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Objective Our objective was to examine the effects of duration of zilpaterol hydrochloride (ZH) supplementation on growth performance, estimated dietary energetics, carcass characteristics, and meat quality in crossbred yearling heifers when slaughtered at lighter, less-mature final weight. Materials and Methods Treatments consisted of a finishing diet based on steam-flaked corn supplemented with (1) 0 ZH (negative control); (2) 0.15 mg of ZH/kg of live weight supplemented for 20 of the final 23 d of the finishing period; (3) 0.15 mg of ZH/kg of live weight supplemented for 25 of the final 28 d of the finishing period, or (4) 0.15 mg of ZH/kg of live weight supplemented for 30 of the final 33 d of the finishing period. Results and Discussion Duration of ZH supplementation did not affect (P ≥ 0.15) any of the variables measured. Compared with the control, ZH increased (P ≤ 0.02) carcass-adjusted weight gain, G:F, and apparent dietary NE. Zilpaterol supplementation also increased (P ≤ 0.05) hot carcass weight, carcass DP, and LM area without effects on USDA QG, fat thickness, or KPH fat. Zilpaterol supplementation increased (P Implications and Applications Zilpaterol hydrochloride supplementation in heifers slaughtered at a final weight that was less than was estimated to be mature (460 kg) improved growth performance, hot carcass weight, carcass DP, LM area, and retail cuts in a manner consistent with results of previous studies in which heifers were slaughtered at heavier (>550 kg) BW. Effects of ZH on meat quality was not significant. Reducing ZH feeding duration from 30 to 20 d may not adversely affect growth performance, carcass characteristics, and meat quality.

Forty-eight (37.7 ± 3.4 kg, initial shrunk live weight) lambs were used in a 61 d experiment to evaluate the energy value of grease trap waste (GT) at four levels of supplementation (0%, 2%, 4%, and 6%). Supplemental GT replaced cracked corn in the basal diet. The GT contained 6.4% moisture, 3.1% impurities, and 79.8% total fatty acids (FA). Increasing GT level in diets did not affect dry matter intake and daily weight gain but linearly increased gain efficiency and estimated dietary net energy (NE). However, the ratio of observed-to-expected diet NE decreased with increased levels of GT. The estimated NE values for GT based on FA intake were in close agreement (98% and 102% of predicted, respectively) with those NE values determined by replacement technique for 2% and 4% supplementation level. However, the observed NE value for GT supplemented at the 6% level was 9% lower than predicted. Kidney–pelvic–heart fat increased as level of GT supplementation increased; otherwise, carcass characteristics and shoulder composition were not affected. We conclude that GT is a suitable alternative to conventional feed fats in diets for finishing lambs. The estimated NE of GT is 93% the energy value assigned by current standards for tallow and yellow grease.

Ninety young crossbreed bulls (approximately 25% Zebu breeding with the remainder represented by continental and British breeds in various proportions, initial weight=228.04±7.06 kg) were used in a 84-day feeding trial to assess the effects of treatments in feedlot cattle fed transition diets during high ambient temperatures. Treatments consisted of a steam-flaked corn-based diets (average 1.95 Mcal ENm/kg) supplemented with: 1) 20 mg monensin/kg diet (MON, Rumensin, Elanco Animal Health, Indianapolis, IN], and 2) 100 mg of blend of essential oils /kg diet plus 0.1 mg 25-hydroxy-vitamin-D3/kg diet (EO+HyD; CRINA® Ruminants and HyD®, DSM Nutritional Products, Basel, Switzerland). Both dry matter intake (DMI) and climatic variables were measured daily and the temperature humidity index (THI) was estimated. Daily maximal THI remained over 80 during the whole trial (avg. THI = 82.67). Cattle supplemented with EO+HyD increased average daily gain in 8.7% (1.446 vs. 1.320 kg/day, P < 0.01), gain-to-fed ratio in 4.5% (0.199 vs. 0.190; P = 0.03), final weight in 10.05 kg (349.48 vs. 339.43; P = 0.04) and tended (P = 0.07) to shown greater dietary net energy (2.5%) and observed-to-expected dietary NE ratio (3%). Even when EO+HyD tended to increase (4.3%; P = 0.06) DM intake, intake pattern variation were not different (P = 0.38) between MON and EO+HyD (Figure 1). Then, difference in ADG and final BW between MON and EO+HyD was not only a reflection of difference in energy intake, was also caused by difference in efficiency of energy utilization during conditions of high ambient temperature (a reduction of 7% in the estimated increase of coefficient of maintenance by heat load). Results indicate that supplementation with a combination of essential oil blend plus 25-hydroxy-vitamin-D3 can have greater beneficial effects than supplemental monensin on daily weight gain, final weight and feed intake during initiation-transition phase of cattle raised under high ambient temperature.

Forty-eight Pelibuey × Katahdin (27.87±4.71 kg) intact lambs were used in a growth-performance trial lasted 87 days to assess the effects of treatments. Lambs were assigned to one of six weight groupings in 24 pens (6 replicas per treatment). Basal diet was comprised by cracked corn (14% CP and 2.08 Mcal ENm/kg) and was supplemented as follows: 1) No additives (Control); 2) supplemented with a blend of essential oils at dose of 150 mg EO/kg diet DM (EO, CRINA® Ruminants, DSM Nutritional Products); 3) supplemented with 150 mg EO plus 560 mg alpha-amylase/kg diet DM (EO+ENZ, RONOZYME® Rumistar, DSM Nutritional Products), and 4) supplemented with antibiotic virginiamycin (VM, Stafac 500, Phibro Animal Health) at dose of 28 mg virginiamycin/kg diet DM. Growth performance and dietary energetics were very similar (P > 0.97) between EO and VM. In such way that, compared to Control, lambs supplemented with EO and VM tended (P = 0.09) to shown greater final weight (3.1%) and average daily gain (ADG; 5.9%) without difference on DMI (P = 0.99); thus, gain-to-feed ratio (GF) and observed dietary net energy (NE) were average improved in 5.7% (P < 0.01). Compared to Controls, combining EO plus ENZ tended to increased DMI (6.8%, P = 0.09), but increased in 10.4% ADG (P < 0.01) and in 4.4% (P = 0.02) feed efficiency. Lambs supplemented with EO shown lower (P ≤ 0.10) kidney-pelvic-heart fat than Controls and VM lambs. Compared to Controls, additive supplementation decreased (P ≤ 0.03) the relative weight of intestines, the effect being more pronounced with EO supplementation. Compared to VM, supplemental EO (alone or combined with enzyme) shown lower (10.1%, P ≤ 0.04) visceral fat. Supplemental essential oils is a viable alternative to virginiamycin in finishing high-energy diets for lambs. Combining essential oils plus amylase can be a strategy to promote better daily gain weights allowing target final weight at shorter time.

Author(s): Rivera-Villegas, A; Estrada-Angulo, A; Castro-Perez, BI; Urias-Estrada, JD; Rios-Rincon, FG; Rodriguez-Cordero, D; Barreras, A; Plascencia, A; Gonzalez-Vizcarra, VM; Sosa-Gordillo, JF; Zinn, RA | Abstract: ObjectiveWe compare the effects of three different approved sources of supplemental zilpaterol on growth-performance responses and carcass characteristics of finishing lambs.MethodsTwenty four Pelibuey×Katahdin lambs (46.75±2.43 kg) were used in a 33-day feeding trial. Lambs were fed a dry rolled corn-based finishing diet. Treatments consisted of the non-supplemental basal diet (Control) versus the basal diet supplemented with 125 mg zilpaterol/kg of diet (as fed basis) from three commercial sources marketed in Mexico: Zilmax (ZIL), Grofactor, and Zipamix.ResultsCompared to controls, zilpaterol (ZH) supplementation did not affect dry matter intake (DMI), but increased carcass adjusted daily weight gain (ADG, 36.7%), gain efficiency (34.2%), and dietary net energy (26.0%), and decreased (23.4%) the ratio of observed:expected DMI. Compared to controls, supplemental ZH increased hot carcass weight (6.4%), dressing percentage (3.2%), m. longissimus thoracis (LM) area (15.6%), and shoulder muscle:fat ratio (28.7%), but decreased kidney-pelvic-heart fat, and fat thickness. Supplemental ZH increased 10.9% and 14.3% whole cut weight of loin and leg, respectively, and the proportion (as percentage of cold carcass weight) of leg (4.3%). These increases were reflected in greater forequarter and hindquarter weights. Lambs fed ZH increased (4.6%) empty body weight (EBW) and reduced (14.7%) liver/spleen weight (as g/kg EBW). Likewise, ZH supplementation tended (p = 0.08) to lower (8.9%) visceral fat. Growth performance, energetic efficiency, hot carcass weight, dressing percentage, LM area and whole cuts were not different across supplemental ZH sources. However, compared with non-supplemented controls, only ZIL appreciably decreased carcass fat distribution, including fat thickness, percentage kidney pelvic and heart fat, shoulder fat, and visceral fat.ConclusionSupplemental ZH increases ADG, gain efficiency, carcass dressing percentage, and LM area. The magnitude of these responses was similar among ZH sources. Nevertheless, compared with non-supplemented controls, only ZIL appreciably decreases carcass fat. The basis for this is uncertain, but indicative that some practical differences in zilpaterol bio-equivalency may exist across commercial sources tested.

Sorghum panicle residue (SPR), a by-product of Sorghum vulgare, obtained in the manufacture of brooms and wisks, has potential as a partial substitute for grain in growing-finishing diets for feedlot lambs. Accordingly, 48 Pelibuey×Katahdin lambs (initial weight=16.2±4.3 kg) were used in an 84-d growth-performance trial to evaluate its comparative feeding value. Lambs were blocked by weight and assigned within weight groupings to 12 pens (4 lambs per pen). The SPR was finely ground before it was incorporated into the diet. The basal diet contained 60% whole grain sorghum (WGS; DM basis). Dietary treatments consisted in the replacement of WGS with 0, 50, or 100% SPR. Replacement of WGS with SPR decreased (linear effect, P=0.04) average daily gain (ADG), and tended to increase (linear effect, P=0.06) dry matter intake (DMI). Replacement of WGS with SPR decreased (linear effect, Plt;0.01) gain efficiency (ADG : DMI), and observed dietary net energy (NE), as well as hot carcass weight, dressing percentage, kidney-pelvic-heart fat, and back fat thickness (linear effect, P⩽.05) Other carcass characteristics and wholesale cuts as a percentage of cold carcass weight were not affected by dietary treatments. It is concluded that SPR is a palatable feed ingredient for inclusion in finishing diets for feedlot lambs. The comparative NE values for SPR are 1.50 and 0.91 Mcal/kg for maintenance and gain, respectively, 75% the NE value of WGS. These NE values reflect the greater fiber content of SPR. To the extent that dietary energy density limits energy intake (and hence daily weight gain), appropriate constraints on level of SPR incorporation is warranted.

A total of 90 young crossbreed bulls (initial weight=228.04±7.06 kg) were used in a 171-day feeding trial in order to evaluate the combination of supplemental blend of essential oils (Crina® Ruminants; DSM Nutritional Products) plus 25-hydroxy-vitamin-D3 (HyD®, DSM Nutritional Products; EO+HyD) on growth performance and carcass characteristics in cattle finishing under tropical conditions. Cattle were blocked by weight into 2 blocks and randomly allocated to 2 treatments (9 pens/treatment, 5 bulls/pen). Cattle were fed with a steam-flaked corn-based diets (average diet NEm= 1.95 Mcal/kg during first 84-d, and 2.15 Mcal/kg during the remaining 87-d). Treatments consisted of: 1) EO+HyD supplementation along fattening period (171-d), or 2) supplementation with monensin (Rumensin®, Elanco Animal Health; 20 mg/kg diet) during the first 84-d and monensin (20 mg/kg diet) plus virginiamycin (Stafac®, Phibro Animal Health; 20 mg/kg diet) during remaining time (87-d). The average THI during course of the experiment was 76.67±2.7 with a maximum of 85.46±2.2 and minimum of 68.29±2.6. There were no statistical differences (P > 0.10) between EO+HyD and ionophores/antibiotic supplemented cattle on DM intake (7.575 vs 7.534 kg/d), average daily gain (1.433 vs 1.406 kg), or gain-to-feed ratio (0.189 vs 0.187). However, cattle fed with EO+HyD tended (P = 0.07) to have heavier carcass weight in 5.2 kg (304.9 vs 299.7 kg), showed greater LM area (89.89 vs. 82.77 cm², P < 0.01) and greater estimated retail yield (1.6%, P = 0.02) than cattle receiving ionophores/antibiotic mixture. Cattle receiving EO+HyD showed more percentage of carcass classified as Choice (14.28 vs 13.33%) and “Select” (59.52 vs 44.44%) and lower percentage of carcass classified as “Standard” (26.20 vs 42.23%). The combination of a blend of essential oils plus 25-hydroxy-Vit-D3 (EO+HyD) in finishing phase improve carcass characteristics. Supplemental EO+HyD is a viable alternative to supplemental monensin, or monensin plus virginiamycin used in growing-finishing diets for feedlot cattle.

To examine the growth of Candida norvegensis (strain Levazoot 15), four experiments were conducted with different sources of energy, nitrogen, vitamins, and microminerals. Optical density was used as an indirect measure of strain growth in a fully randomized factorial design, in which principal factor A was the source of energy, nitrogen, vitamins, or microminerals and principal factor B was the measurement time point (0, 20, or 40 h). The results showed that the yeast strain used glucose (primarily sucrose and lactose) as the energy source and tryptone as the nitrogen source. The addition of B-complex vitamins or microminerals was not necessary for strain growth. It is concluded that the strain Levazoot 15 preferentially utilizes glucose as a source of energy, tryptone as a source of nitrogen and manganese as a mineral source, and that no vitamin source was necessary for growth.

Thirty-six Pelibuey × Katahdin crossbred intact male lambs (28.5 ± 3.5 kg) were used in a 56-d experiment in a randomized complete block design to evaluate the effects of a standardized mixture of essential oils (EO) versus monensin sodium (MON) on growth performance, dietary energy, and carcass characteristics. Lambs were fed a corn-based finishing diet (13.8 % CP and 2.14 Mcal NEm/kg DM) supplemented with: 1) no additive (Control), 2) 30 mg MON/lamb, and 3) 150 mg EO/lamb. Water consumption of EO and Control lambs was not different. In contrast, lambs fed MON consumed 18.1 % less (P

Probiotics (beneficial living microorganisms) and prebiotics (fiber, cell wall material, mannan polysaccharides derived through hydrolysis of yeast cell walls) are feed additives that may have beneficial extra-nutritional pharmaceutical and/or metabolic effects on livestock health and growth performance. Due to differences in modes of action, their combination may have additive effects on digestion and fermentation in ruminants. For this reason, four male lambs (Dorper; 45.1 ± 2.7 kg initial weight) with “T” cannulas in the rumen were used in a 4 × 4 Latin square experiment to evaluate the effects of single or combined supplementation of probiotics and prebiotics on ruminal fermentation and total tract digestion. Dietary treatments consisted of a cracked corn-based basal finishing diet supplemented with: 1) no eubiotics (Control); 2) 3 g of live saccharomyces cerevisiae /lamb/day (2 × 1010 cfu/g, SC), 3) 3 g of mannan oligosaccharide (30 % w/w) plus b-glucans (20 % w/w) /lamb/day (MOS), and 4) combination of 1.5 g/day SC and 1.5 g/day MOS (SCMOS). Compared to controls, SC supplementation tended (P = 0.09) to increase total tract digestion of DM and OM, and increased (P

Forty male lambs (31.53 ± 3.8 kg initial LW) were used in a 70-d feedlot finishing trial. Dietary treatments consisted of a conventional corn-based finishing diet supplemented with 0, 2, 4 or 6 g tannin extract/kg dietary dry matter. The tannin extract (TAN) contained a minimum of 70% tannin, comprised of a 50:50 blend of both condensed and hydrolyzable forms. Supplemental TAN increased (linear effect, P

Four Holstein steers (266 ± 13 kg) with ruminal and duodenal cannulae were used to evaluate the effect of inclusion of different levels of urea (0%, 0.4%, 0.8% and 1.2%) in a steam-flaked, corn-based finishing diet containing dried distillers grains plus solubles (DDGS) on the site and extent of N compounds and organic matter (OM) digestion, and on the ruminal N-NH3 and blood concentrations of urea nitrogen. Increasing the urea levels linearly decreased the OM flow to the duodenum ( P

Four cannulated Holstein steers (137± 9.7 kg live weight, LW) were used in a 4 × 4 Latin square design to examine the effects of feeding a standardized mixture of synbiotic-glyconutrients (GLY) on the characteristics of site and extent of digestion and ruminal fermentation in steers fed a high-energy diet. Treatments consisted a daily intake of 0, 8, 16 or 24 g of GLY/steer. Supplemental GLY was top dressed and mixed directly with the basal diet at time of feeding. Experiment lasted 84-d with experimental periods of 21-day duration. Supplemental GLY increased, in a quadratic manner, the flow of nonammonia-N and microbial N to the small intestine, and ruminal microbial and protein efficiencies, being maximal (P≤ 0.02) at a dosage of 16 g/d. Supplemental GLY did not affect ruminal digestion of organic matter (OM) and neutral detergent fiber (NDF), but linearly decreased (P=0.04) ruminal starch digestion. Postruminal and total tract N digestion was increased, being maximal (P≤0.02) at 16 g/d dosage level. Supplemental GLY linearly increased (P=0.02) ruminal pH, and tended (P=0.08) to linearly decrease ruminal molar proportion of butyrate without effects on ruminal molar proportion of acetate and propionate. It is concluded that GLY supplementation does not affect the site and extent of digestion of OM and NDF, but enhances net ruminal microbial synthesis and postruminal and total tract N digestion. Supplemental GLY increases ruminal pH and modifies rumen fermentation. The greater response to GLY supplementation was at a dosage of 0.12 g / kg LW (equivalent to a dietary concentration of 0.55% "as-fed" basis).

Recent findings have shown that microbial nitrogen flow and digestible energy of diets are increased when urea is combined with a slow-release urea (SRU) in diets with a starch to acid detergent fibre ratio (S:F) 4:1. This affect is attributable to enhanced synchrony between ruminal N availability for microbial growth and carbohydrate degradation. To verify the magnitude of this effects on lamb performance, an experiment was conducted to evaluate the effects of combining urea and a SRU in diets containing S:F ratios of 3:1, 4:1, or 5:1 on performance, dietary energetics and carcass characteristics of finishing lambs. For that, 40 Pelibuey×Katahdin lambs (36.65±3 kg) were assigned to one of five weight groupings in 20 pens (5 repetition/treatments). The S:F ratio in the diet was manipulated by partially replacing the corn grain and dried distiller's grain with solubles by forage (wheat straw) and soybean meal to reach S:F ratios of 3:1, 4:1 or 5:1. An additional treatment of 4:1 S:F ratio with 0.8% urea as the sole source of non-protein nitrogen was used as a reference for comparing the effect of urea combination vs. conventional urea at the same S:F ratio. There were no treatment effects on dry matter intake (DMI). Compared the urea combination vs urea at the same S:F ratio, urea combination increased (p

Twenty Pelibuey×Katahdin ewes (35±2.3 kg) were used to determine the effects of the consumption of standardized plant extract containing a mixture of quaternary benzophenanthridine alkaloids and protopine alkaloids (QBA+PA) on growth performance, dietary energetics, visceral mass, and ruminal epithelial health in heat-stressed ewes fed with a high-energy corn-based diet. The basal diet (13.9% crude protein and 2.09 Mcal of net energy [NE] of maintenance/kg of dry matter) contained 49.7% starch and 15.3% neutral detergent fiber. Source of QBA+PA was Sangrovit RS (SANG) which contains 3 g of quaternary benzophenathridine and protopine alkaloids per kg of product. Treatments consisted of a daily consumption of 0 or 0.5 g SANG/ewe. Ewes were grouped by weight and assigned to 10 pens (5 pens/treatment), with two ewes per pen. The experimental period lasted 70 days. The mean temperature humidity index during the course of this experiment was 81.7±1.0 (severe heat stress). There were no treatment effects on water intake. Dry matter intake was not affected (p = 0.70) by treatments, but the group fed SANG had a numerically (11.2%) higher gain in comparison to the control group, SANG improved gain efficiency (8.3%, p = 0.04), dietary NE (5.2%, p

Nueve híbridos de sorgo (Sorghum bicolor L. Moench) se analizaron para determinar la relación de sus características físicas [materia seca (MS), peso de mil granos (PMG), tamaño de partícula (TP), densidad relativa(DR), superficie de área (SA), partículas por gramo (PPG), endospermo duro (END-DU), endospermo blando (ENDBL)]; y químicas [nitrógeno total (NT), fibra detergente ácido (FDA), fibra detergente neutro (FDN), contenido de almidón (ALM), almidón soluble (AlmS), almidón insoluble (AlmNS). La digestión ruminal esperada (DRUM) se estimó con las fracciones de AlmS y AlmNS in vitro. El promedio de PMG, TP, DR, SA, PPG y END-DU fue de 24.61 g, 3.17 mm, 1.30 g/cm3, 17.44 cm2/g, 30.33 y 46.68 %, respectivamente El promedio (%) de MS, PC, FDN, FDA, ALM, AlmS y AlmNS fue de 92.47, 8.19, 19.17 y 8.30, 69.58, 6.00 y 47.74 respectivamente. La concentración de taninos fue baja (0.05) entre las variables físicas o químicas con el contenido total de almidón en el grano; sin embargo las variables densidad relativa y superficie de área, permiten incrementar el poder de predicción de la digestibilidad ruminal del almidón (DRUM,%= 74.058 - 0.108END-DU + 0.027SA – 5.887DR, R2= 0.77, P

Twenty-four male lambs (24.93 ± 0.93 kg) were used in order to evaluate the effects of chromium methionine (Cr) supplementation in high-energy finishing diets on the carcass characteristics and chemical composition of the longissimus muscle (LM). Treatments were 0.00, 0.60, 1.20, and 1.80 mg Cr/lamb daily. The experiment lasted 56 days. There were no effects of treatments on dry matter intake, feed to gain ratio, and final weight, which averaged 35.24 ± 1.01 kg. Supplemental Cr linearly decreased fat thickness enough to improve the estimated yield grade from 1.82 to 1.42 with no effect on the other carcass traits measured. Fat concentration in the LM decreased linearly as the level of Cr increased in diets, but protein concentration remain constant and so the protein/fat ratio in the LM increased. It is concluded that Cr supplementation has a modulating effect on carcasses by reducing fat; maximal response was reached at a daily dose of 1.80 mg Cr/head.

Los efectos de la suplementación (0, 2, 4, y 6%, en base seca de la dieta) de aceite de nuez purgante (Jatropha curcas, JCO) sobre las características de la canal, la composición tisular y la concentración de ácidos linoleicos conjugados (CLA) en músculo se evaluó en veinte corderos machos intactos, alimentados con una dieta de finalización durante un periodo de 56 días. La proporción de ácido linoleico en JCO fue de 50%. Los corderos fueron faenados con un peso final de 54,03 ± 2,9 kg. No hubo efecto de los tratamientos en el peso de la canal caliente (PCC), el área del músculo longissimus (ML) o la grasa pélvica-renal. Sin embargo, a medida que aumentó la suplementación de JCO, se disminuyó el rendimiento de la canal y aumentó el espesor de grasa dorsal. El aumentar JCO en la dieta disminuyó la proporción del músculo y aumentó la proporción de grasa en la paleta. El contenido de ácido esteárico (C18:0) en ML no se vio afectado por JCO. Sin embargo, JCO aumentó linealmente el total de CLA en ML, y por tanto, la proporción CLA:C18:0. El peso corporal vacío o la masa visceral no fueron afectados por JCO. El incrementar JCO en la dieta aumentó la grasa visceral por el aumento de la grasa mesentérica. Se concluye que la suplementación con JCO no afecta negativamente el PCC o el área de ML y representa una alternativa viable para aumentar la concentración total de CLA en la carne de corderos en finalización., The effects of purging nut (Jatropha curcas, JCO) supplementation (0, 2, 4, and 6%, DM basis of diet) on carcass traits, tissue composition and conjugated linoleic acids (CLA) concentration in muscle was evaluated in twenty intact male lambs fed a finishing diet during 56 d. The linoleic acid proportion in JCO was 50%. Lambs were harvested at a final weight of 54.03±2.9 kg. There were no treatment effects on hot carcass weight (HCW), longissimus muscle (LM) area nor kidney-pelvic fat. However, as JCO supplementation increased, dressing percentage was decreased and fat thickness was increased. Increasing JCO in diet decreases the proportion of muscle and increases the proportion of fat in whole shoulder clod. Content of stearic acid (C18:0) in LM was not affected by JCO. However, JCO linearly increased total CLA, and hence, the CLA:C18:0 ratio. Empty body or visceral mass were not affected by JCO. Increasing JCO in diet increases visceral fat mainly through increased mesenteric fat. It is concluded that supplemental JCO does not negatively affect HCW and LM area, and represents a viable alternative for increasing CLA concentration in meat of finishing feedlot lambs.

Forty ewes (31.725±1.44 kg initial LW) were used to evaluate the effects of clinoptilolite (ZEOL) supplementation(0, 1, 2, and 3%, DM basis of diet) as substitute of soybean meal (SBM) in a finishing corn-based diet on growth performance, dietaryenergetics, and carcass traits. The experiment lasted 56 days. For each percentage of substitution of SBM by ZEOL, the crude proteinand net energy (NE) of basal diet were decreased in 0.37 percentage units and 0.02 Mcal/kg, respectively. There were no treatmenteffects (P>0.27) on average daily gain (ADG), dry matter intake (DMI), and gain efficiency (ADG/DMI). Dietary NE was notaffected by ZEOL supplementation (P≥0.69). However, due to the inertness (it does not provide energy) of ZEOL, itself, the ratio ofobserved-to-expected dietary NE linearly increased (P=0.02) and the ratio of observed-to-expected DMI linearly decreased (P=0.02)with ZEOL supplementation. Clinoptilolite supplementation linearly decreased fat thickness (P=0.02) and visceral fat (P=0.03) withno effects (P≥0.12) on other carcass measures or the organ tissue weights (as proportion of g/kg of empty body weight). Dilution ofCP and dietary NE by substitution of SBM by zeolite up to 3% did not negatively affect growth performance and carcass traits. Thisresult suggests that the inclusion of up to 3% of clinoptilolite in substitution of a high protein source (SBM) on finishing diets has apositive effect on the utilization of dietary energy., Se utilizaron 40 ovejas (31,725 ± 1,44 kg PV inicial) para evaluar la suplementación (0, 1, 2 y 3%, en base seca de ladieta) de clinoptilolita (ZEOL) en sustitución de la harina de soya (SBM) en una dieta de finalización a base de maíz en el crecimiento,balance energético de la dieta y características de la canal. El experimento duró 56 días. Para cada porcentaje de sustitución de SBM porZEOL, la proteína cruda y la energía neta (EN) de la dieta basal se redujo en 0,37 unidades porcentuales y 0,02 Mcal/kg, respectivamente.No hubo efecto de los tratamientos en la ganancia diaria de peso (GDP), el consumo de materia seca (CMS) o la eficiencia alimenticia(GDP/CMS). La EN de la dieta no se vio afectada por la administración de ZEOL, pero debido a la característica inerte de ZEOL larelación de EN dietética observada-a-esperado aumentó linealmente y la proporción de observado-a-esperado del CMS disminuyó conla suplementación ZEOL. La clinoptilolita disminuyó linealmente el espesor de la grasa y la grasa visceral, sin efectos en otras medidasde la canal o del peso de los órganos (como proporción de g/kg de peso corporal vacío). La sustitución de SBM por zeolita hasta 3%no afectó negativamente el crecimiento y las características de la canal, resultando que la inclusión de hasta 3% de clinoptilolita ensustitución de una fuente de alta proteína (SBM) en dietas de acabado tuvo un efecto positivo en la utilización de energía de la dieta.

The objective of this experiment was to determine the effects of partial replacement of dietary dry-rolled corn (DRC) and soybean meal (SBM) in isonitrogenous diets with different levels (0, 70, 140, and 210 g/kg) of seed cake obtained from a nontoxic variety of Jatropha curcas on growth performance, dietary energetics, plasma metabolites, carcass characteristics, and visceral mass in 32 Pelibuey × Katahdin lambs. Jatropha seed cake (JSC) was obtained by mechanically pressing whole seed and contained 262 g/kg crude protein (CP), 473 g/kg neutral detergent fiber (aNDFom), 402 g/kg acid detergent fiber (ADF), 7 g/kg starch, 60 g/kg ether extract, and 938 g/kg of organic matter. The JSC substitution decreased linearly (P=0.02) final weight and average daily gain but did not affect (P=0.47) dry matter intake (DMI), thus efficiency of gain was decreased (P

Recent findings have shown that microbial nitrogen flow and digestible energy of diet are increased when urea (U) is combined with a slow-release urea product (SRU) in diets with a starch:acid detergent fibre (S:ADF) ratio of 4.5, while feed grade U has shown greater effects on growth performance or dietary energy utilization when the diet contains a S:ADF ratio of greater than 5.0. These results can be partially explained by the better synchronization of ruminal degradation rates between those U sources with the carbohydrates of the diets. Therefore, 60 crossbreed steers (372.4 ± 15 kg) were used to evaluate the effects of combining U and SRU in a diet with a S:ADF ratio of 4.5 vs. U that was supplemented in diets with different S:ADF ratios (3.5, 4.5 and 5.5) on growth performance, dietary energetics and carcass characteristics. U combination did not affect average daily gain (ADG), but reduced dry matter intake [DMI, as % of body weight (BW)] enough to increase feed efficiency (G:F) and dietary net ene...

While there is very little empirical data with feedlot lambs, the current standards assigns the same energy value to distillers dry grain with solubles (DDGS) and corn. Since the basis of energy of corn is starch while in DDGS are the proteins and fat content, in the vast majority of the studies comparisons were made between in non-isoenergetic diets, situation that make it difficult to accurately determine the feeding value of DDGS included at high levels. For the latter, the objective of this experiment was to determine in isoenergetic diets the effects of replacing partially dry-rolled corn (DRC) and soybean meal (SBM) with different levels (0, 15, 30 and 45%) of dried distillers grains with solubles (DDGS) on growth performance, dietary energetics, carcass characteristics, and visceral mass in finishing hairy lambs. DDGS substitution improved (linear P = 0.04) final weight and average daily gain, but as a consequence of a tendency (P = 0.06) to increase dry matter intake (DMI) with DDGS substitution, there were no advantages (P ≥ 0.33) on gain efficiency, dietary energetic or observed-to-expected DMI. DDGS substitution did not affect dressing percentage and backfat thickness, but increased (linear, P ≤ 0.03) hot carcass weight and kidney, pelvic and heart fat (KPH) and decreased (linear, P = 0.05) longissimus muscle area (LM). There were not treatments effects on carcass composition, but increased DDGS level in substitution tended to linearly decrease, as a percentage of cold carcass weight, muscle (P = 0.08) and increase carcass fat (linear, P = 0.10). There were no effects of substitution with DDGS on wholesale cuts. Replacing corn and SBM with DDGS increased (linear P = 0.03) empty body weight (EBW, as percentage of full weight) but influence on organ weights as a proportion of EBW (g/kg EBW) were small. The feeding value of DDGS is similar to that of dry-rolled corn (∼9.62 MJ ENm/kg), this feeding value decreases as the inclusion level of DDGS increases beyond 30% because to the removal of starch instead NDF and the potential reduction of digestibility of fat. The drastically change of source of energy (fat and protein instead starch) can affect the deposition of body fat and the area of LM. Based on DMI and performance observed in the present study, DDGS is a suitable substitute for a portion of the dry-rolled corn and SBM in a finishing diet; however, at high levels of inclusion, it tends to decrease the LM area and increase the KPH.

As a result of the cost of grains, the replacement of grains by co-products (i.e. DDGS) in feedlot diets is a common practice. This change produces diets that contain a lower amount of starch and greater amount of fibre. Hypothetically, combining feed grade urea (U) with slow release urea (Optigen) in this type of diet should elicit a better synchrony between starch (high-rate of digestion) and fibre (low-rate of digestion) promoting a better microbial protein synthesis and ruminal digestion with increasing the digestible energy of the diet. Four cannulated Holstein steers (213±4 kg) were used in a 4×4 Latin square design to examine the combination of Optigen and U in a finishing diet containing different starch:acid detergent fibre ratios (S:F) on the characteristics of digestive function. Three S:F ratios (3.0, 4.5, and 6.0) were tested using a combination of U (0.80%) and Optigen (1.0%). Additionally, a treatment of 4.5 S:F ratio with urea (0.80% in ration) as the sole source of non-protein nitrogen was used to compare the effect of urea combination at same S:F ratio. The S:F ratio of the diet was manipulated by replacing the corn grain by dried distillers grain with solubles and roughage. Urea combination did not affect ruminal pH. The S:F ratio did not affect ruminal pH at 0 and 2 h post-feeding but, at 4 and 6 h, the ruminal pH decreased as the S:F ratio increased (linear, p

Four male lambs (Katahdin; average live weight 25.9±2.9 kg) with "T" type cannulas in the rumen and proximal duodenum were used in a 4×4 Latin square experiment to evaluate the influence of supplemental dry distillers grain with solubles (DDGS) levels (0, 10, 20 and 30%, dry matter basis) in substitution for dry-rolled (DR) corn on characteristics of digestive function and digestible energy (DE) of diet. Treatments did not influence ruminal pH. Substitution of DR corn with DDGS increased ruminal neutral detergent fiber (NDF) digestion (quadratic effect, p

Four cannulated Holstein steers (26495 kg) were used in a 44 Latin square design to evaluate the influence of feeding different levels (0, 10, 20, or 30 g/steer/d) of live yeast (LY) on microbial protein synthesis and characteristics of digestion of the finishing diet. The LY contained 5.510 9 CFU/g. Ruminal pH was not affected by LY supplementation. LY level decreased linearly duodenal flow of ruminal digestion of neutral detergent fiber (NDF) but did not affect duodenal flow of feed N, nonammonia N, or microbial N. LY supplementation did not affect ruminal digestion of organic matter (OM), N, microbial efficiency, or N efficiency but linearly increased ruminal digestion of NDF. Total tract digestion of OM, NDF, and digestible energy improved linearly as LY level supplementation increased. Supplemental LY improves NDF and OM digestion enough to improve the DE of the diet, and the level of supplementation affects the magnitude of the responses.

The objective of this experiment was to determine the feeding value of a mechanically extracted nontoxic variety of oil (JCO) as source of energy for feedlot lambs. Twenty Pelibuey × Katahdin lambs were individually fed a dry-rolled-corn-based finishing diet supplemented with 0%, 2%, 4%, or 6% JCO (diet dry matter basis). Supplemental JCO replaced dry rolled corn in the basal diet. Fatty acid composition of JCO was C16:0, 14.0%; C18:0, 8.2%; C18:1, 26.0%; C18:2, 50.3%, and C18:3, 0.4%. Daily intakes of JCO averaged 24.7, 51.1, and 77.3 g/day or 0.57, 1.08, and 1.62 g/kg LW for the 2%, 4%, and 6% levels of supplementation, respectively. Supplemental JCO did not affect ( = 0.33) dry matter intake (DMI), but tended to increase (linear effect, = 0.06) average daily gain, efficiency of gain (linear effect, < 0.01), and dietary net energy (linear effect, < 0.01) and decreased (linear effect, < 0.01) the ratio of observed/expected DMI. At low levels (20 g/kg diet dry matter) of supplementation, the net energy (NE) value of JCO corresponds closely (0.99) to the NE value assigned by current standards (), and this NE value decreased linearly as the inclusion level of JCO increased. There were not treatment effects on plasma metabolites. Across treatments, the concentrations of hemoglobin (11.64 ± 1.08 g/dL), hematocrit (39.15 ± 3.67%), glucose (85.2 ± 17.64 mg/dL), creatinine (1.43 ± 0.28 mg/dL), and urea (20.70 ± 4.35 mg/dL) were within normal (9-15 g/dL, 27%-40%, 50-90 mg/dL, 1.0-1.8 mg/dL, and 15-50 mg/dL, for hemoglobin, hematocrit, glucose, creatinine, and urea, respectively) ranges for healthy lambs. Based on DMI, performance and plasma metabolites observed in this study, nontoxic JCO is a suitable source of energy in finishing diets for lambs.

Four Holstein steers (271 ± 11 kg) with cannulae in the rumen and proximal duodenum were used to study the influence of method of surfactant (Tween 80) supplementation on characteristics of digestion and feeding value of fat. Treatments consisted of a steam-flaked corn-based finishing diet supplemented with: (1) no supplemental fat, no surfactant; (2) 6% supplemental fat (yellow grease, no surfactant; (3) 5.75% supplemental fat plus 0.25% Tween 80 (TW) added to the diet as part of the premix (TW was mixed with premix before incorporation with grain in the mixer, as second step in diet preparation) and (4) 5.75% supplemental fat plus 0.25% TW combined directly with the supplemental fat (TW was mixed with supplemental fat before incorporation into the feed mix as penultimate step in diet preparation). There was no surfactant by supplemental fat interactions (p > 0.05). Surfactant did not affect (p > 0.05) site and extent of organic matter (OM), starch, N, acid detergent fiber (ADF) and fatty acid (FA) diges...

Rios Rincon, F.G., Barreras-Serrano, A., Estrada-Angulo, A., Obregon, J.F., Plascencia-Jorquera, A., Portillo-Loera, J.J. and Zinn, R.A. 2010. Effect of level of dietary zilpaterol hydrochloride (β2-agonist) on performance, carcass characteristics and visceral organ mass in hairy lambs fed all-concentrate diets. J. Appl. Anim. Res., 38: 33–38. To evaluate the influence of zilpaterol (β2-agonist) supplementation level on growth performance, energy retention, carcass characteristics and visceral organ mass lambs were fed a dry-rolled corn-based finishing diet supplemented with 0, 0.12 or 0.18 mg/kg BW d−1 zilpaterol hydrochloride. Zilpaterol supplementation increased carcass adjusted daily gain (40.0%, P

Four Holstein steers (328 ± 14 kg) with ruminal and duodenal cannulas were used in a 4 × 4 Latin square design to examine the effect of level of zeolite supplementation (0, 10, 20 or 30 g clinoptilolite-Ca/kg of diet) in a steam-flaked corn-based finishing diet on the characteristics of ruminal fermentation and nutrient digestion. Zeolite was top-dressed with the basal diet at time of feeding; therefore, intake of organic matter (OM), neutral detergent fibre (NDF), starch and N was equal in all treatments. Zeolite supplementation did not affect site and extent of digestion of N or NDF. Zeolite linearly decreased (P < 0.01) NH3-N flow to duodenum, but did not affect duodenal flow of microbial N, feed N, or microbial efficiency. Inclusion of zeolite linearly increased (P = 0.02) ruminal OM digestion and tended (linear, P = 0.08) to increase ruminal digestion of starch. Zeolite supplementation increased (linear effect, P < 0.01) faecal excretion of ash, resulting in decreased total tract DM digestion (linear effect, P = 0.04). However, total tract digestion of OM tended to increase (P = 0.06) with increasing zeolite supplementation. Thus, dilution of the diet with zeolite did not depress dietary digestible energy. There were no treatment effects on ruminal pH. Total ruminal volatile fatty acid concentration tended (P = 0.08) to increase as zeolite increased. Zeolite supplementation decreased ruminal molar proportion of acetate and increased molar proportion of propionate (linear effect, P < 0.01), resulting in decreased (linear effect, P < 0.01) of acetate: propionate ratio. Supplementation with zeolite at levels of up to 30 g of zeolite/kg of diet may enhance ruminal OM digestion, largely due to the tendency of increased ruminal starch digestion. Zeolite supplementation altered ruminal volatile fatty acid molar proportions (decreased acetate : propionate ratio), and therefore may have an positive impact on energy efficiency.

Robles-Estrada, J.C, Barreras-Serrano, A., Contreras, G., Estrada-Angulo, A., Obregon, J.F., Plascencia, A. and Rios, F.G. 2009. Effect of two p-adrenergic agonists on finishing performance and carcass characteristics in lambs fed all-concentrate diets. J. Appl. Anim. Res., 36: 33–36. To assess the effect of feeding two (β-adernergic agonists [β-AA, type β1: 20 ppm ractopamine hydochloride (RAC), type β2: 6 ppm zilpaterol hydrochloride (ZIL)] on performance, 60 Pelibuey × Katahdin (34.4 ±2.94 kg) crossbred male lambs were used in a 32-d feeding trial. DM intake was not affected by treatments. Compared with controls, average daily gain and feed efficiency were improved with RAC supplementation, but final live weight, average daily gain and gain: feed were the best on ZIL supplemented group. No differences in carcass characteristics were detected among control group and RAC supplementation. It is concluded that β-AA supplementation increase growth performance in lambs as results of greater muscle a...

Forty-eight Pelibuey × Katahdin (38.8 ± 0.67 kg) crossbred male lambs were used in a 32-day feeding trial (four pens per treatment in a randomized complete block design), to evaluate the influence of zilpaterol (β 2 -agonist) supplementation level on growth performance and carcass characteristics. Lambs were fed a dry-rolled corn-based finishing diet (3.04 Mcal/kg of ME) supplemented with 0, 0.15, 0.20, or 0.25 mg/kg of live weight d −1 zilpaterol (as zilpaterol chlorhydrate, Zilmax ® , Intervet Mexico, Mexico City). DM intake averaged 1.099 ± 0.042 kg/d and was not affected ( P = 0.40) by treatments. Compared with control lambs, zilpaterol supplementation increased gain efficiency (15.8%, P P = 0.03), and tended to increased daily gain (16%, P P P = 0.20) carcass weight, longissimus muscle area (LM), or fat thickness, but increased (2.3%, P = 0.04) carcass dressing percentage and reduced (36%, P P P P P −1 .

El objetivo de este estudio fue evaluar el efecto de la adición de diferentes niveles (0, 1,5, 3 y 4,5%) de zeolita en dietas integrales de finalización sobre la respuesta productiva y la eficiencia en la utilización de la energía neta de la dieta de ovinos de pelo. Para lo anterior, 40 ovinos machos ¾Katahdin × ¼Pelibuey (peso inicial = 32,28±2,34 kg) se asignaron a 20 corraletas (2 ovinos/corraleta, 5 corrales/tratamiento) alimentándose durante 75 días con alguno de los 4 tratamientos. Las dietas ofrecidas fueron tipo integral. La dieta testigo (sin zeolita) contenía 16,51% de proteína cruda (PC) y 1,39 McalENg/kg y la cantidad total de zeolita incluida en cada tratamiento sustituyó al maíz y a la pasta de soja en partes iguales. Por cada nivel de sustitución del maíz-pasta de soja se disminuyó la concentración de PC en 0,11 puntos porcentuales y la energía neta en 0,03 Mcal/kg. El sustituir maíz y pasta de soja por zeolita hasta un nivel de 1,5% en la dieta no afectó el consumo de materia seca (MS), la ganancia diaria, la eficiencia alimenticia, la utilización de la energía neta de la dieta (EN observada sobre la EN esperada) o la retención aparente de energía por unidad de MS consumida. El aumentar a el nivel de suplementación de zeolita por encima de 1,5% incrementó la eficiencia alimenticia, la utilización de la energía neta de la dieta y la retención aparente de energía por unidad de MS consumida siendo la respuesta máxima para el nivel de inclusión de 3% (componente cuadrático, p

Forty-eight crossbred heifers (378.1±18 kg) were used in a 56-d feeding trial (four pens per treatment in a randomised complete block design) to evaluate the influence of ionophore supplementation on growth performance, dietary energetics and carcass characteristics in finishing cattle during a period of heat stress. Heifers were fed a diet based on steam-flaked corn (2.22 Mcal NEm/kg) with and without an ionophore. Treatments were: i) control, no ionophore; ii) 30 mg/kg monensin sodium (RUM30); iii) 20 mg/kg lasalocid sodium (BOV20), and iv) 30 mg/kg lasalocid sodium (BOV30). Both dry matter intake (DMI) and climatic variables were measured daily and the temperature humidity index (THI) was estimated. The maximum THI during the study averaged 93, while the minimum was 70 (THI average = 79.2±2.3). Compared to controls, monensin supplementation did not influence average daily gain, the estimated NE value of the diet, or observed-to-expected DMI, but tended (p = 0.07) to increase (4.8%) gain to feed. Compared to controls, the group fed BOV30 increased (p≤0.03) daily gain (11.8%), gain to feed (8.3%), net energy of the diet (5%), and observed-to-expected DMI (5.2%). Daily weight gain was greater (7.6%, p = 0.05) for heifers fed BOV30 than for heifers fed MON30. Otherwise, differences between the two treatments in DMI, gain to feed, and dietary NE were not statistically significant (p>0.11). Plotting weekly intakes versus THI, observed intake of controls was greater (p0.05) in the ionophores group (CV = 1.7%) than in the control group (CV = 4.5%). Inclusion of ionophores in the diet resulted in relatively minor changes in carcass characteristics. It is concluded that ionophore supplementation did not exacerbate the decline of DM intake in heat-stressed cattle fed a high-energy finishing diet; on the contrary, it stabilised feed intake and favoured feed efficiency. Ionophore supplementation reduced estimated maintenance coefficients around 10% in finishing cattle during a period of heat stress. This effect was greatest for heifers supplemented with 30 mg lasalocid/kg of diet.