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Two experiments were designed to evaluate the impacts of supplementing lasalocid (LAS), narasin (NAR), or virginiamycin (VRM) on rumen fermentation parameters, apparent nutrient digestibility, and blood parameters (Exp. 1), as well as feed intake and performance (Exp. 2) of Nellore cattle consuming a forage-based diet. In Exp. 1, 32 rumen-fistulated Nellore steers (initial shrunk body weight [BW] = 355 ± 4.4 kg) were assigned to a randomized complete block design. Within block, animals were randomly assigned to one of four treatments: 1) forage-based diet without feed additives (CON), 2) CON diet plus 13 mg/kg of dry matter (DM) of NAR, 3) CON diet plus 20 mg/kg of DM of sodium LAS, or 4) CON diet plus 20 mg/kg of DM of VRM. No treatment effects were detected (P ≥ 0.32) for intake and apparent digestibility of nutrients. Steers fed NAR had the lowest (P ≤ 0.01) molar proportion of acetate on day 28, 56, and 112 vs. CON, LAS, and VRM steers, whereas acetate did not differ (P ≥ 0.25) between LAS, VRM, and CON steers from day 28 to 84. On day 112, steers fed LAS had a lower (P < 0.02) molar proportion of acetate vs. VRM and CON, whereas it did not differ between CON and VRM (P > 0.33). Steers receiving NAR had a greater (P ≤ 0.04) ruminal propionate vs. CON, LAS, and VRM, whereas LAS steers had greater (P < 0.04) propionate vs. CON and VRM steers on day 28 and 112, and it did not differ (P > 0.22) between CON and VRM. In Exp. 2, 160 Nellore bulls were blocked by initial shrunk BW (212 ± 3.1 kg) in a 140-d feedlot trial. Diets contained the same treatments used in Exp. 1. Bulls fed NAR had greater (P < 0.02) average daily gain (ADG) vs. CON and VRM, and similar (P = 0.17) ADG between NAR and LAS, whereas ADG did not differ (P > 0.28) between LAS, VRM, and CON bulls. A treatment effect was detected (P = 0.03) for dry matter intake, being greater in NAR vs. CON, LAS, and VRM bulls, and similar (P > 0.48) between CON, LAS, and VRM bulls. A tendency was detected (P = 0.09) for feed efficiency, which was greater (P < 0.02) in NAR bulls vs. CON and VRM, and similar (P = 0.36) between NAR and LAS bulls. From day 112 to 140, bulls receiving NAR were heavier (P < 0.03) vs. CON, LAS, and VRM bulls, but no differences were observed (P > 0.51) between CON, LAS, and VRM bulls. Collectively, ruminal fermentation profile and intake were impacted by NAR supplementation, which partially contributed to the enhanced performance of Nellore bulls receiving a forage-based diet. [ABSTRACT FROM AUTHOR]

We analyzed the effects of Glycyrrhiza polysaccharide (GCP) on growth performance, appetite, and hypothalamic inflammation-related indexes in broilers. One-day-old male AA broilers were randomly divided into four groups: Control , L-GCP , M-GCP , and H-GCP (0, 300, 600, and 900 mg GCP/kg feed), with six repetition cages for each treatment and 12 broilers in each repeat for a period of 42 days. From day 1 to day 21, the addition of GCP to the diet significantly improved the ADFI and the ADG of broilers, and the mRNA levels of NPY and AgRP were significantly increased while POMC and CART were decreased in the hypothalamus of broilers; GCP also significantly decreased the mRNA levels of IL-1β , IL-6 , TNF-α , TLR-4 , MyD88 , and NF-κB , and increased the IL-4 and IL-10 in the hypothalamus from day 1 to day 42. The concentrations of appetite-related factors and inflammatory factors in serum were changed in the same fashion. Supplementation with 600 mg/kg GCP had the optimal effect in broilers, and GCP has the potential to be used as a feed additive in the poultry production industry. [ABSTRACT FROM AUTHOR]

Plant secondary metabolites (PSM) such as condensed tannins, hydrolysable tannins, saponins and essential oils purportedly impact rumen fermentation at low inclusion rates in beef cattle diets. Twelve steers (347 ± 23 kg BW) of British and continental influence were allocated to 1 of 4 replicated 3 x 3 Latin squares. Latin squares each had 14 d periods (10 d adaptation and 4 d for sample collection). All cattle were fed ground warm-season hay (89.5% DM, 92.8% OM, 65.9% NDF, 43.6% ADF, 6.70% CP) at 1.5% of BW (DM-basis) and supplemented with soybean meal at 0.18% of BW (DM-basis) once daily. Treatments consisted of a blend of tannins, saponins and essential oils provided at 0% (Control), 0.1% (Low) and 0.3% (High) of hay offering. Treatments were mixed with daily soybean meal allotment and provided before feeding of hay. Urine and feces were completely collected from d 11 through 14 at 0730 h and daily amounts of urine and feces produced were measured gravimetrically. Measures of gaseous exchange were determined via indirect calorimetry on d 13 and 14. Open-circuit respiration calorimeters (91.4 x 91.4 x 191.2 cm) were used to collect respired gas and ruminal methane production. Total oxygen consumption and production of carbon dioxide and methane were calculated from the difference in concentration of oxygen, carbon dioxide, and methane from air exhausted from each calorimeter and concentration of oxygen, carbon dioxide, and methane in ambient air and multiplied by amounts of air flowing from each calorimeter standardized for temperature, pressure, and humidity. Data were analyzed for a Latin square using the MIXED procedure of SAS with fixed effect of treatment, period and square and random effect of steer. Linear and quadratic contrast coefficients were assigned using PROC IML for uneven spacing of treatments. Significance was declared when P ≤ 0.05. Per experimental design, forage N and OM intake did not differ (P ≥ 0.77). Apparent total tract digestion of OM, NDF and ADF did not differ (P ≥ 0.66) among treatments. Fecal nitrogen excretion, and the percentage of N excreted in feces increased linearly (P = 0.01). N balance tended (P = 0.08) to decrease linearly with increasing PSM supplemented. Methane (L/kg DMI) was not affected (P = 0.28) by treatments. Methane, GE, DE, and ME (mcal/kg DMI) was unaffected (P = 0.19) by treatment. Under the conditions of this experiment, a blend of PSM had little effect on rumen fermentation or energy metabolism in beef steers. [ABSTRACT FROM AUTHOR]

One hundred and forty-four Angus × Simmental steers were allotted by body weight (BW ; 363 kg), breed composition, and farm origin to a 3 × 2 factorial arrangement of six treatments (4 pens per treatment) to determine the effect of Mootral (garlic + citrus extract; 0.25% of the diet dry matter [ DM ] vs. 0.0%) on methane (CH 4 ) emissions, growth, and carcass characteristics of feedlot cattle. During the first 84 d, cattle were fed three different forage concentrations in the diet (15%, 41.5%, or 68% corn silage) with or without Mootral. From day 85 to slaughter, corn silage was included at 15% of the diet DM with or without Mootral. CH4 emissions were measured on day 42 to 46 and day 203 to 207. Data were analyzed using the GLIMMIX procedure of SAS. Mootral did not affect CH4 emissions on days 42 to 46 (P ≥ 0.47), but there was a forage effect, where steers fed the 68% corn silage emitted more CH4 on a g/d (P = 0.05) and a g/kg of dry matter intake (DMI ; P = 0.007) basis and tended (P = 0.07) to produce more CH4 on g/kg BW basis compared to steers fed the 15% corn silage diet. On day 203 to 207, steers fed Mootral emitted less (P ≤ 0.03) CH4 on a g/d, g/kg DMI, and g/kg BW basis compared to steers not fed Mootral. There was an interaction (P = 0.03) between forage concentration and Mootral for DMI from day 0 to 84, where Mootral decreased DMI of steers fed 15% corn silage but did not affect DMI of steers fed 41.5% or 68% corn silage. There were no effects (P ≥ 0.22) of forage concentration or Mootral on BW or average daily gain at any time, or on DMI from day 84 to slaughter and overall. However, overall calculated net energy for maintenance (NE m ) and net energy for gain (NE g ) tended to be greater for steers fed Mootral (P ≤ 0.10). Intake from day 0 to 84 was lower and gain:feed from day 0 to 84 and overall was greater (P = 0.04) for steers fed 68% compared to steers fed 41.5% corn silage. Calculated NEm and NEg from day 0 to 84 and overall were greater for steers fed 68% corn silage compared to steers fed 41.5% corn silage (P ≤ 0.03). Mootral tended to decrease (P ≤ 0.09) fat thickness and yield grade. In conclusion, increasing forage concentration increased CH4 emissions and Mootral decreased CH4 production in 15% corn silage diets and tended to improve carcass leanness. [ABSTRACT FROM AUTHOR]

The objective of this randomized controlled trial was to determine the performance effects of milk replacer supplemented with a feed additive high in beta-glucans for male dairy calves. Holstein male calves (n = 147) were enrolled in a 76-day randomized block trial in two blocks. Upon enrollment, calves were assigned to one of the four following treatments: Control with no beta-glucan supplementation (BG0; n = 36; BW = 48.32 ± 3.73 kg), 1 g· animal-1· d-1 (BG1; n = 38; BW = 48.29 ± 2.89kg), 3 g· animal-1· d-1 (BG3; n = 37; BW = 48.31 ± 3.23 kg), and 5 g· animal-1· d-1 (BG5; n = 36; BW = 48.47 ± 3.00 kg) of beta-glucans. The beta-glucan supplement was blended with milk replacer (24% CP, 20% fat; 130 g/L) and fed to calves during the morning milking. Calves were individually housed, had unlimited access to water, and a pelletized calf starter (20% CP). Calves were fed 5 L/d of milk replacer divided into two equal meals until d 15; milk feeding plan increased until d 35 (8 L/d), on d 36, milk allowance was gradually reduced until weaned on d 56 (2.5 L/d). Calf starter intake and body weight were recorded weekly until d 77. Disease treatment was recorded daily. A mixed linear model determined the effect of treatment on calf starter intake and average daily gain. The model included treatment if the calf was ever treated with antibiotics for respiratory disease and/or diarrhea, study period, and a treatment by period interaction. Block was considered a random factor. The total milk replacer intake was 5.73 ± 0.08, 5.71 ± 0.08, 5.73 ± 0.01, 5.73 ± 0.01 L/d for BG0, BG1, BG3 and BG5, respectively. Calf grain intake by treatment was 58.10 ± 12.02, 54.58 ± 8.11, 56.86 ± 11.8, 56.73 ± 15.52 for BG0, BG1, BG3 and BG5, respectively. Overall, 55% and 71% of all calves were treated at least once for diarrhea, and respiratory disease respectively. The percentage of animals treated for diarrhea by treatment were 45.00, 57.50, 50.00, and 32.50% for BG0, BG1, BG3, and BG5, respectively. For respiratory disease, the percentage of animals treated was 72.5, 72.5, 70.0, and 70.00 for BG0, BG1, BG3, and BG5 treatments, respectively. There was a significant interaction between treatment and study period where the control group had greater starter intake during the postweaning period (BG0 = 0.78 ± 0.01, BG1= 0.82 ± 0.01, BG3 = 0.81 ± 0.02, BG5 = 0.82± 0.01 kg/d; P < 0 .001). No treatment or treatment by study period effects was observed for average daily gain (P = 0.79, P = 0.89, respectively). Future research should investigate the effects of beta-glucans on blood metabolites and palatability throughout the calf-rearing period. [ABSTRACT FROM AUTHOR]

We examined the effects of rumen-bypass protein supplement on growth performance, hepatic mitochondrial Electron Transport Chain (ETC) activities, and mRNA expression of innate and adaptive immune genes of beef steers with divergent residual feed intake (RFI) phenotype. Thirty-nine crossbred beef steers (average BW = 492 ± 36 kg) were used in a generalized randomized block design with a 2 × 2 factorial arrangement of treatments for a 42-d experimental period. The factors evaluated were 1) RFI classification [low-RFI (-2.12kg/d) vs. high-RFI (2.02kg/d)], and 2) feed additive: rumen-bypass protein supplement (RCP; 227 g· steer-1· day-1) vs. Control diet (CON; 0 g/d), resulting in four treatments: Low-RFI-CON (n = 10), low-RFI-RCP (n = 9), high-RFI-CON (n = 10), and high-RFI-RCP (n = 10). The rumen-bypass protein supplement (84% CP) is a blend of hydrolyzed feather meal, porcine blood meal, and DL-methionine hydroxy analogue. The beef steers were stratified by BW and randomly assigned to treatments and housed in four pens equipped with two GrowSafe feed bunks each to measure individual DMI. Body weight was measured every 7 days. Liver tissue was sampled on d 42 from all animals using a liver biopsy needle for mRNA expression analysis of 84 immune genes and analysis of mitochondrial ETC activities of complexes I - V. No effects of supplemental feed additive or RFI × feed additive interactions were observed (P > 0.05) for ADG and DMI. Compared with high-RFI, low-RFI beef steers tended to have less DMI (13.6 vs 12.9 kg/d; P = 0.09) but ADG was similar for the two RFI groups. Feed additive × RFI interactions were observed (P = 0.05) for mitochondrial activities of Complexes IV, V, and mRNA expressions of some immune genes. Supplemental RCP increased Complex IV (39.2 nmol/min/mg) activity and reduced that of Complex V (94.1 nmol· min-1· mg-1) in high-RFI beef steers whereas the activity of Complex IV (13.1 nmol· min-1· mg-1) was reduced and that of Complex V (120 nmol· min-1· mg-1) was increased in low-RFI beef steers. Supplemental RCP increased (P < 0.05) the mRNA expression of TLR2 [fold change (FC) = 1.17 vs 0.98], TLR3 (FC = 1.49 vs 0.97), NFKB1 (FC = 1.02 vs 0.90), and IL23A (FC = 1.35 vs 1.07) in high-RFI beef steers but the expression of these genes were not altered in low-RFI beef steers. In conclusion, RCP supplementation did not affect the growth performance and the observed effects on hepatic immune gene expression and activities of mitochondrial ETC complexes are dependent on the RFI phenotype of the beef steers. Further research should explore the mechanism responsible for the interactions between RCP supplementation and RFI status. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the effects of supplementing different ratios of phytogenic feed additive (PFA) to weaned pigs challenged with pathogenic Escherichia coli (E. coli) on growth performance, nutrient digestibility, intestinal barrier integrity, and immune response, and to determine the optimal mixing ratio for PWD prevention. A total of 48 four-week-old weaned pigs with initial body weight of 8.01 ± 0.39 kg were placed in individual metabolic cages, and then randomly assigned to eight treatment groups. The eight treatments were as follows: a basal diet without E. coli challenge (negative control, NC), a basal diet with E. coli challenge (positive control, PC), PC with supplementing 0.1% mixture of 20 % bitter citrus extract (BCE), 10% microencapsulated blend of thymol and carvacrol (MEO), and 70% excipient (T1), PC with supplementing 0.1% mixture of 10% MEO, 20% premixture of grape seed and grape marc extract, green tea, and hops (PGE), and 60% excipient (T2), PC with supplementing 0.1% mixture of 10% BCE, 10% MEO, 10% PGE, and 70% excipient (T3), PC with supplementing 0.1% mixture of 20% BCE, 20% MEO, and 60% excipient (T4), PC with supplementing 0.1 % mixture of 20% MEO, 20% PGE, and 60% excipient (T5), and PC with supplementing 0.1 % mixture of 10% BCE, 20% MEO, 10% PGE, and 60% excipient (T6; Table 1). The experiments were progressed in 16 days, including 5 days before and 11 days after the first E. coli challenge (d 0). In the E. coli challenge treatments, all pigs were orally inoculated by dividing a total of 10 mL of E. coli F 18 for 3 consecutive days from d 0 post-inoculation (PI). Compared with the PC group, the PFA2 and PFA6 groups significantly increased (P < 0.05) feed efficiency and decreased (P < 0.05; Table 2) diarrhea during the entire period (Table 3). At d 11 PI, the PFA6 group significantly improved (P < 0.05) gross energy digestibility compared with the PFA1 group (Table 4). The PFA6 group significantly decreased (P < 0.05) tumor necrosis factor a (TNF-a) and interleukin- 6 (IL-6) in serum (Table 5) and increased (P < 0.05) the villus height to crypt depth ratio (VH:CD; Table 6; Figure 1). The PFA2 significantly decreased (P < 0.05) the relative protein expression of calprotectin in the ileum (Table 7). In conclusion, improvements in growth performance, diarrhea reduction, and immunity enhancement are demonstrated when 10% BCE, 20% MEO, 10% PGE, and 60% excipient are mixed. [ABSTRACT FROM AUTHOR]

Our objective was to evaluate the effects of 3-Nitrooxypropanol (3-NOP) associated with different feed additives on performance, carcass characteristics and enteric methane (CH4) emissions. Twenty-seven Nellore bulls (initial BW, 410 ± 6 kg) were randomly allocated to three treatments with nine replicates per treatment (animal as experimental unit). The animals were fed a high-concentrate feedlot diet (R:C, 10:90) for 102 days, according with the following three treatments: 1) Control (CTRL): Sodium Monensin (26 mg/kg DM); 2) BOV: Control + 3-NOP (Bovaer;100 mg/kg DM); 3) BOVPERF (Bovaer Performance pack): Control + 3-NOP (100 mg/kg DM) + Essential oils (Crina Ruminants, 100 mg/kg DM) + 25-OH-Vitamin D3 (Hy-D, 0.10 mg/kg DM) + carbo-amino-phosphochelate of chromium and zinc (0.4 and 60 mg/kg of DM, respectively). The gases emissions (CH4 and H2) and DMI variables were assessed individually, by using the GreenFeed and Intergado electronic system placed in the feedlot pen, respectively. The BW of Yearling bulls were recorded at the beginning and final of the experiment after 16-h fasting (Table). Data were analyzed by ANOVA using the PROC MIXED of SAS 9.4, in which means comparison were evaluated by Tukey test at P < 0.05. Feeding BOVPERF increased DM intake during adaptation period (P = 0.04), and over the total period (P < 0.01) compared with control with no difference on feed efficiency (P =0.61). There was no difference (P > 0.05) on DMI between CTRL and BOV. Animals fed BOVPERF had greater HCW (+13 kg, P = 0.04) and greater carcass ADG (+120 g/d, P = 0.04) compared with CTRL. Animals fed BOV and BOVPERF emitted 39% less CH4 (P < 0.01) and produced 292% more H2 (P < 0.01) compared with CTRL. In addition, there were significant reductions in methane intensity, as measured by the ratios CH4/kg DM (-42%; P < 0.01), and CH4/kg carcass ADG (-41.13%; P < 0.01) for animals fed with BOV and BOVPERF compared with CTRL. We conclude that feeding Bovaer performance pack reduces methane emissions and increases carcass production in feedlot beef cattle. [ABSTRACT FROM AUTHOR]

Yeast derivatives enhance beef cattle performance (Torres et al., 2022), allowing farmers to increase feedlot financial income. However, yeast derivatives vary on yeast species, grown medium, purity, technological processing, yeast cell parts marketed. Thus, in these experiments, we aimed to understand the potential of different yeast derivatives to manipulate performance, feed intake, and feeding behavior. In experiment 1, 1,760 non-castrated males were used to study performance and feed intake. These animals were distributed in large pens, mimicking actual feedlot operations. In xperiment 2, 96 animals with radio frequency identification ear tags were allocated in small groups with induvial access to automatic feeders equipped with scales to study daily individual feeding behavior. Animals were allocated to four treatments: 1) Control, no yeast derivative; 2) AY - 7g/animal/day, autolyzed Saccharomyces cerevisiae grown on sugarcane molasses, RumenYeast (ICC, São Paulo, Brazil); 3) YM - 3g/animal day, yeast rich in soluble yeast metabolites; 4) YB - 5g/animal/day, yeast blend (live Yeast plus autolyzed Yeast. Orthogonal contrasts were performed comparing control against AY, YM, and YB. Differences were declared significant at P < 0.05 and as a trend when 0.05 < P < 0.10. Pen was considered as the experimental unit for experiment 1. For experiment 2, animals were considered the experimental unit. Regarding experiment 1, AY tended to increase adjusted average daily gain and hot carcass weight (Table 1). Dry matter intake did not differ between treatments in experiment 1 (large pen trial). Looking at individual intake data, experiment 2, feeding behavior and water intake changed when yeast derivatives were included in the diet. In general, animals supplemented with AY spent less time eating, which was more evident in the adaptation period (Table 1). AY and YB had stimulated feed intake in some periods of experiment 2. However, the evident less time spent eating by the AY group promoted a greater feeding rate (kg ingested/min) markedly compared with YM and YB, but in general, also greater than control. Considering the initial period of feedlot operations, this greater feeding rate could favor animals supplemented with AY to adapt faster to feedlot diet/feeding conditions. All yeast derivatives increased water intake. In summary, autolyzed Saccharomyces cerevisiae grown on sugarcane molasses increased beef cattle performance and feeding rate. This change in feeding behavior may accelerate the adaptation of beef cattle in the transition from the backgrounding phase to the feedlot operation. [ABSTRACT FROM AUTHOR]

Feeding ruminants with a blend of autolyzed yeast grown on sugarcane molasses and live yeast allows nutritionists to explore synergistic effects on digestion and performance (Angulo et al.,2021; Zapata et al., 2021). However, the feeding behavior and the challenges faced in large pen feedlot operations differ from the behavior and challenges faced by animals studied in small groups or metabolic cages. Therefore, we aimed to study the feeding behavior and performance of beef cattle fed in groups in large pens, mimicking the feedlot operations of leading producers and exports of meat in the world. The trial lasted 112 days and was conducted in Nutripura's research center in the midwest of Brazil. Six hundred five non-castrated males (Nelore and F1 Nelore-Angus), 405 kg (± 35), distributed in 20 pens, were divided into two treatments: 1) Control, a diet with no yeast additives; 2) Yeast Blend (YB), a diet with a blend of autolyzed yeast and live yeast, SymbioYeast, 7g/anima/day (ICC, São Paulo, Brazil). Both diets contained monesin (28 mg/kg DM). The data were analyzed in the software SAS following the model Yijk= μ+Ti + Fj + Bk +eijk (μ = general mean; T = treatment effect; F = Breed effect; B = backgrounding phase effect; e = error). Initial body weight was used as a covariable to analyze final body weight and average daily gain (ADG). Dry matter intake increased (P < 0,05) when animals were supplemented with YB (10,99kg vs. 11,12kg). Final body weight and hot carcass weight tended (0.1 > P = 0.05) to increase when YB was added to the diet. (598 kg vs. 602 kg, 343 kg vs. 345 kg). The ADG was unaffected (P = 0.1069, control 1.735 kg, and YB 1.768 kg). Increasing DMI is a well now property of some yeast derivatives (Torres et al., 2022). This may be related to changes in digestion (Torres et al., 2022) and the diet's palatability. The palatability of yeast products is claimed on organoleptic and flavor characteristics (Tao et al., 2023). Drone photos taken every 15 minutes suggested that YB altered how animals interact with feed. Feed was delivered between 0700 h and -0930 h and 1300 h and 1530 h. After delivery, a greater percentage of the visit of the animals to the feed bunkers in YB groups. This behavior was even more evident in the morning feed delivery (Figure 1). In summary, YB increased intake and performance. It also changed the interest of animals in visiting feed bunk. [ABSTRACT FROM AUTHOR]

This presentation aims to review advances in mathematical models used in poultry nutrition and production in the past decades and present an overview of the current status. Models have been developed to improve understanding of growth, voluntary feed intake, nutrient utilization, body composition, responses to nutrient supply, environmental changes, and stressors. Growth models for broilers, turkeys, ducks, layers, and breeders are available mainly based on the Gompertz curve, but a few other mathematical functions are also used. A few models can simulate egg production in layers and breeders. The EFG and Avinesp models, tools from feed additive and genetic companies, among others, will be described or mentioned. These models can describe genetic differences and estimate energy, amino acids, calcium, and phosphorus requirements or multiple biological responses to specific nutrient levels. Most models use the concept of ideal protein or balanced protein to describe responses to amino acid levels. However, very few models can describe responses to modifications of one or two specific amino acids. Compartmental models are mainly based on main chemical components such as water, body and feather protein, fat, and ash. Poultry models seldom consider variability due to feeding ingredient quality, fiber, fat, other mineral composition, or variation in nutrient digestibility. However, some models can predict responses to exogenous enzymes. Most applications can predict body weights and yields at a specific age, and some can estimate nitrogen, calcium, and phosphorus excretion. These models can be integrated with feed formulation software, economic data, and optimizers to simulate multiple conditions and estimate biological, economic, and environmental optimums. Poultry enterprise models can describe the whole production system, estimate the optimum combination of resources, aid in planning and scheduling, and determine strategies for growth. Currently, no official recommendations from academic or private groups are based only on models to estimate nutrient levels. Combinations of empirical data and model results are frequently used for nutritional decision-making. A few tools are available for specialized personnel to decide the energy and amino acid levels to use. The application of electronics and telecommunications triggered the fast production of enormous volumes of data from diverse poultry production sectors. This big data avalanche is starting to help modelers to integrate more accurate information and incorporate natural variability. However, integration between current models and significant data results is still under development. Despite increasing international collaboration in modeling, poultry model developments keep great independence and fundamental differences. One critical issue needed for faster development of poultry modeling is to increase education in modeling. The lack of academic programs offering modeling classes related to poultry caused the low current application of models. However, awareness about the benefits of modeling has increased in the past few years, and efforts are under development. [ABSTRACT FROM AUTHOR]

In the US, beef cattle feedlots commonly use antibiotic feed additives, such as tylosin and virginiamycin, to prevent liver abscesses, which can cause significant economic losses and animal welfare concerns. However, growing public and regulatory pressure to curb the proliferation of antibiotic resistant bacteria has prompted a need to reduce or eliminate their use. As an alternative, our group is working on a bacteriophage-based feed additive that targets Fusobacterium necrophorum, the primary cause of bovine liver abscesses, with the aim of reducing or eliminating the dependence on antibiotic feed additives. Using a combination of phage isolation techniques, we identified and characterized fifteen new F. necrophorum phages belonging to six genetically distinct groups. These phages exhibited a broad intraspecific host range and could infect various contemporary F. necrophorum strains isolated from different regions of the United States. All the phages were temperate, with dsDNA genomes ranging from around 36 kbp to 114 kbp. Almost all contemporary F. necrophorum isolates were found to have one or more active prophages upon bacterial genome sequencing and prophage induction. In vitro evolution resulted in the recovery of a potential virulent mutant, fBB37, which inhibited the growth of the high leukotoxin-producing F. necrophorum 8L1 strain for over 40 hours in vitro. Phage cocktails proved effective for up to 60 hours. After minimal optimization, most phages demonstrated high productivity (> 109 PFU/mL) and little yield variation during scale-up, highlighting their commercial potential. Unexpectedly, we discovered a previously unrecognized Fusobacterium species, Fusobacterium varium, is widely prevalent and frequently the most abundant member of the genus in cattle rumen. Previous studies on liver abscess control in cattle have almost exclusively focused on F. necrophorum, which may explain the lack of effectiveness observed. To elucidate the ecological role and potential pathogenicity of ruminal F. varium, we conducted genome sequencing and found these bovine strains to have multiple virulence factors and high similarity to human clinical isolates. However, phages with the ability to infect F. varium were plentiful in rumen fluid, with several demonstrating purely lytic activity. To assess the safety and in vivo dynamics of F. necrophorum and F. varium phage cocktails, a smallscale animal trial was recently conducted with ten cannulated cattle. [ABSTRACT FROM AUTHOR]

Artificial neural networks (ANN) are a type of machine learning model that has been applied to various genomic problems, with the ability to learn non-linear relationships and model high-dimensional data. ANNs also have the potential in genomic prediction by capturing the intricate relationship between genetic variants and phenotypes. However, there is currently a limited effort to investigate the performance and feasibility of ANNs for pig genomic predictions. In this study, we evaluated the predictive performance of TensorFlow's ANN models with one-layer, two-layer, and three-layer structures (with zero, one, and two hidden layers, respectively), in comparison with five linear methods, including GBLUP, LDAK, BayesR, SLEMM and scikit-learn's ridge regression using data of six quantitative traits including off-test body weight (WT), off-test back fat thickness (BF), offtest loin muscle depth (MS), number of piglets born alive (NBA), number of piglets born dead (NBD), and number of piglets weaned (NW). Furthermore, we assessed the computational efficiency of ANNs on both CPU and GPU. The benchmarking was based on crossvalidations of 26,190 genotyped pigs. We employed hyperband tuning to optimize the hyper-parameters and select the best model among one-layer, two-layer, and three-layer structures. Results showed that the one-layer structure, which is equivalent to ridge regression, yielded the best performance comparable to that of GBLUP. Using the optimal hyper-parameters for two-layer and three-layer structures, ANNs underperformed GBLUP in terms of accuracy. Of the five linear methods, BayesR and SLEMM performed similarly and the best, followed by LDAK, scikit-learn's ridge regression, and GBLUP. Moreover, SLEMM was the fastest, which completed training with 21k individuals and 30k SNPs in 2.6 minutes. Compared with CPUs, GPUs exhibited a comparable computational speed for one-layer ANN but offered significant gains in computational efficiency for multi-layer ANNs. Based on our analysis of optimal hyper-parameters for two-layer ANN with BF, we found that using a GPU can lead to a five-fold increase in processing speed compared with using a conventional CPU, but it is still slower than GBLUP. In addition, hyper-parameter tuning (particularly for L2 regularization and the number of dense units in hidden layers) is critical for improving the genomic prediction accuracy in pigs. In conclusion, we found ANN with up to three layers could not improve genomic predictions compared with routine linear methods for pig quantitative traits. [ABSTRACT FROM AUTHOR]

Plant based dietary ingredients contain non-starch polysaccharides (NSP). Both soluble and insoluble NSP may limit intestinal absorption and digestion of dietary nutrients along the intestinal tract of monogastric animals. Increased digesta viscosity also occurs, which results in satiety and potential health issues. DIGESTAWell XG (Probiotech International Inc.), a commercially available enzyme-based feed additive that contains increased endo-1,4-ß-xylanase and endo-1,3(4)-ß-glucanase activity, hydrolyzes NSP resulting in increased nutrient availability and digestibility. Therefore, it was hypothesized that nursery pigs consuming low net energy (NE) diets with DIGESTAWell XG will demonstrate similar growth performance as nursery pigs consuming greater NE diets. A 47-day trial was conducted with 21-day old nursery pigs (6.0 kg) allocated to three groups: control (CON), low energy (-56 kcal/kg feed; LE), and low energy + enzyme (LE+E). All groups had 13 pens of 28 pigs (n = 364), and received wheat and corn mix based diets that had a similar NSP content (11.4%). CON diets had greater NE (2,456 kcal/kg feed) relative to the LE and LE+E groups (2400 kcal/kg feed). The diet of the LE+E group was supplemented with DIGESTAWell XG at 0.22kg/Ton of feed. For each pen the daily feed intake, weekly weight, diarrhea index and mortality were recorded. Data were analyzed by an ANOVA model (Statistix 8.0; Analytical Software, FL) including treatment and pen as fixed and random effects, respectively, and a Chi-square test for pairwise differences. Compared with both CON and LE, LE+E increased (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI) during weeks 4 to 7 and weeks 1 to 7, and significantly increased final weight (Table 1). During weeks 1 to 3, ADG and ADFI did not differ between CON and LE+E groups, and the LE+E group was significantly greater than LE. Over the entire period, LE impacted (P < 0.05) negatively the feed conversion ratio (FCR) compared with CON, however, during weeks 4-7 the LE+E had similar FCR compared with CON (P > 0.05). No significant effects were observed on mortality or diarrhea index. In conclusion, DIGESTAWell XG improves piglet performance when dietary NE content is decreased which may offer some formulation flexibility. [ABSTRACT FROM AUTHOR]

A finishing experiment was conducted to determine the effects of Enogen Feed Corn inclusion in comparison with a control corn hybrid within natural and conventional feeding programs on finishing performance. The experiment used 400 crossbred steers (initial BW = 384 ± 33 kg) and 200 crossbred heifers (initial BW = 330 ± 19 kg) in a 2×2 factorial arrangement of treatments with 10 replications of steers and 5 replications of heifers per treatment. Factors were Enogen Feed Corn (EFC) or control corn hybrid inclusion as dry-rolled corn and corn silage within conventional and natural feeding programs. Cattle assigned to the conventional program were fed rations that contained feed additives and received implants whereas cattle in the natural program received neither. Performance data were analyzed as a 2×2×2 factorial assessing interactions between sex, feeding program, and corn hybrid inclusion. A sex by feeding program by corn hybrid (P = 0.01) interaction was observed for dry matter intake (DMI). Interactions between sex and feeding program were observed for carcass adjusted final BW (final BW; P < 0.01), average daily gain (ADG; P < 0.01), feed efficiency (G:F; P < 0.01), and hot carcass weight (HCW; P = 0.01). No significant corn hybrid by sex interactions (P ≥ 0.12) or corn hybrid by feeding program interactions (P ≥ 0.13) were observed. Inclusion of EFC in natural heifer diets tended to increase DMI by 0.4 kg/d (P = 0.10), while hybrid inclusion had no impact on DMI of conventional heifers. Feeding EFC in conventional steer diets tended to increase DMI by 0.4 kg/d (P = 0.06) compared with steers consuming the control corn hybrid diet. Corn hybrid had no impact on DMI in natural steer diets (P = 0.15). Carcass adjusted final BW decreased by 75 kg in natural steers and 41 kg in natural heifers compared with conventional programs (P < 0.01). Natural heifers gained 0.24 kg/d less than conventional heifers (P < 0.01). Feeding steers in the natural program reduced ADG by 0.43 kg/d in comparison with conventional program steers (P < 0.01). Compared with natural cattle, G:F improved by 13.0% when heifers were fed in a conventional program (P < 0.01) and 19.4% when steers were fed in a conventional program (P < 0.01). Feeding program had no effect on marbling (P = 0.38) while conventional cattle had greater 12th rib fat than natural cattle (P < 0.01). Inclusion of EFC had no effect on ADG (P = 0.71), G:F (P = 0.22), or HCW (P = 0.57). The incorporation of implants and feed additives within the finishing period increased final BW, HCW, and ADG leading to improved G:F in steers and heifers, with the improvement being greater in steers. [ABSTRACT FROM AUTHOR]

Several feed additives have shown benefits throughout the literature in improving growth performance and carcass characteristics when fed to finishing pigs. The mechanisms of action of these feed additives may be by improving health status, energy metabolism, and/or nutrient digestibility. However, the results have been variable and have not been well summarized. In addition, few of the feed additives have a review of all the available literature, and to our knowledge, no review summarizes each feed additive in one centralized effort. Therefore, this review summarizes the available research on feed additives fed in swine diets for the grow-finish phase (Table 1). The feed additive categories chosen for this review were acidifiers, betaine, Cr, conjugated linoleic acid (CLA), Cu, direct-fed microbials (DFM), carbohydrases, proteases, phytases, multi-enzymes, essential oils (EO), L-carnitine, yeasts, and Zn. Research articles were collected from online research databases. Inclusion and exclusion criteria were utilized to select qualified research articles. The percentage difference for each response variable between the treatment and control group was calculated to determine the magnitude of effect. Results indicated that positive outcomes for each feed additive can be found; however, the magnitude of improvement varied, and many experiments did not observe statistically significant improvements in response criteria. For G:F, acidifiers (n = 65 total comparisons, 3.1% improvement across all comparisons), betaine (n = 35, 2.7%), CLA (n = 57, 3.5%), multi-enzymes (n = 29, 3.3%), DFM (n = 66, 3.3%), L-carnitine (n = 24, 2.5%), and yeasts (n = 33, 2.7%) showed relatively large and positive effects (> 2%) across a reasonable number of comparisons (n > 20) with > 14% of them being statistically (P≤ 0.10) positive. For ADG, DFM (n = 71, 3.3%), Cu (n = 155, 2.5%), L-carnitine (n = 24, 2.1%), and multi-enzymes (n = 29, 3.1%) showed relatively large and positive effects (>2%) across a reasonable number of comparisons (n >20) with > 21% of them being statistically (P ≤ 0.10) positive. Moreover, except for betaine, Cr, CLA, and L-carnitine, most feed additives showed little, inconsistent, or non-significant effects on carcass characteristics. The improvements in carcass characteristics were probably due to the improved energy metabolism. Publication bias and the location of studies need to be considered when evaluating the data, as many studies that show no effect might not be published. Furthermore, even though the economics was not discussed in this review, the decision to include feed additives in the pig diets should consider the return on investment based on the price and the magnitude of benefit. In conclusion, this literature review provides descriptive analysis and databases for commonly used feed additives in the hope of better understanding the effect of feed additives on improving the efficiency of swine production. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the inclusion of narasin, salinomycin, or flavomycin for 140 d on ruminal fermentation parameters, apparent nutrient digestibility, and performance of Nellore cattle offered a forage-based diet. In experiment 1, 32 rumen-cannulated Bos indicus Nellore steers [initial body weight (BW) = 220 ± 12.6 kg] were assigned to individual pens in a randomized complete block design according to their initial shrunk BW. Within block, animals were randomly assigned to 1 of 4 treatments: (1) forage-based diet without feed additives (CON ; n = 8), (2) CON diet plus 13 ppm of narasin (NAR ; n = 8), (3) CON diet plus 20 ppm of salinomycin (SAL ; n = 8), or (4) CON diet plus 3 ppm of flavomycin (FLA ; n = 8). The experimental period lasted 140 d and was divided into 5 periods of 28 d each. The inclusion of feed additives did not impact (P ≥ 0.17) dry matter intake (DMI), nutrient intake, and apparent total tract digestibility of nutrients. Nonetheless, steers fed NAR had lower (P < 0.01) molar proportion of acetate compared with CON, SAL, and FLA steers, whereas ruminal acetate tended to be greater (P < 0.09) for SAL vs. CON and FLA, but did not differ (P = 0.68) between CON vs. FLA steers. Ruminal propionate was the highest (P < 0.01) for steers fed NAR and did not differ (P > 0.20) between CON, SAL, and FLA. Consequently, NAR steers had the lowest (P < 0.01) Ac:Pr ratio, whereas Ac:Pr did not differ (P > 0.18) among CON, SAL, and FLA. Total volatile fatty acids were greater (P < 0.04) for NAR and CON vs. SAL and FLA, but did not differ (P > 0.67) among NAR vs. CON and SAL vs. FLA. In experiment 2, 164 Nellore bulls (initial shrunk BW = 299 ± 2.5 kg) were assigned to feedlot pens for 140 d in a randomized complete block design. Within block (n = 10), animals were randomly assigned to the same treatments used in experiment 1. Average daily gain was greater (P < 0.01) in NAR vs. CON, SAL, and FLA bulls, and did not differ (P > 0.12) between CON, SAL, and FLA bulls. Bulls fed NAR had greater (P < 0.02) DMI (as kg/d or % BW) and final shrunk BW compared with CON, SAL, and FLA bulls, whereas DMI and final shrunk BW did not differ (P > 0.26) between CON, SAL, and FLA bulls. Feed efficiency, however, was not impacted (P = 0.51) by any feed additives used herein. Collectively, narasin was the only feed additive that benefited performance and ruminal fermentation of Nellore animals fed a forage-based diet. [ABSTRACT FROM AUTHOR]

Yeast products are extensively used as additives in livestock feed to improve their growth performance and intestinal health. A total of 90 crossbred finishing pigs were allocated to one of three treatments according to their BW and sex (2 barrows and 2 gilts) with 6 replicates per treatment and 5 pigs per pen for eight weeks. The dietary treatments were CON -basal diet, CON + 0.05% yeast hydrolysate (YH), CON + 0.1% YH. The yeast hydrolysate supplement used in this study was commercially prepared in the name of CALMORIN. The active ingredients of YH were 40% of crude protein, 3.5% of nucleotides, 23% of ß-glucans, 4.9% glutamic acid, and 15% of mannan-oligosaccharides. Data were subjected to the statistical analysis as a complete randomized design using the GLM procedures of SAS and the pen was used as the experimental unit. Linear and quadratic polynomial contrasts were performed to determine the effects yeast in the diet with P < 0.05 indicating significance. Dietary inclusion of YH supplement linearly increased (P < 0.05) body weight and average daily gain of pigs at wk 4,8, and overall trail period (respectively). Moreover, apparent total digestibility of dry matter, nitrogen, and energy showed linear (P < 0.05) improvement in pigs fed graded level of YH supplementation. Also, the inclusion of YH supplementation linearly increased (P < 0.05) the fecal microbial lactobacillus population. Furthermore, during the end of the trial, pigs fed YH tended to linearly increase (P < 0.05) backfat thickness and lean meat percentage and linearly reduce drip loss (P > 0.05) from meat sample on day 3 and 5 of storage. In conclusion the growth performance, nutrient digestibility, lactobacillus count, and meat quality of finishing pigs were positively enhanced by yeast hydrolysate supplement in the diet. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of a combination of feed additives with complementary functional properties on the intestinal microbiota, homocysteine, and vitamins E and B status as well as systemic immune response of weanling piglets. At weaning, 32 litters were assigned to one of the following dietary treatments (DT): 1) conventional diet (CTRL); 2) CTRL diet supplemented with antibiotics (ATB); 3) a cocktail of feed additives containing cranberry extract, encapsulated carvacrol, yeast-derived products, and extra vitamins A, D, E, and B complex (CKTL); or 4) CKTL diet with bovine colostrum in replacement of plasma proteins (CKTL + COL). Within each litter, the piglets with lowest and highest birth weights (LBW and HBW , respectively) and two piglets of medium birth weight (MBW) were identified. The MBW piglets were euthanized at 42 d of age in order to characterize the ileal and colonic microbiota. Blood samples were also collected at weaning and at 42 d of age from LBW and HBW piglets to measure insulin-like growth factor-1 (IGF-1), cysteine, homocysteine, and vitamins E, B6, and B12, and to characterize the leukocyte populations. At 42 d of age, cytokine production by stimulated peripheral blood mononuclear cells was also measured. In a second experiment, piglets were reared under commercial conditions to evaluate the effects of the DT on the growth performance. At the indicator species analysis, the highest indicator value (IV) for Succinivibrio dextrinosolvens was found in the CKTL group, whereas the highest IV for Lactobacillus reuteri and Faecalibacterium prausnitzii was evidenced in the CKTL + COL group (P < 0.05). Compared with the other DT, CTRL piglets had higher concentrations of homocysteine, whereas the CKTL and CKTL + COL supplementations increased the concentrations of vitamins E and B12 (P < 0.05). DT had no effect on IGF-1 concentration and on blood leukocytes populations; however, compared with HBW piglets, LBW animals had lower values of IGF-1, whereas the percentages of γδ T lymphocytes and T helper were decreased and increased, respectively (P < 0.05). CKTL + COL also improved the growth performance of piglets reared under commercial conditions (P < 0.05). This study highlights the impact of birth weight on piglet systemic immune defenses and the potential of weaning diet supplemented with feed additives and bovine colostrum to modulate the homocysteine metabolism and the intestinal microbiota. [ABSTRACT FROM AUTHOR]

As an alternative to antimicrobial growth promoters, fermented feed (FF) has been continuously developed for two decades; however, its effects on feed, performance, digestibility, and meat quality of pigs have yet to be systematically and comprehensively evaluated. This study aimed to (i) quantitatively evaluate the effects of fermentation on nutritional components of feed stuffs; (ii) quantitatively evaluate the effects of FF on pig growth performance, digestibility, and meat quality; and (iii) explore the dose–effect relationship. From PubMed and Web of Science (searched range from January 1, 2000 to April 4, 2019), we collected 3,271 articles, of which 30 articles (3,562 pigs) were included in our meta-analysis. Our analysis revealed that fermentation significantly increased the CP content in feed (P < 0.05). For weaned piglets and growing pigs, FF significantly improved ADG, G:F, DM digestibility, N digestibility, and energy digestibility (P < 0.05). However, compared with the basal diet, FF had no significant effects on growth performance and nutrient digestibility in finishing pigs (P > 0.05). In the subgroup analyses, fermented ingredients increased the growth performance of weaned piglets and growing pigs, and fermented additives promoted the growth of pigs at all stages. The dose–effect analysis confirmed that the optimal doses of fermented ingredients and additives were 8% and 0.15%, respectively. Furthermore, FF had beneficial impacts on meat quality through increased lightness, redness, marbling and flavor and reduced drip loss (P < 0.05). In conclusions, FF improved growth performance and meat quality primarily due to its positive effects on nutritive value and utilization. [ABSTRACT FROM AUTHOR]

Boar taint is an off odor and flavor that occurs once meat from uncastrated male pigs is heated, and results from the deposition of androstenone in the fat. Androstenone circulates between the liver and gut via the enterohepatic circulation, where it can be recirculated back to the liver or deposited in the fat. Previous studies from our lab have demonstrated that adding activated charcoal (AC) to feed is effective at disrupting enterohepatic circulation and preventing boar taint; however, AC is expensive and currently not approved for use as a feed additive. Spent filter aid (SFA) is a byproduct of corn syrup production, contains up to 33% diatomaceous earth (DE), and can be used as an energy source. DE and biochar have been used to bind toxins in the gastrointestinal tract and have a high surface area and porosity like that of AC. Additionally, biochar is approved and used as a feed additive in cattle production, and both biochar and SFA are available at a much lower cost. Therefore, the objective of this study was to evaluate the androstenone binding efficiency of SFA and biochar in vitro to assess their suitability as potential dietary treatments for preventing boar taint. AC, biochar and SFA were incubated for 30 minutes at 37℃ with radiolabeled androstenone, estrone sulphate (E1S), or estrone (E1) dissolved in buffer. Following incubation, the unbound radioactive steroid fraction was quantified using a scintillation counter and binding efficiency was calculated using a modified Michaelis-Menten equation. Statistical analysis was conducted with a 2-way ANOVA in SAS with Tukey-Kramer's post hoc test. The binding efficiency (Bmax/K) of AC was greater than both biochar (P < 0.0001) and SFA (P < 0.0001). However, the maximum binding (Bmax) of androstenone by AC (97.30% ± 0.44) was 13% greater than that of biochar (84.53% ± 0.79) and nearly double that of SFA (50.50% ± 0.22). Of the binding agents tested, SFA had some selective binding for androstenone as the Bmax for androstenone was greater than both E1S (P < 0.0001) and E1 (P = 0.0013). These results suggest that biochar may be a suitable alternative to AC for use as a feed additive as it can bind high concentrations of androstenone, and its binding characteristics were most like AC. Future animal studies are needed to evaluate the effects in vivo to assess the efficacy of biochar as a dietary treatment for boar taint. [ABSTRACT FROM AUTHOR]

Our objective was to evaluate the effects of supplementation using different feed additives on the apparent digestibility and carcass traits of feedlotfinished steers fed a diet consisting of 35% forage and 65% concentrate. This study was a randomized block experimental design with two treatments: Diet containing sodium monensin + virginiamycin (MO+VM, 20 ppm and 15 ppm, respectively); and Diet with a blend of essential oils (Crina Ruminants, 90 ppm) + exogenous α-amylase (Ronozyme Rumistar, 560 ppm) + 25-hydroxy-vitamin-D3 (Hy-D, 0.1 ppm), (EO+ENZ+HYD), with nine repetitions each (pens), where each experimental unit was represented by a pen (with two animals each). Thirty-six 50% Angus blood steers with an average initial weight of 400 kg were evaluated along an experimental period of 112 days, with 28 adaptation days and 84 evaluation days, divided into 3 periods of 28 days each. The digestibility evaluation was carried out at the end of the first and third experimental periods, both in a continuous time of 48 hours. For this, daily intake and leftovers were measured, total feces were collected, diets and leftovers from each pen were sampled for laboratory analysis. At the beginning and end of the experiment, using ultrasound, carcasses were analyzed for loin eye area, marbling ratio, subcutaneous fat thickness (SFT), and rump fat thickness (RFT). Means were compared by ANOVA using the GLM procedure (SAS, 1993), adopting a significance level of 5%. Fecal output (kg· day-1), both in dry matter and natural matter, and fecal DM content were similar between treatments (P > 0.05). Feeding EO+ENZ+HYD reduced (P < 0.05) fecal starch percentage by 20% and improved (P < 0.05) the apparent digestibility of DM and starch (5.16%, 67.40% and 95.50%) compared with the use of MO+VM (6.41%, 66.47% and 94.27%). These better results suggest an effect of a more favorable fermentation of the diet caused by modulation of the ruminal microbiota, optimization in the use of starch and increase in microbial protein synthesis caused by supplementation with EO+ENZ+HYD. Animals supplemented with EO+ENZ+HYD had greater (P < 0.05) RFT (12.22 mm) at slaughter compared with those supplemented with MO+VM (10.42 mm), and greater marbling and RFT gain over the finishing period (0.58 points and 7.50 mm) than those supplemented with MO+VM (0.32 points and 5.93 mm) after 112 days of feedlot. In conclusion, the blend of essential oils + exogenous α-amylase + 25-hydroxy-vitamin-D3 was effective in replacing the combination sodium monensin + virginiamycin, improving the apparent digestibility of DM and starch, as well as increasing marbling and carcass cover fat deposition of feedlot-finished steers. [ABSTRACT FROM AUTHOR]

Phytogenic feed additives (PFA) have been shown to provide anti-inflammatory, anti-microbial and antioxidant properties across many species including livestock and can positively influence animal performance. The objective of this study was to evaluate the effects of feeding a PFA to growing and finishing beef steers on growth performance, feed efficiency, carcass traits, and liver abscesses. Forty-five crossbred steers (initial BW; 272 ± 20.5 kg) were housed in individual pens and used in a randomized complete block design including a 110-d growing period followed by a 120-d finishing period. The steers were blocked by BW and randomly allocated to 1 of 3 treatments: control (CON) basal diet without PFA or monensin; basal diet with a phytogenic feed additive (PFA; 500 mg· animal-1·/day-1) or basal diet with monensin (MON; 300 mg/head/d). The growing diet consisted of 60% silage and 40% concentrate, while the finishing diet consisted of 10% silage and 90% of concentrate (DM basis). In the growing period, dry matter intake (DMI) did not differ; whereas, final BW (415 vs. 403 kg; P = 0.10) and average daily gain (1.31 vs. 1.20 kg/d; P = 0.12) was numerically greater with PFA than CON, respectively, with no difference from MON. Feed efficiency (gain:feed) in the growing period was greater (P = 0.04) with MON (173 g/kg) than PFA (161 g/kg) and CON (156 g/kg). In the finishing period, growth performance, feed efficiency, carcass traits did not differ among treatments; whereas, DMI was numerically less (P = 0.11) with PFA (10.2 kg/d) than CON (10.8 kg/d), but there was no difference between PFA and MON (9.8 kg/d). The percentage of abscessed livers did not differ between PFA and CON, but the proportion of abscessed livers tended (P = 0.09) to be greater with MON compared with PFA and CON, without difference in severely abscessed livers among treatments. These results indicate that feed efficiency of growing steers was not improved by PFA to the level with MON. However, supplementation of PFA or MON resulted in similar finishing performance and feed efficiency. [ABSTRACT FROM AUTHOR]

The mitigation of greenhouse gases is a strong trend in promoting the intensification of ruminant production through greater efficiency in the use of dietary energy. The objective of this study was to evaluate the effects of the inclusion of the NC Conf Engorda Greentech mineral mixture containing feed additives to replace the regular mineral mixture in corn-based substrates on the production of gases and methane. The experiment was carried out under anaerobic conditions using ANKOM Gas Pressure Monitor bottles at 39 °C containing artificial saliva, ruminal fluid, and two grams of substrates from each treatment: (MI) Control, 1.62 g of corn and 0.38 g of mixture mineral; and (MM) 1.28 g of corn and 0.72 g of NC Conf Engorda Greentech (Suplemento Nutrição Animal) containing 0.326% of glucomannans, 0.253% of mannans, 0.200% monensin and 1x106· kg-1 UFC of Saccharomyces cerevisiae. Duplicate substrates and duplicate blanks were fermented for each treatment in two runs, with a total of four repetitions per treatment. The accumulated pressure resulting from the fermentation was measured automatically over 48 h using the Gas Monitor software connected to the ANKOM modules of each bottle. The conversion of pressure to gas volume was calculated as follows: Volume (mL) = 2.3932 + 3.4053 × pressure (R2 = 0.9146; n = 1.151). At the end of each run, a gas sample was collected from each bottle to measure methane concentration using gas chromatography. To obtain the methane production for every 100 mL of gas produced, the total volume of methane produced was multiplied by 100 and divided by the total gas production. Data were analyzed in a completely randomized design using analysis of variance (ANOVA) at a = 0.05. There was a 24.53% decrease in the total gas production in the MM treatment (64.79 mL) compared with the MI substrate (48.90 mL; P = 0.0084; Table 1). Methane production decreased from 46.5 to 14.91 mL in the presence of MM (P < 0.001). A reduction from 71.96 to 30.59 mL of methane was observed for every 100 mL of gas produced when feed additives were included (P < 0.001). The Saccharomyces cerevisiae strain is a precursor of mannans, which, like glucomannans, acts as a prebiotic, and together with monensin, influences the selection of the ruminal microbiota and modifies the volatile fatty acid profile, increasing the molar proportion of propionate, and consequently reducing methane production. The addition of the NC Conf Engorda Greentech mineral mixture with glucomannans, mannans, monensin, and Saccharomyces cerevisiae decreased the production of gases and methane in a corn-based substrate. [ABSTRACT FROM AUTHOR]

Our objective was to evaluate the effect of including a phytogenic additive in protein supplement on performance of grazing Nellore bulls during growing phase in the rainy season. One hundred and fourteen animals (iBW, 273 ± 4.46 kg) were allocated for 152 days in six paddocks of Brachiaria brizantha cv. Marandu (~7 ha each), with automatic feeders and scales (in drinkers, Intergado, Brazil); and randomly distributed in six treatments fed on protein supplement (30% Crude protein): 1) Negative Control (CON), with no additive; 2) Monensin (MON; positive control, 15 ppm) 3) Digestarom (DSM Nutritional Products) at 0.2 g· animal-1·/day-1 (D0.2); 4) Digestarom at 0.4 g· animal-1·/day-1 (D0.4); 5) Digestarom at 0.6 g· animal-1·/day-1 (D0.6) and 6) Digestarom at 0.8 g· animal-1·/day-1 (D0.8). Supplement offered and additives inclusion were adjusted weekly, based on the intake of the previous week. Supplement intake (SI, measured by the automatic feeders) and Average Daily Gain (ADGs; measured subtracting final and initial fast BW, divided by 152 days; and ADGf; measured by the automatic scales) were evaluated during this study. Data were analyzed by SAS PROC GLIMMIX and significance of 5% was adopted. Means of Digestarom levels were compared with the CON and MON, and of the MON was compared with the CON using a Dunnett test. MON reduced (P < 0.05) SI (175 g/d) compared with CON (433 g/d) and all Digestarom levels (423, 303, 468 and 332 g/d respectively). D0.4 and D0.8 also reduced SI when compared with CON. The ADGs and the ADGf of animals on D0.6 (927 and 1.262 g/d) were greater (P < 0.05) compared with CON (0.860 and 1.127 g/d) and MON (0.840 and 1.114 g/d). The other levels of Digestarom [D0.2 (0.886 and 1.107 g/d), D0.4 (0.823 and 1.054 g/d), and D0.8 (0.853 and 1.071 g/d)] did not differ from CON and MON. D0.6 did not reduce SI (compared with CON; P > 0.05) and increased ADGs and ADGf (compared with CON and MON; P < 0.05). Feeding Digestarom at the dose of 0.6 g· animal-1· / day-1 may increase BW gain of grazing growing bulls during rainy season. [ABSTRACT FROM AUTHOR]

This study conducted at São Paulo State University feedlot, Dracena campus, Brazil, was designed to evaluate the addition of either sodium butyrate (BUT) or exogenous fibrolytic enzymes (ENZ) on dry matter intake (DMI), ruminal pH, short-chain fatty acids (SCFA), and rumen disappearance rate of Angus cattle. Three Angus steers, cannulated in the rumen (+ 690 kg), were used in a replicated 3 x 3 Latin square, resulting in 6 experimental periods, in a total of 203 days of study. Each experimental period lasted 28 days; 14 days of adaptation diets, and 14 days of the finishing diet containing 85% concentrate (71% finely-ground corn). Cattle were given a 7-day washout interval between periods, where they were allowed to graze. The experimental diets fed to the animals were different only with respect to the feed additives used, according to the treatments: Control (CTL; no feed additives added), ENZ [0.01% of diet dry matter (DM)], and BUT (0.3% and 0.1% of diet DM during adaptation and finishing phases, respectively). The DMI was measured daily, and rumen pH and temperature were measured by data loggers on days 25 and 26 of each experimental period. The rumen fluid samples were collected at 0, 4, 8, and 12 hours after feeding on day 26 of each period to determine the molar proportion of SCFA. The rumen of the animals was emptied on day 27 at 1100 h (3 hours after feeding) and day 28 at 0800 h (before feeding) in each experimental period. The rumen contents were separated into solid and liquid fractions and then weighed. Based on the solid and liquid mass values obtained, as well as the DM intake, the rumen disappearance rate was calculated and expressed in %/h. Data were analyzed by PROC MIXED of SAS (2003), using Tukey's test to compare means when appropriate, considering P = 0.05 as significant. The DMI was not affected (P > 0.76) by treatments in this study. Likewise, no treatment effect was observed on minimum, maximum, and mean ruminal pH (P > 0.23). The pH time below 6.2, 5.6, and 5.2 was not affected by treatments (P > 0.45), as well as pH area under 6.2, 5.6, and 5.2 (P > 0.55). Rumen temperature was lower in cattle fed ENZ when compared with those fed CON and BUT (39.63°C vs. 40.12°C and 40.02°C, respectively; P = 0.04). Furthermore, the molar proportions of SCFA were not affected by treatments (P > 0.71). Cattle consuming ENZ increased ruminal disappearance rate (%/h) when compared with CTL-fed cattle (8.61 vs 6.36; P = 0.05). Thus, the addition of BUT to feedlot diets did not cause any impact on ruminal fermentation parameters; however, the use of ENZ promoted small benefits that deserve further investigation. [ABSTRACT FROM AUTHOR]

Objective of the current study was to evaluate the effects of tannin supplementation on cattle growth performance, energetic efficiency, and carcass characteristics of calf-fed steers. One hundred and sixty dairy steer calves with initial body weight (IBW) of 129.85 ± 3 kg, were blocked by IBW and randomly assigned to 40 pens (4 steers/pen; 10 pens per dietary treatment). Dietary treatments were: 1) Control (no additives); 2) MON (30 mg/kg monensin); 3) TAN (15 g/kg ByPRO; 70% condensed tannin; Silvateam USA, Tontitown, AR); and 4) MON+TAN (30 mg/kg monensin + 15 g/kg ByPRO). All steers were fed a similar steam-flaked corn-based diet (63.5% steam-flaked corn, 12.0% hay, 17.5% of dry distillers grains with solubles, 4.0% cane molasses, and 3.0% vitamin/mineral supplement). All cattle were slaughtered after 328 days of feed. There were no effects (P = 0.13) of dietary treatment on final BW (615 ± 22 kg), overall average daily gain (1.48 ± 0.07 kg/day), overall dry matter intake (7.93 ± 0.39 kg/day), overall gain to feed ratio (0.187 ± 0.07), and overall observed vs. expected net energy for maintenance and gain (1.00 ± 0.03 and 1.00 ± 0.04, respectively). However, cattle receiving MON or MON+TAN supplementation increased (P = 0.04) BW and gain to feed ratio in the first 112 days on feed compared with cattle in the control treatment. Moreover, cattle in the 2 dietary treatments receiving monensin supplementation tended (P = 0.09) to increase average daily gain and gain to feed ratio on the first 112 days on feed compared with cattle in the control treatment. There were no effects (P = 0.22) of feed additive supplementation on hot carcass weight (380.7 ± 14.7 kg), dressing percentage (61.83 ± 1.05%), kidney, pelvic, and heart fat (3.32 ± 0.19%), backfat thickness (0.73 ± 0.12 cm), longissimus muscle area (83 ± 4.83 cm2), marbling score (494 ± 48), and calculated yield grade (2.94 ± 0.24). Moreover, there were no effects (P = 0.55) of dietary treatment on percent of liver abscess incidence, regardless of diet, calf-fed steers in the current study had 3.75% of liver with abscess. [ABSTRACT FROM AUTHOR]

The optimization of the nutritional program of calves is essential for the sustainability and profitability of dairy companies. The use of additives such as Monensin allows to improve growth efficiency; however, concerns about the use of antibiotics in animal feed are growing. Therefore, the use of alternative products that can replace antimicrobial feed additives is necessary. Our objective was to evaluate the use of a combination of saponins and tannins in rearing stage of Holstein calves. A total of 36 female calves (BW, 114 ± 11 Kg; age, 86 ± 6 days) were distributed in 3 groups (n = 12/group) in a completely randomized design, using BW as criteria for assignment to each treatment (diet): 1) CON: without additives, 2) MON: Sodium Monensin (MON, 60 mg/kg DM, Elanco, Indianapolis, IN), 3) BXS: (900 mg/kg DM, a mixture of saponins and tannins, Silvafeed BXS, Silvateam, Argentina). The animal was used as the experimental unit. The calves were fed individually during an adaptation period of 10 days to the diet and a measurement period of 62 days. Body weight assessments were performed at the beginning and end of the measurement period with 12 previous hours of fasting. The feed intake was determined daily by measuring offer and rejection, and the conversion efficiency was determined using the quotient between the average daily gain and dry matter intake. Data were analyzed using PROC GLM of SAS, considering treatment as a fixed effect. Means differences were compared using Tukey's test, considering significance when P value = 0.05. BXS and MON had increased final BW than CON (181, 181, and 174 kg respectively, P = 0.03). ADG was greater in BXS and MON than CON (1.075, 1.080, and 0.958 kg/d respectively, P = 0.03). BXS had similar DMI than MON but greater than CON (5.29, 5.13, and 4.62 Kg/d respectively, P = 0.03). The G:F was similar between treatments (0.208, P = 0.69). In conclusion, a combination of saponins and tannins can be used as an alternative additive to improve the performance of Holstein calves in rearing stage. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effects of a slow-released nitrogen (N) ingredient in association or not with monensin on the performance, metabolism, and carcass parameters of finishing young bulls. To investigate these outcomes, 112 Nellore young bulls (380 kg ± 16.2) were used in a 2 × 2 factorial arrangement. The young bulls were allocated to 28 feedlot pens (four animals per pen) and fed a finishing high starch (51% starch) corn grain and corn silage-based diet. The following treatments were randomly assigned to the experimental units: 1) Control (CON, n = 7), finishing diet without additives; 2) Monensin-enriched diet (MON, n = 7), monensin (Rumensin, Elanco Animal Health, Greenfield, IN) provided at a level of 30 mg per kg of dry matter (DM); 3) Gradual-N-release enriched diet (SRN, n = 7), slow-N-release supplement (Timafeed Boost, Roullier Group, Saint-Malo, France) provided at a dose of 250 g per animal per day; or 4) Monensin + SRN diet (MON + SRN, n = 7), monensin (30 mg per kg of DM) associated with the SRN (250 g per animal per day). The experimental period comprised 102 days, with the first 15 days designated for diet adaptation. The average daily gain (ADG) over the experimental period was reduced for young bulls fed SRN + MON (P = 0.02) compared with those fed only SRN. Young bulls fed MON had greater DMI during the finishing phase than MON × SRN (P = 0.03). Overall, young bulls fed CON diet had greater day-by-day dry matter intake (DMI) variation than other treatments (P = 0.05). The SRN inclusion in the diet improved feed efficiency by 5.7% (P = 0.04). Young bulls fed diets without SRN inclusion tended to have higher blood urea concentration (P = 0.06). Blood D-lactate and glucose levels were similar between treatments (P = 0.21). The SRN use tended to increase (P = 0.09) DM digestibility (5.6% increase). The microbial crude protein was reduced by MON + SRN association (P = 0.02) compared with other treatments. The hot carcass weight was greater for the SRN group compared with MON × SRN (P = 0.02). The use of SRN in the diet increased (P = 0.04) total and daily carcass gain, carcass yield, and biological efficiency. In summary, although additional studies are suggested, these data indicate that the association between SRN and monensin might require careful consideration when used in finishing diets. The SRN inclusion in finishing diets without monensin shows important potential for increasing animal performance and efficiency. [ABSTRACT FROM AUTHOR]

Genetic selection for animals more tolerant or less sensitive to inadequate water availability may become critical to beef production, particularly as water resources become scarce or represent a meaningful cost to producers. The objectives of this study were 1) to explore the genetic component and environmental sensitivity (ES) of dry matter intake (DMI) to water restriction (WR), and 2) to evaluate genetic-byenvironment interactions (G×E) with respect to WR using a reaction norm. A group of 788 crossbred steers arranged across seven cohorts were provided feed and water whereby daily water intake (WI) and DMI values were recorded automatically on an individual basis. After an initial acclimation period, data were collected for 70 days in which ad libitum water was provided and baseline WI was determined on each steer. Next, steers were restricted by approximately 10% of their baseline WI every seven days until 50% WR was achieved and subsequently maintained for 42 days. The reaction norm was modeled with a linear random regression allowing for additive genetic animal-specific intercepts and slope parameters as a function of the WR environmental covariate. The relationship covariance matrix for the additive genetic animal parameters was estimated using genotypes. The model was fit using the THR3GIBBSf90 program in the BLUPf90 software. The additive genetic variances for animal-specific intercepts and WR-driven slopes, as well as their covariance, were estimated. The estimated (posterior median and 95% highest posterior density) ES to WR, represented by the regression coefficient on the WR covariate, was -0.410 (-0.422, -0.399) kg daily DMI per 10% WR, indicating evidence for population-level DMI sensitivity to WR. The estimated additive genetic correlation between animal-specific intercept (i.e., ad libitum WI) and animal-specific slope (i.e., sensitivity to WR) was -0.75 (-0.88, -0.59), supporting an association between selection for increased DMI at ad libitum WI and ES. The additive genetic correlation between DMI at 0% and 25% WR was estimated at 0.96 (0.94, 0.99) and at 0% and 50% WR was 0.78 (0.65, 0.91), thereby indicating G×E had limited influence on the overall EBV ranking of animals as WR increased. The results of this study do not indicate major G×E concerns in DMI with respect to WR in the overall population; however, ES to WR may be important to producers as selection on DMI at ad libitum WI could increase ES. [ABSTRACT FROM AUTHOR]

Precision Livestock Farming (PLF) is a technology-driven approach comprising sensors, cameras, global positioning system tracking, and data analytics to collect real-time data on animal behavior, health, welfare, and performance that enables feedyard operations to make informed decisions and take proactive measures to ensure optimized management and the well-being of their livestock and production efficiency. PLF systems leverage advanced analytical tools and techniques, such as artificial intelligence (AI), including machine learning and deep learning, by integrating data provided by various sensors and software with related datasets and standard AI models to obtain unique data-driven decisions on a range of management practices. The most imminent benefits of PLF include reduced environmental impact and increased profitability. Current PLF tools for climatesmart feedyard operations include 1) feed management systems that use data from feed intake and animal behavior to optimize feed efficiency and minimize waste, which has the potential to decrease the amount of greenhouse gas (GHG) emissions linked to livestock feeding and feed production; 2) environmental monitoring systems to collect local temperature, humidity, and air quality to optimize the pen environment, which can reduce stress on animals, reduce diseases, such as the incidence of respiratory and foot infections, and improve their overall health; 3) feeding systems to use data from individual animals to provide individualized feed and nutrient programs, thus, helping to improve and select for feed efficiency and reduce the amount of feed wasted, assisting with mitigating GHG emissions associated with livestock feeding and feed production; 4) individual animal monitoring systems to access behavior, health and well-being of individual animals that, through early disease symptoms detection, can prevent and reduce recovery time, and reduce the amount of medication applied to animals, reducing GHG gas emissions associated with pharmaceutical products; and 5) waste management systems to help reduce GHG emissions associated with manure production by optimizing manure management and reducing the amount of waste, which can also help reduce unpleasant odors and improve the overall environment conditions in and around feedyards. Waste management systems could also measure the soil and water contamination with fugitive nutrients, feed additives, implants, antibiotics, and other pharmaceuticals administrated to animals to maintain health standards. The adoption of PLF tools in feedyard operations aims to create a sustainable and efficient livestock industry by reducing waste, optimizing resources, and improving animal welfare through advanced technologies and analytical tools. Additionally, PLF tools enable feedyards to optimize feeding and breeding programs, minimize waste and environmental pollution, and improve the quality and safety of animal products. In today's fast-paced industry, PLF tools are essential for feedyard operations to monitor, analyze, and make informed decisions about the well-being and production efficiency of their livestock, ultimately contributing to a more sustainable and efficient livestock industry. [ABSTRACT FROM AUTHOR]

Previous studies have shown that the use of additives to enhance intake and immunity at farm arrival could be a strategy to minimize the negative effects of stress and feed restriction during transportation in unweaned calves. Unweaned dairy beef calves are fed low liquid feeding programs to avoid mechanical diarrheas and to enhance the consumption of solid feed to increase growth. A total of 78 dairy beef calves (57.8 ± 1.64 kg) coming from auction market were used to evaluate the effect of various feed additives [FA; comprising palatability enhancers (PE), standardized olive pomace extract (OE), and tributyrin (TB)] added to the milk replacer (MR) and concentrate or only to the concentrate on performance until 1 week after weaning. Calves were distributed in 6 treatments: calves fed MR and concentrate without FA (CTR-CTR; n = 13); calves fed MR without FA and concentrate with PE (CTR-PE; n = 13); calves fed MR without FA and concentrate with complete mixture OE + TB + PE (CTR-COM; n = 13); calves fed MR and concentrate with PE (PEPE; n = 13); calves fed MR with PE and concentrate with complete mixture OE + TB + PE (PE-COM; n = 13); calves were fed MR with complete mixture OE + TB + PE and concentrate with PE (COM-PE; n = 13). At arrival calves were only fed 2 L of MR twice daily at 12.5% and concentrate feed ad libitum. On day 35 of the study, animals were submitted to a social stress challenge, calves within one treatment were mixed for 24 h, and on day 36, calves returned to their home pens and the afternoon milk was removed. On day 42, all calves were weaned, and they were followed until day 49. Data were analyzed with a mixed-effects model. No differences were observed in concentrate intake the first week after transportation. However, an interaction between treatment and time (P < 0.01) was observed among treatments in concentrate intake from day 35 until day 49 when calves were already weaned. The PE-PE and PE-COM calves had a greater (P < 0.10) concentrate intake from day 28 to day 42 than CTR-CTR or CTR-PE calves, while from day 42 to day 49 the CTR-COM was the group of calves with the greatest concentrate intake. Although no differences were observed on final BW among treatments, the CTR-COM calves had numerically greater ADG than the rest of the treatments. In unweaned dairy beef calves with liquid feeding restriction, the mixture of palatability enhancers, standardized olive pomace extract, and tributyrin potentially increases concentrate intake and growth when added in the concentrate feed. [ABSTRACT FROM AUTHOR]

The gastrointestinal tract of unweaned calves is compromised after the stress and feed restriction due to marketing and transportation. The use of feed additives to enhance intake and gut immunity at farm arrival could be a strategy to minimize those negative effects. A total of 70 dairy beef calves (50.9 ± 1.66 kg) coming from auction market and with a compromised gut integrity at arrival were used to evaluate the effect of various feed additives [FA; comprising palatability enhancers (PE), standardized olive pomace extract (OE), and tributyrin (TB)] on performance until 2 weeks after weaning. Calves were distributed in 5 treatments: calves fed milk replacer (MR) and concentrate without FA (CTR; n = 14); calves fed MR and concentrate with PE (PE; n = 14); calves fed MR with OE + PE and concentrate with PE (OEPE; n = 14), calves fed MR with TB + PE and concentrate with PE (TBPE; n = 14); and calves fed MR with OE + TB + PE and concentrate with PE (complete - COM; n = 14). At arrival animals received 2.5 L of MR twice daily at 12.5% and ad libitum concentrate feed. On day 35 of the study, animals were submitted to a social stress challenge, calves within one treatment were mixed for 24 h, and on day 36, calves returned to their home pens and the afternoon milk was removed. On day 42, all calves were weaned, and they were followed until day 56. Data were analyzed with a mixed-effects model. After transportation calves had an average of 1.6 ± 0.09 mg/L of serum Cr-EDTA the first week after arrival indicating that those calves had increased gastrointestinal permeability and a compromised gut barrier for a full week; consequently, concentrate intake during that week was decreased for all treatments (P = 0.56) with an average of 27 g·calf-1·d-1. An interaction between treatment and time (P < 0.01) was observed on concentrate intake the last two weeks of the study when calves were already weaned; on week 7, from day 42 to d 49, COM and TBPE calves had greater concentrate intake than CTR calves, and PE and OEPE did not differ among others; and on week 8, between day 42 and day 49, COM calves had the greater concentrate intake than CTR, while other treatments were in between. Although only numerical differences were observed in final BW, COM calves were heavier than the rest of the treatments at the end of the study. In calves with severe problems of gastrointestinal permeability at arrival, the mixture of palatability enhancers, standardized olive pomace extract, and tributyrin increases concentrate intake and potentially improve the recovery of the animals. [ABSTRACT FROM AUTHOR]

Beef cattle are a major contributor to methane (CH4) emissions. Enteric CH4 is produced by archaea, mostly hosted by ruminal protozoa, thus, changes in protozoa counts have been associated with CH4 production. Therefore, reliable ruminal protozoa count (PROT) is essential to evaluate CH4-mitigation strategies. Typically, PROT are done by fixation with methyl-green-formalin-saline solution (MFS), which reveals ciliate numbers but not ruminal protozoa viability (VIAB). The Trypan Blue Exclusion Method (TBEM) involves an intracellular probe that dyes the cytoplasm of apoptotic eukaryotic cells with membrane damage, but few studies report its use for PROT. Therefore, our objectives were to establish culture conditions to use the TBEM for PROT and VIAB under different diets (Exp. 1) and feed additives. In Exp. 1 ruminal fluid was collected from 4 Angus-crossbred ruminally cannulated steers receiving a high-grain diet (NOYE) alone or supplemented with 28 g/d of a product of yeast fermentation (YEAST). Filtered and diluted ruminal fluid was incubated (39°C, 95% CO2) with (SUB) or without (NOSUB) the substrate diet in three types of containers; 125 mL bottles (BOT), Erlenmeyer (ERL), or 16 × 125 mm Hungate tubes (TUB). After 8, 12, 24, and 48 h PROT and VIAB were determined using the TBEM, gas production, and CH4 concentration were measured. Exp. 2 involved in vitro batch culture incubations with a silage-based substrate (CON), plus a 50:50% mix of condensed and hydrolysable tannins (TAN), cashew nutshell extract (CNSE), or citral (CIT) at 0.3, 0.02, and 0.2% of substrate DM, respectively. At 0 and 48 h PROT, VIAB, volatile fatty acids (VFA), CH4, in vitro organic matter digestibility (IVOMD), and gas were determined. In Exp-1, PROT and VIAB were greater in TUB (P = 0.01) at 24 h and in BOT at 48 h (P < 0.01), particularly with SUB (P < 0.01). Supplementation of YEAST reduced VIAB in BOT and TUB compared with ERL (P < 0.01). In Exp. 2, TAN (P < 0.01) and CIT (p 0.05) reduced PROT and VIAB at 24 and 48 h (P < 0.01). Additionally, TAN reduced gas production (P < 0.01), and IVOMD (P < 0.01) coinciding with previous studies reporting protozoa reduction. Protozoa/mL were similar to previous reports with MFS in cows (1.5 × 104) and steers (3.7 × 103). In both experiments, PROT and VIAB reductions by YEAST, TAN and CIT coincided with a reduction of CH4, gas, and IVOMD. Differences in PROT with some studies using MFS might be associated with losses of small Entodinium during initial filtrations. When cultured in BOT with substrate, TBEM is a viable, simple, rapid, and cost-effective methodology to evaluate PROT and VIAB after a nutritional challenge. The ability to assess membrane disruptions associated with protozoa apoptosis in the TBEM is one its greatest advantages. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Multiple promising approaches to reducing enteric methane emissions from livestock have evolved over the past decade, including animal and feed management, dietary interventions, and feed additives. Explore methods and technologies that have potential to transform livestock production for broader and greater economic and environmental impacts, and the opportunities that lie ahead to propel conservation to the next level. [ABSTRACT FROM AUTHOR]

Swine feed additives is general terminology used for a wide range of non-nutritive products to help improve growth, health, and carcass characteristics. There are numerous classifications of feed additives that are currently used world-wide. To properly access the value of a feed additive to achieve desired goals, understanding the 1) mode(s) of action, 2) efficacy with different diet formulation strategies, 3) influence of herd health status, and 4) consistency of predicted response are vital. For the swine industry to advance on-farm sustainability for improved carbon, nitrogen and phosphorus efficiency, efficacious feed additives must be a utilized tool. This needs to be done in unison with best management practices already in place (e.g., optimized feed formulation, precise feed manufacturing and processing, advancing genetics, improving herd health) to provide complimentary, not competing results. Also, strategic emphasis must be placed on maintaining efficacious and economical feed additives in the marketplace to prevent loss of their use. Ractopamine hydrochloride is just one example that was routinely fed to most US finishing pigs in diets before marketing but now is not used due to export market access. At the same time, pharmacological levels of Zn and Cu have illustrated clear benefits on pig growth, health and subsequently welfare, but regulatory action based on excretion levels and potential connections to antimicrobial resistance have begun to limit their use in certain countries. These examples highlight the need for correctly designed, unbiased research to provide consumers, human health professionals, and regulatory personnel information to make accurate decisions regarding various feed additives. Finally, innovation to advance the efficacy and predictability of feed additives such as in-feed enzymes, acidifiers, direct feed microbials, yeasts, fatty acids, trace minerals, ionophores, and others is needed. These products must be a component of current and long-term producer profitability, nutritional efficiency, and sustainability. [ABSTRACT FROM AUTHOR]

Previously, we observed a linear improvement in feed conversion and no difference in body weight (BW) in broiler chickens fed increasing additions of choline chloride in a diet with reduced digestible methionine (dMet) reared under summer environmental conditions. Poor uniformity in broiler carcass weights can negatively impact processing yields and profitability. The objective was to evaluate the impacts of increasing choline concentration on BW variation of broilers from the previous study. Yield Plus × Ross 708 male broilers (n = 2,232) were reared for 41 d on used litter in floor pens (n = 31 birds per 2.3 m² pen). Birds were fed 1 of 6 corn and soybean meal-based, reduced dMet diets containing 0, 400, 800, 1,200, 1,600, or 2,000 mg added choline chloride per kg of feed (n = 12 pens per treatment). Diets were provided in 3 phases: starter from d 0 to 15 with 0.42% dMet, grower from d 16 to 28 with 0.42% dMet, and finisher from d 29 to 41 with 0.37% dMet. Rearing temperatures began at 34.4 °C, were reduced over 21 d to 26.7 °C and maintained there until d 41. Individual weights were collected at 15, 28, and 41 d. Broilers (n = 10 per pen based on proximity to pen median BW) were processed on d 43. The distance of each bird from both mean and median of the pen, added choline treatment, and whole flock BW over time was calculated. Uniformity was reported comparing within a pen to the pen, treatment, and flock averages. Intra-pen CV was calculated using pen mean and median weights. Data were analyzed as a 1-way ANOVA using SAS PROC GLIMMIX with added choline as main effect. Means were separated at P ≤ 0.05 with tendencies declared at 0.05 < P ≤ 0.10 using the PDIFF option, and orthogonal contrasts were evaluated. Supplementing the diet with choline increased individual bird distance from the treatment and flock average BW from d 15 to 41 (P ≤ 0.0244). Intratreatment and flock uniformity showed a quadratic response to increasing additions of choline at d 41 (P ≤ 0.0214) as did the CV within pens at d 41 (P = 0.0455). Variability of carcass part weights of birds selected for processing was not impacted by choline addition. While supplementing dMet-deficient diets with choline chloride can improve broiler feed efficiency without impacting BW, it may alter variation among individual birds depending on the concentration in the diet. These results indicate that there is variation in how individual birds respond to choline chloride additions and highlight the importance of analyzing variation as part of comprehensive feed additive evaluation to deepen the understanding of its impacts. [ABSTRACT FROM AUTHOR]

The objectives of this study were to examine the impacts of active live yeast (Saccharomyces cerevisiae) as a dietary feed additive on dry matter intake, feed sorting, gut permeability, ruminal pH and volatile fatty acids (VFA) concentration, as well as fecal pH and VFA concentration in cattle fed a highgrain finishing diet and subjected to a ruminal acidotic challenge. Fifteen Hereford X Charolais heifers were blocked by BW into three blocks. Heifers were randomly assigned within block to one of two dietary treatments; CON (no additive), or YST (3 g· animal-1· day-1 of active live S. cerevisiae) added to a steam-flaked corn diet (83% steam-flaked corn, 8% wheat straw, 5% soybean meal protein mix, 4% vitamin and minerals on a DM basis). The experimental timeline was as follows: 30 d adaptation (ADPT), 5 d baseline (BASE), 5 d ruminal acidosis challenge (CHAL), and three subsequent 5 d recovery phases (REC1, REC2, and REC3). On day 2 of each phase and days 2 and 4 of CHAL, 179 mM Cr-EDTA and 360 mM Co-EDTA were infused into the omasum and rumen, respectively, as gut permeability markers. Within each phase, in-dwelling pH probes were used to capture reticulo-ruminal pH every 5min for 96 consecutive hours, rumen fluid and fecal grab samples were collected once for every 3 h in a 24 h period, and blood was collected at 2, 4, 12, and 24 h after each Co and Cr infusion. Dry matter intake and feed sorting were measured daily for each animal. Statistical analysis was conducted using PROC GLIMMIX in SAS as a randomized complete block design with block, treatment, and phase as fixed effects and animal as a random effect. Ruminal acidosis was successfully induced using this method, as suggested by the statistically significant reduction in minimum pH and increase in pH range in the CHAL phase compared with other phases of the experiment (P ≤ 0.02). Recovery from the ruminal acidosis challenge was detected within the REC1 phase when comparing minimum pH (CHAL 5.25 vs. REC1 5.54; P = 0.001). Additionally, the sorting behavior of some particle sizes was significantly impacted by phase (P ≤ 0.01). Overall, the addition of yeast to the diet did not impact feed intake, sorting behavior, spot ruminal and fecal pH, volatile fatty acid concentrations in ruminal fluid or feces, or the uptake of Cr-EDTA and Co-EDTA. These results suggest that adding live S. cerevisiae yeast at this dose in a high-grain finishing diet does not impact feed intake, gut permeability, or the production of VFA when ruminal acidosis is induced. [ABSTRACT FROM AUTHOR]

Sow body condition is important for maximizing life-time productivity, milk production and progeny performance. Data from a total of 4,367 sows (76PIC, 4291Genesus) were used to investigate relationships between sow body condition at entry to farrowing house (body weight, back fat, body condition score) versus reproductive performance and milk production. Data were from a commercial farm from 2018-2020. Sow data were stratified by parity: Class 1 (parity 1), 2 (parity 2-4) and 3+ (parity 4 and above). Sow entry weight (with fetuses), backfat, and body condition score (scale 1-5) were measured at entry to farrowing house and at weaning. Milk production was calculated using the method of Hansen et al. (2012). Standard sow performance was collected via data software (Agriness). Data were plotted and assessed for commercially relevant relationships among dependent and independent variables. Single factor linear regression was used to calculate linear slope and slope standard error between variables of interest within parity. The farm represents typical north American performance with average piglets born alive13.9, total piglets born 15.6, number of piglets weaned 10.5. Regardless of parity, sow body weight at entry had the greatest positive linear relationship to reproductive productivity. Heavier weight at entry was positively related to number of total piglets born, born piglets alive, litter birth weight and milk production. Heavier primiparous sows at entry had greater piglet weight gain and weaning weight. A positive linear relationship (evidenced by non-zero linear slope) was observed between sow back fat loss and milk production in primiparous sows. Relationships among sow back fat, body condition score and productivity were weak (confidence interval of slope included zero). Sow backfat at entry did not impact lactation feed intake. This might be due to high average lactation feed intake (average 8 kg/d) in this farm. Slightly positive regression was observed between sow weight and lactation intake in primiparous sows but not in older sows. Most commercial farms do not have weighing equipment. Sow body condition score is often used as an economic method but highly variable depending on farm personnel. Our investigation suggests that sow body weight is important for sow reproductive performance. Gilt body weight at entry is positively related to litter birth weight and weaning weight. Future research is needed to better understand sow body composition (fat and lean percentage) on productivity and find economic ways to collect these parameters at commercial farms. [ABSTRACT FROM AUTHOR]

L-Carnitine is a feed additive involved in the transport of fatty acids into the mitochondria to produce energy. With this mechanism, L-Carnitine can enhance the ability to use fat for energy. The objective of this study was to determine the effects of adding L-Carnitine throughout the entire grow-finishing period or just 28 d before marketing on growth performance and carcass characteristics. A total of 1,833 mixed-sex growing-finishing pigs (PIC 337 × 1050; initially 26.5 ± 0.33 kg) were used in a 112-d growth trial to determine the effects of adding L-Carnitine throughout the entire grow-finishing period or just the last 28 d before marketing. There were 26 replicate pens per treatment and 20 (group 1) or 27 (group 2) pigs per pen in a completely randomized design. There were three treatment diets: 1) control with no added L-Carnitine; 2) diets containing 50 ppm of L-Carnitine for the entire trial; or 3) control diet until d 84 and then a diet containing 50 ppm of L-Carnitine. On day 84, one-half of the control pens were randomly assigned to the diet containing 50 ppm of L-Carnitine. The experimental diets were corn-soybean meal-DDGS-based and were fed in 4 phases. From d 0 to 84, statistical analyses compared the 52 pens of pigs fed the control diets with the 26 pens of pigs that were fed diets with L-Carnitine. From d 85 until market, comparisons were made using all 3 treatments. In the first 28 d, pigs fed L-Carnitine had greater (P < 0.002) BW, ADG, and ADFI and similar G:F (P = 0.459) as those fed the control diet (Table 1). From d 0 to 84, pigs fed L-Carnitine had a tendency (P = 0.052) for greater ADFI, but there was no evidence (P > 0.14) of differences for ADG, G:F, removals, and mortalities. From d 85 to market and overall, there was no evidence of differences (P > 0.22) for ADG, ADFI, G:F, or removals and mortalities. For carcass traits, no difference (P > 0.54) in HCW, yield, backfat, lean, and loin depth were detected between treatments. In conclusion, added L-Carnitine improved performance in the early grow-finishing phase compared with control. However, this effect was not detectable at market, with no impact on overall growth performance, removals and mortalities, or carcass characteristics when added for the entire grow-finishing period or just the 28 d before marketing. [ABSTRACT FROM AUTHOR]

Environmental methane production continues to be an ongoing global concern and interest is growing to reduce total methane production. As a part of this collective effort mitigation of methane production in ruminants has become one of the targets for ongoing research. Several strategies have emerged including dietary manipulation, administration of unique feed additives that specifically target methanogens, and host animal modulation approaches. Most of these efforts have focused on the rumen methanogen population and understanding their ecology in relationship to the non-methanogen microbial population. However, there is potential for methane production in the hindgut of the ruminant animal, and this should be considered in any overall strategy for mitigation of methane production in ruminants. The emphasis of this presentation is to discuss the current knowledge and future prospects for understanding the contribution of hindgut methanogens to overall ruminant methane production and their potential for contribution to mitigation of ruminant methane production. [ABSTRACT FROM AUTHOR]

Research efforts are underway to identify methane mitigators in the dairy sector to reach net zero carbon emissions, and ideally, net negative global emissions. Methane mitigation is multifactorial, including strategies in genetics, management, diet composition, diet nutrient composition, and implementation of feed additives. Research efforts thus far have primarily focused on adult ruminants. Research on how calf management and its impact on phenotypic traits including milk production and methane production is currently lacking. Supplying different levels of nutrients in late lactation results in demonstrated splits in feed intake, average daily gain, metabolism, and greenhouse gas emissions from their offspring. Post-calving, nutrient-restricted heifers entering the lactating herd are hypothesized to be less productive and have greater environmental impact due to reduced productive efficiency relative to their control herd mates. Identification of feed additives that are locally sourced, alter the rumen microbiome, and have lifetime reductions on emissions are under investigation. Further research efforts include identifying metabolic and genetic profiles to identify animals in early life as either high or low methane emitters. Being able to classify animals early in life can reduce the total economic inputs used to raise animals and reduce the total environmental impact of these animals through early culling or intervention of high methane emitting animals. The goal of this presentation is to discuss current knowledge and future potential of calf management, feeding regimes, and feed additive implementation to reduce methane emissions and total environmental impact in the dairy industry. [ABSTRACT FROM AUTHOR]

Antibiotics remain the most effective tool for treating and preventing animal diseases in livestock production. However, the widespread use of antibiotics in food animals, as well as concerns about antibiotic resistance among bacterial pathogens, have raised awareness of the need to limit their use. As neonatal dairy calves are very susceptible to gastrointestinal infections that can result in high mortality and morbidity, the need to find alternatives to antibiotics has become a priority. Although essential oils (EO) have emerged as promising anti-microbial alternatives, their potential effects on the rumen microbiome are still poorly understood due to the complexity of their chemical components and limited understanding of their mechanisms of action. To gain further insight into the effects of EO on the bacterial communities of pre-weaned calves, we investigated the rumen metagenome of neonatal Holstein dairy calves that had been supplemented with 3.75g/feeding of a blend of EO (carvacrol, caryophyllene, p-cymene, cineole, terpinene, and thymol) as part of a previous study. Genomic DNA extracted from rumen contents collected from one of the EO-supplemented animals was used for high throughput sequencing using an Illumina Miseq (2x250) platform. Raw sequence reads were assembled into genomic contigs using custom-written Perl scripts. Coding sequences (CDS) were identified and annotated using RAST, with assignment of open reading frames (ORFs) to metabolic pathways using KEGG pathways. After assembly, a total of 3,052 contigs between 279 and 259,890 nt in length were obtained. From this set, 571 contigs affiliated to Prevotella ruminicola, representing 18.7% of total contigs built, were further analyzed. Data mining for specific functions within categories such as 'protein metabolism', 'carbohydrates metabolism', and 'amino acids and derivatives' was performed. This analysis resulted in the identification of all the enzymes involved in glycolysis. Two outcomes were predicted for pyruvate: conversion to lactate through lactate dehydrogenases (EC 1.1.1.27, EC 1.1.1.28), and the production of formate and acetyl-CoA through the activity of pyruvate formate-lyase (EC 2.3.1.54). Acetate (acetate kinase, EC 2.7.2.1) and propionate (Propionate kinase, EC 2.7.2.15) were other predicted end products. In addition to glucose fermentation pathways, enzymes potentially involved in the utilization of plant-based secondary metabolites were also identified, such as enzymes involved in Quinate-Chorismate metabolism: 3-dehydroquinate dehydratase (EC 4.2.1.10), Shikimate 5-dehydrogenase I alpha (EC 1.1.1.25), Shikimate kinase (EC 2.7.1.71), 5-Enolpyruvylshikimate-3-phosphate synthase (EC 2.5.1.19), and Chorismate synthase (EC 4.2.3.5). Identification of such metabolic pathways suggests that perhaps the supplemented EO additive could be used as a precursor for the synthesis of aromatic amino acids. Together, these findings indicate that EO supplementation may benefit animal health and performance by promoting the growth of bacterial species that can metabolize compounds in EO additives. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine whether feeding live yeast to sows from day 85 of gestation and through lactation influences pig performance and microbiomes in the postweaning period. Three dietary treatments were imposed on mixedparity sows during late gestation and lactation based on the inclusion level (%) of Actisaf Sc47 in corn/soybean meal-based diets: Control (C, 0%), Low (L, 0.1%), and High (H, 0.5%). Pigs (n = 240; 80/maternal dietary treatment group) were selected randomly at weaning (~19 days old) for further performance data collection throughout the nursery period. A subset of these pigs (n = 180; 60/maternal treatment group) were selected randomly for microbiome sampling through fecal swabs collected on days 4 (T1) and 28 (T2) postweaning. Pigs were housed in pens in a confinement nursery barn according to maternal dietary treatment group (10 pigs/pen; 0.28 m2/pig of floor space; 8 pens/treatment group). Treatment groups were kept separate from each other by maintaining one empty pen between treatment groups to prevent potential microbial cross-contamination. Pigs were balanced by litter, body weight, and sex during nursery allotment. Pigs had ad libitum access to water and a common industry-relevant diet, fed in four phases from weaning through day 42. Pigs were weighed individually at the end of each dietary phase (d4, d14, d28, d42). DNA was extracted from fecal swabs and sequenced on the MiSeq platform, targeting the V4 variable region of the 16S rRNA bacterial gene. Sequence data were analyzed using QIIME2 and DADA2, plus various packages within the R statistical software. Performance data were analyzed using repeated measures and generalized linear mixed models that included maternal treatment as a fixed effect, maternal parity as a random effect, and pen as the experimental unit. Daily weight gain was greater for L pigs (0.47 kg) compared with H pigs (0.42 kg; P < 0.05), while ADFI was increased for L pigs (0.57 kg) compared with both C and H pigs (0.49 and 0.47 kg, respectively; P < 0.05; see Table). No differences in microbiome diversity were observed at either time-point. However, microbiome composition differed based on maternal treatment group at both time-points (T1: PERMANOVA, R² = 0.02, P = 0.001; T2: PERMANOVA, R² = 0.04, P = 0.001). These results indicate that live yeast supplementation in sow diets in late gestation and lactation may have lasting effects on pig performance and microbiome composition in the post-weaning period. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate effects of live yeast supplementation of sow diets during late gestation and lactation on sow reproductive performance and piglet microbiome development. Three dietary treatments were imposed on mixed-parity sows (n = 92) from three contemporary farrowing groups during late gestation and lactation. Dietary treatments were based upon the inclusion level (%) of Actisaf Sc47 in corn/soybean meal-based diets: Control (C, 0%), Low (L, 0.1%), and High (H, 0.5%). Sows were fed their assigned gestation diet (1.8 kg ·animal-1·day-1/) from days 85 to 110 of gestation. On day 111 of gestation, sows were fed their assigned lactation diet (3.6 kg/head/day) until parturition. Sows were allowed ad libitum access to their assigned lactation diet beginning day one postpartum until piglets were weaned. Fecal and vaginal swabs were collected from all sows on day 85 of gestation (T1-S) and the day before parturition (T2-S). Colostrum and milk samples were collected from 30 focal sows (10/treatment group), and fecal swabs were collected from 6 piglets per focal sow (n = 180) at 24 to 36 hours after birth (T1-P) and weaning (T2-P, ~19 days old). Extracted DNA from swab samples was sequenced on the MiSeq platform targeting the V4 variable region of the 16S rRNA bacterial gene, and sequence data were analyzed using DADA2 plus various packages within the R statistical software. Generalized linear mixed models were built for sow performance data using the R lme4 package, with treatment as a fixed effect, and farrowing group, parity, and sire as random effects. Piglet performance models also included sex as a fixed effect and maternal origin instead of sire as a random effect. No significant differences were observed among dietary treatment groups for gestation or lactation length, lactation feed intake, sow body weights, sow backfat depth, litter size at birth or weaning, pre-weaning piglet mortalities, or piglet growth performance. Although alpha and beta diversity did not differ among maternal dietary treatment groups in sow colostrum, milk, fecal, or vaginal samples (T1-S or T2-S), several taxa were significantly enriched or less abundant in sow samples based upon dietary yeast inclusion levels. Diversity of piglet fecal microbiomes was not different across maternal dietary treatment groups, but community composition was different at both time-points (T1-P: PERMANOVA, R² = 0.13, P = 0.02; T2-P: PERMANOVA, R² = 0.01, P = 0.048). These results indicate that yeast supplementation in sow diets in late gestation and lactation may influence development and composition of piglet gut microbiomes in early life. [ABSTRACT FROM AUTHOR]

An experiment was conducted to test the hypothesis that supplementing diets with a blend of medium chain fatty acids (MCFA) and a phytogenic feed additive (Fresta Protect, Delacon, Linz, Austria), together or separately, would improve growth performance and stool quality of nursery pigs challenged with Escherichia coli (ETEC). A total of 200 pigs [5.52 ± 0.17 kg body weight (BW)] were weaned at 17 to 19 days of age, allotted to 40 pens (5 pigs/pen), and allowed to acclimate for 2 days before initiation of dietary treatments. Pens were blocked by BW and randomly assigned to 1 of 5 treatments: negative control (NC), NC + 55 mg/kg carbadox (Positive control; PC), NC + 1.0% MCFA, NC + 0.1% phytogenic, or NC + 1.0% MCFA and 0.1% phytogenic. All pigs were administered an oral gavage of 5 mL ETEC (blend of K88+ and F18+) with a final titer of 1010 CFU/pig on day 5 and 6. Body weights were recorded on days 0, 4, 11, and 18, whereas feed intake was recorded for the overall trial (day 0 - 18). Fecal scores were assessed daily on an ordered likert scale to determine the joint probability of more normal stool quality. Data were analyzed using the lme4 package of R 4.1.2, and the statistical models included the fixed effect of treatment and random effect of BW block. Growth performance data were assumed to be normally distributed, whereas mortality and stool quality were analyzed using generalized linear mixed models specifying binomial and multinomial distributions, respectively. Contrasts were used to test for effects of dietary additive (carbadox, MCFA, phytogenic, or MCFA and phytogenic) compared with NC (Table 1). Results indicated postchallenge BW, post-challenge and overall average daily gain (ADG), and overall gain:feed (G:F) were greater (P < 0.05) for PC than for NC. In the pre-challenge phase, dietary inclusion of MCFA reduced (P < 0.05) final BW and ADG compared with NC, but overall G:F was greater (P < 0.05) than NC when the MCFA blend was fed. Inclusion of the phytogenic increased (P < 0.05) ADG in the post-challenge period and G:F in the overall trial compared with NC. The combination of MCFA blend and phytogenic resulted in increased (P < 0.05) post-challenge final BW, post-challenge ADG, and overall ADG compared with NC. All treatments, except MCFA blend, tended (P < 0.10) to reduce mortality compared with NC. The PC, MCFA blend, and combination treatments resulted in a greater (P < 0.05) probability of normal stool quality than NC. In conclusion, supplementation of the phytogenic and the combination of MCFA with phytogenic improved growth performance and tended to reduce mortality of nursery pigs under ETEC challenge. Furthermore, the combination improved stool quality. [ABSTRACT FROM AUTHOR]

Three experiments were conducted to determine the optimal dietary standardized ileal digestible (SID) lysine and CP concentrations for finishing pigs over 100 kg BW. In Exp. 1, 253 pigs (DNA 600 × 241, initially 102.0 kg) were used in a 23-d trial with 7 to 8 pigs per pen and 8 pens per treatment. Dietary treatments contained 4 SID lysine concentrations (0.45, 0.55, 0.65, or 0.75%). To formulate the experimental diets, a corn-soybean meal diet with 0.45% SID lysine was formulated without L-lysine HCl. Then, a corn-soybean meal diet containing 0.75% SID lysine was formulated including 0.23% L-lysine HCl. The 0.45 and 0.75% SID lysine diets were blended to provide the 0.55 and 0.65% SID lysine diets. Increasing SID lysine increased (quadratic, P < 0.05) ADG and ADFI with pigs fed 0.55% SID lysine having the greatest final BW. Marginal improvements in gain:feed (G:F; quadratic, P = 0.058) and carcass yield (linear, P = 0.051) and reduction in backfat (quadratic, P = 0.074) were also observed with increasing SID lysine. The quadratic polynomial models predicted maximum ADG and G:F at 0.62 and 0.63% SID lysine, respectively. The broken-line linear model predicted no further improvement in G:F over 0.55% SID lysine. In Exp. 2, 224 pigs (PIC 327 × 1050, initially 109.4 kg) were used in a 20-d trial with 7 pigs per pen and 7 to 8 pens per treatment. Dietary treatments included 4 concentrations of CP (10, 11, 12, or 13%) that were formed by reducing the amount of L-lysine HCl in a corn-soybean meal diet. Increasing CP increased (linear, P < 0.05) ADG and ADFI with the greatest responses observed in pigs fed the diet with 12% CP. Increasing dietary CP also improved (linear, P < 0.05) G:F, final BW, and hot carcass weight (HCW). In Exp. 3, 238 pigs (DNA 600 × 241, initially 111.8 kg) were used in a 26-d trial with 7 to 8 pigs and 6 pens per treatment. Dietary treatments included 5 concentrations of CP (9, 10, 11, 12, or 13%). Increasing CP improved (quadratic, P < 0.05) ADG and G:F with the greatest response observed in pigs fed 13% CP. Increasing CP marginally increased (quadratic, P < 0.074) HCW, with the greatest response observed in pigs fed 12% CP. In conclusion, the SID lysine requirement for pigs from 100 to 122 kg was 0.55 to 0.63% depending on the response criteria with performance maximized with diets containing 12 to 13% CP. [ABSTRACT FROM AUTHOR]

Three experiments were conducted to determine the optimal dietary standardized ileal digestible (SID) lysine and CP concentrations for finishing pigs over 100 kg BW. In Exp. 1, 253 pigs (DNA 600 × 241, initially 102.0 kg) were used in a 23-d trial with 7 to 8 pigs per pen and 8 pens per treatment. Dietary treatments contained 4 SID lysine concentrations (0.45, 0.55, 0.65, or 0.75%). To formulate the experimental diets, a corn-soybean meal diet with 0.45% SID lysine was formulated without L-lysine HCl. Then, a corn-soybean meal diet containing 0.75% SID lysine was formulated including 0.23% L-lysine HCl. The 0.45 and 0.75% SID lysine diets were blended to provide the 0.55 and 0.65% SID lysine diets. Increasing SID lysine increased (quadratic, P < 0.05) ADG and ADFI with pigs fed 0.55% SID lysine having the greatest final BW. Marginal improvements in gain:feed (G:F; quadratic, P = 0.058) and carcass yield (linear, P = 0.051) and reduction in backfat (quadratic, P = 0.074) were also observed with increasing SID lysine. The quadratic polynomial models predicted maximum ADG and G:F at 0.62 and 0.63% SID lysine, respectively. The broken-line linear model predicted no further improvement in G:F over 0.55% SID lysine. In Exp. 2, 224 pigs (PIC 327 × 1050, initially 109.4 kg) were used in a 20-d trial with 7 pigs per pen and 7 to 8 pens per treatment. Dietary treatments included 4 concentrations of CP (10, 11, 12, or 13%) that were formed by reducing the amount of L-lysine HCl in a corn-soybean meal diet. Increasing CP increased (linear, P < 0.05) ADG and ADFI with the greatest responses observed in pigs fed the diet with 12% CP. Increasing dietary CP also improved (linear, P < 0.05) G:F, final BW, and hot carcass weight (HCW). In Exp. 3, 238 pigs (DNA 600 × 241, initially 111.8 kg) were used in a 26-d trial with 7 to 8 pigs and 6 pens per treatment. Dietary treatments included 5 concentrations of CP (9, 10, 11, 12, or 13%). Increasing CP improved (quadratic, P < 0.05) ADG and G:F with the greatest response observed in pigs fed 13% CP. Increasing CP marginally increased (quadratic, P < 0.074) HCW, with the greatest response observed in pigs fed 12% CP. In conclusion, the SID lysine requirement for pigs from 100 to 122 kg was 0.55 to 0.63% depending on the response criteria with performance maximized with diets containing 12 to 13% CP. [ABSTRACT FROM AUTHOR]

The use of active dried yeast (ADY) in the diets of feedlot steers may improve feed efficiency, growth performance, and reduce days on feed. Strategic timing of ADY inclusion in the diet may increase feed conversion or aid in the dietary transition from growing to finishing diets. One hundred twenty steers, blocked by weight, were fed four diets for 164 d: grower (70 d), first transition diet (7 d), second transition diet for (7 d), and finisher (80 d) in a GrowSafe System. Four treatment sequences of ADY inclusion were evaluated in a Balaam's design where steers were fed a control diet before and after the grower phase (CC), control before and ADY after the grower phase (CY), ADY before and control after the grower phase (YC), and ADY before and after the grower phase (YY). A random coefficients model was used to evaluate the following variables of interest: feeding performance and growth traits, including biometric measurements and carcass ultrasound measurements, and carcass characteristics. Treatment was a fixed effect and block was a random effect. Treatment did not affect feeding performance or behavior (P ≥ 0.14). The rate of change of biometric measurements were not different (P ≥ 0.16) across treatment groups except for rib girth circumference, which was greater for the YY and CY groups intermediate for the CC group and least for the YC group (0.828 and 0.809 vs. 0.751 vs. 0.666 cm/d, respectively; P < 0.01). Faster growth rates of rib girth circumference resulted in larger final measurements for steers that were finished on ADY (P < 0.01). Ultrasound measurements (backfat, LM area, intra-muscular fat, and rump fat) were not different across treatments (P ≥ 0.15). However, there was a tendency for the YC group to have a slower rate of back fat deposition than other treatment groups (P = 0.09). Steers' final shrunk BWs did not differ (P = 0.61), but shrink percentage was greater for CC than for YY groups (3.7% vs. 2.7%, respectively; P = 0.05). Carcass characteristics were not different across treatments (P ≥ 0.20). Crude fat, CP, ash and moisture analyses of the 9th to 11th rib section were not different across treatments, and there was no difference in adjusted final shrunk BW (P ≥ 0.45). Feeding the ADY strain used in this study to growing and finishing feedlot steers increased rib girth circumference development rate and reduced shrink loss without affecting feeding behavior, feeding performance, or carcass characteristics. [ABSTRACT FROM AUTHOR]