Performance Of Feedlot Cattle Research Articles

PSV-7 greatOPlus (extruded blend of flaxseed and Nannochloropsis oculata biomass) improves finishing cattle performance and carcass characteristics

Abstract Our objective was to investigate impact of feeding greatOPlus (GOP), an extruded mixture of flaxseed and Nannochloropsis microalgae biomass (NBO3 Technologies LLC; Manhattan, KS) on feedlot cattle performance and carcass characteristics. Yearling steers (n = 700; 374 ± 8.2 kg initial body weight) were blocked by initial body weight and assigned randomly, within block, to 28 feedlot pens containing 25 animals/pen. Cattle were vaccinated against viral and clostridial pathogens and treated for internal and external parasites (Bovishield Gold 5, Ultrabac 7 Somubac, and Dectomax injectable; Zoetis Animal Health), and implanted with a combination implant (Component TE-200; Elanco USA). The control diet (CON) consisted of 58.3% steam-flaked corn, 20% wet corn gluten feed, 2.56% soybean meal, and 4.17% vitamin/mineral/feed additive premix. For the GOP diet, a portion of the corn and all of the soybean meal were replaced with 10% GOP (dry basis) to create isonitrogenous diets. Cattle were fed once daily, ad libitum. After 175 d on feed, animals were weighed and transported to a commercial abattoir for harvest. Animal performance measurements included average daily gain (ADG), dry matter intake (DMI), and gain to feed ratio (G:F). Hot carcass weight (HCW) and incidence of abscessed livers were assessed on the day of harvest, and marbling score, 12th rib fat thickness, longissimus muscle area, and USDA yield and quality grades were determined following 48 hours of refrigeration. Cattle fed GOP had greater DMI and ADG (P< 0.05) compared with cattle fed CON, but G:F was not affected by treatment (P > 0.10). Cattle fed GOP had greater HCW compared with those fed CON (422.8 vs 409.5 kg; P < 0.01) and tended to produce more Prime and Choice carcasses (87.4 vs 83.0%; P = 0.11) with greater 12th rib backfat (1.55 vs 1.49 cm; P < 0.02) and greater yield grades (2.91 vs 2.75; P < 0.01). Marbling score (488 vs 491), longissimus muscle area (94.1 vs 93.4 cm2) and liver abscess incidence (12 vs 16% for CON and GOP, respectively) were unaffected by treatment (P > 0.10). Carcass values were calculated using base prices, premiums, and discounts published by USDA, and were greater for cattle fed GOP compared with cattle fed the control diet ($2,122 vs $2,059; P < 0.01). Including greatOPlus at 10% of the diet dry matter improved cattle performance, largely as a result of its impact on DMI and ADG.

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

Abstract 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.

163 Impact of feeding wet or dry traditional or fractionated (Solbran) distiller’s grains on feedlot cattle performance and carcass characteristics

Abstract Solbran (ICM, Colwich, KS) is new corn byproduct of ethanol production composed of fiber plus condensed distiller’s solubles and can be fed dry (Dry Solbran; NDF = 41.1%; CP = 21.84%; Ether extract = 8.4%), or wet (Wet Solbran; NDF = 49.7%; CP = 22.67%; Ether extract = 8.5%). The objective of this study was to evaluate the energy value of dry and wet Solbran compared with traditional dry- (DDGS) and wet- distiller’s grains plus solubles (WGGS) in beef cattle finishing diets. The treatments included a control (CON) with no distiller’s grains compared with the inclusion of DDGS, WDGS, Dry Solbran and Wet Solbran at two levels (20% and 40%) resulting in a 2 × 2 × 2 + 1 factorial. Orthogonal contrasts defined linear and quadratic effects of byproduct inclusion through the common intercept of CON. Additionally, interactions among inclusion (20% or 40%), moisture (dry and wet) and processing method (Solbran or traditional) were evaluated as a 2 × 2 × 2 factorial without CON. There was a linear increase in dry matter intake (DMI) by adding DDGS, Dry Solbran, and Wet Solbran (P < 0.01) and a tendency for a linear increase in dry matter intake (DMI) with WDGS (P = 0.07). There was a linear increase in ADG by adding DDGS or Wet Solbran (P < 0.05) and a tendency for a linear increase in average daily gain (ADG) with the addition of Dry Solbran or WDGS (P < 0.10). These changes in DMI and ADG resulted in a linear decrease in gain to feed ratio (G:F) when Dry Solbran was added (P < 0.01), and a tendency towards a linear decrease in G:F when DDGS was added (P < 0.10). The inclusion of Wet Solbran or WDGS did not influence G:F (P = 0.45). For the 2 × 2 × 2 factorial, there was a 2-way interaction for moisture by inclusion of byproduct for G:F where wet byproduct fed at 40% of the diet resulted in the greatest G:F and 40% dry byproduct resulted in the least G:F (P = 0.04). This interaction was driven by an increase in DMI for 40% byproduct when fed dry, and a reduction in DMI for both 20 and 40% byproduct fed wet. There was no difference in ADG between the treatments (P = 0.75). For the main effect byproduct type, steers fed Solbran had greater DMI (P < 0.01) with no difference in ADG (P = 0.79), resulting in a 3% reduction in G:F (P = 0.03) for steers fed Solbran but greater marbling (P < 0.01). Impact of feeding distillers grains byproducts on DMI, ADG, and G:F are impacted by the processes used in the ethanol plant, whether wet or dry, and dietary inclusion.

High deoxynivalenol and ergot alkaloid levels in wheat grain: effects on growth performance, carcass traits, rumen fermentation, and blood parameters of feedlot cattle.

This study was designed to assess the impacts of a mixture of deoxynivalenol (DON) and ergot alkaloids (EAs) on growth performance, rumen function, blood parameters, and carcass traits of feedlot cattle. Forty steers (450 ± 6.0kg) were stratified by weight and randomly allocated to 1 of 4 treatments; control-low (CON-L), control-high (CON-H) which contained low or high wheat screenings that lacked mycotoxins at the same level as the mycotoxin-low (MYC-L; 5.0mg/kg DON, 2.1mg/kg EA), and mycotoxin-high (MYC-H: 10mg/kg DON, 4.2mg/kg EA) diets that included wheat screening with mycotoxins. Steers were housed in individual pens for a 112-day finishing trial. Intake was 24.8% lower (P < 0.001) for MYC steers compared to CON steers. As a result, average daily gains of MYC steers were 42.1% lower (P < 0.001) than CON steers. Gain to feed ratio was also lower (P < 0.001) for MYC steers compared to CON steers. Platelets, alanine aminotransferase, globulins, and blood urea nitrogen were lower (P ≤ 0.008), and lymphocytes, glutathione peroxidase activity (GPx), and interleukin-10 (IL-10) were elevated (P ≤ 0.002) in MYC steers compared to CON steers. Hot carcass weights and backfat thickness were reduced (P < 0.001) in MYC steers, resulting in leaner (P < 0.001) carcasses and higher (P < 0.007) meat yield compared to CON steers. Results suggest that a mixture of DON and EAs negatively impacted health, performance, and carcass traits of feedlot steers, with the majority of this response likely attributable to EAs. However, more research is needed to distinguish the relative contribution of each mycotoxin to the specific responses observed.

Effect of woodchip bedding during wet conditions on feedlot cattle productivity, behaviour and relative adrenal gland weight

Problems associated with muddy pens have been identified as some of the most serious animal welfare issues related to outdoor feedlot beef production, but there is relatively little work examining the use of woodchip bedding for lot-fed beef cattle under conditions of cold, wet, but non-freezing winters on soil under-bases. This study examined the effects of graded levels of woodchip on the performance and behaviour of feedlot cattle housed in wet pen conditions. Bos taurus steers (n = 300; 379.1 ± 24.1 kg) were blocked by weight and breed and randomly assigned to 30 10-steer feedlot pens provided with either no woodchip bedding (Control, n = 10) manure interface only, or 15 cm depth of woodchip bedding (W15, n = 10) or 30 cm depth of woodchip bedding (W30, n = 10). The steers were housed in these treatment pens for 109 days on a feedlot ration, and the pens were irrigated so that approximately 74 mm of total precipitation (irrigation + natural rainfall) fell onto the pen surface every 30 days. Temperatures were mostly <20 °C maximum and −1 to 5 °C minimum. Steers were weighed on five occasions. Animal position and posture in pen were recorded once a week over an 8-hour day-time period. Carcase characteristics were measured, and adrenal gland weights were recorded. Providing woodchip bedding increased liveweight gain (P < 0.001) and gain:feed (G:F, P = 0.012) after day 28, increased DM intake (DMI) after day 92 (P = 0.049), and increased carcase weight (P = 0.001) and dressing percentage (P = 0.023). There was no additional benefit of W30 over W15 for liveweight gain or DMI, but the benefit of W15 for G:F was lower than that of W30 by the end of the feeding period (P = 0.012). There were no effects of bedding on other carcase quality traits. Steers in Control pens utilised the front of the pen for lying and standing more than the W15 and W30 steers (P < 0.001) suggesting the steers in the Control pens perceived the front of the pen as less aversive, potentially due to increased drainage compared to rest of the pen and proximity to feed bunk. Adrenal gland weight/kg and carcase weight tended to be higher in the Control treatment group than the W30 steers (P = 0.077). This research has demonstrated that for a 109-day feeding period in cold, wet conditions, steer performance and welfare can be improved by providing a minimum of 15 cm woodchip bedding.

337 Supplementation of a Kaolin and Yeast-Based Feed Additive on Performance of Feedlot Cattle

Abstract The objective of this project was to examine the effectiveness of feeding a kaolin and yeast-based feed additive on the performance of feedlot cattle. Seventy-five steers (initial BW; 545 ± 42.4 kg) were blocked by BW and randomly allocated into 25 blocks of 3 steers (n = 25 per treatment) in a randomized complete block design with 3 treatments including control, low (10 g/day) and high (15 g/day) kaolin and yeast-based feed additive (FA) supplementation. The steers were fed a finishing diet consisting of 7% corn silage, 1% straw, and 92% corn-based concentrate (DM basis). The duration of the feeding period was 120 days. Supplementation of high grain finishing diet with FA did not affect feed intake (average, 12.4 kg/d), final BW (average, 768 kg), averaged daily gain (average, 1.77 kg/d), carcass traits, and abscessed livers. However, increasing the feeding of FA (0, 10, 15 g/d) to finishing steers linearly (P = 0.05) improved feed efficiency from 0.139 to 0.143 and 0.148 kg gain/kg feed and linearly (P = 0.06) improved net energy for maintenance from 2.05 to 2.10 and 2.15 Mcal/kg and net energy for growth from1.39 to 1.43 and 1.47 Mcal/kg, respectively. Fecal IgA concentration linearly (P = 0.06) increased from 15.0 to 22.7 and 30.1 µg/g with increasing FA addition, suggesting an improvement in nutrient absorption, and potentially better gut health. The increasing addition of FA also linearly (P = 0.03) increased plasma lipopolysaccharide binding protein (LBP) concentration from 46.3 to 56.2 and 64.7 µg/mL but decreased blood total antioxidants from 0.282 to 0.251 and 0.204 mM. These results suggest that the addition of FA may support gut health.

PSXII-18 The Probiotic Containing Bacillus Licheniformis and Bacillus Subtilis Improves Feed Efficiency in Beef Cattle

Abstract The aim of this study was to investigate the effects of a probiotic containing B. licheniformis and B. subtilis on fecal characteristics, blood parameters, and performance in feedlot cattle. One hundred and forty-four single-sourced Angus x Nellore bulls (initial shrunk BW = 401 ± 45.5 kg) were randomly assigned to 1 of 2 treatments (4 bulls per pen; 18 pen replicates per treatment). Treatments consisted of a finishing diet containing no probiotic (CONTROL) or a diet with 2 g of probiotic/bull/d (PROB). The probiotic was composed of B. licheniformis CH200 and B. subtilis CH201 (3.2 x 109 CFU/g; BOVACILLUS). The diet was formulated using NASEM (2016) to provide an ADG of 1.9 kg/d (23% of corn silage, 65% of ground corn, 8% of soybean meal, 1% of urea, and 3% of mineral mix; DM basis). Bulls were adapted to the finishing diet over a 15-d period and fed for a total of 84 d. Fecal samples were collected on d 33 and 63. Blood samples were collected on the day of shipping to slaughter. Statistical analysis of experimental data was performed using the MIXED procedure of SAS 9.4. An α of 0.05 determined significance and an α of 0.06 to 0.10 was considered a tendency. No differences were obtained for initial BW, final BW, ADG, hot carcass, and dressing. Dry matter intake was reduced by 4% (P = 0.002) and G:F was increased by 6.3% (P = 0.036) in bulls consuming PROB diet. Regarding blood parameters, no differences were observed for glucose, haptoglobin, and LBP. There was a tendency of greater plasma urea (P = 0.09) in bulls consuming CONTROL diets. Fecal characteristics (DM, starch, N, pH, and scoring) were not different between treatments. Overall, dietary supplementation with B. licheniformis and B. subtilis improves feed efficiency in feedlot cattle.

PSIX-18 A Meta-Analysis on Undigestible Neutral Detergent Fiber as a Predictor for Feedlot Cattle Performance and Carcass Characteristics

Abstract Undigestible neutral detergent fiber (uNDF) is a non-nutritive component of the diet representing the portion of neutral detergent fiber (NDF) that is not digested. The uNDF amount affects ruminal fill, passage rate, diet digestibility, and cattle performance. Therefore, a meta-analysis was conducted to evaluate the potential use of dietary uNDF to predict finishing feedlot cattle performance and carcass characteristics. A specific search string was used to obtain 22 eligible experiments forming a database in which models were developed. The search string used was as follows “(feedlot OR beef) AND (forage OR roughage OR iNDF OR uNDF) AND (dressing percentage OR dressing %) AND (liver abscess) AND (feed efficiency OR GF OR FG) AND (DMI) AND (ADG) AND (rumen pH OR ruminal pH OR reticulo-ruminal pH)”. Due to the lack of measurement and reporting of uNDF in the literature, the dietary uNDF of each treatment included in the meta-analysis was estimated using data from the Cumberland Valley Analytical Services database. A comparison of uNDF and NDF as predictor variables of performance was also assessed. Models were developed using a mixed model approach, where experiment was modelled as a random effect. Models with dry matter intake (DMI), implant or tylosin as driving variables alongside uNDF concentration or uNDF intake lowered the root mean square prediction error (RMSPE) and improved the concordance correlation coefficient (CCC). The comparison of uNDF and NDF as predictors of outcomes demonstrated more accurate predictions with uNDF as the driving variable. Developed models from this meta-analysis can reasonably predict average daily gain, DMI, dressing percentage, final body weight, dressing percentage, feed efficiency, and hot carcass weight in healthy Bos taurus feedlot cattle. Results suggest there is still more to be discovered about uNDF and its impact in diets for finishing cattle and that uNDF may be a more informative metric than NDF alone. Further research to improve the characterization of forage in the diets of beef cattle is recommended.

401 Dietary Starch Dilution Strategies to Improve Feedlot Cattle Performance and Rumen Health

Abstract This study evaluated starch dilution with different sources of fiber from terminal implant to harvest on feedlot cattle performance, rumen buffering characteristics, and carcass outcomes. Steers (n = 416) were allocated to 48 pens in a randomized complete block design and assigned to 1 of 4 dietary treatments. Treatments were steam-flaked corn-based diets: CON; 7.5% corn stalks fed for the entire feeding period or CON followed by CS; 14.8% corn stalks, WD; 9.5% wet distillers grains with solubles and 7.5% corn stalks, or NR; 19.0% wet distillers grains with solubles and 0.0% corn stalks fed from terminal implant to harvest. Steers were transitioned to CS, WD, and NR over 6 d using a two-ration system. Within each pen, 2 steers received an indwelling rumen pH bolus and a 3-axis accelerometer ear-tag to quantify rumination. Treatment differences were considered statistically significant when P &amp;lt; 0.10. Dry matter (DM) and metabolizable energy (ME) intake were greatest for cattle consuming CS, intermediate for WD and CON, and least for NR (P &amp;lt; 0.01). The average daily gain (ADG) did not differ among treatments (P = 0.18); however, feed efficiency (G:F) was least for NR, intermediate for WD, and greatest for CS and CON (P = 0.10). Steers consuming CS had more (P = 0.08) 12th rib fat than NR, WD, or CON, but no other differences (P ≥ 0.24) in carcass characteristics were observed. A treatment × day interaction (P &amp;lt; 0.01) was observed for daily rumination time and ruminal pH. Results suggest that increasing the concentration of corn stalks in the diet post-terminal implant increased DM and ME intake and rumination; replacing corn stalks with wet distillers grains with solubles improved G:F and reduced rumination with minimal impacts on ruminal pH.

341 Effect of Multispecies Fungal Culture Extract Supplementation on the Growth Performance and Carcass Characteristics of Feedlot Cattle

Abstract To evaluate the effect of supplementing feedlot cattle with a multispecies fungal culture extract (MFE; Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, Aspergillus terreus, Phlebia radiata, Pyricularia oryzae, Stropharia coronilla, Thanatephorus cucumeris, Trichoderma longibrachiatum, Trichoderma reesei, Trichoderma viride) in growth performance and carcass characteristics, Angus × SimAngus-crossbred steers (n = 14) and heifers [n = 46; body weight (BW) 344 ± 21 kg] were used in randomized complete block design. Cattle were blocked by BW and housed in 4 feedlot pens (randomly assigned 2 pens per treatment) where a hay-based diet was fed for 84 d (backgrounding), followed by a ground corn-based finishing diet. Subsequently, cattle were harvested upon reaching desired 12th rib fat thickness (2.0 cm). Diets were offered ad libitum and with (MFE) or without (CON) the inclusion of the multispecies fungal culture extract supplement. Steers were weighed at 28-d intervals throughout the experimental period and carcass data were provided by a USDA grader. All data were analyzed using the PROC MIXED procedure of SAS considering the fixed effect of treatment and sex, and the random effect of block and pen (block). During the 84-d period of the backgrounding phase, feeding MFE increased (P = 0.05, Table 1) the average daily gain (ADG) by ~10%, and tended to increase (P = 0.06, Table 1) the dry matter intake (DMI). No differences were observed in the gain to feed ratio (G:F) between treatments (P = 0.67, Table 1). At the conclusion of the 84-d period, cattle fed MFE were heavier (P = 0.04, Table 1) than cattle in the CON treatment. In the finishing phase, no treatment differences were observed (P ≥ 0.36) for the ADG, DMI, and G:F. At the end of the experiment, cattle supplemented with MFE were heavier (P = 0.04, Table 1) than cattle in the CON treatment. The quantity of days on feed in the finishing diet required to reach harvesting target was not different (P = 0.60) among treatments. For the carcass characteristics, dietary inclusion of the MFE tended to increase the hot carcass weight (P = 0.10, Table 2) and increased the marbling score (P = 0.01, Table 2). No treatment effect was detected (P ≥ 0.25, Table 2) for the dressing, longissimus muscle area, 12th rib fat thickness, kidney-pelvic-heart fat content, and yield grade. Results from this study suggest that dietary inclusion of a multispecies fungal culture extract might improve the growth performance of beef cattle fed forage-based diets, as well as their carcass characteristics after conclusion of the feedlot finishing phase.

P79 Effects of laidlomycin, monensin and virginiamycin on dry matter intake, performance and ruminal health of feedlot cattle

P79 Effects of laidlomycin, monensin and virginiamycin on dry matter intake, performance and ruminal health of feedlot cattle

P68 A microencapsulated blend of essential oils and yeast culture combined with monensin improved feedlot cattle performance and ameliorated heat stress

P68 A microencapsulated blend of essential oils and yeast culture combined with monensin improved feedlot cattle performance and ameliorated heat stress

Effect of dry or temper rolling of high- or low-protein wheat and its impact on rumen parameters, growth performance, and liver abscesses in feedlot cattle

This study assessed the impact of dry- (DR) versus temper-rolled (TR) and low- (13%, LP) versus high-protein (18%, HP) wheat on ruminal fermentation, growth, and liver abscesses in feedlot cattle. Crossbred Angus steers (302 ± 34 kg; n = 160; 24 ruminally cannulated) were used in a backgrounding (BG) to finishing (FN) trial. The BG diet consisted of 60% barley silage, 35% wheat, and 5% supplement, and the FN diet contained 10% barley silage, 85% wheat, and 5% supplement (dry matter basis). Four transition (TN) diets were used to adapt cattle to the FN diet. A numerical increase in large particles and reduction in small particles occurred when both HP and LP wheat were TR, with this response being greater for HP wheat. Steers experienced lower ( P ≤ 0.03) ruminal pH with HP-DR and LP-TR than HP-TR wheat during TN. Steers fed HP wheat BG diets tended to exhibit greater ( P ≤ 0.09) gain:feed and NEg than steers fed LP wheat. Greater ( P = 0.01) average daily gains were exhibited by FN steers fed LP wheat. Liver abscesses were more ( P &lt; 0.001) severe with HP wheat. While HP wheat improved the growth of BG cattle, it increased the severity of liver abscesses during FN.

35 Effects of Supplementing Pre- and Pro-Biotic Feed Ingredients on Performance, Health, and Physiological Responses in Feedlot Cattle

Abstract This experiment examined the effects of a synbiotic supplement (yeast-derived prebiotic + Bacillus subtilis probiotic), which replaced or was fed with feed-grade antimicrobials (monensin and tylosin), on performance and health responses of feedlot cattle. Angus-influenced steers (n = 192) from 4 different sources were weaned and transported 800 km to an experimental feedlot. Steers arrived on d 0 and a shrunk body weight (BW) was recorded. Steers were then ranked by source and shrunk BW and allocated to 1 of 24 drylot pens (8 steers/pen). Steers a received free-choice diet of 3 treatments: 1) monensin and tylosin (RT; 360 mg/steer/day from Rumensin and 90 mg/steer/day from Tylan; Elanco Animal Health, Greenfield, IN), 2) yeast-derived ingredient and B. subtilis probiotic (CC;8 g∙steer-1∙day-1 of Celmanax and 28 g∙steer-1∙day-1 of Certillus; Church and Dwight Co., Inc., Princeton, NJ), or 3) a combination of RT and CC (RTCC). Animals were adapted to diets in a stepwise manner which consisted of a receiving diet (d 0 to 56), two step-up diets (step-up: d 57 to 63; step-up 2: d 64 to 70), and a final diet (d 71 to slaughter). The cattle were slaughtered in four groups according to BW and balanced by treatments. More specifically, 33 steers were slaughtered on d 200, 33 steers on d 230, 63 steers on d 257, and 63 steers on d 285. Upon slaughter, hot carcass weight, backfat thickness, Longissimus muscle area, USDA marbling score, USDA yield/quality grades, and liver abscess score were recorded. Overall, feed intake during the duration of the experimental period (d 0 to slaughter) was greater (P &amp;lt; 0.01) in CC compared with RT and RTCC. However, no differences were observed for ADG (P = 0.61), final BW (P = 0.67), or morbidity (P = 0.15). With increases in intake but no differences in ADG the CC group had lower feed efficiency (P = 0.02) when compared with RT and RTCC. Upon slaughter, CC had higher marbling scores compared with RT (P = 0.04). Both the CC and RTCC cattle had larger Longissimus muscle area (P = 0.07) and more carcasses grading choice or better (P &amp;lt; 0.01) when compared with RT. Whereas, hot carcass weight, backfat thickness, and yield grade did not differ among treatments (P ≥ 0.20). There was tendency observed for liver abscesses (P ≤ 0.09) to be greater in CC compared with RT and RTCC. Overall, supplementing feedlot steers with RT and CC improved feed intake and some carcass measures despite the decreased feed efficiency experienced by these cattle but combining CC and RT did not yield any additional performance or health benefits.

37 Supplemented with Yucca Schidigera Extract to Feedlot Cattle Consuming Diets with or Without Monensin

Abstract This experiment compared performance and physiological responses of feedlot cattle receiving a saponin containing feed ingredient manufactured from purified extract of Yucca schidigera [Micro-Aid (MA); DPI Global, Porterville, CA] which replaced or was fed in conjunction with feed-grade antimicrobials. Yearling, Angus-influenced steers (n = 20) arrived at the experimental feedlot on d -19 and a shrunk body weight (BW; 309 ± 4 kg) was immediately recorded. Steers were ranked by BW and allocated to 4 groups of 30 steers each. Groups were housed in of 4 drylot pens equipped with GrowSafe automated feeding systems (4 bunks/pen) during the experiment (d -15 to 69). On d 0 groups were randomly assigned to receive a total mixed ration containing: monensin and tylosin (RT; 360 mg/steer daily from Rumensin and 90 mg/steer daily from Tylan; Elanco Animal Health, Greenfield, IN) and/or 4 g/steer daily of MA in a 2 × 2 factorial arrangement of treatments. During the experimental period non-supplemented (CON) steers received a total mixed ration containing no additives. Individual feed intake was recorded daily, and steer BW was recorded every 28 d and before slaughter. Steers were slaughtered according to BW and slaughter groups were balanced by treatments (36 steers on d 120, 36 steers on d 146, and 48 steers on d 174). Carcass traits were recorded upon slaughter. On d 55 eight rumen-cannulated heifers were housed with yearling steers (1 pair/pen). Pairs rotated among groups every 21 d, resulting in a 4 × 4 Latin Square design (n = 8 per treatment) with a 5-day washout between rotations. Rumen fluid was collected from pairs on d 55, 75, 90,110, 125, 145, 160, and 180 (beginning and end of each 21-day rotation) and pH was recorded immediately after collection. No RT × MA treatment interactions were detected (P &amp;gt; 0.10). Feed intake was decreased (P &amp;lt; 0.01) in steers receiving RT, whereas feed efficiency was greater (P = 0.02) in steers receiving RT. Carcass variables including hot carcass weight, backfat thickness, Longissimus muscle area, marbling, yield grade, and percent of carcasses grading choice or better did not differ among treatments (P ≥ 0.17). Rumen fluid pH was greater (P = 0.04) in steers receiving RT. Steers receiving MA had greater (P = 0.03) rumen fluid pH and decreased (P = 0.04) rumen fluid viscosity. Collectively, supplementing feedlot cattle with Yucca schidigera extract improved rumen pH and viscosity, but failed to impact performance or carcass measures in feedlot cattle.

Supplementing pre- and probiotic ingredients to feedlot steers: effects on health, growth performance, and physiological responses.

Feedlot diets are often enriched with additives to mitigate health disorders and promote cattle performance, including the feed-grade antimicrobials monensin and tylosin. However, alternative feeding strategies are warranted given the increasing regulations regarding the use of antimicrobials in feedlot diets. This study evaluated the performance, physiological, and health responses of feedlot cattle offered a synbiotic supplement (yeast-derived prebiotic+Bacillus subtilis probiotic), which replaced or was fed in conjunction with monensin and tylosin. Angus-influenced steers (n=192) from four different cowherds were weaned on day -1 and transported (800km) to the feedlot. Steers were allocated to 1 of 24 pens (eight steers/pen) upon arrival on day 0. Pens were assigned to receive (n=8/treatment) a total-mixed ration (TMR) containing: (1) monensin and tylosin (RT; 360mg/steer daily from Rumensin and 90mg/steer daily from Tylan; Elanco Animal Health, Greenfield, IN, USA), (2) yeast-derived ingredient and B. subtilis probiotic (CC; 18g/steer daily of Celmanax and 28g/steer daily of Certillus; Church and Dwight Co., Inc., Princeton, NJ, USA), or (3) a combination of RT and CC (RTCC). Steers were slaughtered according to BW in four groups balanced by treatment and pens and received treatments for 252±4days. No treatment effects were detected (P≥0.17) for steer BW gain and morbidity responses. Mean TMR intake was greater and gain:feed ratio was less (P≤0.01) in CC compared with RT and RTCC steers. Mean plasma leptin concentration was greater (P≤0.05) in CC compared with RT and RTCC steers. Steers receiving CC had greater (P≤0.04) concentrations of plasma cortisol, haptoglobin, glucose, and beta-hydroxybutyrate, and less (P≤0.05) concentration of non-esterified fatty acids compared with RT and RTCC steers on day 14 of the experiment. Carcass marbling was greater (P=0.01) in CC compared with RT steers and tended to be greater (P=0.07) in RTCC compared with RT steers. Proportion of carcasses that graded Choice or better and Longissimus muscle area were greater (P≤0.05) in CC and RTCC compared with RT steers. Incidence of liver abscesses was less (P=0.01) in RTCC compared with CC steers and tended to be less (P=0.09) in RT compared with CC steers. Results from this experiment indicate that the synbiotic supplement may replace monensin and tylosin without reducing steer BW gain, with potential improvements to carcass quality traits.

Feedlot performance, rumen and cecum morphometrics of Nellore cattle fed increasing levels of diet starch containing a blend of essential oils and amylase or monensin.

Feed additives used in finishing diets improve energy efficiency in ruminal fermentation, resulting in increased animal performance. However, there is no report evaluating the effect of BEO associated with exogenous α-amylase in response to increased starch content in feedlot diets. Our objective was to evaluate increasing levels of starch in the diet associated with a blend of essential oils plus amylase or sodium Monensin on performance, carcass characteristics, and ruminal and cecal morphometry of feedlot cattle. 210 Nellore bulls were used (initial body weight of 375 ± 13.25), where they were blocked and randomly allocated in 30 pens. The experiment was designed in completely randomized blocks in a 3 × 2 factorial arrangement: three starch levels (25, 35, and 45%), and two additives: a blend of essential oils plus α-amylase (BEO, 90 and 560 mg/kg of DM, respectively) or sodium Monensin (MON, 26 mg/kg DM). The animals were fed once a day at 08:00 ad libitum and underwent an adaptation period of 14 days. The diets consisted of sugarcane bagasse, ground corn, soybean hulls, cottonseed, soybean meal, mineral-vitamin core, and additives. The animals fed BEO35 had higher dry matter intake (P = 0.02) and daily weight gain (P = 0.02). The MON treatment improved feed efficiency (P = 0.02). The treatments BEO35 and BEO45 increased hot carcass weight (P < 0.01). Animals fed BEO presented greater carcass yield (P = 0.01), carcass gain (P < 0.01), rib eye area gain (P = 0.01), and final rib eye area (P = 0.02) when compared to MON. The MON25 treatment improved carcass gain efficiency (P = 0.01), final marbling (P = 0.04), and final subcutaneous fat thickness (P < 0.01). The use of MON reduced the fecal starch% (P < 0.01). Cattle-fed BEO increased rumen absorptive surface area (P = 0.05) and % ASA papilla area (P < 0.01). The MON treatment reduced the cecum lesions score (P = 0.02). Therefore, the use of BEO with 35 and 45% starch increases carcass production with similar biological efficiency as MON; and animals consuming MON25 improve feed efficiency and reduce lesions in the rumen and cecum.

Effect of probiotic lactobacilli supplementation on growth parameters, blood profile, productive performance, and fecal microbiology in feedlot cattle

Lactic acid bacteria (LAB) selected on the basis of probiotic characteristics were administered to beef feedlot catlle and the effect on body condition/growth and nutritional-metabolic status as well as on E. coli O157:H7 fecal shedding, were investigated. A feeding trials involving 126 steers were used to evaluate the effects of Lactobacillus acidophilus CRL2074, Limosilactobacillus fermentum CRL2085 and Limosilactobacillus mucosae CRL2069 and their combinations (5 different probiotic groups and control) when 107-108 CFU/animal of each probiotic group were in-feed supplemented. Cattle were fed a high energy corn-based diet (16 to 88%) and samples from each animal were taken at 0, 40, 104 and 163 days. In general, animals body condition and sensorium state showed optimal muscle-skeletal development and behavioral adaption to confinement; no nasal/eye discharges and diarrheic feces were observed. The nutritional performance of the steers revealed a steady increase of biometric parameters and weight. Animals supplied with L. mucosae CRL2069 for 104 days reached the maximum mean live weight (343.2 kg), whereas the greatest weight daily gain (1.27 ± 0.16 Kg/day) was obtained when CRL2069 and its combination with L. fermentum CRL2085 (1.26 ± 0.11 kg/day) were administered during the complete fattening cycle. With several exceptions, bovine cattle blood and serum parameters showed values within referential ranges. As a preharvest strategy to reduce Escherichia coli O157:H7 in cattle feces, CRL2085 administered during 40 days decreased pathogen shedding with a reduction of 43% during the feeding period. L. fermentum CRL2085 and L. mucosae CRL2069 show promise for feedlot cattle feeding supplementation to improve metabolic-nutritional status, overall productive performance and to reduce E. coli O157:H7 shedding, thus decreasing contamination chances of meat food products.

Feeding 3-nitrooxypropanol reduces methane emissions by feedlot cattle on tropical conditions.

Our objective was to evaluate the effects of feeding 3-nitrooxypropanol (3-NOP; Bovaer®, DSM Nutritional Products) at two levels on methane emissions, nitrogen balance and performance by feedlot cattle. In exp. 1, a total of 138 Nellore bulls (iBW, 360 ± 37.3kg) were housed in pens (27 pens with either 4 or 5 bulls per pen) and fed a high-concentrate diet for 96 days, containing 1) no addition of 3-NOP (control), 2) inclusion of 3-NOP at 100mg/kg DM, and 3) inclusion of 3-NOP at 150mg/kg DM. No adverse effects of 3-NOP were observed on DM intake, animal performance and gain:feed (P > 0.05). In addition, there was no effect (P > 0.05) of 3-NOP on carcass characteristics (subcutaneous fat thickness and rib eye area). In exp. 2, 24 bulls (iBW, 366 ± 39.6kg) housed in 12 pens (two bulls/pen) from Exp.1 were used for CH4 measurements and nitrogen balance. Irrespective of the level, 3-NOP consistently decreased (P < 0.001) animals' CH4 emissions (g/d; ~ 49.3%), CH4 yield (CH4/DM intake; ~40.7%) and CH4 intensity (CH4/ADG; ~38.6%). Moreover, 3-NOP significantly reduced the gross energy intake lost as CH4 by 42.5% (P < 0.001). The N retention: N intake ratio was not affected by 3-NOP (P = 0.19). We conclude that feeding 3-NOP is an effective strategy to reduce methane emissions, with no impairment on feedlot cattle performance.

Effect of 3-nitrooxypropanol on enteric methane emissions of feedlot cattle fed a tempered barley-based diet with canola oil.

A dose-response experiment was designed to examine the effect of 3-nitrooxypropanol (3-NOP) on methane (CH4) emissions, rumen function and performance of feedlot cattle fed a tempered barley-based diet with canola oil. Twenty Angus steers of initial body weight (BW) of 356 ± 14.4kg were allocated in a randomized complete block design. Initial BW was used as the blocking criterion. Cattle were housed in individual indoor pens for 112 d, including the first 21 d of adaptation followed by a 90-d finishing period when five different 3-NOP inclusion rates were compared: 0mg/kg DM (control), 50mg/kg DM, 75mg/kg DM, 100mg/kg DM and 125mg/kg DM. Daily CH4 production was measured on d 7 (last day of starter diet), 14 (last day of the first intermediate diet), and 21 (last day of the second intermediate diet) of the adaptation period and on d 28, 49, 70, 91 and 112 of the finisher period using open circuit respiration chambers. Rumen digesta samples were collected from each steer on the day prior to chamber measurement post-feeding, and pre-feeding on the day after the chamber measurement, for determination of rumen volatile fatty acids (VFA), ammonium-N, protozoa enumeration, pH and reduction potential. Dry matter intake (DMI) was recorded daily and BW weekly. Data were analyzed in a mixed model including period, 3-NOP dose and their interaction as fixed effects, and block as a random effect. Our results demonstrated both a linear and quadratic (decreasing rate of change) effect on CH4 production (g/d) and CH4 yield (g/kg DMI) as 3-NOP dose increased (P < 0.01). The achieved mitigation for CH4 yield in our study ranged from approximately 65.5% up to 87.6% relative to control steers fed a finishing feedlot diet. Our results revealed that 3-NOP dose did not alter rumen fermentation parameters such as ammonium-N, volatile fatty acids (VFA) concentration nor VFA molar proportions. Although this experimental design was not focused on the effect of 3-NOP dose on feedlot performance, no negative effects of any 3-NOP dose were detected on animal production parameters. Ultimately, the knowledge on the CH4 suppression pattern of 3-NOP may facilitate sustainable pathways for the feedlot industry to lower its carbon footprint.