replacement heifer analysis was conducted with a maximum of 48 treatment means in 18 experiments. The mature cow analysis included 21 publications and 26 mean comparisons. The metaphor package (version 2.4-0; Viechtbauer, 2010) for R (version 4.0.3; www.r-project.org) was used to determine the overall effect size of monensin compared to a negative control. Each study’s n, means, and SEM or P-value was used to calculate the mean difference and estimate of within study variance for responses of interest. For replacement heifers, average daily gain (+0.03 ± 0.008 kg/d), feed efficiency (+0.013 ± 0.008 gain:feed), and percentage cycling before the breeding season (+15.9 ± 5.13%) were increased (P < 0.01), while dry matter intake (-4.3%) and age at puberty (-8.9 ± 1.48 d) were decreased (P < 0.01). Six studies reporting ad libitum forage intake for mature cows showed that monensin decreased (P = 0.008) DMI by 0.85 ± 0.322 kg/day. Six studies showed monesin increased (P = 0.01) milk yield 0.39 ± 0.15 kg/day by mature cows in early lactation. There were no differences in artificial insemination pregnancy nor total pregnancy for either the heifer or mature cow data sets. This analysis also indicates potential for use of monensin in beef cow production systems, but further research is needed to elucidate the effects on DMI and milk production in beef cows.
350 Nutrient Movement in the Environment: Confined versus Grazing Systems
Authors: Brito Andre F , Almeida Kleves V
Published: October 2021

Grazing systems perform multiple ecosystem services including food production, climate regulation, nutrient cycling, and erosion control. Ruminants can also express their natural behaviors on pasture, with recent research revealing that dairy cows were more motivated to go outside for grazing than stay indoors consuming fresh TMR offered immediately after the afternoon milking. In addition, consumers often associate grazing systems with “healthier and happier cows” and are willing to pay premiums for “grass-fed” dairy products. However, milk production and nutrient utilization generally decrease in pasture-based compared with confinement systems, which may reduce farm profitability depending on milk pay prices. It should be noted that there is limited research reporting milk N efficiency (milk N/N intake) or methane emissions in confined versus grazing dairy cows using data collected from the same experiments. Therefore, our overarching objective was to build data sets to compare nutrient utilization in dairy cows under confinement or grazing management where milk N efficiency or methane emissions or both were reported in the same study. Dietary strategies to mitigate methane emissions in grazing dairy systems such as the use of high-quality forages (e.g., brassicas, perennial ryegrass), concentrate and seaweed supplementation, and forage species and management will be explored. For instance, Jersey cows grazing forage canola offered at 40% of the total DM emitted 31% less methane than those kept indoors and fed TMR (419 vs. 289 g/d, respectively) in an experiment conducted at the University of New Hampshire. Methane yield and methane intensity also decreased (P < 0.001) by 29.3% and 23.4%, respectively, in the same study. Irish researchers reported that methane production (-37%), yield (-11.5%), and intensity (-13%) decreased significantly in Holstein-Friesian cows offered perennial ryegrass herbage versus TMR. Data from whole-farm models comparing confinement and grazing systems will be presented and discussed.
347 Enteric Methane: Current Measurement and Assessment Techniques
Authors: Hristov Alexander N
Published: October 2021

Enteric methane (ECH4) emissions from ruminants can be measured directly or indirectly using various techniques and recent reviews have discussed advantages and disadvantages of these techniques. The GLOBAL NETWORK project (GN; an international consortium of animal scientists) examined techniques for measuring ECH4, including respiration chambers, the sulfur hexafluoride tracer (SF6) technique, and techniques based on short-term measurements of gas concentrations in samples of exhaled air. The latter category includes automated head chambers (i.e., the GreenFeed system; GF), use of carbon dioxide as a marker, and (handheld) laser methane detection. The conclusion from this analysis was that “there is no ‘one size fits all’ method for measuring ECH4 emission by individual animals” and appropriate and frequent calibrations and recovery tests are necessary with all methods. The team also concluded that the need for screening large numbers of animals (for example, for genomic studies), does not justify the use of measurement methods that are inaccurate. Timing of sampling/data collection is critical for the spot-sampling techniques, such as GF. It is a well-established fact that ECH4 emission is closely related to animal’s dry matter intake (DMI) and feeding patterns. Therefore, data collection using GF has to be sufficiently long and frequent, during both day and night hours, to fully represent the diurnal patter of ECH4 emission. The in vitro gas production and analysis technique can be used to screen feed additives or other ECH4 mitigation treatments, but data must be always confirmed/supported by animal (preferably long-term) studies. ECH4 emission can be also predicted based on dietary or animal variables. Large databases developed by the GN project have confirmed that DMI is driving ECH4, but other factors, such as dietary neutral detergent fiber, milk yield and composition (dairy cows), or dietary forage inclusion and animal’s body weight (beef cattle) can improve prediction accuracy.
356 Anomalies of Carbohydrate Digestion and Metabolism by Ruminants
Authors: Owens Fredric N
Published: October 2021

Carbohydrate, derived either from plant cell walls (neutral detergent fiber; NDF) from fresh or conserved forages consumed by cows and growing cattle or from starch of grains and concentrates in commercial feedlot diets, provides most of the dietary energy for ruminant growth and production. The ruminants’ ability to harvest forage from remote, inaccessible locations, to scavenge energy from NDF of feeds and byproducts of grain largely indigestible by non-ruminants, and to employ non-protein N to form protein-rich, nutrient-dense foods for humans are key ecological advantages over non-ruminants. Outlined below are some topics needing research attention. First, feed composition tables invariably indicate that the digested energy (DE) of carbohydrates is 4.4 kilocalories per gram, yet the gross energy (GE) of purified carbohydrate polymers (starch; cellulose, glycogen) averages 4.18; monomers (hexoses, pentoses) average 3.74. Having DE exceed GE violates the first Law of Thermodynamics! Might this 5 percent discrepancy reflect underestimations of fecal lignin or of protein digestibility due to metabolic fecal N? Favoring feeds rich in carbohydrate, this discrepancy confounds formulation of least-cost diets. Secondly, site of digestion of carbohydrate alters its metabolizable energy (ME). Fermentation, though required to yield ME from NDF, generates methane and heat. In contrast, starches and sugars that escape ruminal fermentation, if digested in the small intestine, circumvent these losses increasing their relative ME. Unfortunately, when ruminally fermented, starch, either directly or via pH depression, reduces NDF fermentation; might ruminal NDF digestion be increased by feeding NDF plus buffer versus concentrate diet components asynchronously? Third, carbohydrate metabolites lost in urine (lactate, pentoses, hippuric acid) need further quantification. Finally, ruminally-formed metabolites (methylglyoxal, methane) adversely affect animal health and energetics. Ruminal modification (site- or time-targeted enzymes or inhibitors; altering the ruminal microbiome with pre- or probiotics, inoculants, nutraceuticals) should help enhance ruminant productivity and sustainability.
355 Mineral Metabolism
Authors: Spears Jerry W
Published: October 2021

This presentation will highlight historic discoveries in mineral metabolism in ruminants. At least 15 minerals can be classified as essential based on their involvement in one or more metabolic functions in mammals. Deficiencies of all essential minerals have occurred naturally or have been induced experimentally in ruminants. Cobalt was shown to be essential for ruminants in 1935 based on its ability to correct naturally occurring deficiency signs in Australia. This discovery occurred 13 years before cobalt was shown to a component of vitamin B12. Low serum magnesium concentrations also were associated with grass tetany in cattle before magnesium was found to be essential for the rat in 1931. The value of supplemental salt for cattle was demonstrated in the 1800’s and a salt deficiency was experimentally induced in dairy cows in 1905. Over 50 years later sodium was identified as the mineral primarily responsible for salt deficiency. Naturally occurring deficiencies of phosphorus and copper were observed in grazing ruminants shortly after they were reported to be essential for rats. Copper toxicosis also became recognized as a practical problem, especially in some breeds of sheep. Selenium was shown to prevent white muscle disease in 1958. Because of its known toxicity and lack of a specific metabolic function, it was not until 1979 that Food and Drug Administration approved the addition of 0.1 mg Se/kg DM (later increased to 0.3 mg/kg) from inorganic sources to ruminant diets. This approval occurred after the identification of glutathione peroxidase as a selenium metalloenzyme in 1972. In 2009, the Food and Drug Administration approved the use of chromium propionate as a source of supplemental chromium for cattle at levels up to 0.5 mg Cr/kg DM. The approval of chromium propionate was based on its safety and ability to enhance insulin sensitivity in cattle.
358 Effect of Molasses Type on Pre-weaning Lamb and Ewe Performance
Authors: Harrelson Patricia L , Harrelson Flint W , Runnels Montana , Reed Audrey
Published: October 2021

The objective of this study was to investigate the effects of form of molasses on lamb and ewe performance. Creep feeding of lambs is essential to lamb growth, rumen development, and reduction of milk production from dams. Molasses is often added for increased palatability and energy. Crossbred lambs (n = 47; average age = 30 d) and their accompanying dams (n= 35) were assigned to one of two treatments using a completely randomized design with similar distributions of single and twin-born lambs and sexes. Treatment diets were formulated to be isonitrogenous and contained either wet (WMOL) or dry (DMOL) molasses. Dry molasses was added at 10% of the diet DM, whereas, wet molasses was added at 14.3% of the diet DM. Lambs were fed creep rations for 42 d prior to weaning. Creep feed was provided ad libitum and mixed grass hay was offered free-choice. Lamb weights were recorded weekly until weaning (d 42) and ewe BCS was measured at d 0 and d 42 (weaning). Overall lamb ADG was comparable (DMOL = 0.268 kg/hd, WMOL = 0.293 kg/hd; P = 0.30). Lamb weaning weights were similar between DMOL and WMOL (DMOL = 27.9 kg; WMOL = 27.5; P = 0.79). Ewe BCS was similar (P = 0.88) between DMOL and WMOL at 1.4 and 1.4, respectively. Estimated creep intake was calculated based upon total consumption following the end of the project and was found to be similar between treatments (DMOL = 0.54 kg/hd/d; WMOL = 0.59 kg/hd/d). Lamb pre-weaning growth and ewe performance was similar between DMOL and WMOL. Further research is needed to further explore the economic impact and use post-weaning.
362 Summary of North Carolina Small Ruminant Producer Performance Record Collection Questionnaire
Authors: Weaver Andrew R , Shaeffer April D
Published: October 2021

Growing interest and demand for small ruminant production in the Southeastern United States has garnered the need for improved productivity and greater Extension education programs. To better understand North Carolina small ruminant producer performance record collection, a needs assessment questionnaire was conducted. An online questionnaire was sent to sheep and goat producers via Extension email lists and state producer organizations. Producers were given nine weeks to respond to the survey and provided three email reminders. All responses were anonymous. The survey reached approximately 1200 producers. Of those, 131 agreed to the consent form, indicated they owned sheep and/or goats, and completed subsequent questions. A portion of respondents did not answer all questions. Of the 76 goat producers, 75.0% had 25 or less mature breeding females. Of the 75 sheep producers, 58.7% had 25 or less mature breeding females. Twenty producers had both sheep and goats. The portion of producers recording birth (62.6%) and rear (42.7%) type data on their entire flock was numerically greater than those recording birth (29.0%) and weaning (16.8%) weights on their entire flock. In terms of FAMACHA scores, 19.8% record data on their entire flock compared to 41.2% that record some data and 22.1% with no records. 45.8% of producers indicated no fecal egg count (FEC) records with 27.5% recording some FEC data. In terms of genetic selection tools, 41.2% of producers had not heard of estimated breeding values (EBVs) compared to 39.7% that indicated a basic understanding and 3.8% that use EBVs. This aligns with the 44.3% of producers that have not heard of the National Sheep Improvement Program and 38.2% that have a basic understanding. These data indicate the need for greater collection of performance records and participation in genetic evaluation programs among small ruminant producers in North Carolina.
360 Body Temperature of Hair Sheep Ewes During the Postpartum Period and Around the Time of Mating in an Accelerated Lambing System in the Tropics
Authors: Godfrey Robert , Lakos Sue A
Published: October 2021

The study was conducted to evaluate body temperature of hair sheep ewes at various stages of the production cycle in an accelerated lambing system in the tropics. Multiparous St. Croix White (STX: n = 7) and Dorper x STX (DRPX; n = 7) ewes lambing in October and raising single lambs weaned at 120 d were used. Synchronized breeding began at 96 d postpartum. Vaginal temperature (VT) was measured at 10-min intervals for 96 h at 38 and 66 d post-partum (PP1, PP2) and at 2 days after mating (PM) using data loggers. Daily minimum, maximum and range of VT were determined for ewes within PP1, PP2 and PB. Data were analyzed using GLM procedures of SAS with breed, day and time (PP1, PP2, PM) in the model. Mean ambient temperature, temperature-humidity index and solar radiation at PP1, PP2 and PM were 24.8 °C, 25.2 °C, 23.8 °C, and 74.7, 74.9, 73.3, and 180 W/m2, 160 W/m2 and 155 W/m2, respectively. Minimum VT was lower (P < 0.002) in STX than DRPX ewes at PP1, PP2 but not PM (38.27 ± 0.04 vs 38.44 ± 0.04 °C, 38.16 ± 0.04 vs 38.33 ± 0.04 °C, 38.47 ± 0.04 vs 38.58 ± 0.04 °C, respectively). There was no difference in maximum VT between breed or time (P > 01.0). There was no breed difference (P > 0.10) in range of VT, but the range of VT was lower (P < 0.0001) at PM compared to PP1 and PP2 (1.22 ± 0.04 vs 1.77 ± 0.04 vs 1.63 ± 0.04 °C, respectively). These results show that tropically adapted STX ewes have lower body temperatures, as shown by the lower minimal VT which indicates a degree of nighttime cooling, during the postpartum period compared to DRPX ewes in a tropical environment.
513 Late-Breaking: Effects of Dietary Protein Content and Crystalline Amino Acid Supplementation Patterns on Gut Health of Weaned Pigs Raised Under Different Sanitary Conditions
Authors: Lee Jinyoung , Vega Caroline Gonzalez , Htoo John K , Yang Chengbo , Nyachoti Martin
Published: October 2021

The objective of this experiment was to investigate the effects of dietary crude protein (CP) content and crystalline amino acids (CAA) supplementation patterns on the histomorphology, immune response, and microbial metabolites in weaned pigs under clean (CSC) or unclean sanitary conditions (USC). One hundred forty-four piglets (6.35 ± 0.63 kg BW) were assigned to 1 of 3 diets: a high CP (HCP; 21%) and two low CP (LCP; 18%) diets supplemented with 10 crystalline indispensable amino acids (IAA) to meet all IAA requirements or only 6 IAA (Lys, Met, Thr, Trp, Val, and Ile) to meet IAA requirements except for Leu, His, and Phe. Each treatment had 8 replicates per sanitary condition with 3 pigs per pen. The CSC room was cleaned and washed weekly, whereas the USC room remained unwashed throughout the experiment and had sow manure spread in the pens. Data were analyzed using the MIXED procedure of SAS with orthogonal contrasts. Pigs fed the LCP diets had longer (P < 0.05) jejunal villi and higher villus height to crypt depth ratios than those fed the HCP diet. No significant difference is found in histomorphology between pigs fed LCP diets with different CAA supplementation patterns. Pigs raised under USC had greater (P < 0.05) plasma interleukin (IL)-10 and IL-6 concentrations and reduced (P < 0.05) plasma tumor necrosis factor-alpha concentration. Also, the LCP diets resulted in a greater (P < 0.05) plasma IL-10 concentration. Interactions (P < 0.05) between sanitation and dietary CP content were observed for goblet cell density and acetate and total volatile fatty acids contents in the jejunum. In conclusion, CAA supplementation patterns did not affect gut morphology in weaned pigs. Feeding LCP diets to weaned pigs improved gut morphology and microbial metabolites in jejunum under USC and ameliorated systemic inflammation induced by USC.
507 Late-Breaking: Heat Stress and Mitoq Supplementation Impact Skeletal Muscle Mitochondrial Capacities in Pigs
Authors: Wesolowski Lauren T , Guy Chloey P , Mayorga Edith J , Rudolph Tori E , Freestone Alyssa D , Rhoads Robert P , Baumgard Lance H , Selsby Joshua T , White-Springer Sarah H
Published: October 2021

Heat stress can negatively impact pig health and performance but the effects of heat stress on skeletal muscle mitochondrial function are largely unknown. We hypothesized that mitochondrial function and capacity would be impaired in heat stressed (HS) compared to thermoneutral (TN) pigs but mitochondrially-targeted coenzyme Q (MitoQ) supplementation would rescue the impairment. Oxidative portions of the semitendinosus muscle were evaluated from TN and HS gilts receiving no supplementation (CON) or MitoQ for 2 d prior to and during the 24h environmental heat treatment (n = 8 per group). Mitochondrial oxidative phosphorylation (P) and electron transfer (E) capacities were determined via high resolution respirometry and mitochondrial volume density and function were quantified by citrate synthase (CS) and cytochrome c oxidase activities, respectively. Data were analyzed using linear models in SAS v9.4 with fixed effects of heat, MitoQ treatment (trt), and heat×trt interaction. There were trends for the interaction of trt and heat (P≤0.1) on integrative (per mg tissue) and intrinsic (relative to CS) P with complexes I and II (PCI+II), maximum noncoupled E (ECI+II), and E with complex II only (ECII), in which all measures were greater in HS-MitoQ than TN-MitoQ (P≤0.03), but measures did not differ due to HS in CON pigs. The contribution of leak to total E (flux control ratio, FCRLeak) was lesser in HS-MitoQ than HS-CON, TN-CON, and TN-MitoQ (P≤0.02). The FCRPCI was greater (P≤0.05) while the FCRPCI+II was lesser (P=0.01) in TN compared to HS pigs. Finally, the FCRPCI+II was greater (P=0.02) while the FCRECII tended to be lesser (P=0.09) for CON than MitoQ pigs. Neither mitochondrial volume density nor function were affected by HS or MitoQ supplementation. In total, these data indicate improved mitochondrial capacities following heat stress in pigs receiving MitoQ but no difference in mitochondrial capacities in unsupplemented, HS pigs.
516 Late-Breaking: Iturin a Protects the Intestinal Mucosal Integrity Against E. coli Containing the Gene Coding for Heat-stable Enterotoxin B
Authors: Zhou Jia-yi , Liu Zhen-hua , Gao Chunqi , Yan Huichao , Wang Xiu-qi
Published: October 2021

Enterotoxigenic E. coli causes severe infectious diarrhea with high morbidity and mortality in weanling pigs mainly through the production of heat-stable enterotoxins. Iturin A, originally isolated from the insect Hyalophora cecropia, exerts strong antibiotic activity against Gram-positive and Gram-negative bacteria. Thus, our study investigated whether iturin A could protect the intestinal epithelium from the insults of E. coli Rosetta containing the gene coding for heat-stable enterotoxin b (STb-Rosetta). Twenty-eight piglets were divided into four groups and were orally administered PBS (control), 0.16 g/kg BW iturin A, 2 × 109 CFU STb-Rosetta, and 0.16 g/kg BW iturin A + 2 × 109 CFU STb-Rosetta respectively for 8 days. The intestinal epithelial morphology and barrier function were assessed by H&E staining and Ussing chamber, and the growth advantage in enteroids derived from jejunal crypts of piglets in each group was used to evaluate the intestinal stem cell (ISC) activity. The results showed that iturin A increased the average daily gain (ADG) and average daily feed intake (ADFI) of piglets exposed to STb-Rosetta (P < 0.05). Meanwhile, STb-Rosetta-induced decrease in jejunum weight and damage to jejunal morphology and barrier function were significantly improved after iturin A supplementation (P < 0.05). Furthermore, the jejunal crypt cells from piglets in the iturin A + STb-Rosetta group had greater growth advantages of ISCs compared with the STb-Rosetta group, including enteroid forming efficiency, surface area, budding efficiency, and branching coefficient (P < 0.05). Our results indicate that iturin A protects against STb-Rosetta-induced intestinal mucosal injury, which provides an intervention strategy that regulates the function of ISCs in the high turnover-rate crypt-villous axis under ETEC infection. This study was supported by the National Natural Science Foundation of China (31872389, 32072777) and Basic and Applied Basic Research Foundation of Guangdong Province (2019B1515210021).
509 Late-Breaking: Effect of a Sensory Additive on Sow Reproductive Performance
Authors: Davis Nathan , Tsia Tsungcheng , Bass Benjamin , Tedo Gemma , Morais Sofia , Maxwell Charles
Published: October 2021

The addition of a sensory additive to sow diets during the summer improved feed intake during lactation, and litter performance. The aim of this study was to evaluate the impact of the sensory additive on sow lactation performance during cooler temperatures. Three consecutive groups (n = 61 total) of sows were farrowed during winter (October, December and January). Sows were weighed, and back fat depth was measured, at 110 d of gestation prior to entering the lactation room, and again at weaning. The sows were sorted by parity, and then allotted by BW at d 110 to Control or 0.075% sensory additive (Luctamax® SowVive, Lucta S.A., Spain). Experimental diets were offered upon entry to the lactation room and fed through weaning. Feed disappearance was recorded every three days. Sows were fed 2.72 kg/head/day until farrowing, and then allowed to eat ad libitum from 24 hours post-farrowing until weaning. Data were analyzed using the PROC MIXED procedure of SAS as an RCBD with treatment as the fixed effect and group as a random effect. No differences were observed on sows feed intake (P > 0.4), 10th rib backfat thickness change (P = 0.632) and body weight change from d 110 of gestation to weaning (P = 0.65, Table 1). Sows fed the sensory additive lowered preweaning mortality by 4.9% (P = 0.051), and weaned an additional 1.42 piglets (P = 0.026) with similar weaning weights (P = 0.86) when compared to control. In conclusion, in the current study, lactation diets supplemented with a sensory additive improved litter performance and helped maintain sow body condition.
475 The Effect of Increasing Total Sulfur Amino Acids to Lysine Level and Methionine Source on Growth Performance and Oxidative Parameters of Nursery Pigs Fed Oxidized Soybean Oil
Authors: Acosta Jesus A , Chen Ju Xing , Hancock Deana , Vásquez-Añón Mercedes
Published: October 2021

Total sulfur amino acids (TSAA): Lys level and Met source effects on growth performance and oxidative status were evaluated in nursery pigs fed oxidized soybean-oil. A total of 240 weaned pigs (BW=5.84± 0.96kg) were blocked by BW and randomly allotted to 60 pens. Treatments included a positive control containing fresh soybean-oil (PC) and 4 peroxidized soybean-oil treatments in a 2×2 factorial of 2 Met sources (DL-Met vs. 2-hydroxy-4-(methylthio)butanoate [HMTBa]) and 2 standardized ileal digestible TSAA: Lys levels (L1=0.58 vs. L2=0.65). Diets were fed for 42d. One pig per pen was euthanized at d42 for tissue analyses. Data were analyzed using PROC MIXED procedure of SAS. TSAA: Lys ratio did not affect ADG and ADFI. Met source did not affect ADG. HMTBa tended to increase ADFI compared to DL-Met (P = 0.08). There was a tendency for interaction between TSAA: Lys level and Met source for G: F (P = 0.07); pigs fed HMTBa-L1 tended to have decreased G: F compared to HMTBa-L2 and DL-Met-L1-L2. HMTBa had increased liver total antioxidant status (TAS) compared to DL-Met (P = 0.02). There was no TSAA:Lys level effect on TAS. Comparing PC to peroxidized treatments: pigs fed HMTBa-L1 and DL-Met-L1 tended to have decreased ADG (P ≤ 0.10) and DL-Met-L2 had decreased ADG (P < 0.05) than PC. HMTBa-L2 was similar to PC. Pigs fed DL-Met-L1 had decreased (P < 0.05) and DL-Met-L2 tended to have decreased ADFI (P ≤ 0.10) than PC. HMTBa-L1-L2 were similar to PC. All peroxidized treatments had similar G:F compared to PC. Pigs fed DL-Met-L2 tended to have decreased TAS compared to PC (P ≤ 0.10), but PC was similar to pigs fed DL-Met-L1 and HMTBa-L1-L2. In conclusion, under an oxidative challenge, HMTBa, at a TSAA: Lys ratio of 0.65, maintained nursery pigs’ growth performance and oxidative status.
480 Current Knowledge Gaps in Swine Nutrition
Authors: Haydon Keith D
Published: October 2021

Swine nutrition has advanced greatly during my tenure in the industry; from balancing on crude protein using a Pearson Square to SID amino acid ratios, NE and digestible/available Ca and P. However, practicing nutritionist are still challenged with many unknowns such as how to minimize environmental footprint, feeding during health challenges all while trying to minimize feed cost. We now have 8 of the 10 essential AA commercially available; why can we still not maintain performance levels when feeding very low crude protein levels? The NE system has provided additional precision, but we have gaps particularly when dealing with high fiber ingredients. Do we even know how to correctly measure fiber components, let alone what is their energy contribution to the pig? Is it time for a productive energy system focused on carcass gain? We have long known the negative performance impacts of activating the immune system, but yet we understand essentially nothing on how to modify diets during a health challenge event. We have made tremendous strides in microbiome analyses. Do we know to how feed/manage the biome for optimal GI health? Enzyme technology has advanced greatly over the past decade, with phytase as common in the diet as salt. However, we have yet to understand how to get consistent performance responses with the vast number of carbohydrases, proteinases and lipases currently available. While we have come far, but we still have many challenges. However, we see great opportunities for swine nutrition community to continue to provide solutions in the coming years to meet these new challenges.
493 Awardee Talk: Filling Knowledge Gaps in Quantitative Genetics Through Online Education
Authors: Lewis Ronald M
Published: October 2021

The genomic revolution has been compared to the industrial revolution, with caveats that it has happened faster and will have a far greater impact on our lives. Interpreting and using knowledge emanating from this revolution requires unique skills. Providing education in quantitative genetics that keeps pace with that need, particularly where expertise and funds are limited, remains challenging. One solution is sharing resources and capacities across-institutions to deliver high-quality instruction online. Beginning with 4 universities in 2007, expanding to 7 in 2012, a multi-state U.S. consortium built an online Masters-level curriculum in quantitative genetics and genomics. Sixteen courses were developed, each revised based on review by 2 academic peers and an instructional designer. Over 330 students from 34 U.S. and 5 international institutions have completed over 1,200 credit hours. Anonymous student feedback has been overwhelmingly positive. The curriculum was established with funding from two USDA-NIFA Higher Education Challenge grants. In 2015 it was integrated into AG*IDEA, a national consortium offering online courses in agriculture. A permanent infrastructure was thereby established with students earning formal academic credit. Only students matriculated at one of 19 AG*IDEA member universities can enroll directly, sadly limiting access, especially to international students. A potential constraint of online instruction is a disconnect with students. In some courses, a blended-learning format has been introduced with a weekly virtual recitation session. To increase engagement, an experiential learning opportunity also is offered. This entails a web-based simulation game—CyberSheep—where students apply genetic principles to a virtual breeding cooperative. Additionally, CyberSheep is typically played by 400 undergraduate students at 5 U.S. universities each academic term, contributing to their learning of animal genetics. Outcomes of these initiatives demonstrate that online training can be an effective tool to fill knowledge gaps in quantitative genetics, with opportunity to reach a wider audience.
PSIV-B-29 Evaluating the effect of different feeding strategies in feeding behavior through a novel behavior index integrating several components of the feeding behavior of finishing pigs
Authors: Salgado Hector H , Méthot Steve , Remus Aline , Letourneau-Montminy Marie-Pierre , Pomar Candido
Published: October 2021

Feeding behavior is an area of study that links the nutritional and behavioral sciences. However, describing the feeding behavior of pigs is difficult given the diversity of variables available and the large day-to-day intra-animal variation. The objectives of this study were to create an index integrating information from several components of feeding behavior that accounts for intra-animal variation, and to evaluate the capability of this index to study the impact of different feeding strategies in pigs’ feeding behavior. Feed intake information from 160 pigs during the last 28 days of the finishing phase from 3 datasets was used. For each pig, the sum of the absolute values of the deviation areas between the regression line of the relative cumulative feed intake and the observed cumulative feed intake was used to calculate the weekly index measuring the irregularity of feed intake (IIFI). Spearman’s correlations of IIFI with the number of daily meals (r = -0.42; P < 0.001), meal duration (r = 0.38; P < 0.01), and feed intake per meal (r = 0.41; P < 0.01) indicate that pigs with high IIFI have fewer meals of longer duration and higher feed intake compared to pigs with low IIFI. Analysis of variance in datasets 1 and 2 showed that moving from conventional to feeding precision systems does not interfere with the feeding behavior of finishing pigs (P > 0.05). In dataset 3, pig feeding behavior was more regular in control diets than for pigs fed fibrous diets (IIFI; 164 vs. 197, respectively; P < 0.05). Additionally, IIFI was smaller in pigs fed canola than in pigs fed wheat by-product diets. These results indicate that IIFI integrates information from several components of the feeding behavior of pigs and demonstrates its potential to evaluate the effect of feeding strategies on feeding behavior.
PSI-B-22 Analysis of the development of high-quality corpus luteum of the ovaries in recipient heifers
Authors: Shcherbak Oksana , Sidashova Svitlana , Popova Iryna , Kovtun Svitlana
Published: October 2021

For effective embryo transplants, it is important to select among the repair heifers recipients with high-quality corpus luteum, corresponding in morphometric parameters to the development of 7–8 days of the estrous cycle. It is known that ipsilateral embryo transplants are more effective than contralateral ones. Therefore, for the effective organization of groups of recipients, it is necessary to have a prognosis for the development of corpus luteum differentially on the left or right ovary. The data on the ratio of these indicators have been insufficiently studied. To resolve this issue, sexually mature repair heifers of the Ukrainian red dairy breed (n = 201) were rectally examined during spontaneous (n = 92) and induced (n = 109) cycles (first time on day 0, again - on 7–8 day). In the group of heifers with a spontaneous cycle, it was found that after ovulation of the follicle on the right ovary, high-quality yellow bodies are formed in 71.4% of individuals, and premature lysis of the yellow bodies was found in 28.6%. On the left ovary, respectively -58.3% and 41.7%. In the induced group of recipients, after ovulation, high-quality yellow bodies were formed on the right ovary in 65.2% of individuals, prematurely lysed yellow bodies - in 34.8%; on the left, respectively - 55.8 and 44.2%. The study found that the right pair gonad is functionally dominant in repair heifers. In induced cycles, premature lysis of the corpus luteum (more by 6.28%; P < 0.001) occurs more often than spontaneous ones. The data obtained reveal the morphological and functional patterns of development of high-quality corpus luteum of the ovaries, the presence of which undoubtedly increases the level of engraftment of preimplantation embryos in cattle.
PSVI-17 Dissimilarities in thyroid profiles and pregnancy rates in dairy cows with different polymorphic variants of the DIO1 gene
Authors: Aleynikova Olga V , Mityashova Olga S , Kostyunina Olga V , Bardukov Nikolay V , Lebedeva Irina Y
Published: October 2021

Thyroid hormones are implicated in regulation of the reproductive function in cattle. In turn, thyroid metabolism is determined by the activity of different types deiodinases. Our research was aimed to compare post-insemination thyroid profiles and pregnancy rates in dairy cows with different SNP genotypes in the deiodinase gene of the first type (DIO1). Thirty lactating Russian Black Pied cows were synchronized using the Ovsynch protocol and artificially inseminated (AI). Blood samples from the cows were collected on Days 0, 7, 14, 21, and 33 after AI. Hormonal levels in the serum were measured by ELISA. Pregnancy was confirmed by progesterone concentrations and ultrasonography. Genetic variants for the DIO1 gene were tested by RT-PCR and polymorphism at position 13149 (NC_037330) was found. The occurrence frequency of cows with genotypes CC, CG, and GG was 43.3, 33.3, and 23.3 %, respectively. A proportion of pregnant cows in the CC group was higher than in the CG group (84.6 vs. 40.0%, P < 0.05) and tended to be higher than in the GG group (42.9%). The concentration of triiodothyronine (T3) in the blood of CC animals did not change during the studied period, whereas that in CG animals decreased between Days 0 and 14 (from 1.60±0.21 to 1.10±0.22 nmol/L, P < 0.05). Concurrently, the T3 concentration on Day 0 was 1.4 times lower (P < 0.05) in the CC group than in the CG group. Furthermore, the level of reverse T3 on Day 7 in the GG group was 1.3 times higher (P < 0.05) than in the CC or CG groups. Thus, cows with DIO1 gene CC genotype have a higher reproductive ability than cows with CG or GG genotypes, which may be due to peculiarities of thyroid profiles during the first two weeks of pregnancy. The study was supported by Russian Ministry of Science and Higher Education (0445-2021-0004).
PSVI-1 Evaluation of the synergistic effect of iron and an aqueous extract of oak bark on rumen microbiome of cattle
Authors: Atlanderova Kseniya , Duskaev Galimzhan
Published: October 2021

The search for new substances, alternatives to feed antibiotics in animal husbandry, is relevant in connection with the development of antibiotic resistance of pathogenic microorganisms. Substances of plant and mineral origin including nanoforms are of particular interest. The experiment studied the synergistic effect of iron (Fe; d = 80 nm) and an aqueous extract of oak bark (Ex; 1:10) on the microbiome of ruminal fluid of bulls (age 14 months, n = 5). Group I - control; Group II - Ex (0.6 ml / kg / lm); Group III - Fe (0.1 mg/kg/FM) with Ex in the same dosage. The collection of ruminal fluid was performed through a chronic ruminal fistula. Metagenomic analysis of cicatricial fluid was performed on a MiSeq device (Illumina, USA). Analysis of the data showed that the Bacteria domain is more influenced by Ex, there is a decrease by 27.0% (P ≤ 0.05), while in group III by 3.0% relative to the control. At the phylum level, Bacteroidetes and Firmicutes had the greatest importance, in group I their ratio was 39.3 and 54.7%, in group II - 37.7 and 56.4%, in group III - 46.1 and 47.0% of the total the number of bacteria. The use of Ex increases the amount of Bacilli by 14.7 and 13.4 (P ≤ 0.05) % relative to groups I and III. The introduction of the composition Ex and Fe increases Lachnospiraceae - 15.0% and Ruminococcaceae - 8.1% of the total number of microorganisms and reduces Streptococcus relative to other groups by 1.3 and 14.9% (P ≤ 0.05). Thus, the combined use of Ex and Fe affects the numerical value of microorganisms, as well as their ratio in the rumen through inhibition. At the same time, the data obtained require further research, including in vivo experiments. This research was performed with financial support from the RSF (20-16-00088).
PSVI-13 Changes in the taxonomic composition of the rumen of ruminants when introducing fat components into the diet
Authors: Shoshina Oksana , Shejjda Elena , Shajahmetova Elvina , Lebedev Svyatoslav , Duskaev Galimzhan , Kvan Olga
Published: October 2021

Fats are concentrated energy sources for cattle growth, but their inclusion in the diet has a huge impact on the taxonomic composition of the rumen. The aim of this study was to evaluate the effect of supplemental linseed oil administration (3% of dry matter (DM) diet) on microbiota and DM digestibility in the rumen. The studies carried out on Kazakh white-headed bull calves, aged 15 months, with chronic rumen fistula (diet - 70% grassland hay, 30% barley grain). Dietary dry matter digestibility (in-vitro in an artificial rumen system, for 24 hours) analyzed daily for 10 days, and microflora (fluid-bound) analyzed using high-throughput 16SrRNA gene sequencing (Illumina). Inclusion of LO showed a slight 3.5% increase in DM digestibility compared to C (52.0% versus 53.9%). The taxonomic composition of the rumen microbiocenosis in group C was mainly represented by the phylum Firmicutes (54.7%) and Bacteroidetes (39.3%), while other phylum numbers were less than 2%. When LO was injected, the dominance of phylum Bacteroidetes (64.2%), phylum Firmicutes (19.3%), and Verrucomicrobia (5.3%) was noted. The calculation of the Shannon index showed an increase in species diversity in the group that received LO. It was H’= 0.76, while in CH’= 0.42. The Simpson dominance index in group C was 0.44, in the group receiving LOD = 0.54. The obtained data show a positive effect. The linseed oil allow to increase the biodiversity of the rumen microbiome and the digestibility of DM feed, which can be used in fattening young cattle. This research performed with financial support from the project 0761-2019-0005.