bluuebunny/crossref_metadata_2025 huggingface dataset:
195 Incidence of porcine ear necrosis in nursery pigs under commercial conditions is reduced with stimbiotic
Authors: Merriman Laura A , Wilcock Pete , Becker Spenser , Cordero Gustavo
Published: May 2024

Three studies were conducted to evaluate the potential benefit of a stimbiotic on porcine ear necrosis and the fecal microbiome in nursery pigs. In experiment 1, 600 mixed-sex piglets were randomly placed in 20 pens with 30 pigs/pen (n = 10). The pigs were fed a common wheat and barley-based nursery diet (CON) or CON with stimbiotic (Signis, 0.15g/kg; STB). Incidence of ear necrosis was recorded on individual animals at 28 d post-weaning. Mortality was analyzed using ANOVA and PEN was evaluated using a chi-square test. In experiment 2, a total of 65,200 pigs were placed on trial in 8 nursery barns. Treatments were assigned to a quadrant within each barn (n = 8). Newly weaned pigs were fed a common corn-soy nursery diet (CON) or CON with stimbiotic (Signis, 0.1g/kg; STB). Ear necrosis was classified as either: 1) nominal lesions or 2) moderate to severe lesions and was recorded at 1, 3, and 5 wk post weaning. Mortality and injectable treatments were recorded. Mortality data were analyzed using a binomial regression. A Poisson regression was used to analyze the incidence of PEN and injectable treatment rate with the fixed effect of treatment and random effects of sow farm, site, and barn. In experiment 3, a total of 47,200 pigs in 10 nursery barns were randomly assigned to either a standard nursery diet (CON) or CON with stimbiotic (Signis, 0.1 g•kg-1•ton-1; STB). Mortality was recorded throughout the 6-wk trial and PEN score was recorded at d 42. Fecal samples were collected on 7, 21, and 42 d post-weaning for 16S rRNA sequencing and predictive metabolic function analysis. In experiment 1, no differences in mortality were observed (P > 0.10). A total of 156 pigs in the CON fed group developed PEN, whereas only 27 pigs in the STB group developed PEN (52% vs. 9%; P < 0.01). In experiment 2, there was no difference among treatments for mortality. Pigs fed the STB treatment required 15% fewer injectable treatments than pigs fed the control (P < 0.05). No differences of PEN were observed in wk 1 and 3; however, at 5 wk post-weaning, incidence of PEN was 23% less in pigs fed the STB the the control fed pigs (P < 0.05). In experiment 3, the pigs fed STB had decreased incidence of ear necrosis (3.09% vs 4.08%; P < 0.05) and mortality (2.42% vs 2.86%; P < 0.05), overall reducing PEN and mortality by 32% and 18%, respectively. The fecal microbiome of pigs fed CON was associated with the chondroitin sulfate degradation pathway, an important component of cartilage. In conclusion, feeding a stimbiotic appears to be beneficial in nursery pigs to help alleviate challenges with PEN, which is potentially driven by a beneficial shift in the pig’s microbiome.
254 Effect of feeding high oleic soybean oil to finishing pigs on growth performance, carcass characteristics, and meat quality
Authors: Atoo Ashir Foreman , Levesque Crystal L , Thaler Robert C , Underwood Keith , Beyer Erin S , Palencia Jorge Y Perez
Published: May 2024

The objective of this study was to evaluate the effects of dietary fat source and feeding duration on growth performance, carcass characteristics, and meat quality of finishing pigs. Finishing pigs [n = 450; 21 wk of age; initial body weight (BW) = 113.7 ± 8 kg] were housed in 90 pens and assigned to one of five dietary treatments in a 2 × 2 + 1 factorial design. Dietary treatments consisted of two fat sources (CWG: 4% inclusion of choice white grease and HOSO: 4% inclusion of high oleic soybean oil) each provided 2 or 4 wk before marketing. The “+1” diet was a corn-based diet without fat inclusion (CON). Observations included pig growth performance (on d 14 and d 28 of feeding), carcass characteristics (12 pigs per treatment at marketing), fatty acid profile in the loins and bellies, and a consumer sensory evaluation. Data were analyzed using PROC MIXED in SAS considering dietary treatment as a main effect, feeding duration, and their interactions. Contrast tests were used to compare dietary treatments with control group. From d 14 to 28 and overall experimental period (d 0–28), pigs fed fat-supplemented diets had a greater (P < 0.05) average daily gain and gain to feed ratio than CON fed pigs. There was no significant difference (P > 0.05) in growth performance when comparing fat sources or feeding periods. Pigs supplemented with either CWG or HOSO showed a tendency to have a greater (P < 0.1) belly weight and belly yield, and a lesser (P < 0.1) loin yield and loin muscle area when compared with CON pigs. Loins from the 2-wk period of fat supplementation had darker (Coloration l, P < 0.05) meat coloration when compared with 4 wk. The loin from pigs fed fat sources had greater (P < 0.05) concentration of oleic acid and eicosenoic acid when compared with CON. This improvement was mainly from HOSO. When CWG was compared with HOSO, pigs fed CWG had a greater (P < 0.05) concentration of palmitic acid and stearic acid while the HOSO pigs had a greater concentration of oleic acid and linolenic acid in the loin. In the belly, CON had greater (P < 0.05) concentration of palmitic acid and stearic acid while pigs fed fat sources had a greater concentration of oleic acid and eicosenoic acid. Bellies from HOSO had greater (P < 0.05) concentration of oleic acid and α-linolenic acid methyl ester while CWG had greater concentration of g-linolenic acid. As for the sensory evaluation, the palatability and acceptability of pork were not affected (P > 0.05) by dietary treatments. In conclusion, supplementation with HOSO not only improved performance but tended to improve some carcass characteristics and increased the concentration of oleic acid and some other unsaturated FAs with a concomitant decrease in the concentration of some saturated FAs in pork.
108 Estimating net energy of soybean meal for 47 to 110 kg growing pigs using a growth assay
Authors: Guo Jiyao , Wantanasak Apichat , Zhang Fengrui , Wang Taiji , Stoner Gary
Published: May 2024

The NE of SBM for growing pigs with body weight (BW) from 47 to 110 kg was determined in the current study using the growth assay. In the first study, a total of 826 pigs (B =, 46.8 ± 2.5 kg) in 44 pens (18 to 19 pigs per pen, 11 pens per treatment) were randomly allotted into one of 4 dietary treatments with initial BW and sex as blocks for 21 d: Corn-SBM based diets with 29.0, 25.7, 22.3, or 19.0% of SBM. Compared with the first study, the second study was conducted with a total of 820 pigs at greater BW (67.0 ± 3.4 kg). Pens were randomly allotted into one of 4 dietary treatments for 42 d: Corn-SBM based diet with 29.0, 25.0, 21.0, or 17.0% of SBM. NE of corn [2,674 kcal/kg, as fed basis, dry matter (DM) 87.1%] was calculated according to NRC (2012) and determined with the analyzed nutrient composition. SBM used in both experiments contained 89.4% of DM, 46.6% of CP, 5.9% of starch, 1.6% of EE, 8.5% of NDF, 6.3% of ADF, and 6.1% of ash. The reduced level of SBM was replaced with corn and crystalline amino acids. Data were analyzed by linear and quadratic contrasts using the Proc MIXED of SAS. In the early growing phase (47 to 67 kg), increasing SBM levels from 19.0 to 29.0% tended to linearly decrease average daily feed intake (ADFI; Linear, P = 0.081, 2.09, 2.03, 2.03, and 2.00 kg/d) but did not affect average daily gain (ADG) or final BW. On the contrary, increasing SBM levels decreased ADG and ADFI in pigs growing from 67 to 110 kg (linear, P < 0.05, ADG: 1.03, 1.02, 1.01, and 1.00 kg/d; ADFI: 2.72, 2,64, 2.63, and 2.58 kg/d). Linear regression analysis showed that, to maintain calorie efficiency, the estimated NE of SBM for pigs growing from 47 to 67 kg is 3,000 kcal/kg (as fed basis), which is 1.12 times corn NE. The estimated NE of SBM for pigs growing from 67 to 110 kg is 2,705 kcal/kg (as fed basis), which is 1.01 times corn NE. Taken together, the results suggest that NE of SBM is close to or greater than NE of corn, warranting the necessity to evaluate the energy of feed ingredients in pigs growing in different phases. The predicting equation of SBM NE (Eq. 1-3 and 1-8, NRC 2012) is recommended to be modified by timing a coefficient of 1.36 or 1.19 for early- or late-growing pigs, respectively, according to the NE of SBM calculated from growth performance data in this study.
168 Effects of feeding barley-based diets differing in fermentable starch and fiber on nutrient digestion and body composition in weaned pigs
Authors: Sanchez-Zannatta Joaquin J , Wang L F , Beltranena Eduardo , Beattie Aaron D , Newkirk Rex N , Zijlstra Ruurd T
Published: May 2024

Hulled and hull-less barley grains containing low insoluble fiber are alternative energy sources in weaning diets but are typically not part of weaned pig diets. The range in fermentable starch and fiber content among barley cultivars presents opportunities to investigate whether these fermentable carbohydrates of barley grain do influence nutrient digestion, gut short chain fatty acid (SCFA) profile and body composition. To explore, pigs [n = 40; body weight (BW) = 8.6 kg; 1-wk post-weaning] were housed individually and fed 1 of 4 diets containing 600 to 705 g of cereal grain/kg: 1) low-fermentable wheat (LFW); 2) high β-glucan, hull-less barley (HFBB); 3) high amylose, hull-less barley (HFAB); or 4) low-fermentable hulled barley (LFB). Diets provided 10.2 and 9.8 MJ NE/kg, and 1.32 and 1.21 g standardized ileal digestible (SID) lysine/MJ NE for phase 1 (d 0–14) and phase 2 (d 15–28), respectively. At the end of the trial, feces were collected, and pigs were slaughtered to collect digesta and the carcass that was subsequently ground. Subsamples of feces, digesta, and carcasses were freeze-dried and analyzed. The apparent ileal digestibility (AID) of crude protein (CP) and gross energy (GE) did not differ among diets. The AID of β-glucan was 3 times greater (P < 0.05) for LFW than HFBB and HFAB, while AID of starch was 12% less (P < 0.05) for HFAB than the other diets. Apparent total tract digestibility (ATTD) of GE and CP was 4.2 and 8.9% less (P < 0.05), respectively, for the 3 barley diets than the wheat diet. The apparent hindgut fermentation (AHF) of β-glucan was 2.6 times greater (P < 0.05) for HFAB and HFBB than LFW, while AHF of starch was 7.5 times greater for HFAB than LFW. The calculated NE value was greatest (P < 0.05) for LFW, intermediate for HFBB and HFAB, and least for LFB. Among diets, HFAB increased (P < 0.05) the concentration of butyrate (indicator of gut health) and propionate in cecal and colonic digesta, with butyrate up to 50% more (P < 0.05) than that of LFW. Carcass protein and lipid concentration did not differ among pigs fed the 4 diets. In conclusion, feeding barley instead of wheat grain to weaned pigs reduced diet nutrient digestibility but did not affect carcass protein and lipid concentration. Feeding high amylose barley increased gut SCFA concentration. Barley grain with increasing fermentable carbohydrates can thus be included as alternative ingredient in diets of young pigs.
2 Another renaissance for bile acid gastrointestinal microbiology
Authors: Ridlon Jason
Published: May 2024

The field of bile acid microbiology in the gastrointestinal tract is going through a current rebirth after a peak of activity in the late 1970s and early 1980s. This renewed activity is a result of many factors including the discovery near the turn of the century that bile acids are potent signaling molecules, technological advances in next generation sequencing, computation, culturomics, gnotobiology, and metabolomics. The current state of the field with particular emphasis on questions that have remained unanswered for many decades in both bile acid synthesis by the host, and metabolism by the gut microbiota will be addressed. Current knowledge of established enzymatic pathways including bile salt hydrolase, hydroxysteroid dehydrogenases involved in the oxidation and epimerization of bile acid hydroxy groups, the Hylemon-Bjӧrkhem Pathway (HBP) of bile acid C7-dehydroxylation, and the formation of secondary allo-bile acids are described. Aspects of bile acid conjugation and esterification, and evidence for bile acid C3- and C12-dehydroxylation that are less well understood, but potentially critical for our understanding of bile acid metabolism in the human gut will be covered. The physiological consequences of bile acid metabolism for human health, important caveats and cautionary notes on experimental design and interpretation of bile acid metabolism are also explored.
56 Metabolic status of respiratory disease challenged beef steers altered by intranasal Zn and vitamin A treatments
Authors: Rients Emma L , Franco Carlos , McGill Jodi , Hansen Stephanie L
Published: May 2024

Bovine respiratory disease (BRD) is a major cause of morbidity and mortality in the cattle industry. Increasing the ability of a calf to respond to disease is of interest due to the loss of production during disease. Zinc and vitamin A (VA) are key micronutrients involved in many immunologic processes such as cell signaling and mucosal immunity. Angus crossbred steers [n = 48; body weight (BW) = 333 ± 4.2 kg] were utilized in this 14-d BRD challenge investigating intranasal (IN) treatments of Zn and VA. Steers were split into two groups (n = 24) with identical disease challenge and sample collection schedules. Before disease challenge, steers were housed at the Iowa State University Beef Nutrition farm (BNF). Steers were weighed on d -2 and -1 of viral challenge and trucked for 6 h before delivery to the Iowa State University Animal Resource Station. On d 0, steers were challenged with an aerosol inoculation with 104 TCID50 BRSV followed by 5x108 CFU of Mannheimia haemolytica on d 5. On d 4, steers received IN treatments of Zn (ZN; ZnO nanoparticles), VA (VA), Zn and VA (VA+ZN), or control with no IN treatment (CON). For trace mineral and VA analysis, liver biopsies were collected on d -9 and 20 and plasma collected on d 0, 4 (trace mineral only), 5, 7 and 14. Steers were tested for viral shedding on d 0, 4, 5, 7, 10 and 14. RNA was isolated from bronchioalveolar lavage (BAL) cells (d 0 and 7) for gene expression related to inflammation, VA and trace mineral metabolism. Statistical analysis was completed using the GLIMMIX and MIXED procedures in SAS 9.4. Throughout the study, viral shedding was not affected by intranasal treatment (P ≥ 0.59). There were no group × TRT × day effects for plasma trace minerals (Cu, Zn, Fe) or VA concentrations (P ≥ 0.18). Intranasal VA prevented a decrease in plasma VA on d 5, after which all treatments were similar (P < 0.01). There were no TRT × day effects for plasma Zn and Cu (P ≥ 0.50). Post challenge, liver VA was increased in VA treated steers compared with steers not treated with VA (P = 0.04). Liver Mn tended to be increased post challenge in IN ZN treated steers (P = 0.08). IN Zn treated steers tended to have lesser expression of IL-10 in BAL cells on d 7 post infection (P = 0.07). Local IN supplementation of Zn and VA can have systemic and local affects on respiratory disease challenged steers and may support increased response to disease.
57 Effect of diet mixing strategies on growth performance and carcass characteristic in feedlot steer
Authors: Waldon Naomi , Garcia Lyda , Clevenger Doug , Relling Alejandro E
Published: May 2024

Our objective was to determine the effects of a feeding management strategy on growth and carcass quality and characteristics on finishing feedlot beef cattle. Angus-Simmental steers (n = 60), blocked by body weight (BW), were housed in individual pens and randomly assigned to treatments. Treatments were total mixed ration (TMR) or a non-mixed diet (Split). The diet contained 67.5% of dry rolled corn, 18% of distiller grains with soluble, 2.5% soybean meal, 7% hay, and 5% of mineral and vitamin mixed. The diet composition for both treatments was similar, the only difference was the use of a TMR or that the concentrate was fed separately from the hay on the Split treated calves. Feed intake was monitored through slick bunk management in both treatments. For the Split assigned calves, if any hay or concentrate was left in the bunk on two consecutive days, the total feed was decreased by 5%; maintaining always the 93% concentrate and 7% forage ratio. Steers were weighed monthly and feed samples were collected for nutrient composition analysis semimonthly. Monthly weights and intakes were used to calculate average daily gain (ADG) and gain to feed ratio (G:F). Steers were slaughtered per block when the average weight of the block reached 555 kg. Carcasses were evaluated 48 h post slaughter. Carcass yield and quality factors were evaluated at the 12th/13th rib interface. Data were analyzed as randomized complete block design. Considering the fixed effect of the feeding strategy and the random effect of block. We did not observe differences (P > 0.17) in growth performance or carcass characteristics variables due to management strategy (Table 1). The lack of observed differences due to treatment might be because the ratio of concentrate and forage intake was similar for both groups, in addition to the slick bunk management in both treatments, which forced steers to eat all their ration, independent of the treatment, to continue to receive the same amount of feed.
164 Impact of varying dietary inclusion of modified distiller’s grains plus solubles weekly compared with constant inclusion on feedlot cattle performance and carcass characteristics
Authors: Sousa Debora Gomes , McDermott Rebecca L , Norman Mitch M , MacDonald James C , Stock Rick A , Erickson Galen E
Published: May 2024

The use of distiller’s grains in feedlot diets was abundant due to supply and price, but the availability to feedlots and greater prices of distiller’s grains has led to reduced inclusion and more variation in supply, and thus, inclusion within the feeding period for cattle. The hypothesis was that varying inclusion of modified wet distiller’s grains plus solubles (MDGS) in the diet would negatively impact cattle performance due to changing dietary starch concentration and risk of acidosis. One solution to help with ruminal acidosis concerns with variable MDGS inclusion would be increasing roughage inclusion. Therefore, our objective was to evaluate if varying the inclusion of MDGS at normal and 2X normal roughage inclusion influences performance of finishing cattle. In this study, crossbred steers (n = 576) with an initial body weight (BW) = 379 kg (SD= 11 kg) were evaluated for performance and carcass traits over the 143 d on study. Two inclusions of grass hay (6% and 12%) and three treatments related to MDGS (no inclusion, constant inclusion at 25% MDGS, and varying inclusion between 15 and 35% MDGS) were tested in a 2 × 3 factorial. Variable inclusion was accomplished by randomly selecting inclusions of 15, 20, 25, 30, or 35% each week with inclusion averaging 25% over the entire feeding period. There was no interaction between grass hay inclusion and MDGS inclusion (P ≥ 0.67) for performance data except a tendency (P = 0.09) for a gain to feed (G:F) interaction. In treatments fed 12% hay, G:F increased for cattle fed either MDGS inclusion (25% constant or varying inclusion) compared with 0% MDGS. In cattle fed 6% hay, G:F was similar between 0, 25 constant or variable 25% MDGS treatments. There was not an interaction due to a different response of variable versus constant inclusion of MDGS when more hay was included, as hypothesized. The 25% constant MDGS and 25% variable MDGS treatments did not differ (P ≥ 0.22) in average daily gain (ADG), hot carcass weight, or G:F. There was a tendency for cattle fed varying inclusion of MDGS to eat less (P = 0.10), but this difference was small (0.1 kg/d). In general, cattle fed MDGS (constant or varying) had greater dry matter intake and ADG, with greater fatness and marbling compared with cattle fed without MDGS (P ≤ 0.01). As for the degree of liver abscess severity, there was no interaction between treatments. Our results show that although varying supply of MDGS in diets is not recommended or desired, if it occurs and inclusions vary from 15 to 35%, these weekly adjustments did not negatively affect gain or feed efficiency in this study.
297 Effects of plasma zinc concentration on longissimus thoracis metabolic status of beef steers
Authors: Ortner Brock M , Smerchek Dathan T , Hansen Stephanie L
Published: May 2024

The objective of this study was to examine the role of Zn status on muscle glucose and other metabolites. Angus steers [n = 144; body weight (BW) = 525 ± 30 kg] with varying plasma Zn concentration and implant status served as the initial pool for this secondary experiment. Steers were assigned to one of two implant (IMP) treatments: no implant (NO) or Component TE-200 (TE-200; Elanco, Greenfield, IN) on d 0. Zinc was supplemented as ZnSO4 at 0 mg Zn/kg dry matter (DM; analyzed 54 mg Zn/kg DM), 30 mg Zn/kg DM, or 100 mg Zn/kg DM, starting 60 d before implant day. Steers were fed via GrowSafe bunks (GrowSafe Systems Ltd., Airdie, AB, Canada), and steer was experimental unit. Steers were fed in two blocks with a 14-d stagger for sample logistics. Blood and muscle biopsies of the longissimus thoracis were collected on d 40 after implant, a minimum of 2 h post-feed delivery. Plasma Zn was quantified via ICP-OES and 144 samples were stratified into quantiles by plasma Zn concentration. Samples (n = 12 low and 12 high from NO and TE-200 groups) were identified and designated as low plasma Zn (LOW, 1.1 mg Zn/L average) and high plasma Zn (HI, 1.6 mg Zn/L average) treatments (TRT). Muscle samples from these 48 steers were homogenized and derivatized for subsequent analysis via gas chromatography-mass spectrometry (GCMS) for non-targeted metabolomic analysis. Data were analyzed as a complete randomized design using the MIXED procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) with fixed effects of TRT, IMP, BLOCK, and TRT×IMP. A TRT×IMP effect was observed for muscle glycine (P = 0.02) where LOW/IMP was similar to HI/NO but had greater glycine concentrations than LOW/NO and HI/IMP. There was a tendency for a TRT×IMP (P = 0.07) effect where LOW/IMP and HI/NO tended to have greater concentrations of hydroxyisovaleric acid. Given the role of glycine in protein synthesis and hydroxyisovaleric acid in leucine metabolism these data suggest differential protein responses to implants in cattle of lesser vs. greater plasma Zn concentrations. Hydroxybutyric acid, a ketone body which can be utilized for energy, tended to be greater in muscle of steers receiving an IMP (P = 0.09). Contrary to our hypothesis that greater plasma Zn would support differential muscle glucose metabolism, no effects of plasma Zn TRT or IMP were noted for glucose, lactate, and other detected metabolites. Both LOW and HI plasma Zn concentrations were still considered adequate, and future research should explore the impact of distinctly deficient and adequate plasma Zn concentration on glucose metabolism pathways in muscle.
298 Impact of ruminal acidosis on cattle energy metabolism
Authors: Linder Haley F , Li Jiangong , Berger Larry L , Green-Miller Angela R , McCann Joshua C
Published: May 2024

The objective of this study was to determine the impact of a bout of ruminal acidosis on energy metabolism of cattle unadapted to a high concentrate diet. Eleven ruminally cannulated steers [body weight (BW) = 352 kg ± 27] were blocked into 3 groups based on initial BW. Before the start of the experiment, animals were consuming a forage-based diet as well as adapted to the headbox style respiration chambers. Additionally, before the experiment, gas emission data were collected over a 24-h period when cattle received an ad libitum forage-based diet for use as a covariate in the statistical analysis. For the experiment, steers were moved into headboxes at the conclusion of a 24-h fast and subsequently received 1 of 2 treatment diets: control (CON), forage-based diet or acidosis (AC), concentrate-based diet. Steers remained in the headboxes for 48 h. Gas concentrations from each headbox were collected hourly and analyzed with an infrared photoacoustic gas analyzer. Ruminal pH, fecal pH, volatile fatty acids, and lactate were also measured during the acidosis challenge. Data were analyzed with the MIXED procedure of SAS 9.4. A treatment × day effect (P = 0.03) was observed for dry matter intake with intake being similar for both CON and AC steers on d 1 but AC steers consuming 2.02 kg less on d 2. Treatment affected ruminal pH (P < 0.01) as CON steers had a greater ruminal pH than AC steers. Greater total volatile fatty acids (P < 0.01) were observed for steers on AC treatment compared with CON. A treatment × time interaction (P < 0.01) was observed for ruminal lactate concentration with AC steers having greater concentrations from h 16 to 36. Fecal pH was affected by a treatment × time interaction (P = 0.05) as AC steers had lower fecal pH from h 24 to h 32. Over the 48-h observation period, there was a treatment × time interaction (P = 0.04) for carbon dioxide production as AC steers produced less CO2 after h 24. No treatment × time interaction was detected for oxygen consumption. However, there was a time effect (P < 0.01). Respiratory quotient was not affected by treatment, day, or their interaction (P ≥ 0.19). Heat production tended (P = 0.06) to be different between treatments, with AC having less heat production than CON. Thus, the effects of ruminal acidosis on gas emissions and energetics may be more transient during the time course of an acidotic bout or have a longer duration even after ruminal pH has recovered.
217 Weaning weight associated with improved nursery pig growth rate
Authors: McCallum Michelle , Krahn Gregory , Mahoney Julie , Hinson Rodney , Eden Chris L
Published: May 2024

Heavier body weight (BW) at weaning is associated not only with heavier birth weight, but also with heavier downstream BW at nursery exit and at fixed-time marketing. To further address management implications of wean weight (WW), this study evaluated WW impact on nursery pig start-up, gain to feed ratio (G:F), and performance variation from 6 to 20 kg BW. Individual BW were collected at the time of weaning using the LeeO individual animal identification system. Pigs (n = 1,054; PIC 800 x DNA 241 F1) were blocked by wean age (20.1 ± 0.8 d) and sex, ranked in order of individual WW (5.94 ± 1.35 kg), and split into eight WW groups each representing 12.5% of the weaning population (P < 0.05; Table 1). Similar sized pigs were housed together (12 pigs/pen, 11 replicate pens/WW group) and fed a common 4-phase nursery diet for 42 d post-wean. Pen weights and feed disappearance were recorded at d 7, 14, 21, and 42, and individual BW were collected at d 42. Data were analyzed using linear mixed effects models in the lme4 package of R. Body weight differences (P < 0.05) between each WW group were evident on d 0 and through d 7 post-weaning. The lightest 12.5% of the weaning population had the greatest (P < 0.001) individual pig BW coefficient of variation (CV) at weaning and d 42 whereas no differences (P > 0.05) in d 42 BW CV were evident among the other WW groups. During the first week post-weaning, average daily feed intake (ADFI) diverged (P < 0.05) between the lightest 12.5% (113 g/d) and the heaviest 25% (134 g/d) of the wean population. From d 0 to 42, the lightest 12.5% WW pigs had slower average daily gain (ADG; P < 0.001), less ADFI (P < 0.001), and reduced exit BW (P < 0.001) than the other WW groups. Neither ADG nor ADFI differed (P > 0.05) among the median 50% of the population from d 0 to 42. No differences (P > 0.10) in overall nursery G:F between any WW groups were observed. Across the population, regression analysis indicated a 0.45 kg increase in WW resulted in a 1.0 kg increase (linear, P < 0.001) in nursery exit BW. Moreover, both ADG and ADFI as a percentage of BW increased as WW decreased, suggesting lighter WW pigs have competitive growth capacity to their heavier WW counterparts through 20 kg BW. Data demonstrates WW influences nursery exit weight of pigs fed a common diet. Future research should explore solutions to increase growth rate of light WW pigs.
218 Weaning weights associated with improved performance of grow-finish pigs
Authors: Krahn Gregory , McCallum Michelle , Mahoney Julie , Hinson Rodney , Eden Chris L
Published: May 2024

This study was conducted to evaluate the downstream impact of wean weight (WW) on finishing pig performance. Individual body weights (BW) were recorded at the time of weaning using the LeeO individual animal identification system. Finisher performance evaluation started at d 57 post-weaning. Pigs (n = 1,276; PIC 800 x DNA 241 F1) were blocked by wean age (20.6 ± 1.5 d) and sex, ranked in order of individual WW (6.05 ± 1.43 kg), and divided into BW quartiles to create four WW treatment groups [WW Quartile (Q) 1, 2, 3, and 4; Table 1]. Pigs (n = 21) in the same Q were housed in each pen yielding 15 replicate pens per quartile. Pigs were fed common diets formulated in a 4-phase sequence from the time of placement in the finisher through marketing, which occurred on a fixed-BW basis targeting 131.5 kg. Pen BW and feed disappearance were recorded every 3 wk and at marketing, and individual BW were recorded on d 134 post-weaning. Data were analyzed using linear mixed effects models in the lme4 package of R. Differences in mean BW of each Q were evident at weaning (P < 0.001), start of finisher evaluation (d 57, P < 0.001), and through d 121 (P < 0.001); by d 144, the BW between Q3 and Q4 did not differ (126.6 vs 129.0 kg, respectively, P > 0.05). Overall average daily gain (ADG) and average daily feed intake (ADFI) were greater (P < 0.001) for finishing pigs of either Q3 or Q4 compared with Q1, but no difference (P > 0.10) in gain to feed ratio (G:F) was observed between quartiles from 28.0 to 131.5 kg BW. Pigs in Q3 and Q4 required fewer (P < 0.001) days on feed than pigs in either Q1 or Q2, which culminated in an overall linear (P < 0.001) effect such that a 0.45-kg advantage in WW resulted in 2.25 d less to reach a market BW of 131.5 kg. Coefficient of variation (CV) in BW at d 134 post-weaning was greater (P < 0.001) for pigs in Q1 compared with pigs in Q2, Q3, or Q4. Backfat depth was thicker (P < 0.05) for Q1 pigs compared with Q4 pigs but did not differ from pigs in Q2 or Q3. A decrease (P < 0.001) in carcass ADG was seen for pigs in the lightest 50% of the population compared with those in Q4. In conclusion, even though feed efficiency was not impacted by WW, heavier WW resulted in fewer days to reach desired market weight while simultaneously resulting in improved carcass characteristics.
219 Effect of stocking density on F1 gilt grow-finish performance
Authors: Self Rachel , Henry Clara K , Mainquist-Whigham Christine , Cross Amanda , Stephenson Ethan , McNeil Brady
Published: May 2024

As replacement rates in the swine industry have increased, gilt development units have increased the number of females developed in the same allotted space. The impact of decreasing space is not well understood on the developing gilt. Therefore, the objective of this study was to evaluate differences in grow-finish performance for developing gilts housed at different stocking densities. At 10 wk of age 824 F1 females (DNA L241, DNA Genetics, Columbus, NE) were randomly allotted to 12 pens per treatment of either 0.71 m2 (n = 360), 0.93 m2 (n = 264), or 1.25 m2 (n = 204). Body weights (BW) were individually collected at 10, 24, and 31 wk of age. Backfat and loin depth were measured using an Exxago Ultrasound between the 10th and 11th rib at 24 and 31 wk of age. Feed consumption was measured at the pen level using a Feed Logic system. Mortality date, reason, and BW were recorded throughout the grow-finish phase. At 10-wk of age, there was no significant difference in BW between the treatments. Differences in BW were observed between treatment 0.71 m2 at 119.3 kg compared with 0.93 m2 and 1.25 m2 at 123.4 kg and 125.6 kg, respectively (P < 0.01). All stocking densities were significantly different (P < 0.01) at 31 wk of age with 0.71 m2 at 142.4 kg, 0.93 m2 at 152.4 kg and 1.25 m2 at 156.5 kg. Backfat and loin depth were significantly different at 24 wk for 0.71 m2 compared with 0.93 m2 and 1.25 m2 (P < 0.05). At 31 wk of age, all treatments were significantly different for backfat with 0.71 m2 at 16.1 mm, 0.93 m2 at 18.0 mm and 1.25 m2 at 19.1 mm (P < 0.05). Feed conversion was not different across treatments from 71 d of age until 84 d of age and from 84 until 111 d of age. However, feed conversion was significantly different from 111 d until 167 d of age for 0.71 m2 at 3.83 compared with 1.25 m2 at 3.40 (P < 0.10). Mortality was not different between treatments (P < 0.05). Gilts that were assigned to the least square foot treatment grew slower and had decreased backfat and loin depth. This could potentially impact the timing of the estrus detection and matings in the replacement gilt population. Overall, producers looking to improve the BW of females entering the breeding herd should evaluate increasing the space allotted per female in their gilt developer.
41 Is there anything we can do to lessen the severity of PRRSv?
Authors: Yeske Paul
Published: May 2024

Veterinarians and the swine industry continue to battle PRRS virus (v), as demonstrated by both the MSHMP (Morrison Swine Health Monitoring Project) and the SDRS (Swine Disease Reporting System). Both systems depict a continued increase in PRRSv prevalence and percentage of positive cases. The PRRSv variants that are circulating today seem to be more severe, especially in the last 2 to 3 yr, with more significant health and production losses in the nursery and finishing phases for prolonged periods of time. The best thing that can be done is to avoid having the virus with a good bioexclusion plan and if sites become infected, a strong biocontainment plan to avoid contaminating more sites should be considered. Realizing that bioexclusion is not always possible and sites will become infected, there are methods to help to reduce the impact of the virus. With the concerns of recombination pushing the virus evolution along faster, more producers are working toward eliminating field viruses from their systems. The use of filtration both on sow farms and nurseries has become more common as well as an additional method of bioexclusion. In the face of an outbreak, obtaining an accurate diagnosis is still one of the most important things that we do. In farrow to wean farms, serum samples are generally used when clinical signs (e.g., abortions, off feed) are observed to target testing to specific animals that are more likely to allow for early detection. In nursery and finishing sites, the use of oral fluid has worked very well as a screening tool when there are clinical signs or problems within a group or flow. Fortunately, there are differential tests that can be used to identify field infection and vaccines strains (since most wean to finish pigs are vaccinated in pig dense areas). With severe strains, depopulation and repopulation strategies have become more popular as a control method, but the majority of herd would use a herd closure. However, the amount of time required for these closures is extending, which lengthens the impacts on sow farms. Among wean to finish systems, the use of depopulating and cleaning up the site is used most, with only routine down times. Anti-inflammatories can also be administered in the acute phase of the outbreak in addition to the use of antibiotics to control secondary bacterial infections, as well as providing a good environment to allow the pigs to better deal with the disease. It’s best to keep the virus out of the herd with a good bioexclusion program. However, when we do have outbreaks, anti-inflammatory and antibiotics to help the pigs through it are important to utilize as we work to eliminate the field virus from the herd.
86 Assessment of sow hemoglobin concentration and its impact on farrowing duration
Authors: Sheffield Sydney L , McClellan Katlyn A , Levesque Crystal L
Published: May 2024

Prolonged farrowing duration may have detrimental effects on sows, leading to physical strain and potential complications post farrowing. Severe hypoxia experienced by piglets during farrowing can result in stillbirths or birth of weak piglets, increasing the likelihood of pre-weaning mortality. While the prevalence of anemia in sows has recently gained attention, the consequences of this condition are not yet well understood. Blood concentration of hemoglobin (Hb) has a role in oxygen carrying capacity and thus may influence the resilience of a sow during farrowing. Evaluating Hb in sows before farrowing could offer insights for improving sow welfare and reducing pre-weaning mortality. The primary objective of this study was to examine the relationship between sow Hb and farrowing duration. A total of 57 sows (n = 5, 6, 29, and 17 of parity 1, 2, 3, and 4, respectively) were monitored for Hb using a Hemocue Hb 201+ handheld Hb monitor where sow blood samples were collected before farrowing (on d 112) and between 40 and 48 h after farrowing (i.e., on d 2) from an ear vein using a 20 G needle. Sows were categorized as anemic (Hb < 10 g/dL) or non-anemic (Hb ≥ 10 g/dL) based on their Hb at d 112. Among sows that were evaluated, 25 were classified as non-anemic- and 32 were classified as anemic. Surveillance cameras were employed to record the farrowing process for each sow, accompanied by human observation. The time of birth for each piglet was recorded to calculate average birthing interval. Within 12 h of birth, all piglets were weighed individually. Stillborn piglets were identified using a lung flotation test conducted within 1 h of birth. The correlation between sow Hb, farrowing duration, stillborn piglets, and total piglets born was evaluated using the PROC CORR procedure and Proc Mixed in SAS was used to test the effect of Hb category on farrowing duration with total piglets born as a covariate. A negative correlation was observed between pre-farrow Hb and farrowing duration (r = -0.62, P < 0.0001). No correlation was observed between farrowing duration and total born (r = 0.22, P = 0.11). However, a significant weak correlation was found between farrowing duration and stillborn piglets (r = 0.32, P = 0.01). Anemic sows had prolonged farrowing duration (7.2 h ± 0.92 min, P = 0.0005) compared with non-anemic sows (3.5 h ± 0.88 min, P = 0.0005). There was no difference in litter size (16.41 ± 0.7 vs 16.3 ± 0.7) for anemic and non-anemic sows, respectively. These findings highlight the importance of sow Hb status at farrowing and indicate sows with decreased Hb may experience prolonged farrowing duration. Strategies to identify anemic sows before farrowing may reduce stillborn rate and improve sow resilience after farrowing.
94 Effects of orally administered Megasphaera elsdenii during finishing diet realimentation on feedlot steer fecal consistency, clinical depression, and rumination
Authors: Schoelerman Zachary , Rusche Warren C , Smith Zachary K , Francis Forest L
Published: May 2024

The objective of the study was to determine the effects of oral administration of Megasphaera elsdenii NCIMB 41125 (ME) during finishing diet realimentation on fecal consistency, clinical depression, and rumination of feedlot steers. Steers [n = 60; initial body weight (BW) = 591 kg ± 38 kg] were assigned to microbial supplement treatment in a randomized complete block design. Treatments were 1) no ME (CON); and 2) orally administered microbial supplement (1 x 1010 colony forming units ME/capsule; LP) immediately before diet reintroduction. Preceding study initiation, steers consumed a finishing diet with 88% concentrate [dry matter (DM) basis] primarily consisting of whole shelled corn and corn silage for 200 d. Steers were transported from a local feedyard 27 km and upon arrival offered ad libitum long stem hay. Forty-eight h after arrival, steers were reintroduced to a 90% concentrate (DM basis) finishing diet with consisting of dry-rolled corn, dried distiller’s grains plus solubles, liquid supplement, and wheat hay. The diet was introduced initially at 1.5% BW on 0 d, and daily delivery was increased until cattle reached their intake plateau at which point a slick bunk management system was employed. At initial processing, all steers received respiratory and clostridial vaccines and were fitted with wireless rumination tags to track daily rumination throughout the 42-d study. Fecal consistency (FCS) and clinical depression scores (CD) were collected starting 24 h after diet initiation, and subsequent collections occurred at 24 h intervals until 168 h. Fecal consistency was recorded on 20 random pen surface fecal samples and CD was recorded for individual steer. Categorical distributions for FCS and CD were analyzed with the Fisher’s Exact Test. Rumination data was analyzed as a linear mixed model with fixed effects of treatment, days on feed (DOF), and their interaction with a random effect of block and DOF as a repeated measure. For all analyses, P ≤ 0.05 was declared significant and 0.05 > P ≤ 0.10 was considered a tendency. No difference (P ≥ 0.49) was observed for CD at all time points. Additionally, no difference (P ≥ 0.12) was observed for FCS at 24, 48, 72, 120, 144, and 168 h. Fecal consistency tended (P = 0.10) to differ at 96 h, with CON exhibiting a 67% decrease in FCS 1 and 2. No significant (P ≥ 0.78) treatment × DOF interaction was noted for daily minutes ruminating. A significant (P < 0.01) DOF effect was realized for daily minutes ruminating. Minutes ruminating differed (P < 0.01) between treatments, with CON steers ruminating 6% more minutes daily than LP steers. Oral administration of ME had minimal effects on FCS and CD and decreased daily rumination time in feedlot steers during finishing diet realimentation.
82 Relationships between performance traits and osteochondrosis of the hock in Standardbred racehorses
Authors: Frake Ella , Tate Nicole , McCoy Annette , McCue Molly
Published: May 2024

Equine osteochondrosis (OC) is a developmental orthopedic disease that results in abnormal articular cartilage and often the formation of osteochondral bone chips (osteochondrosis dissecans). Standardbreds, a breed predominately used in harness racing, are prone to the development of OC. This study aimed to quantify the relationship between OC and key performance traits, fastest mile time, annual earnings, and consistency in race times over career, using a cohort of 347 North American Standardbred horses. Radiographic examination of the tarsi was previously performed to identify horses as OC-affected (n = 155) or healthy (n = 192). Performance data was acquired from the United States Trotting Association (USTA) detailing horse identification, performance, and lifetime race record. Linear mixed multiple regression models were constructed to evaluate the relationship between OC and performance. A total of 24 performance related variables (e.g., age, gait, track) were evaluated for inclusion in the model through subset variable selection and goodness of fit as determined by Schwarz’s Bayesian Information Criterion (SBC). Preliminary results indicate that healthy horses exhibit significantly faster mile times (P < 0.001) compared with their OC-affected counterparts. However, no significant association was detected between OC status and annual earnings (P > 0.2) or consistency in race times over career (P > 0.2). Ongoing analyses are currently being conducted to assess additional predictors and performance variables for a potential association with osteochondrosis. This study emphasizes the importance of implementing effective strategies for OC management and improving breeding selection practices when producing offspring with desired performance characteristics.
PSII-7 Effect of endophyte-infected tall fescue on body weight, vital signs, and liver function of beef heifers
Authors: Takashe Joao Vitor G , Sallem Ahmed , Matthews Jackson , Shike Daniel W W , Braz Camila U
Published: May 2024

Tall fescue was first introduced to the United States over 70 years ago. Since then, it has become the most common forage source for beef cattle in the Southeastern region of the US. Most tall fescue establishes a symbiotic relationship with a toxic fungal endophyte (Epichloë coenophiala), which contributes to the improved vigor of the plant due to acquired resistance to grazing, insects, heat, and drought. However, when consumed by cattle, it may cause fescue toxicosis, a condition characterized by reduced feed intake, body weight (BW) loss, vasoconstriction, and impaired reproductive performance in livestock species. Therefore, the aim of this study was to investigate the effect of endophyte-infected tall fescue consumption on growth performance and health-related traits in beef cattle. For this purpose, 24 Simmental x Angus heifers were divided into two dietary treatments, in which 12 heifers received endophyte-free tall fescue seeds (E-) and 12 heifers were fed with endophyte-infected tall fescue seeds (E+, 6,764 ppb of ergovaline) mixed with the diet for 45 d. The E+ heifers received a daily dose of 20 μg of ergovaline per kg of BW. The E- heifers received the same quantity of seeds as the E+ heifers. For each heifer, phenotypes related to growth (BW), vital signs (respiration rate [RR], and body temperature [TEMP]), and liver functions (serum albumin [ALB], alkaline phosphatase [ALP], aspartate aminotransferase [AST], gamma-glutamyltransferase [GGT], cholesterol [COL], bilirubin [BIL], and triglycerides [TRI]) were analyzed at the end of the experiment. Phenotypes were analyzed using a linear model in R with diet included as a fixed effect. For analysis of BW, the BW at the beginning of the trial was included in the model as a covariate. Results showed that COL and ALP were significantly less (P < 0.05) in the E+ heifers compared with the E- (-32.92 ± 11.16 mg/dL and -32.33 ± 13.95 U/L, respectively). Conversely, E+ heifers had greater (P < 0.05) BW, RR, TEMP, and AST when compared with E- heifers (-17.82 ± 5.12 kg, 25.83 ± 5.52 breaths/min, 0.56 ± 0.12 oC, and 5.83 ± 2.18 U/L, respectively). Measurements of ALB, BIL, GGT, and TRI were not different between E+ and E- heifers. Our results suggest that heifers consuming endophyte-infected tall fescue have compromised vital signs and metabolically altered liver, which may impair growth performance. This study increases our understanding of the biological mechanisms affected by the fescue toxin in beef cattle.