bluuebunny/crossref_metadata_2025 huggingface dataset:
79 Effects of dietary net energy and neutral detergent fiber levels on growth performance and carcass characteristics of growing finishing pigs
Authors: Lu Ning , Vier Carine , Cast Wayne , Orlando Uislei , Gonçalves Márcio , Zhou Xun , Young Malachy
Published: November 2020

Our objective was to determine the effects of feeding different net energy (NE) and neutral detergent fiber (NDF) on performance of growing-finishing pigs from 30- to 135-kg. A total of 2,058 barrows and gilts (PIC 380×Camborough, initial BW 33.4±0.60 kg) were used in a 97-d growth trial with 21 pigs per pen and 14 pens per treatment in a randomized complete block design. Treatments were formulated to contain 2.11, 2.21, 2.32, 2.42, 2.53, 2.63, and 2.73 Mcal NE/kg; and 24.2, 19.7, 15.1, 10.6, 10.2, 9.8, and 9.5% NDF throughout the experiment. Wheat, wheat byproducts, barley, rye, peas, fababeans, and canola oil were used with NRC (2012) loading values to achieve the treatments. Dietary lysine levels were set to meet PIC2016 lysine requirements for finishing gilts. Experimental data were analyzed using generalized linear mixed models and linear and quadratic polynomial contrasts were built with pen as the experimental unit. Increasing NE or decreasing NDF improved (linear and quadratic, P< 0.05) average daily gain (ADG), gain-to-feed ratio (G:F), carcass ADG, and carcass G:F (Table 1); but reduced (linear and quadratic, P< 0.05) average daily feed intake (ADFI). Comparing to pigs fed 2.42 Mcal/kg diet (energy equivalent to a corn-soybean meal diet), even though those fed 2.11 Mcal/kg diet had 8.7% increment on ADFI, daily NE intake was still 5.4% less. Hot carcass weight, backfat depth, and carcass yield increased (linear and quadratic, P< 0.05) and lean yield decreased (linear and quadratic, P< 0.05) with increasing dietary NE and decreasing NDF. No evidence for differences (P >0.10) were observed for loin depth. Removal and mortality rate was reduced (quadratic, P< 0.05) with increasing dietary NE and decreasing dietary NDF. In summary, increasing dietary NE while reducing dietary NDF resulted in improvements on growth performance, carcass characteristics, and removal and mortality rate.
167 Analysis of variation in net energy prediction of feed ingredients fed to swine
Authors: Aldenhoven Noud , Gutierrez Nestor A , Jaworski Neil W , van Laar Harmen
Published: November 2020

Precision of NRC and CVB net energy (NE) prediction equations was investigated by taking into account natural and analyzed variation of the chemical components (e.g., moisture, protein, starch, NDF, ADF, sugars, fat) for six feed ingredients used in swine diets. Precision is defined as the variation of the NE formula given the variation of its chemical components. Stochastic variables were substituted for the component values and the variation in nutrient composition was algebraically, not statistically, propagated to the NE value for both equations. This was done both, for the naturally occurring variation as published in CVB, and for a range of analytical variation values associated with wet chemistry analysis based on a range of values obtained by published ring-tests. Consequently, variation of the NE value and the contribution to variation of each chemical component in the NE equation were calculated. The variation of NE prediction using CVB is lower than using NRC. The main contributor for increased variation of the NRC NE is the NDF fraction. Whereas in CVB, this is replaced by the NSP fraction which is computed as a residue from the other chemical component values, forcing the sum of the composition to add to 100%. Furthermore, it was determined that analyzing all nutrients, in particular NDF and ADF, did not always reduce the variation of the NE equations. In conclusion, analytical variation, especially fiber analysis, must be critically examined and, preferably, sum to 100% to increase precision in the prediction of NE in feed ingredients. Otherwise, the use of a residue fraction, although nutritionally difficult to justify, actually increased precision in the NE equations. Note that it is unfair to compare both NE formulas based on precision alone. An interesting follow-up question is to take accuracy also into account when comparing CVB and NRC.
208 Do prediction equations with high R-squared in low sample size studies have high predictive ability?
Authors: Serão Nick , Petry Amy
Published: November 2020

The use of R-squared as a measurement of prediction in regression is a common practice in animal nutrition studies. Generally, studies use data used to estimate the prediction equation to calculate the R-squared of the equation, which does not represent prediction. The objective was to evaluate the predictive ability of prediction equations using independent datasets. Data were simulated in based on previously reported prediction equations for ADG in nursery pigs: 152 + 195(SID_Lysine%). A completely randomized design with SID_Lysine% levels of 1.2, 1.3, and 1.4% was used. Data were simulated for three CVs representing low, moderate, and high variation in ADG, for low number of replicates per treatment (RepTreat; 4 to 10, every 2). Data were simulated and analyses performed 300 times for each scenario. Prediction equations were estimated for each scenario when significant effect of SID_Lysine% was followed by a significant orthogonal contrast testing the linear effect of SID_Lysine% (P-value< 0.05), and their R-squared were calculated (R2_training). The prediction equation was used to test the fit of the other datasets, and their R-squared were calculated and averaged for each prediction equation (R2_prediction). The relationship between R2_training and R2_prediction was assessed through Spearmen’s correlation and regression of R2_prediction on R2_training, across scenarios. The R2_training and R2_prediction averages were similar with 94.5% and 93.9%, 66.0% and 63.5%, and 46.1% and 42.7%, for low, moderate, and high CVs, respectively. The rank-correlation between R2_training and R2_prediction increased with CV: 0.23, 0.67, and 0.77, for low, moderate, and high CV, respectively. From regression analysis of R2_prediction on R2_training, as CV increased bias increased, with prediction equations with greater R2_training overestimating R2_prediction, and prediction equations with lower R2_training underestimating R2_prediction. These results indicate that in small sample sizes (≤10 per treatment), as CV increases, models with high R-squared are overestimated, and are not as predictable.
171 Young Scholar Presentation: Dietary supplementation of Bacillus subtilis influenced intestinal health and metabolomic profiles of weaned pigs experimentally infected with a pathogenic E. coli
Authors: Kim Kwangwook , He Yijie , Xiong Xia , Ehrlich Amy , Li Xunde , Raybould Helen , Atwill Edward Robert , Maga Elizabeth , Jørgensen Jens , Liu Yanhong
Published: November 2020

There is growing evidence to support the beneficial effects of supplementing direct-fed microbials (DFM) on performance, health status, and immune responses of weaned pigs. Therefore, the objective of this study was to investigate dietary supplementation of Bacillus subtilis (DSM 25841) on growth performance, diarrhea, gut permeability, immunity and metabolomic profiles of weaned pigs experimentally infected with a pathogenic F18 Escherichia coli (E. coli). E. coli infection reduced (P < 0.05) growth performance and intestinal villi height, whereas increased (P < 0.05) diarrhea and permeability in the jejunum compared with non-challenged control. Supplementation of Bacillus subtilis linearly enhanced average daily gain of E. coli infected pigs (d 0 to 5 post-inoculation (PI), P < 0.05; d 0 to 11 PI, P = 0.058). Inclusion of high dose Bacillus subtilis reduced (P < 0.05) jejunal permeability on d 5 and d 11 PI compared with the E. coli challenged control. E. coli challenged control pigs up-regulated (P < 0.05) the mRNA expression of SLC5A10 and MUC2 on d 5 PI, but down-regulated (P < 0.05) expression of SLC5A10, MUC2, and CLDN1 on d 11 PI in jejunal mucosa. Supplementation of Bacillus subtilis linearly up-regulated (P < 0.05) the mRNA expression of CFTR and ZO1 on d 5 PI and SLC5A10 and MUC2 on d 11 PI in jejunal mucosa of E. coli infected pigs. E. coli infection increased (P < 0.05) the mRNA expression of several immune genes in the ileal mucosa, while inclusion of Bacillus subtilis linearly down-regulated gene expression of IL1A on d 5 PI (P = 0.07) and IL6 on d 11 PI (P < 0.05) in ileal mucosa of E. coli infected pigs. Supplementation of Bacillus subtilis modified (Fold change > 1.5; FDR < 0.20) metabolomic profiles in colon digesta, related to pathogenesis and amino acid metabolism. In conclusion, supplementation of Bacillus subtilis enhanced growth rate, improved gut health, and modified metabolomic profiles of weaned pigs experimentally infected with a pathogenic E. coli.
181 Effects of Aspergillus oryzae prebiotic on energy and nutrient digestibility of growing pigs
Authors: Zhu Jinlong , Shurson Gerald C , Whitacre Lynsey , Ipharraguerre Ignacio R , Urriola Pedro E
Published: November 2020

The objective of this study was to determine the effects of an Aspergillus oryzae prebiotic (AOP, Amaferm®) on nutrient digestibility in growing pigs fed high fiber diets. Eighteen growing barrows (initial BW = 50.60 ± 4.90 kg) were surgically equipped with a T-cannula at the distal ileum. Three diets were formulated by including 29.65% corn-distillers dried grains with solubles (DDGS), 36.65% rice bran (RB) or 24.59% wheat middlings (WM) in corn and soybean meal-based diets to meet nutrient requirements for 50 to 75 kg growing pigs. Three additional diets were formulated by supplementing 0.05% AOP at the expense of corn in DDGS (DDGS + AOP), RB (RB + AOP), and wheat middlings (WM + AOP) diets. Pigs were allotted randomly to a triplicated 6 × 2 Youden square design with 6 diets and 2 successive periods. Feces and ileal digesta were collected for 2 d after a 21 d adaptation period, and nutrient content was analyzed to calculate apparent total tract digestibility (ATTD) and apparent ileal digestibility (AID). Standardized ileal digestibility (SID) of amino acids was calculated by correcting AID with basal endogenous amino acid losses determined from the same set of pigs. Supplementation of 0.05% AOP increased (P < 0.05) ATTD of DM, GE, CP, NDF, and ash in DDGS, RB, and WM diets. Diet DE was 35 kcal/kg greater (P < 0.05) in pigs fed AOP supplemented diets compared with those fed diets without AOP. Pigs fed DDGS+AOP diet had greater (P < 0.05) AID of ether extract compared to those fed DDGS diet. However, supplementation of AOP did not (P > 0.05) affect AID of GE, DM, CP, NDF, ash or SID of amino acids. In conclusion, supplementation of AOP in high fiber diets containing DDGS, RB, or WM increased total tract energy value and nutrient digestibility.
184 Effects of phytogenic feed additives and Ractopamine HCl on growth performance and carcass characteristics in grow-finish pigs
Authors: Zheng Lan , Ramirez Shelby , Raj Murugesan G , Hendel Erika , Tacconi Antonia
Published: November 2020

The objective of this experiment was to evaluate the effects of a phytogenic feed additive (PFA-F, Digestarom® Finish, BIOMIN America Inc.) on growth performance and carcass characteristics of grow-finish pigs compared to a control, two commercial PFA products (A and B), and a ractopamine feeding program. Two hundred pigs (Choice Genetics, BW = 24.88 ± 0.53 kg) were randomly allotted to 5 dietary treatments and fed diets based on 4 dietary phases. Dietary treatments consisted of: CON, a corn-soybean meal based diet; RAC, 4.5 ppm Ractopamine HCl was added into CON for the last 21 d; PFA-A (commercial product A) was added into CON when pigs reached 90 kg of BW; PFA-B (commercial product B) was added into CON from 75 kg of BW; PFA-F was added into CON from the beginning (25 kg of BW). Body weight and feed disappearance were recorded at the end of each phase, and carcass traits were measured at the end of the trial. Data were analyzed using the Mixed procedure of SAS. No differences were observed from phase 1 to phase 3 among the treatments. At the end of phase 4, RAC had a higher (P < 0.05) BW than the CON, PFA-A, or PFA-B (127.5 vs.123.1 or 121.5 kg); however, no difference between RAC and PFA-F in BW (127.5 vs.124.0 kg) was found. Pigs fed PFA-F had a higher (P < 0.05) hot carcass weight than those of fed CON or PFA-B (93.0 vs. 88.8 or 88.8 kg). No differences were found in lean percentage, fat depth, and loin depth among the treatments. In conclusion, PFA-F (Digestarom Finish) supplementation resulted in similar growth performance and hot carcass weight when compared to a Ractopamine feeding program during the grow-finish period, whereas either commercial product A or B had significantly lower performance than feeding Ractopamine.
261 Increasing dietary amylose reduces rate of starch digestion and increases microbial fermentation in weaned pigs
Authors: Tan F P Y , Wang L F , Beltranena E , Zijlstra R T
Published: November 2020

Beneficial effects of SCFA in modulating gut health stimulated interest on dietary strategies to increase intestinal microbial activity and digesta SCFA. Amylose has lower apparent ileal digestibility (AID) than amylopectin. In the large intestine, undigested starch is fermented by microbes producing SCFA. The objective was to determine effects of increasing dietary amylose on starch flow and metabolite profile along the intestinal tract in weaned pigs. Weaned pigs (n=32; initial BW, 8.4 kg) were randomly allocated to 4 diets containing 67% starch with 0, 20, 35, or 70% amylose in a randomized complete block design. On day 21, pigs were euthanized to collect digesta and feces for evaluating starch digestion and metabolite profiles. Apparent hindgut fermentation (AHF) was calculated as apparent total tract digestibility minus AID. Feed intake was 12% lower (P < 0.05) and growth rate was 18% lower (P < 0.05) for pigs fed 70% amylose than pigs fed 0, 20, or 35% amylose. Feed efficiency was greatest (P < 0.05) for pigs fed with 35% amylose. The AID of starch was 44% lower (P < 0.05) in pigs fed 70% amylose. Starch was completely digested by the proximal colon in pigs fed 0, 20, or 35% amylose, but AHF of starch was 14% greater (P < 0.05) in pigs fed 70% amylose. Increasing dietary amylose did not alter digesta SCFA in the small intestine, but increased (P < 0.05) digesta SCFA in the cecum, specifically acetate and total SCFA, and increased (P < 0.05) propionate and valerate in all sections of the colon. In conclusion, increasing dietary amylose in weaned pigs stimulated hindgut fermentation of starch with a corresponding increase in digesta total SCFA in the cecum and colon. Optimizing dietary amylose may exert its effect as dietary prebiotic while promoting an optimal growth rate in young pigs.
274 Determination of phosphorus requirement of lactating sows based on 24-hour urinary phosphorus excretion
Authors: Grez-Capdeville Mariola , Lu Ning , Orlando Uislei , Bergstrom Jon , Crenshaw Thomas D
Published: November 2020

The objective was to determine phosphorus (P) requirement of lactating sows using 24-hour urinary P excretion as the response criteria. The underlying assumption was that urinary P remains low and constant until the requirements are met then increases as P consumption increases. Thirty-six crossbred PIC Camborough sows (parity 3 to 7) were randomly assigned to 1 of 6 corn-soybean-meal diets with increasing dietary total P (tP) levels (0.40, 0.48, 0.56, 0.64, 0.72, and 0.80%) and a constant calcium (Ca) to tP ratio (1.25:1). Diets were fed from breeding until the end of lactation. Urine and blood samples were collected on days 4 and 18 of lactation and analyzed for P and Ca concentrations. Data were analyzed using MIXED and NLIN procedures of SAS. Phosphorus requirements were estimated using a broken-line regression model. Plasma Ca (ranging from 12.1 to 10.3 mg/dL) was not affected by dietary treatments, and was maintained within the normal physiological range on day 4 and 18 of lactation. Plasma P (ranging from 2.9 to 6.4 mg/dL) linearly increased (P < 0.05) with increasing dietary tP levels on day 4 and 18 of lactation. Only sows fed the 0.40% tP diet failed to maintain plasma P concentrations within the normal physiological range. Clinical signs of P and Ca deficiencies were not observed. Differences in sow and litter performance among treatments were not detected. A nonlinear response of urinary P excretion to dietary P intake was observed. Based on a broken-line linear model fit to 24-hour urinary P excretion, minimum tP requirements of sows at day 4 and 18 of lactation were 0.47 and 0.54%, respectively. In conclusion, 24-hour urine P excretion provided sensitive criteria for estimates of tP requirements in lactating sows. Efforts to adjust heteroscedasticity for animals fed dietary P above the estimated requirement need further evaluation.
273 Impact of either high energy or high SID Lys:ME on Parity 1 performance in lactation
Authors: McCormick Katherine A , Johnston Michael E , Petersen Grant I
Published: November 2020

Primiparous sows may have difficulty consuming sufficient feed during lactation to account for energy lost in milk production, development, and body maintenance. Addition of higher energy and/or higher standardized ileal digestible (SID) Lys may improve gilt and litter performance. One hundred seventy-two primiparous DNA F1 females were randomly allotted within breeding/farrowing group, previous treatment, and entry weight at farrowing to one of four dietary treatments. Treatments were arranged in a 2 x 2 factorial with energy (3186 and 3332 kcal/kg ME) and SID lysine (1.15 and 1.30%). Sows were weighed upon entry and exit of the farrowing room. Feed disappearance was calculated as the total amount of feed provided to the sow during lactation. A post-farrow weight model was utilized to assess true weight loss in lactation. Litters were standardized within 24 h of birth, and individual pig birth and weaning weights were recorded. The wean to estrus interval was also measured. Data were analyzed as a randomized complete block design with the fixed effect of treatment and the random effect of replicate. Addition of high energy and/or high lysine did not impact (P > 0.10) piglet wean weight or sow average daily feed intake. High energy diets reduced (P < 0.05) sow weight loss post-farrow by 15.5% from 8.75 to 7.39 kg. High SID lysine diets reduced (P < 0.05) number of sows not expressing estrus by day 9 post-wean from 13.0 to 7.7% of sows eligible for insemination. The high SID lysine diets targeted 70 g/d and led to an increase (P < 0.05) of 10.3% of sows displaying estrus on day 4 and 5. These data show that higher levels of SID lysine to target 70 g/d in lactation can improve wean to estrus interval, and potentially decrease non-productive sow days.
279 Evaluation of the NRC (2012) model in estimating standard maintenance metabolizable energy requirement of PIC sows during mid-gestation
Authors: Knauer Mark , Purvis Jerry , Lu Ning , Orlando Uislei , Vier Carine , Cast Wayne
Published: November 2020

The objective was to evaluate the NRC (2012) model in predicting standard maintenance metabolizable energy (MEm) of PIC sows during mid-gestation. A total of 201 PIC Camborough sows (parity 1 to 10) were randomly assigned to 1 of 4 treatments in a complete randomized design between day 36 and 46 post-breeding. Treatments consisted of feeding sows with daily feed allowances to meet 80, 90, 100 or 110% of MEm calculated as MEm, kcal/day = 100 × (body weight)0.75. A common corn-soybean meal-based diet with 3,302 kcal of ME/kg and 0.61% standardized ileal digestible lysine was fed for 28 days. Sow body weight (BW) and sow body condition caliper score (CS) were captured at day 0, 14 and 28. Data were analyzed with PROC GLM of SAS with sow as experimental unit. Average sow parity and feed allowance were 4.2 and 1.79 kg/day, respectively. Average sow BW and sow CS at day 0, 14 and 28 were 234, 233 and 242 kg and 14.9, 14.9 and 14.8, respectively. Increasing feed allowances to meet 80 to 110% of MEm requirement increased (linear, P< 0.01) average daily gain (ADG; 0.100, 0.259, 0.417 and 0.440 kg/d, respectively). The estimated regression equation was ADG, kg/day = -0.83 + 1.193 × MEm, estimating the MEm to maintain BW was below 80% of NRC (2012) estimate. Caliper score change (CSC) increased (linear, P< 0.01) with increasing feed allowances to meet 80 to 110% of MEm requirement (-0.78, -0.26, 0.13, and 0.35, respectively). The estimated regression equation was CSC = -3.73 + 3.78 × MEm, estimating the MEm to maintain CS at 98.7% of NRC (2012) estimate. In summary, results showed that the MEm to maintain BW and CS for PIC sows during mid-gestation was below 80% and at 98.7%, respectively, of NRC (2012) estimated requirement.
271 Maternal transfer of phytogenic compounds supplemented during gestation and/or lactation of hyperprolific sows: effects on reproductive performance and colostrum-milk features
Authors: Reyes-Camacho David , Pérez José Francisco , Aumiller Tobias , van der Klis Jan Dirk , Solà-Oriol David
Published: November 2020

Improvement on litter size in hyperprolific sows has decreased piglet’s birthweight and increased newborn mortality. Besides, no significant changes have been reported on the sow colostrum-milk composition. Phytogenic compounds (PC) are phytochemicals that may promote swine health and performance. This study aims to evaluate the effects of PC maternal transfer on reproductive and litter performance, and sows colostrum-milk features. Eighty-one hyperprolific sows were assigned to 3 treatments. Control sows were unsupplemented, whereas treated sows were offered supplemented diets with 1 g/kg of a blend of PC (BPC) during gestation and lactation (GL), or only lactation (L). Maternal transfer of PC into the amniotic fluid and milk were determined by using gas chromatography and mass spectrometry. Farrowing and litter performance were monitored. Moreover, the colostrum and milk composition, and milk inhibitory activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Lactobacillus plantarum, and Candida albicans were determined. Data were analyzed with ANOVA by using the MIXED procedure of SAS, while, Fisher test for milk bacteriostatic activity was performed. Thymol, anethole, linalool, and eucalyptol were transferred via amniotic liquid, whereas, p-cymene, thymol, and anethole were also transferred into the milk (P < 0.05). No differences (P > 0.05) were observed on number of total born piglets (C 17.14, L 17.75, and GL 19.16). However, BPC supplementation increased (P = 0.007) the piglets born alive (C 14.53, L 15.33, and GL 17.60), while reduced (P = 0.031) the newborn piglets BW. Colostrum protein in GL and milk fat contents in L and GL (Table 1) were increased (P < 0.05). Milk of GL showed inhibitory activity (P < 0.05) against Bacillus subtilis and Staphylococcus aureus. In conclusion, dietary BPC supplementation during gestation and/or lactation increased the number of piglets born alive, enhanced both the colostrum-milk composition, and the milk inhibitory activity against well-known pathogens.
28 Steroid hormones are differentially abundant in sows with elevated risk for pelvic organ prolapse during late gestation
Authors: Kiefer Zoe , Chipman Amanda , Studer Jamie M , Gianluppi Rafael Dal Forno , Keating Aileen F , Gabler Nicholas , Ross Jason W
Published: November 2020

Sow mortality, as the result of pelvic organ prolapse (POP), has increased during recent years in the U.S. swine industry and continues to worsen. The objective of this study was to identify putative biological factors associated with POP risk. We hypothesized sows differing in POP risk would differ in serum factors and steroid hormone profiles. Perineal scores (PS) were assigned to sows (n=2865) during late gestation (days 107-116) to assess POP risk. Sows assigned a PS1 had a presumed low risk of POP while those assigned a PS2 or PS3 had a presumed moderate or high risk of POP, respectively. Subsequently, 1.0, 2.7, and 23.4% of sows scored as PS1, PS2, or PS3, experienced POP, respectively. Blood samples were collected on a subset of sows (n=215) identified as PS3 along with parity-matched PS1 sows at the time of scoring and whole blood was subjected to complete blood count (CBC) analysis. Serum from a subset of these (n=110) samples were also subjected to a 17-panel hormone analysis. Additionally, serum biomarkers of inflammation, C-reactive protein and haptoglobin, were analyzed in PS3 sows that subsequently experienced POP and parity matched PS1 sows that did not experience POP. The CBC analysis revealed a 4.3, 7.8 and 5.9% decrease (P < 0.05) in mean platelet volume, lymphocytes, and monocytes, respectively, in PS3 compared to PS1 sows. Deoxycortisol, androstenedione, androsterone, estrone, β-estradiol, and testosterone were greater (P < 0.05) in PS3 compared to PS1 sows. Circulating haptoglobin was unaffected (P = 0.35) by PS, although C-reactive protein was 24.6% greater (P = 0.02) in PS3 sows. Collectively, serum differences in hormone profiles and biomarkers consistent with inflammation in sows differing in POP risk. This project was supported by the National Pork Board and the Foundation for Food and Agriculture Research.
235 Effects of rapamycin during an acute heat stress exposure in growing pigs
Authors: Mayorga Edith J , Horst Erin A , Goetz Brady M , Rodríguez-Jiménez Sonia , Abeyta Megan A , Al-Qaisi Mohmmad , Lei Samantha , Rhoads Robert P , Selsby Joshua T , Baumgard Lance H
Published: November 2020

Objectives were to determine the effects of rapamycin on biomarkers of metabolism and inflammation during acute heat stress (HS) in growing pigs. Crossbred barrows (n=32; 63.5±0.8 BW) where blocked by BW and randomly assigned to 1 of 4 therapeutic-environmental treatments: 1) thermoneutral (TN) control (n=8; TNCtl), 2) TN and rapamycin (n=8; TNRapa), 3) HS control (n=8; HSCtl), or 4) HS and rapamycin (n=8; HSRapa). The trial consisted of 2 experimental periods (P). During P1 (10d), pigs were fed ad libitum and housed in TN conditions (21.3±0.01°C). During P2 (24h), HSCtl and HSRapa pigs were exposed to constant HS (35.5±0.1°C); while TNCtl and TNRapa remained in TN conditions. Rapamycin (0.15 mg/kg BW) was orally administered twice daily (0700 and 1800 h) during P1 and P2. HS increased rectal temperature, skin temperature, and respiration rate compared to TN counterparts (1.28°C, 8.68°C, and 87 bpm, respectively; P< 0.01). Feed intake (FI) markedly decreased in HS relative to TN treatments (64%; P< 0.01). Additionally, pigs exposed to HS lost BW (4 kg; P< 0.01), while TN pigs gained BW (0.7 kg; P< 0.01). Overall, circulating white blood cells decreased in HS compared to TN pigs (19%; P=0.01). Circulating neutrophils did not differ across treatments; however, lymphocytes, monocytes, and basophils decreased in HS relative to TN pigs (23, 33, and 38%, respectively; P≤0.07). Despite marked changes in phenotypic parameters, circulating glucose and blood urea nitrogen did not differ among treatments (P >0.10). However, insulin:FI increased in HS relative to TN treatments (P=0.04). Plasma non-esterified fatty acids (NEFA) increased in HS relative to TN treatments; although this difference was driven by increased NEFA in HSCtl compared to TN and HSRapa pigs (P< 0.01). In summary, pigs exposed to HS had altered phenotypic, metabolic, and leukocyte responses; however, rapamycin administration had little to no effect on any of the variables measured.
144 Nutritional advances in fetal and neonatal development: stage of gestation and placental nutrient supply
Authors: Lemley Caleb O
Published: November 2020

Placental and fetal development is especially sensitive to direct and indirect effects of the maternal environment. The duration and timing of environmental insults or stimuli in relation to the stage of gestation influences the phenotypic outcomes of offspring. Nutrient restriction during early gestation, such as developing heifers on low-input forage-based management schemes followed by nutrient re-alimentation at pregnancy confirmation, increased late-term uterine artery blood flow relative to maternal body weight compared with conventionally developed heifers. In this study, calf birth weights were not different between low-input vs conventionally developed heifers, which may indicate a compensatory mechanism to safeguard late-term fetal growth. In comparison, nutrient restriction during early to mid-gestation (from day 50 to 180 of pregnancy) decreased uterine artery blood flow, decreased fetal weight, and increased placental blood vessel density in both Brahman and Angus heifers. Moreover, the efficiency of uterine artery blood flow relative to fetal weight was improved in nutrient restricted dams versus adequate fed as well as Brahman vs Angus. These responses indicate improved placental nutrient supply following early to mid-gestation nutrient restriction. Apart from nutritional management, season and melatonin supplementation impacts placental nutrient supply in cattle. Specifically, spring calving heifers with increased uterine artery blood flow had heavier calves at birth compared with their fall calving counterparts. Although several seasonal environmental changes can influence performance and reproductive traits, specific changes in hormone concentrations as a result of photoperiod may alter blood distribution to the reproductive tract. This is apparent when supplementing dairy heifers and beef cows with melatonin during the last third of pregnancy, which increased uterine artery blood flow and calf weaning weights compared with non-supplemented controls. Elucidating the consequences of specific supplements on the continual plasticity of placental nutrient supply will allow us to determine important mediators of fetal growth and development.
2 Evaluation of Masters Choice Corn Silage on Growing Steer Performance
Authors: Xiong jiehua , Boyd Bradley M , McPhillips Levi J , Vosburgh Kyle , Erickson Galen E
Published: November 2020

Corn hybrids can be selected for improved digestion rates using lab techniques, which should impact animal performance. The objective of this study was to evaluate two Masters Choice corn silage hybrids on growing steer performance. In an 84-day growing study, 288 crossbred steers (initial BW = 303 ± 12 kg) were utilized in a generalized randomized block design with three diet treatments, 12 steers per pen and 8 pen replicates per treatment. Diets consisted of 80% corn silage (DM basis) of Masters Choice hybrid MCT6365 RIB (MC1, that has been selected to improve fiber and starch digestion) and MCT6733 GT3000 (MC2, that has been selected to improve fiber digestion) were compared to a conventional corn hybrid Farm Choice (CON, that is commonly grown in Eastern Nebraska). All corn was grown in one field under identity preserved method and harvested at 37-38% DM in three consecutive days. Relative to CON, feeding MC1 resulted in similar dry matter intake (DMI, P = 0.28), but numerically increased average daily gain (ADG, P = 0.14) which significantly improved feed efficiency (G:F, P = 0.02). Feeding MC2 led to greater DMI (P < 0.01), similar ADG (P = 0.45), and lower G:F (P < 0.01) compared to CON. The results suggest that feeding Masters Choice hybrid MCT6365 RIB (MC1) corn silage at 80% of the diet DM improved ADG and G:F by 4.2%, while feeding MC2 decreased G:F by increasing DMI compared to CON. Differences in corn hybrids exist when feeding growing cattle 80% silage.
5 Evaluating Finishing Performance of Cattle Fed HMC:SFC Blends with Modified Distillers Grains
Authors: Troyer Braden , Carlson Zac , McPhillips Levi J , Watson Andrea K , MacDonald James C , Erickson Galen E
Published: November 2020

Steam-flaked corn (SFC) has been widely used in feedlots in the southern United States to improve feed efficiency (G:F) by increasing starch digestibility. Similarly, feedlots in the Midwest have commonly fed high moisture corn (HMC), both to ensure corn supply for the year and to improve G:F. However, popularity of SFC in the Midwest is on the rise, but producers still recognize the benefits of HMC utilization. A study was conducted at the Eastern Nebraska Research and Extension Center (ENREC) to compare finishing cattle performance when fed HMC, SFC, or a blend. The objective was to determine the optimum inclusion of the grains when modified distillers grains (MDGS) was included at 20% of the diet. This study utilized 90 yearling steers (353 kg; SD=5.8 kg) individually fed using the Calan gate system in a completely randomized design with cattle stratified by body weight (BW). Treatments included: 100% HMC, 75% HMC blended with 25% SFC, a 50% blend of the grains, 25% HMC blended with 75% SFC, or 100% SFC (DM basis; % of the 70% grain in the diet). Cattle were on feed 168 days with 3-day initial BW and 1 day final BW. Animal was the experimental unit with 18 replications per treatment. No differences in initial BW, ribeye area, or marbling score between treatments were detected (P > 0.12). Ending BW, hot carcass weight, average daily gain, and G:F all linearly increased with increasing inclusion of SFC in the diet (P < 0.05). Carcass adjusted G:F improved from 0.158 to 0.170 for 100% HMC compared to 100% SFC diets, respectively. In conclusion, feeding higher inclusions of SFC in finishing diets resulted in improved performance compared to HMC in diets containing 20% MDGS.
105 A comparison of long-acting growth-promoting implants and re-implant programs in finishing heifers fed for 184 days
Authors: Crawford Grant , Nichols Wade , Hutcheson John , Streeter Marshall , Nuttelman Brandon , Walter Lee-Anne , Szasz Josh , Bryant Tony
Published: November 2020

Yearling beef heifers (n = 6,239) were used in a randomized complete block design experiment to evaluate the effects of long-acting implants on feedlot growth performance and carcass characteristics when compared with re-implant programs. Heifers (initial BW = 324 kg, SEM = 0.85) were randomized to 1 of 4 implant treatments with 12 pens/treatment: 1) Revalor-IH (80 mg trenbolone acetate [TBA], 8 mg estradiol [E]) at initial processing followed by a Revalor-200 (200 mg TBA, 20 mg E) 90 d later (IH/200); 2) Revalor-200 at initial processing followed by a Revalor-200 90 d later (200/200); 3) Revalor-XH (200 mg TBA, 20 mg E) at initial processing (XH); and 4) Synovex One Feedlot (200 mg TBA, 20 mg E) at initial processing (ONE). Revalor-XH and Synovex One are long-acting implants designed to extend hormone release, eliminating the need to re-implant cattle. After initial processing, XH and ONE heifers were not removed from their pens until harvest. Final BW (556 kg), DMI (7.95 kg/d), ADG (1.26 kg), and feed efficiency (0.158) did not differ (P > 0.23) among treatments. Hot carcass weight (HCW) was greater (P < 0.10) for 200/200 (364 kg) than XH (361 kg) and ONE (360 kg), with no other differences (P > 0.10) in HCW among treatments. Dressing percentage (DP) and longissimus muscle (LM) area were greater (P < 0.01) for 200/200 than all other treatments, and greater for IH/200 than XH and ONE. Marbling score was reduced and average yield grade (YG) was improved (P < 0.01) for 200/200 vs. all other treatments and for IH/200 vs. XH and ONE. Compared with re-implant programs, long-acting implants decreased DP and LM area, increased marbling score and YG, and did not differ in final BW. The Revalor-200/200 re-implant program resulted in improved HCW when compared with long-acting implants.
229 Evaluation of Wheat Blended with Corn in Finishing Diets Containing Wet Distillers Grains
Authors: Coulson Caitlin , Boyd Bradley M , Conroy Brianna , Erickson Galen E
Published: November 2020

An experiment was conducted to evaluate the effect of grain type and wet distillers grains inclusion on finishing cattle performance and carcass characteristics. Yearling steers (n = 320; initial BW = 325 ± 23 kg) were utilized in a 2 x 2 factorial arrangement, with the first factor as grain type at either 100% dry-rolled corn or a 50:50 blend of dry-rolled wheat and dry-rolled corn, and the second factor as wet distillers grains plus solubles (WDGS) inclusion at 12 or 30% of diet DM. There were no interactions between grain type and WDGS inclusion levels (P ≥ 0.21), contrary to our hypothesis that 50:50 wheat blend would improve performance with increased WDGS. There were no differences in DMI, ADG, or G:F (P ≥ 0.29) between 100% DRC or 50:50 blend of DRC and wheat. There was no difference in HCW between grain types (P = 0.84), but LM area was greater (P = 0.02) for steers fed a 50:50 blend of DRC and wheat. There were no differences in 12th rib fat or USDA marbling score between grain types (P ≥ 0.15), but increased LM area in steers fed the blended diet led to improved calculated yield grade (P = 0.04). Increasing WDGS in the diet increased carcass-adjusted final BW (P = 0.03) and improved carcass-adjusted ADG and G:F by 3.8% (P ≤ 0.05). Feeding 30% WDGS increased HCW by 10.9 kg (P = 0.03) and increased 12th rib fat (P = 0.02) compared to feeding 12% WDGS. There were no differences in LM area, USDA marbling score, or calculated YG between WDGS inclusions. These data suggest that increasing WDGS in the diet improves performance regardless of grain type and depending on price, wheat can replace up to 50% of the grain portion of the diet without affecting performance.
250 Evaluation of Green Grass as a feed ingredient in beef finishing rations and impact on cattle performance, carcass characteristics, and fatty acid profiles in meat
Authors: Norman Mitchell M , Bland Nicolas , Boyd Bradley M , Conroy Brianna , Calkins Chris , Watson Andrea K , Erickson Galen E
Published: November 2020

A finishing study used 240 crossbred steers (initial BW=340 ±24 kg) to evaluate performance, carcass characteristics, and fatty acid profiles of beef from finishing steers. Four inclusions (0, 10, 20, 30 % DM basis) of Green Grass displaced dry rolled corn in the finishing diet. Green Grass is a blend of herbs and plants imported from Korea that are high in omega-3 fatty acids with 13.9 % fat,32.0 % CP, and 27.0 % Acid detergent fiber. The remaining diet consisted of 15 % WDGS, 20 % corn silage, and 6 % liquid supplement (DM basis). There were no differences in final BW, gain or carcass traits (P³0.14). Cattle were harvested over three slaughter days and were fed for 190, 199, or 203 days. Dry matter intake linearly increased (P = 0.04)as Green Grass inclusion increased in the diet. A linear response (P£0.01) to feeding Green Grass was observed for G:F, with steers fed Green Grass having lower feed efficiency than control cattle. The G:F of cattle fed Green Grass was 5.4, 3.4, and 6.8 % lower in G:F as inclusion increased suggesting Green Grass has 68.6 % the energy of corn it replaced. Steers fed 30 % Green Grass had a lower marbling score. Linear increases in alpha linolenic acid, trans-unsaturated fatty acids, and omega-3 fatty acids (P£0.01) were observed in steak samples from steers fed increasing inclusion of Green Grass. Including up to 30 % inclusion of Green Grass on a DM basis in finishing diets decreased G:F; however, it appeared to have no other effects on performance or carcass characteristics. Feeding Green Grass linearly improved omega-3 fatty acid concentration in beef.
150 Effects of specialty lipids as alternatives to conventional antimicrobial feed additives on nursery pig growth performance
Authors: Dahmer Payton , Lerner Annie B , Luebcke Grace , Jones Cassandra K
Published: November 2020

There is consumer and regulatory pressure to reduce the use of conventional antimicrobial feed additives in pork production. A total of 360 pigs (DNA 241×600, initially 5.4±0.07 kg BW) were used in a 35-d study evaluating the ability for specialty lipids to replace ZnO or carbadox in nursery diets. Pigs were allotted in a completely randomized design (6 pigs/pen and 10 pens/treatment) to one of six diets: 1) control; 2) control + 3,000 ppm ZnO in phase 1 and 2,000 ppm ZnO in phase 2; 3) control + 50 g/ton carbadox; 4) control + 1% C6:C8:C10 medium chain fatty acid (MCFA) blend; 5) control + 1% proprietary oil blend (Feed Energy Corp., Des Moines, IA); and 6) control + 1% monolaurate blend (FORMI GML, ADDCON GmbH, Bitterfeld-Wolfen, Germany). Treatment diets were fed in two phases (d 0 to 19) followed by a common diet (d 19 to 35). During the treatment period, pigs fed ZnO or carbadox had greater (P< 0.05) ADG than pigs fed the control or proprietary oil blend, with pigs fed the MCFA or monolaurate blends being intermediate. Pigs fed diets containing ZnO had greater (P< 0.05) ADFI than those fed the control, MCFA, or propriety oil blends. Pigs fed ZnO or carbadox had higher (P< 0.05) blood glucose on d 19 and firmer (P< 0.05) fecal scores on d 3 than pigs fed all other diets. No differences (P >0.05) were observed during the common period (d 19 to 35), however sufficient early growth differences subsequently impacted overall ADG and ADFI. In summary, ZnO and carbadox are valuable additives to maximize early nursery growth, but specialty lipid products may result in similar performance while others may restrict it. Additional research is warranted to identify optimal lipid blends to effectively replace ZnO or carbadox in nursery pig diets.
63 Ileal digestibility of amino acids in a new source of high-protein distillers dried grains with solubles fed to growing pigs
Authors: Acosta Medellin Jessica P , Lee Su A , Stein Hans H
Published: November 2020

The objective of this experiment was to test if standardized ileal digestibility (SID) of AA in a new source of high-protein distillers dried grains with solubles (HP-DDGS) is greater than in conventional distillers dried grains with solubles (DDGS-CV). Nine barrows (initial BW: 67.2 ± 6.4 kg) with a T-cannula in the distal ileum were allotted to a triplicate 3 × 3 Latin Square design with 3 diets and 3 periods. Two diets included HP-DDGS or DDGS-CV as the sole source of CP and AA. A nitrogen-free diet was used to determine basal endogenous losses of CP and AA. The statistical model included ingredient as fixed effect and square, period, and animal as random effects. Results indicated that that HP-DDGS contained more CP and AA compared with DDGS-CV (Table 1). The SID of all AA in HP-DDGS were greater (P < 0.001) compared with DDGS-CV with the exception that the SID of Pro was not different between the 2 sources of DDGS. The greater concentrations of AA and values for SID of AA in HP-DDGS indicate that this new DDGS source has a very high quality and may be a great source of digestible AA in diets fed to pigs.
54 Substrate and inoculum composition affect in vitro model of ruminal acidosis
Authors: Shaw Natalie , Tondini Sara , Shike Daniel W , McCann Joshua C
Published: November 2020

The objective was to create an in vitro model of ruminal acidosis. Ruminal acidosis is a prevalent metabolic disorder in beef feedlot cattle characterized by low rumen pH. Experiment 1 was a 3×3 factorial design testing the interaction between inoculum composition and quantity of substrate. Eighteen flasks containing 150 mL of inoculum were used to evaluate treatments in duplicate. Treatments evaluated inoculum ratios (buffer: rumen fluid) 2:1, 4:1, and 6:1 in combination with substrate levels 5 g, 7.5 g, and 10 g. Manual pH was collected every 4 h for 36 h. Experiment 2 was a completely randomized design with 5 treatments evaluated in triplicate. Treatments consisted of a 4:1 inoculum ratio (150 mL) with the substrate (7.5 g) consisting of 70% corn (PCON), 40% corn (NCON), or increasing inclusions (10, 20, and 30%) of wheat in place of corn (W10, W20, and W30). Flasks were incubated at 39°C for 36 h with continual pH measurement. In exp. 1, 7.5 g of substrate remained between a pH of 5.6 and 5.0 (P ≤ 0.01) for a longer period (880 min) than 10 g of substrate (520 min). In experiment 2, a treatment by time interaction (P ≤ 0.05) was observed for pH with NCON having the greatest pH over 8-36 h and PCON having the lowest pH over 4-8 h. A treatment by time interaction (P = 0.02) was observed for lactate at 20 h with PCON having the greatest and W30 having the lowest concentration. Treatment PCON had the greatest (P < 0.01) acetate and propionate concentration. The W20 treatment remained between a pH of 5.6 and 5.0 (P < 0.01) for a longer period than PCON. Results suggest W20 and PCON may be the most useful in vitro models of ruminal acidosis.
PSV-14 Genome Centric Approaches to Understand Antimicrobial Resistance in the Rumen Microbiome
Authors: Tom Wesley A , Hales Kristin , Wells James , Fernando Samodha
Published: November 2020

Global meat and milk demands are projected to increase by 50% by the year 2050, making a highly efficient cattle industry a top priority. Widespread use of antibiotics over the last 70 years has led to increases in antibiotic resistance genes (ARGs) in microbial populations, posing health risks to animal and human populations. Thus, a thorough understanding of where antibiotic resistance genes reside in microbial ecosystems surrounding livestock is paramount in developing strategies to mitigate transfer of antibiotic resistance. Recent advances in metagenome sequencing have made it possible to predict microbial genomes from shotgun metagenome datasets. However, genomes binned from metagenome data are often smaller than genomes from pure cultures, omitting genetic information that is not part of the core genome e.g. antibiotic resistance. This study uses a new linked-read metagenome sequencing approach, partitioning long fragments of DNA (>40Kbp) into millions of droplets which are individually barcoded giving each strand a unique index, improving metagenome assembly and increasing access to genetic information pertaining to antibiotic resistance. Rumen samples from four animals which received daily antibiotics in feed as well as antibiotic injections were pooled for linked-read metagenome sequencing. Additionally, soil samples from the animal pen were collected from three locations and pooled for analysis. Linked-read sequencing reads were assembled using MEGAHIT and ATHENA assemblers (N50 > 2702bp, 578,838 contigs >1000bp). Metagenome assembled genomes (MAGs) were binned using MetaBAT2, yielding 341 genome bins. Of these, 144 bins were of intermediate to high quality (>70% completeness, < 10% contamination), 79 genomes from rumen and 65 from soil samples, respectively. Genomes were scanned for ARGs (ABRicate), revealing 12 genomes containing ARGs, 5 from rumen, 7 from soil. MAGs possessed genes conferring resistance to penicillin, macrolide, nitroimidazole, aminoglycoside, and tetracycline class antibiotics, helping uncover information about where ARGs are sequestered in their respective environments. USDA is an equal opportunity provider and employer.