B. I. Castro-Pérez

Influence of protein and energy level in finishing diets for feedlot hair lambs: growth performance, dietary energetics and carcass characteristics.

Forty-eight Pelibuey×Katahdin male intact lambs (23.87±2.84 kg) were used in an 84-d feeding trial, with six pens per treatment in a 2×2 factorial design arrangement. The aim of the study was to evaluate the interaction of two dietary energy levels (3.05 and 2.83 Mcal/kg ME) and two dietary protein levels (17.5% and 14.5%) on growth performance, dietary energetics and carcass traits. The dietary treatments used were: i) High protein-high energy (HP-HE); ii) High protein-low energy (HP-LE); iii) Low protein-high energy (LP-HE), and iv) Low protein-low energy (LP-LE). With a high-energy level, dry matter intake (DMI) values were 6.1% lower in the low-protein diets, while with low-energy, the DMI values did not differ between the dietary protein levels. Energy levels did not influence the final weight and average daily gain (ADG), but resulted in lower DMI values and higher gain efficiencies. No effects of protein level were detected on growth performance. The observed dietary net energy (NE) ratio and observed DMI were closer than expected in all treatments and were not affected by the different treatments. There was an interaction (p<0.03) between energy and protein level for kidney-pelvic and heart fat (KPH), KPH was higher in lambs fed high energy and high protein diet but not in high energy and low protein diet. The KPH was increased (20.2%, p = 0.01) in high-energy diets, while fat thickness was increased (21.7%, p = 0.02) in high-protein diets. Therefore, it is concluded that dietary energy levels play a more important role in feed efficiency than protein levels in finishing lambs with a high-energy diet (>2.80 Mcal/kg ME). Providing a level of protein above 14.5% does not improves growth-performance, dietary energetics or carcass dressing percentage.

Effects of feeding different levels of chromium-enriched live yeast in hairy lambs fed a corn-based diet: effects on growth performance, dietary energetics, carcass traits and visceral organ mass

Forty Pelibuey ·Kathdin lambs (35.5 � 0.4 kg) were used in a 56-day feeding experiment to assess the effects of feeding different levels of chromium-enriched live yeast (Cr-YC) on growth performance, dietary energetics, carcass traits and visceral organ mass. The Cr-YC source contained 5.5 · 10 9 colony forming units (CFU) and 0.40 mg of Cr per gram.Treatmentsconsistedofadryrolledcorn-based finishingdietsupplementedwith0,1,2or3gCr-YC/lamb.day.Total daily dosages were: 5.5 · 10 9 CFU and 0.4 mg; 1.1 · 10 10 CFU and 0.8 mg Cr, and 1.65 · 10 10 CFU and 1.2 mg Cr for supplementationlevelsof1,2or3gCr-YC/lamb.day,respectively.Therewerenotreatmentseffectsondrymatterintake.As thelevelofCr-YCsupplementationincreased,averagedailygain,gaintofeedanddietarynetenergywerelinearlyincreased, and observed/expected dry matter intake was linearly decreased. Chromium-enriched live yeast supplementation increased emptybodyweight(EBW),gastrointestinal fillandfullvisceraweight,butdidnotinfluenceorganweightsasaproportionof EBW (g/kg EBW). Cr-YC level did not affect carcass length, backfat thickness, kidney, pelvic and heart fat or body wall thickness,butincreasedhotcarcassweightandlongissimusmusclearea.Ingeneral,treatmenteffectsonpercentageyieldof wholesale cuts (tissue weight as a percentage of cold carcass weight) were small. However, Cr-YC decreased percentage flank. Chromium-enriched yeast supplementation enhances growth rate, longissimus muscle area, and dietary energetic efficiency in finishing feedlot lambs.

Evaluation of isoquinoline alkaloid supplementation levels on ruminal fermentation, characteristics of digestion, and microbial protein synthesis in steers fed a high-energy diet

Four Holstein steers with ruminal and duodenal cannulas were used in a 4 × 4 Latin square design to examine the effect of daily intake of 0, 2, 4 or 6 g/steer of standardized plant extract containing a mixture of quaternary benzophenanthridine alkaloids and protopine alkaloids (QBA+PA) on the characteristics of ruminal fermentation and characteristics of digestion. The basal diet consisted of a steam-flaked corn-based finishing diet that contained 62% corn and 12% sudangrass hay and the rest of diet was composed of mainly dried distillers grains, molasses, fat, and minerals. The source of QBA+PA used was Sangrovit-RS (Phytobiotics Futterzusatzstoffe GmbH, Eltville, Germany) and supplementation levels of 2, 4, and 6 g Sangrovit-RS∙steer∙d, which represented a net daily ingestion of approximately 6, 12, and 18 mg of QBA+PA compounds, respectively. Inclusion of QBA+PA linearly increased ( = 0.04) flow to the duodenum of nonammonia N and linearly decreased ( < 0.01) duodenal flows of ammonia N. Ruminal microbial efficiency (duodenal microbial N; g/kg OM fermented in the rumen) and protein efficiency (duodenal nonammonia N; g/g N intake) were increased ( < 0.05) as the level of QBA+PA increased. There were no effects of QBA+PA supplementation on ruminal, postruminal, and total tract digestion of OM, starch, and NDF, but postruminal and total tract digestion of N increased ( < 0.01) as the level of QBA+PA increased. Digestible energy of the diet tended to increase (linear affect, = 0.09) with QBA+PA supplementation. Ruminal pH and total VFA molar concentrations were not different between treatments. Ruminal NH-N concentration linearly decreased ( = 0.02) with QBA+PA supplementation. Ruminal molar proportion of acetate increased ( = 0.04) as the supplementation level of QBA+PA increased. It is concluded that QBA+PA supplementation enhances efficiency of N utilization in feedlot steers fed a steam-flaked corn-based finishing diet. This effect was due, in part, to enhanced ruminal microbial efficiency, decreased ruminal degradation of dietary nonammonia N, and enhanced postruminal N digestion.

Influence of Ionophore Supplementation on Growth Performance, Dietary Energetics and Carcass Characteristics in Finishing Cattle during Period of Heat Stress

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 (p<0.05) at THI values ≤77 than ionophore groups. When THI values were greater than 79, DMI of control and MON30 were not different (p = 0.42), although less than that of groups fed lasalocid (p = 0.04). Variation in energy intake was lower (p>0.05) 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.

Influence of Quaternary Benzophenantridine and Protopine Alkaloids on Growth Performance, Dietary Energy, Carcass Traits, Visceral Mass, and Rumen Health in Finishing Ewes under Conditions of Severe Temperature-humidity Index

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<0.01) and the observed-to-expected NE (5.9%, p<0.01). Supplemental SANG did not affect (p≥0.12) carcass characteristics, chemical composition of shoulder, and organ weights (g/kg empty body weight) of stomach complex, intestines, and heart/lung. Supplemental SANG decreased liver weight (10.3%, p = 0.02) and increased visceral fat (16.9%, p = 0.02). Rumen epithelium of ewes fed SANG had lower scores for cellular dropsical degeneration (2.08 vs 2.34, p = 0.02), parakeratosis (1.30 vs 1.82, p = 0.03) and neutrophil infiltration (2.08 vs 2.86, p = 0.05) than controls. It is concluded that SANG supplementation helped ameliorate the negative effects of severe heat on growth performance of feedlot ewes fed high-energy corn-based diets. Improvement in energetic efficiency may have been mediated, in part, by anti-inflammatory effects of supplemental SANG and corresponding enhancement of nutrient uptake.

Effects of Replacing Dry-rolled Corn with Increasing Levels of Corn Dried Distillers Grains with Solubles on Characteristics of Digestion, Microbial Protein Synthesis and Digestible Energy of Diet in Hair Lambs Fed High-concentrate Diets

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<0.01), but decreased ruminal organic matter (OM) digestion (linear effect, p<0.01). Replacing corn with DDGS increased (linear, p≤0.02) duodenal flow of lipids, NDF and feed N. But there were no treatment effects on flow to the small intestine of microbial nitrogen (MN) or microbial N efficiency. The estimated UIP value of DDGS was 44%. Postruminal digestion of OM, starch, lipids and nitrogen (N) were not affected by treatments. Total tract digestion of N increased (linear, p = 0.04) as the DDGS level increased, but DDGS substitution tended to decrease total tract digestion of OM (p = 0.06) and digestion of gross energy (p = 0.08). However, it did not affect the dietary digestible energy (DE, MJ/kg), reflecting the greater gross energy content of DDGS versus DR corn in the replacements. The comparative DE value of DDGS may be considered similar to the DE value of the DR corn it replaced up to 30% in the finishing diets fed to lambs.

Comparative evaluation of supplemental zilpaterol hydrochloride sources on growth performance, dietary energetics and carcass characteristics of finishing lambs

Objective We compare the effects of three different approved sources of supplemental zilpaterol on growth-performance responses and carcass characteristics of finishing lambs. Methods Twenty 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. Results Compared 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. Conclusion Supplemental 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.

Impact of dietary inclusion of clinoptilolite as substitute of soybean meal on growth performance, dietary energetics and carcass traits of feedlot ewes fed a corn-based diet

espanolRESUMEN: Se utilizaron 40 ovejas (31,725 ± 1,44 kg PV inicial) para evaluar la suplementacion (0, 1, 2 y 3%, en base seca de la dieta) de clinoptilolita (ZEOL) en sustitucion de la harina de soya (SBM) en una dieta de finalizacion a base de maiz en el crecimiento, balance energetico de la dieta y caracteristicas de la canal. El experimento duro 56 dias. Para cada porcentaje de sustitucion de SBM por ZEOL, la proteina cruda y la energia 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 administracion de ZEOL, pero debido a la caracteristica inerte de ZEOL la relacion de EN dietetica observada-a-esperado aumento linealmente y la proporcion de observado-a-esperado del CMS disminuyo con la suplementacion ZEOL. La clinoptilolita disminuyo linealmente el espesor de la grasa y la grasa visceral, sin efectos en otras medidas de la canal o del peso de los organos (como proporcion de g/kg de peso corporal vacio). La sustitucion de SBM por zeolita hasta 3% no afecto negativamente el crecimiento y las caracteristicas de la canal, resultando que la inclusion de hasta 3% de clinoptilolita en sustitucion de una fuente de alta proteina (SBM) en dietas de acabado tuvo un efecto positivo en la utilizacion de energia de la dieta. EnglishABSTRACT: 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, dietary energetics, and carcass traits. The experiment lasted 56 days. For each percentage of substitution of SBM by ZEOL, the crude protein and net energy (NE) of basal diet were decreased in 0.37 percentage units and 0.02 Mcal/kg, respectively. There were no treatment effects (P>0.27) on average daily gain (ADG), dry matter intake (DMI), and gain efficiency (ADG/DMI). Dietary NE was not affected by ZEOL supplementation (P≥0.69). However, due to the inertness (it does not provide energy) of ZEOL, itself, the ratio of observed-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) with no effects (P≥0.12) on other carcass measures or the organ tissue weights (as proportion of g/kg of empty body weight). Dilution of CP and dietary NE by substitution of SBM by zeolite up to 3% did not negatively affect growth performance and carcass traits. This result suggests that the inclusion of up to 3% of clinoptilolite in substitution of a high protein source (SBM) on finishing diets has a positive effect on the utilization of dietary energy.

Effect of oil supplementation extracted from nontoxic purging nut (Jatropha curcas L) on carcass traits, tissue composition, muscle CLA concentration, and visceral mass of feedlot lambs

espanolRESUMEN Los efectos de la suplementacion (0, 2, 4, y 6%, en base seca de la dieta) de aceite de nuez purgante (Jatropha curcas, JCO) sobre las caracteristicas de la canal, la composicion tisular y la concentracion de acidos linoleicos conjugados (CLA) en musculo se evaluo en veinte corderos machos intactos, alimentados con una dieta de finalizacion durante un periodo de 56 dias. La proporcion de acido 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 area del musculo longissimus (ML) o la grasa pelvica-renal. Sin embargo, a medida que aumento la suplementacion de JCO, se disminuyo el rendimiento de la canal y aumento el espesor de grasa dorsal. El aumentar JCO en la dieta disminuyo la proporcion del musculo y aumento la proporcion de grasa en la paleta. El contenido de acido estearico (C18:0) en ML no se vio afectado por JCO. Sin embargo, JCO aumento linealmente el total de CLA en ML, y por tanto, la proporcion CLA:C18:0. El peso corporal vacio o la masa visceral no fueron afectados por JCO. El incrementar JCO en la dieta aumento la grasa visceral por el aumento de la grasa mesenterica. Se concluye que la suplementacion con JCO no afecta negativamente el PCC o el area de ML y representa una alternativa viable para aumentar la concentracion total de CLA en la carne de corderos en finalizacion. EnglishABSTRACT 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.

Feeding value of supplemental curcas crude oil in finishing diets for feedlot lambs

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.