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

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

PSVIII-3 Hy-D Increases Performance of Nellore Cattle Finished on Pastures with Protein-Energetic Supplement

There is an increasing pressure for technologies to maximize and improve productivity and profitability of beef production. The objective with this trial was to evaluate the effects of 25-OH Vit D3 on performance of finishing Nellore bulls grazing tropical pastures in the transition of rainy to dry season. Nellore bulls (n=240; iBW = 390 ± 8 kg; age, 20 mo) were equally distributed in twenty-four paddocks (2.4 ha) of B. brizantha, cv. Marandú (n=10 animal/paddock), grouped in four blocks (six paddocks per block) according to the pasture availability at the beginning of the study. Experiment was conducted in a complete randomized block design, with 12 replicates (paddocks) per treatment. The treatments consisted of a protein-energetic supplement (Fosbovi Proteico-Energético 25, DSM, Brazil), provided ad libitum, with or without the addition of 25-OH Vit D3 (Rovimix Hy-D 1.25%, Hy-D), in a dose adjusted to ensure a daily intake of 1.0 mg/animal/day. The experiment lasted 92 days. At the beginning and at the end of the experiment, animals were weighed after 16h of total fasting. At the end of the trial, 60 animals per treatment (five animals per paddock) were slaughtered in a commercial slaughterhouse with Brazilian Federal Inspection System, and carcasses were weighed to obtain hot carcass weight (HCW). Data were analyzed according to a complete randomized block design (paddock as the experimental unit). The use of Hy-D (Control vs Hy-D) increased final BW (457 vs 465 kg, P&lt; 0.01); ADG (0.733 vs 0.819 kg/d, P&lt; 0.01); HCW (247 vs 255 kg, P&lt; 0.01) and carcass yield (52.8 vs 53.7 %, P&lt; 0.01). Hy-D supplementation improved animal performance and increased carcass deposition of Nellore cattle on grazing.

PSVIII-2 Hy-D Increases Performance of Grazing Nellore Young Bulls Receiving Protein Supplement in the Growing Phase

Studies demonstrate the benefits of supplementing 25-OH Vit D3 to bovines, few is known about its effect on performance of grazing animals in tropical conditions. Thus, our objective was to evaluate the effects of inclusion of 25-OH Vit D3 (Rovimix Hy-D 1.25%, Hy-D) in protein supplement on performance of grazing Nellore steers during the rainy season. Nellore steers (n=50; iBW of 346 ± 5 kg; age, 14 mo) were used. Animals were equally distributed in two paddocks (25 animals each one) of B. brizantha, cv. Marandú (7.0 ha each), equipped with electronic feeders, that allowed assess to individual supplement intake. The treatments consisted of a protein supplement (Fosbovi Proteico 30, DSM, Brazil), with or without the addition of Hy-D, in a dose adjusted to daily intake of 1 mg/animal/d. The experimental period was 99-d. To avoid possible effects of paddocks, groups of animals were rotated among the paddocks weekly. At the beginning and at the end of the experiment, animals were weighed after 16h of total fasting. At the end of the trial, blood samples from 15 animals per treatment were collected before fasting, to determine serum concentrations of 25-OH Vit D3. Data were analyzed according to a complete randomized block design. The use of Hy-D (Control vs Hy-D) decreased supplement daily intake (0.753 vs 0.529 kg/d; P&lt; 0.02); did not affected final BW (427 vs 423 kg; P &gt;0.10) or ADG (0.810 vs 0.765 kg/d; P &gt;0.10); and increased the supplementation efficiency (1.166 vs 1.591 kg ADG / kg supplement, P&lt; 0.01) and serum 25-OH Vit D3 (27.3 vs 59.3 ng/mL; P&lt; 0.01). It is known that 25-OH Vit D3 has a positive effect on skeletal muscle hypertrophy and the increased serum 25-OH Vit D3 in the present study points that the greater nutritional efficiency of animal receiving Hy-D could be linked to a greater muscle deposition.

335 25-Hydroxyvitamin D3 Associated with Essential Oils and α-Amylase Increases the Performance of Cattle in Intensive Pasture Finishing

Our objective was to evaluate the use of different feed additives in the performance of beef cattle in intensive pasture finishing (TIP), fed a high level of concentrate for 96 days. Nellore bulls (n = 120; iBW 359 kg, ±5.02 kg) were distributed in randomized blocks, allocated in paddocks of 2.4 ha (Urochloa brizantha cv. Xaraés; 10 animals/paddock), with two treatments with 6 replications (paddock as experimental unit), adapted with increasing concentrate, with a target of 2% BW in concentrate DMI (DMIc) on the 10th day. The treatments were: 1) Sodium Monensin (MON), 26mg/Kg MS; 2) Crina, Rumistar + Hy-D, essential oil blend, 90 mg/kg DM + exogenous α-amylase, 560 mg/kg DM + 25 hydroxy-vitamin D3, 1mg/animal/day). The animals were weighed fasting (± 16h) at the beginning and at the end of the experimental period, the DMIc was measured daily by the difference between the offered and the leftovers. Data were evaluated using Glimmix procedure of SAS, whereby means were separated using the PDIFF statement (P &lt; 0.05). The use of CRD increased DMIc (9.1 vs. 8.2 kg/day, P=0.0034), DMIc/BW (2.14 vs 1.97% DMI/BW, p=0.0044), ADG (1.4 vs. 1.2 kg/day, P=0.0241), and final BW (492 vs. 473kg, P=0.0085). Likewise animals fed CRD had greater carcass ADG (1.2 vs 1.0 kg/day, P=0.0034), HCW (292 vs. 277kg, P=0.0121) and tended to have greater dressing % (58.56 vs 59.34, P = 0.07). Additionally, animals fed MON had greater fluctuation in DMIc (5.28% vs 4.53% day, p=0,0278), and took longer days to reach 2% BW in DMIc (22 vs. 12 days, P&lt; 0.05). The use of Crina® RumistarTM + Hy-D® increases carcass production of bovines under intensive pasture finishing.

PSIX-17 Use of Mycotoxin Deactivator Increases Productive Performance by Feedlot Cattle fed a Natural Contaminated Diet

Our objective was to evaluate the effect of including a mycotoxin deactivator on the productive performance of feedlot cattle for 96 days, fed a high concentrate diet. Nellore bulls (iBW, n = 48; 402 kg ±5.02 kg), were allocated in a collective pen with automatic troughs (Intergado, Brazil), randomly distributed in two treatments: 1) Control (CON), with no mycotoxin deactivator; 2) Mycofix Select 5.0 (Myc, Biomin, DSM Nutritional Products, 10g per animal/day). The animals were weighed fasting (±16h) at the beginning and end of the experiment and dry matter intake (DMI) was measured by electronic feeders (Intergado). The diets were analyzed for the presence of naturally occurring mycotoxins by enzyme immunosorbent test, Elisa – AgriQuant (Romer Labs) and the detected results were: Total aflatoxins (AF) &lt; 2.0 μg/kg DM, fumonisins (B1+B2) 0.29 mg/kg DM, deoxynivalenol (DON) 0.38 mg/kg DM and trichotocenes (&lt; 0.25 μg/ kg DM). Data were analyzed by SAS PROC ANOVA for p &lt; 0.05. The MyC provision increased the final BW (561 vs 545 kg, P=0.0465), ADG (1.66 vs 1.50 kg/d, P=0.0458), HWC (317 vs 308 kg, P=0.0492) and the average daily gain in carcass (1.15 vs 1.05 kg/d, P=0.0455) with no effect on DM intake. The use of Mycofix Select 5.0 provided better performance and greater carcass production in Nellore cattle confined with a high concentrate diet with a natural presence of mycotoxins.

PSII-B-19 Adaptation Periods Protocol for Nellore Cattle in Intensive Pasture Finishing

Our objective was to evaluate the performance of Nellore cattle in intensive pasture finishing (TIP), fed for 96 days and submitted to different adaptation periods, aiming to reach 2% of BW of DMI concentrate (DMIc)/BW at the end of the adaptation period. A total of 240 Nellore bulls (iBW 359kg±5.02 kg; 20 mo) were distributed in randomized blocks, allocated in paddocks of 2.4 ha (Urochloa brizantha cv. Xaraés; 10 animals/paddock), with two treatments with 12 replications (paddock as experimental unit). The treatments were: 1) 9 days on adaptation (ADAP9), 2% DMIc/BW on the 10th day; 2) 14 days on adaptation (ADAP14), 2% DMIc/BW on the 15th day. The animals were weighed fasting (± 16h) at the beginning, on day 28, and at the end of the experimental period, the DMIc was measured daily by the difference between offered and leftovers. Data were analyzed using the SAS ANOVA procedure at P&lt; 0.05. Evaluating the period between the beginning and the 27th day, ADAP9 showed greater DMIc (6.9 vs. 6.5kg/d; P=0.009), greater DMIc/BW (1.8 vs. 1.7% BW; P =0.0043) and greater fluctuation in DMIc (9.4 vs. 5.9% DMIc/d; P&lt; 0.001) compared with ADAP14. In the total fattening period, there was no difference between treatments (P &gt;0.05), for DMIc (8.7 vs. 8.5 kg DM/d), DMIc/BW (2 vs. 2% BW), fluctuation in DMIc (4.91 vs. 4.31% DMIr/d), days to reach target (17 vs 20 d), ADG (1.3 vs. 1.3 kg/d), ADG/DMIc (0.127 vs. 0.128), fBW (483 vs. 484kg) and HCW (285 vs. 285kg). The use of an adaptation period of less than 14 days did not improve performance, and therefore would not be recommended.

PSVIII-1 Hy-D Increases Ca, P and Serum Metabolites Related to Growth in Grazing Animals Receiving a P Deficient Supplement

The aim with this trial was to evaluate the effects of 25-OH Vit D3 in serum metabolites of growing grazing Nellore young bulls during the rainy season with two different supplementary P levels. Two independent and sequential trials were performed: first one using a 250 g/kg CP supplement containing 8 g/kg of P, and the second one using the same 25% CP supplement, with no addition of P. In each trial, eighteen young bulls of 385 kg BW and 18 months of age were randomly assigned to the two treatments (n=9 animals/treatment): addition or not (control) of 25-OH Vit D3 (ROVIMIX Hy-D 1.25%, Hy-D) to the supplement. Animals were placed in a paddock of B. brizantha, cv. Marandú, equipped with electronic feeders that provided individual access (animal/treatment). On day 31 of each trial, blood samples were taken for determination of 25-OH Vit D3, IGF-1, Ca, P, Alkaline Phosphatase (ALP), and osteocalcin (OCa). In each trial, data were analyzed according to a complete randomized design. In the first trial (8 g/kg of P in supplement) the use of Hy-D (Control vs Hy-D) increased serum concentrations of 25-OH Vit D3 (25.8 vs 30.0 ng/mL, P&lt; 0.03); not affecting the others variables. In the second trial, when no P was not added to the supplement, the use of Hy-D (Control vs Hy-D) increased serum concentrations of 25-OH Vit D3 (25.4 vs 44.7 ng/mL, P&lt; 0.01); Ca (10.8 vs 11.3 mg/dL, P&lt; 0.07); P (7.4 vs 8.3 mg/dL, P&lt; 0.08); ALP (205 vs 263 U/L, P&lt; 0.04); IGF-1 (256 vs 327 ng/mL, P&lt; 0.07); and did not affect OCa (P&lt; 0.27). These results showed that positive effects of Hy-D on metabolism could be dependent of dietary P level, with Hy-D being able to maintain the levels of Ca, P and serum metabolites related to growth when no P was supplied in the supplement.

PSII-B-14 Combination of Essential Oils, α-Amylase and 25-Hydroxy-Vitamin-D3 Increases Performance by Feedlot Cattle on Adaptation Period

Concerns about the use of in animal feed antibiotics are growing. It is, therefore necessary to develop alternative products that can replace antimicrobial feed additives. Thus, our objective was to evaluate the effects of associating feed additives on feedlot performance of Nellore bulls. Nellore bulls (n= 160; iBW, 380± 5.8 kg; age, 18 mo) were allocated in 20 pens (n=8/pen), in a completely randomized block design, according to the treatments: 1) MON+VM - Sodium Monensin (MON, 25 mg/kg DM, Elanco Animal Health, Indianapolis, IN), + Virginiamycin (VM, 30 mg/kg DM, Phibro Animal Health Corporation, Guarulhos, São Paulo), and 2) CRD - Crina RumistarTM + HyD, a blend of essential oils, 90 mg/kg DM + exogenous α-amylase, 560 mg/kg DM + 25-hydroxy-vitamin-D3 at 1 mg/animal/day (DSM Nutritional Products, Basel, Switzerland). The initial BW was utilized as a criterion for block formation. Pens were considered experimental units (10 pens per treatment). Animals were adapted to the diets during 14 days with gradually increasing concentrate level from 70% to 86% of diet DM, and fed for 90 days. Weight assessments were performed at day 0 and 28 discounted by 4% from the full BW as ruminal fill. Data were analyzed using PROC MIXED of SAS and means were separated using the PDIFF statement, adopting P&lt; 0.05. Feeding CRD increased the DMI (10.54 kg vs. 8.74 kg, P&lt; .0001), ADG (2.00 vs. 1.59 kg/d, P&lt; .0001) and final BW (430 vs. 418 kg, P&lt; .0001) compared with animals fed MON+VM. The fluctuation in dry matter intake (4.55, P=0.24) and G:F (0.186, P=0.15) were similar among treatments. Therefore, the inclusion of Crina RumistarTM +HyD can be used as a tool to increase performance of feedlot adaptation period.

PSVII-7 Effects of Minerals Source Supplementation on Performance and Carcass Production by Feedlot Cattle

Our objective was to evaluate the effects of mineral source supplementation on performance of finishing cattle when fed a high-concentrate diet for 89 days. Angus-Nellore bulls (iBW, n = 32; 472 ± 4.93 kg; age, 18 months) were randomly assigned to two treatments in a completely randomized design, with sixteen replicates per treatment (animal as experimental unit). The control group received a diet containing inorganic minerals (i.e. sulphates) and the other group were supplemented with carbo-amino-phospho-chelates (TM, Tortuga Minerals) as a source of Cr, Se, Zn, Mn, S, Cu and Co. The DM intake and weight of the animals variables were assessed individually using the respective digital devices, Intergado electronic feeders and the Bosch Precision Livestock platform placed in the feedlot pen. Data were analyzed using the MIXED procedure of SAS and means were separated using PDIFF statement, adopting P&lt; 0.05, and the initial BW as a covariate when significant. Supplementation with TM increased the ADG (1.74 vs. 1.55 kg/d, P&lt; 0.01) and final BW (626.96 vs. 609.91kg, P&lt; 0.01) compared with animals supplemented with inorganic sources. Likewise, animals supplemented with TM had better G:F (0.133 vs. 0.123 kg/kg, P&lt; 0.05) and biological efficiency (146.41 vs 134,34 kg DMI/15 kg de carcass; P&lt; 0.05), with no effect on DM intake (~12.94 kg, P=0.43). In addition, supplementation with TM increased final HCW in 13.44 kg (366.57 vs. 353.13 kg; P&lt; 0.01) and carcass ADG in 0.15 kg/d (1.47 vs. 1.32 kg/d; P&lt; 0.01). We conclude that supplementation with carbo-amino-phospho-chelates can be used as a tool to increase productive performance and efficiency by feedlot cattle.

PSVII-14 Feeding carbohydrases to grazing beef cattle under different nutritional strategies on dry season: Ruminal fermentation

The aim with this trial was to evaluate two nutritional plans with the addition of carbohydrases enzyme blend (CEB) on ruminal fermentation of grazing Nellore bulls in dry season. Five rumen cannulated Nellore steers (BW = 350 kg) were used. Animals were randomly assigned to a treatment sequence in a 5×5 Latin square experiment with 15 d-periods (10 d to diet adaptation and 5 d for data collection), following a completely randomized design, being the treatments: mineral-proteic supplementation (Fosbovi® Proteico 35; PS) offered at 0,1% BW (0 or 4.75 g/animal/day of CEB) or mineral-protein-energetic supplementation (Fosbovi® Proteico-Energético 25; PES) offered at 0.3% BW (0, 4.75 or 9.50 g/animal/day of CEB). The CEB was mainly composed by beta-glucanase and xylanase enzymes (Ronozyme® VP and Ronozyme® WX). Both enzymes and supplements were provided by DSM Nutritional Products Brasil S.A. Rumen fluid samples were collected on the last day of each experimental period before (0), and 2, 4, 6, and 8 h after supplements were offered. Data were analyzed using PROC MIXED of SAS. Steers fed PSE had greater (P ≤ 0.041) rumen concentration of acetate, propionate, and butyrate, and lower (P = 0.028) acetate to propionate ratio in comparison with animals fed PS. Rumen acetate concentrations were 61.6 and 58.8 mmol/L and rumen propionate concentrations were 15.2 and 13.7 mmol/L for animals under the PSE and PS, respectively. A quadratic effect (P = 0.048) for carbohydrases enzyme blend was observed in NH3-N ruminal concentration of PES animals, where 4.75 g/day level presented the lower concentrations compared to control (24.13 vs. 32.20 mg/dL). Furthermore, rumen concentrations of acetate (P = 0.002) and propionate (P = 0.021) linearly increased with enzymes inclusion for PSE plan. PSE nutritional strategy positively influence ruminal fermentation of Nellore steers in dry season and its effects can be enhanced with CEB inclusion of 4.75 g/day.

PSXVI-25 25-hydroxy-vitamin-D3 improves productive performance of grazing Nellore cattle during dry season

The aim with this trial was to evaluate three nutritional plans with the addition of 25-hydroxy-vitamin-D3 (HyD®) on performance of grazing Nellore steers in dry season. One hundred and twenty Nellore calves (iBW ± 267 kg; age, 9 mo) were randomly allocated to six paddocks (n = 20/paddock), in the following nutritional plans: mineral-proteic supplementation (PS; Fosbovi® Proteico 35; at 0.1% BW); PS with sodium monensin (PSM; Fosbovi® Proteico 35 M; at 0.1% BW); and mineral-protein-energetic supplementation (PES; Fosbovi® Proteico-Energético 25; at 0.3% BW); all three fed with or without addition of 1 mg/animal/d of 25-hydroxy-vitamin-D3 (HyD®), totaling six treatments. Both HyD® and supplements were provided by DSM Nutritional Products Brasil S.A. The intake and animal weight were collected daily and individually using an automatic feeder/scale system located in each paddock. Data were analyzed using the mixed procedure of SAS and means were compared by orthogonal contrasts (P &lt; 0.05). Animals fed PSE, when compared to PSM and PS, presented higher ADG (PSE = 0.290 vs. PSM= 0.130 and PS = 0.030 kg/day; P &lt; 0.01), FBW (PSE = 302.5 vs. PSM = 282.6 and PS = 271.7 kg; P &lt; 0.01) and supplement intake (PSE = 1.640 vs. PSM = 0.190 and PS = 0.210 kg/day; P &lt; 0.01). Additionally, regardless of nutritional strategy, HyD® supplementation increased ADG in 32 g/day (0.165 vs. 0.133 kg/day; P = 0.05) and FBW in 3.9 kg (287.5 vs. 283.6 kg; P = 0.05), compared to not-supplemented calves. No effects on supplement intake (either expressed in kg/day or %BW) were observed for HyD®. We conclude that 1 mg of HyD® can optimize performance of protein and protein-energetic supplemented cattle raised in tropical conditions during dry period.

PSXIV-13 Supplemental essential oil blends plus 25-hydroxy-vitamin-D3 improve carcass characteristics in cattle finished under tropical conditions

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 &gt; 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 &lt; 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.

PSVII-24 Blend of essential oils plus 25-hydroxy-vitamin-D3 as alternative to the use monensin on growth performance and dietary energetics in feedlot cattle raised under high ambient temperature

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 &lt; 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.

PSXIII-13 Feeding carbohydrases to grazing beef cattle under different nutritional strategies on dry season: feeding behavior

The aim with this trial was to evaluate two nutritional plans with the addition of dosages of carbohydrases enzyme blend on feeding behavior of grazing Nellore bulls in rainy season. One hundred and two contemporary Nellore steers (BW = 294.10 ± 3.35 kg) were equally distributed in six paddocks (17 steers/paddock) following a completely randomized design in a 2x3 factorial arrangement, being the factors two nutritional plans: mineral-proteic supplementation (Fosbovi® Proteico 35; PS) offered at 0,1% BW or mineral-protein-energetic supplementation (Fosbovi® Proteico-Energético 25; PES) offered at 0.3% BW); and three levels of enzymatic carbohydrases blend (0, 4,75 or 9,50 g/animal/day). The enzymatic blend was mainly composed by beta-glucanase and xylanase enzymes (Ronozyme® VP and Ronozyme® WX); Both enzymes and supplemented were provided by DSM Nutritional Products Brasil S.A. Feeding behavior data were collected daily and individually by an automatic scale/feeder system installed in the paddocks. Data were analyzed using PROC MIXED of SAS. Animals fed PES presented greater number of visits to the feed bunks (19.73 vs. 10.12 visits/day; P &lt; 0.0001), to the water fountains (2.95 vs. 2.32 visits/day; P &lt; 0.0001) and greater water intake (22.43 vs. 17.73 L/day; P &lt; 0.0001) in comparison with animals fed PS treatments. Also, animals receiving PES spent more time taking supplement (1.332 vs. 545 seconds/visit; P &lt; 0.0001) and water (203 vs. 153 seconds/visit; P &lt; 0.0001) then PS animals did. No linear and quadratic effects were observed for feeding behavior when including carbohydrases enzymes to PES or PS supplement. PSE nutritional plan positively influence feeding behavior of Nellore bulls in dry season, increasing cattle feed bunk access and water intake in a daily basis.

299 Combination of Essential Oils, α-amylase and 25-hydroxy-vitamin-d3 Increases Carcass Production by feedlot Cattle

Our objective was to evaluate the effects of associating feed additives on feedlot performance of Nellore bulls. One hundred and sixtieth Nellore bulls (iBW, 380± 5.8 kg; age, 18 mo) were allocated in 20 pens (n = 8/pen), in a completely randomized block design, according to the treatments: 1) MON+VM - Sodium Monensin (MON, 25 mg/kg DM, Elanco Animal Health, Indianapolis, IN), + Virginiamycin (VM, 30 mg/kg DM, Phibro Animal Health Corporation, Guarulhos, São Paulo), and 2) CRD - Crina® RumistarTM + HyD® - a blend of essential oils, 90 mg/kg DM + exogenous α-amylase, 560 mg/kg DM + 25-hydroxy-vitamin-D3 at 1 mg/animal/d (DSM Nutritional Products, Basel, Switzerland). The initial BW was utilized as a criterion for block formation. Pens were considered experimental units (10 pens per treatment). Animals were adapted to the diets during 14 days with gradually increasing concentrate level from 70% to 86% of diet DM, and fed for 90 days. Weight assessments were performed at day 0 and 90 after 14h fasting. Data were analyzed using PROC MIXED of SAS and means were separated using the PDIFF statement, adopting P &lt; 0.05. Feeding CRD increased the DMI (12.13 kg vs. 10.52 kg, P &lt; 0.01), ADG (1.86 vs. 1.63 kg/d, P &lt; 0.01) and final BW (542 vs. 521 kg, P &lt; 0.01) compared to animals fed MON+VM. In addition, feeding CRD increased final HCW in 15 kg (311 vs. 296 kg; P &lt; 0.01), carcass ADG in 0,16 kg/d (1.31 vs. 1.15 kg/d; P &lt; 0.01) and dressing percentage in 0.48 percent points (57.34 vs. 56.86%; P &lt; 0.01) compared to MON+VM. The G:F (0.155, P = 0.53) and biological efficiency (137.9 kg DM/15 kg carcass, P = 0.87) were similar among treatments. Therefore, the inclusion of Crina® RumistarTM +HyD® can be used as a tool to increase carcass gain of feedlot finishing cattle.

300 Effects of Associating Feed Additives on Rumen Ph Dynamics by Feedlot Cattle Fed a High-concentrate Diet

Our objective was to evaluate the effects of feed additives on ruminal pH of finishing cattle fed a 90%-concentrate diet. Twenty four 18-mo Angus-Nellore crossbred bulls (IBW, 456 ± 6,5 kg) were allocated in a completely randomized design to three treatments with eight replicates each, as follows: 1) Control (MON) - Sodium Monensin (26 mg/kg DM, Rumensin, Elanco Animal Health); 2) Crina® RumistarTM (CR) - a blend of essential oils, 90 mg/kg DM + exogenous α-amylase, 560 mg/kg DM) and 3) CR + HyD® (25-hydroxy-vitamin-D3 at 1 mg/animal/d, CRD, DSM Nutritional Products). The ruminal pH and temperature was monitored individually for 98 days, using a wireless bolus, (SmaXtec Animal Care, Austria). Data were analyzed using the Mixed procedure of SAS and means comparison evaluated by Tukey test at P&lt; 0.05. During adaptation period (i.e. first 14 days), bulls fed CR and CRD had increased rumen mean pH (6.40 and 6.36 vs. 6.16; P &lt; 0.01) and minimum pH (5.89 and 5.87 vs. 5.57; P &lt; 0.01) than bulls fed MON. In addition, rumen pH from bulls fed CR spent less time below 6.0 than bulls fed MON (256.07 vs. 452.62 min/d; P = 0.05). Regarding the total period, bulls fed MON had lower mean (6.22 vs. 6.51 and 6.42, P &lt; 0.01) and minimum rumen pH (5.60 vs. 5.92 and 5.85, P &lt; 0.01) than bulls fed CR and CRD. Additionally, feeding MON increased time duration of rumen pH (390.79 min/day, P &lt; 0.01) and had a larger area below 6.0 (81.52 min x pH units/day; P &lt; 0.01). Moreover, the addition of monensin increased pH time duration below 5.8 (161.10 vs. 121.13 and 122.56 min/day; P = 0.02) compared with CR and CRD, and increased ruminal temperature (39.60 vs. 39.51 and 39.5 °C; P &lt; 0.01). We conclude that feeding Crina® RumistarTM and Crina® RumistarTM HyD® increased the rumen pH of bulls.

PSXI-26 Blend of essential oils supplemented alone or combined with exogenous amylase compared with virginiamycin on performance of finishing lambs

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 &gt; 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 &lt; 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 &lt; 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.

314 Carbohydrases Enzymes Improve the Productive Performance of Grazing Nellore Bulls Fed Different Nutritional Plans During the Rainy Season

The aim with this trial was to evaluate two nutritional plans with the addition of dosages of carbohydrases enzyme blend on productive performance of grazing Nellore bulls in rainy season. One hundred and two contemporary Nellore steers (BW = 294.10 ± 3.35 kg) were equally distributed in six paddocks (17 steers/paddock) following a completely randomized design in a 2x3 factorial arrangement, being the factors two nutritional plans: mineral-proteic supplementation (Fosbovi® Proteico 30; PS) offered at 0,1% BW or mineral-protein-energetic supplementation (Fosbovi® Proteico-Energético 25; PES) offered at 0.3% BW); and three levels of enzymatic carbohydrases blend (0, 4,75 or 9,50 g/animal/day). The enzymatic blend was mainly composed by beta-glucanase and xylanase enzymes (Ronozyme® VP and Ronozyme® WX); Both enzymes and supplemented were provided by DSM Nutritional Products Brasil S.A. Supplement intake and animal weighting were carried out daily and individually by an automatic scale system installed in each paddock. Data were analyzed using PROC MIXED of SAS and means were compared by polynomial regression. Animals that received PES had greater ADG (0.896 vs. 0.775 kg/day; P &lt; 0.001) compared to those fed PS. Intermediary level (4.75 g/day) of carbohydrate enzymes also presented the highest ADG in PES compared to 0.0 level (0.941 vs. 0.896 kg/day; P = 0.006). Still, higher enzyme levels (9.5 g/day) presented greater ADG on PS, when compared to 0.0 level (0.852 vs. 0.775 kg/day, P = 0.006). PES animals presented greater intake, compared to PS (1.112 vs. 0.432 kg/day, P &lt; 0.001). According to polynomial regression, it is recommended to include 4.75 g/day of these carbohydrases enzymes in PS and 4.39 g/day in PES for growing Nellore bulls in rainy season.

PSXIII-3 Effects of mineral source and additive in mineral supplementation on productive performance of growing beef cattle on tropical pastures

Our objective was to evaluate the effects of mineral supplementation using the association of carboaminophosphochelates as mineral source plus Salinomycin on grazing beef cattle performance during growing phase. A total of 80 Nellore bulls (IBW = 292.72 ± 13.55 kg; Age, ~13 mo) were distributed in 8 paddocks (~2.7 hectares each) planted with Palisade Grass cv. Xaraés during the rainy to rainy-to-dry transition seasons (February to May). The experiment was a randomized complete block design (10 animals/paddock, 4 paddocks per treatment). The mineral supplementation was provided ad libitum and treatments were: Control; Mineral supplementation containing inorganic minerals, and TM+Salinomycin = Mineral supplementation containing carboaminophosphochelates (TM, Tortuga® Minerals) as minerals source (Cr, Se, Zn, Mn, S, Cu e Co) plus Salinomycin (~108 mg per animal/day). The supplement orts were removed and weighted daily to calculate supplement intake. The animals were weighed after a 14 h-fasting at the beginnig and end of the trial (84 days) to calculate weight gain. The paddock was considered the experimental unit and data were analyzed using PROC MIXED of SAS, whereby means were separated using the PDIFF statement (P &lt; 0.05). Supplement intake was similar between treatments (P = 0.13). Animals supplemented with TM+Salinomycin tended to have greater final BW (358 vs. 347, P = 0.07) and increased ADG in 22,3% (0.730 vs. 0.597 kg/d, P = 0.03) compared with animals fed Control. In conclusion, the combination of carboaminophosphochelates minerals plus salynomicin improves grazing beef cattle weight gain, with no deleterious effect on mineral supplement intake.

212 Feedlot performance of Nellore bulls fed different starch levels in the diet associated with feed additives

This study, conducted at DSM Beef Center, Mato Grosso do Sul, Brazil, was designed to evaluate the effects of different starch levels in the diets associated to feed additives on performance of Nellore bulls. The experiment was designed as a completely randomized block, with a 3 x 2 factorial arrangement of treatments, in which 210 18-mo-old yearling Nellore bulls (375.8 ± 16.8 kg) were fed in 30 pens (n = 7/pen), for 90 d according to the treatments: 25% starch (Low-S) + monensin (MON, 26 mg/kg DM); 35% starch (Med-S) + monensin; 45% starch (High-S) + monensin; Low-S + Essential Oils and amylase (CR, Crina®, 90 mg/kg DM and RumistarTM, 560 mg/kg DM, DSM Nutritional products); Med-S + CR; High-S + CR. Each treatment was replicated five times. Weight assessments were performed at day 0 and 90 of the study after 14 h fasting. A significant interaction was observed for final BW (P = 0.04) and HCW (P = 0.01). Cattle fed Med-S and High-S diets containing CR had heavier carcasses than those fed Med-S + monensin (287.4 vs. 270.9 kg) and High-S + monensin (281.4 vs. 263.0 kg), respectively; however, bulls fed Low-S diets with either monensin or CR had similar HCW (P &gt; 0.05, 279.9 vs. 282.8 kg, respectively). In addition, cattle fed CR had greater dressing percentage (P &lt; 0.01; 55.4 vs. 54.6%) regardless of starch levels. An interaction was observed (P = 0.02) for ADG, in which cattle fed Med-S + CR had greater ADG (1.58 kg) than cattle fed MON across all starch levels (1.48, 1.37 and 1.28, respectively) and then those fed High-S + CR (1.48 kg/d; P &lt; 0.01). Similar responses were observed for DMI (P = 0.02). Cattle fed monensin improved G:F in 2.7% compared to those fed CR (0.150 vs. 0.146, P = 0.02). In conclusion, Crina® and RumistarTM increases carcass production of feedlot cattle fed medium and high-starch diets.

PSII-3 Carbohydrases enzymes improve the productive performance of grazing Nellore steers fed different nutritional plans during dry season

The aim was to evaluate two nutritional plans with the addition of dosages of carbohydrases enzyme blend on productive performance of grazing Nellore bulls in dry season. A total of 102 Nellore bulls (BW = 294.10 ± 3.35 kg) were equally distributed in six paddocks (17 bulls/paddock) following a completely randomized design in a 2x3 factorial arrangement, being the factors different nutritional plans (2): mineral-proteic supplementation (PS; Fosbovi® Proteico 35) offered at 0,1% BW or mineral-protein-energetic supplementation (PES; Fosbovi® Proteico-Energético 25) offered at 0.3% BW; and levels of enzymatic carbohydrases blend (3):0,00 (control), 4,75 or 9,50 g/animal/day. The enzymatic blend was mainly composed by beta-glucanase and xylanase enzymes (Ronozyme® VP and Ronozyme® WX) and included in the supplements (both enzymes and supplements provided by DSM Nutritional Products Brasil S.A.). Supplement intake and animal weighting were carried out daily and individually by an automatic scale system installed in each paddock, thus, animal was considered the experimental unit. Data were analyzed using PROC MIXED of SAS and means were compared by polynomial regression. A quadratic effect was observed on enzyme level for ADG in both nutritional plans (P = 0.014), with intermediary dosages presenting the highest values of ADG for PS (0,283 vs. 0,188 kg/day) and PES (0.429 vs. 0.391 kg/day), over control respectively. Although no linear and quadratic enzyme effect was observed for final BW (FBW), animals supplemented with PES presented 20,06 kg higher FBW compared to PS (341,63 vs. 321,57 kg, P &lt; 0.001). An increasing linear effect was observed for supplement intake (kg/day), for both PS and PES (P = 0.020). According the polynomial regression, it is recommended to include 4.67 g/day of carbohydrases blend in PS and 3.77 g/day in PES, being the carbohydrases blend a viable technology to grazing cattle. Moreover, mineral-protein-energetic supplementation can optimize Nellore bulls performance during dry season.

213 Feeding essential oils and α-amylase or its association with 25-hydroxy-vitamin-D3 improves productive performance by feedlot cattle

Our objective was to evaluate the effects of associating feed additives on performance of finishing cattle when fed a high-concentrate diet for 105 days. Twenty-four Angus-Nellore crossbred bulls (iBW, 456 ± 10.04 kg; age, 18 mo) were randomly allocated to three treatments with eight replicates per treatment (animal as experimental unit). The treatments were: 1) Control (MON) - Sodium Monensin, 26 mg/kg DM; 2) Crina® RumistarTM (CR) - a blend of essential oils, 90 mg/kg DM + exogenous α-amylase, 560 mg/kg DM) and 3) CR + HyD® (25-hydroxy-vitamin-D3 at 1 mg/animal/d). The DM intake and animalsˈ weight variables were assessed individually, by using the Intergado® electronic system and the Bosch® Precision Livestock platform placed in the feedlot pen, respectively. Data were analyzed using the Mixed procedure of SAS and means comparison evaluated by Tukey test at P &lt; 0.05. The initial BW was used as a covariate when significant. Feeding CR and CR+HyD increased DMI (13.18 and 12.82 kg vs. 10.77 kg P &lt; 0.01) and tended to increase ADG (1.94, 1.92 vs. 1.68kg/d, P = 0.07) and final BW (654, 652 vs. 628 kg, P = 0.08) compared with MON. Likewise, animals fed CR and CR+HyD had greater carcass ADG (1.38, 1.41 vs. 1.14 kg/d, P &lt; 0.01), and HCW (368.53 and 371.87 vs. 344.13 kg; P &lt; 0.01) compared to MON. In addition, feeding CR+HyD increased the dressing percentage in 2.1 percent points compared with MON (57.4 vs. 55.3%; P &lt; 0.03). The G:F and the biological efficiency were similar among treatments (P = 0.50). We conclude that including Crina® RumistarTM +HyD® can be used as a tool to increase carcass production by feedlot cattle.

PSVII-6 Effects of 25-hydroxycholecalciferol supplementation on gene expression of feedlot cattle

The objective was to evaluate the effects of 25-hydroxycholecalciferol (HyD®, DSM Produtos Nutricionais Brasil S.A.) supplementation in expression of genes related to anabolism and catabolism of feedlot cattle. A total of 120 Nellore bulls (IBW = 370±20 kg) were distributed in 24 fully roofed-pens with concrete floor (5 animals/pen) in a randomized complete block design (8 pens/treatment). The treatments were T1 (control): no supplementation of HyD®; T2: HyD® supplementation at 1 mg/animal/day; T3: HyD® supplementation at 3 mg/animal/day. Basal diet was formulated to meet requirements of finishing bulls, considering an ADG of 1.6 kg/day (Level 2 Nutrition System, Fox et al., 2004). Adaptation to diets followed a step-up scheme for 14 days, with concentrate inclusion being gradually increased from 76 to 91% DM. Finishing diets were offered from 15th to 100th day of feedlot period and animals fed twice a day (0800 and 1500), with bunks managed for a maximum of 5% orts. After slaughter, muscle samples were collected for quantitative evaluation of gene expression using RT-qPCR method, considering the following genes: SOD1 (antioxidant marker), IGF1, IGF2 and MTOR (anabolism), FOXO1, MURF1, Atrogin-1 and MSTN (catabolism). Statistical analysis was performed using PROC MIXED of SAS® and means compared by Tukey test at 5% probability. No significant differences among treatments were observed for SOD1, FOXO1, MURF1 and Atrogin-1 expression (P &gt;0.05). However, tendencies (0.05 &gt; P ≤0.10) could be observed for IGF1, IGF2, MTOR and MSTN expression in animals receiving HyD®, regardless of dosage. These results indicate a positive effect of HyD® on muscular anabolism and protein synthesis on feedlot finishing cattle. Moreover, the greater expression on MSTN suggest a higher protein turnover and muscular growth regulation. In conclusion, HyD® supplementation increased expression of genes correlated to muscular growth and protein synthesis, being a viable technology for beef cattle finished in feedlot systems.

391 Effects of increasing carbohydrases levels on productive performance of beef cattle fed feedlot finishing diets

Our objective was to evaluate the effects of feeding increasing exogenous carbohydrases levels on cattleˈ performance, when fed a 90-d feedlot finishing diet. A total of 240 Nellore bulls (IBW = 389 ± 27 kg) were distributed in 24 pens (10 animals/pen), in a randomized complete block design (6 pens/treatment). The basal diet was composed by 15% sugarcane bagasse, 72.8% ground corn, 7.6% soybean meal and 4.6 % mineral-vitamin premix (DM basis). The treatments were: 1) control: No addition of carbohydrases blend; 2) Blend1, in g/animal/d: 1 g of Ronozyme® WX (xylanase) + 3.75 g of Ronzyme® VP (beta-glucanase); 3) Blend2, in g/animal/d: 2 g of Ronozyme® WX + 7.5 g of Ronzyme® VP and 4) Blend3, in g/animal/d: 4 g of Ronozyme® WX + 15 g of Ronzyme® VP. The animals were fed once a day and had free access to fresh water. Statistical analysis was performed using the MIXED procedure of SAS 9.4, and comparisons were performed out by orthogonal contrasts, which compared the control and treatments, and the linear and quadratic effects of the increasing carbohydrases levels. Statistical significance was declared at P &lt; 0.05, and tendencies considered when 0.05 &lt; P &lt; 0.10. Animals fed carbohydrases had greater (P = 0.045) ADG (1.59 vs. 1.51 kg/d) and tended to have greater (P = 0.069) final BW (533.4 vs. 527.7 kg) compared with control; although no difference were observed on these variables among carbohydrases levels. Feeding carbohydrases increased DM intake, expressed either as kg/d (10.17 vs. 9.92; P = 0.019) and as percentage of BW (2.20 vs. 2.16 %; P = 0.038), compared to control group, respectively. However, no difference was observed among treatments on G:F, and dressing percentage. In conclusion, the addition of carbohydrases blend can improve performance of finishing cattle.

PSIX-40 Exogenous carbohydrases improve carcass characteristics of Nellore beef cattle grazed in tropical conditions

The objective was to evaluate the effects of feeding levels of an exogenous carbohydrases blend on performance and carcass characteristics of grazing Nellore beef cattle. A total of 168 bulls were distributed to twenty Brachiaria brizantha cv. Xaraés paddocks (8 or 10 animals/paddock) in a randomized complete block design, with five replicates (paddocks) per treatment. Bulls were assigned according initial BW (IBW; 369.07±21.13 kg) to receive treatments for 231 days: 1) Control (basal mineral-protein-energetic supplement, no enzyme; PES), Carb1 (PES + 0.83 g of xylanase, RONOZYME® WX; and 3.09 g of beta-glucanase, RONOZYME® VP, both offered/kg PES), Carb2 (PES + 1.65 g of xylanase and 6.18 g of beta-glucanase/kg PES) and Carb3 (PES + 3.30 g of xylanase and 12.38 g of beta-glucanase/kg PES). Evaluated parameters were final BW (FBW), average daily gain (ADG), supplement intake, hot carcass weight (HCW) and dressing %. IBW and FBW were measured after a 12-hour fastening period. Treatments were offered daily in covered group feeders located in each paddock. Animals had free access to supplements and water. Supplements and enzymes were provided by DSM Nutritional Products. Data were analyzed using MIXED procedure of SAS® 9.3, being each paddock the experimental unit. Orthogonal contrasts were used to detect linear and quadratic effects on enzyme levels, with values P ≤ 0.05 considered significant. No linear or quadratic effects (P &gt; 0.05) were observed on supplement intake (2.11 kg/animal/d), FBW (492.03 kg) and ADG (0.532 kg/day). However, a quadratic effect was observed for HCW and dressing %, with animals fed Carb1 presenting 5.69 kg heavier carcass (272.67 vs. 266.98; P = 0.039) and 1.4 p.p. higher dressing % (55.3% vs. 53.9%, P &lt; 0.001) compared with control group. In conclusion, to use carbohydrases enzyme blend improves carcass characteristics and is an interesting technology for Nellore beef cattle grazed in tropical conditions.

Nellore bulls in Brazilian feedlots can be safely adapted to high-concentrate diets using 14-day restriction and step-up protocols

In the present study, the effects of restricted intake of the final finishing diet as a means of dietary adaptation compared with diets increasing in concentrate content (step-up) over periods of 14 and 21 days on growth performance, carcass characteristics, feeding behaviour and rumen morphometrics of Nellore cattle were evaluated. One hundred and twenty 20 months old Nellore bulls (initial BW = 372.2 kg, s.d. = 21.5 kg) were randomly allocated in 24 pens (n = 5 per pen) and fed for 84 days. The study had a completely randomised design with a 2 × 2 factorial arrangement: adaptation using both 14-day and 21-day step-up and restriction protocols. Each treatment was replicated 6 times. One bull per pen was slaughtered (n = 24) at the end of adaptation period to evaluate rumen morphometrics. The remaining bulls (n = 96) were slaughtered at the end of experimental period. Interactions were observed (P &lt; 0.05) for growth performance, feeding behaviour and rumen morphometrics variables. Overall, no protocol or adaptation length main effect (P &gt; 0.05) was observed for any of the growth rate and carcass traits evaluated, except for hot carcass weight (P = 0.03) and dressing percentage (P = 0.04), where bulls adapted for 14 days had heavier carcasses and increased dressing percentage when compared with cattle adapted for 21 days. Cattle adapted for 21 days had a larger (P = 0.005) rumen wall absorptive surface area at the end of adaptation period than those adapted for 14 days; however, no differences were detected at the end of finishing period. Thus, Nellore yearling bulls could be adapted for 14 days regardless of the protocol.

Effects of restricted vs. step up dietary adaptation for 6 or 9 days on feedlot performance, feeding behaviour, ruminal and blood variables of Nellore cattle

This study was designed to determine effects of quantitatively restricted intake of the final finishing diet as a means of dietary adaptation compared with diets increasing in concentrate (step up) over periods of 6 and 9 days on feedlot performance, carcass characteristics, feeding behaviour, blood gas profile and rumen morphometrics of Nellore cattle. One hundred twenty 22-month-old Nellore bulls (352 ± 20 kg) were randomly allocated in 24 pens and fed for 84 days. The experimental design was a completely randomized block with 2 × 2 factorial arrangement of treatments: adaptation using either step up protocol for 6 days or 9 days or restriction protocol for 6 days or 9 days, where the pen (five bullocks/pen; six pens/treatment) was considered the experimental unit. Cattle adapted by step up protocol had significantly greater average daily gain throughout the study when compared to those adapted by restriction protocol, regardless of adaptation length. During the adaptation period, a greater dry matter intake fluctuation was observed for animals maintained on restriction programme when compared to those adapted to the finishing diets using step up protocol. In addition, a protocol × length interaction for rumenitis scores was observed, where the level of injuries to the ruminal wall was significantly higher for the cattle adapted by restriction protocol for 9 days and lower for animals submitted for 9 days to the step up programme. Likewise, a protocol × length interaction for mitotic index was observed, in which cattle adapted by step up protocol for 9 days had lower numbers of cells in mitosis. Thus, the step up protocol led to better feedlot performance, and based on this fact, the length of 9 days promoted better rumen epithelium adaptation of Nellore cattle to high-concentrate diets.

Perfil de ácidos graxos e características da carne de bovinos Nelore confinados com diferentes fontes lipídicas protegidas

O objetivo deste trabalho foi avaliar os efeitos da adição de fontes de lipídeos naturais e protegidos da degradação ruminal na dieta de bovinos Nelore confinados sobre características da carne, concentrações de lipoproteínas sanguíneas e perfil de ácidos graxos da gordura do músculo Longissimus dorsi. Foram utilizados 120 bovinos Nelore, não castrados (366,9±28,7kg), com aproximadamente 24 meses. O delineamento experimental foi inteiramente casualizado, com três tratamentos: (CONTR) sem fonte adicional de lipídeo, (GDESP) com fonte de lipídeo natural (torta de algodão) e (GPROT) com fonte de lipídeo protegido rico em ácidos graxos poli-insaturados. Foram utilizadas 24 baias, cinco animais/baia, com oito repetições/tratamento, sendo as baias consideradas unidades experimentais. Foi observada (P<0,05) interação entre tratamento e dias de mensuração para colesterol e LDL, com maiores valores do tratamento GPROT nos dias 1 e 15, tendo o dia 84 valor intermediário aos demais tratamentos. Observaram-se efeitos de dias de mensuração, em que VLDL e triglicerídeos apresentaram valores crescentes nos dias 15, 84 e 1; enquanto o HDL teve maior valor no dia 1. Foi observado efeito (P<0,05) de tratamento para o perfil de ácidos graxos, com diminuição do C14:1, C16:1 e C17:1 e aumento do ácido transvaccênico, C18:2, ácidos graxos poli-insaturados (AGPI) e da relação AGPI: AGMI (ácidos graxos monoinsaturados) para os tratamentos GPROT e GDESP. Adição de lipídios na dieta, independentemente da fonte, promove melhora na composição de ácidos graxos da carne de bovinos Nelore confinados, aumentando a quantidade de ácidos graxos insaturados sem alterar as características qualitativas da carne.

Effects of flunixin meglumine, recombinant bovine somatotropin and/or human chorionic gonadotropin on pregnancy rates in Nelore cows

The objective was to compare pharmacological strategies aiming to inhibit prostaglandin F2 alpha (PGF(2α)) synthesis (flunixin meglumine; FM), stimulate growth of the conceptus (recombinant bovine somatotropin; bST) and progesterone (P(4)) synthesis (human chorionic gonadotropin; hCG), as well as their combinations, regarding their ability to improve pregnancy rates in beef cattle. Lactating Nelore cows (N = 975), 35 to 70 days postpartum, were synchronized and inseminated by timed artificial insemination (TAI) on Day 0. On Day 7, cattle were allocated into eight groups and received one of the following treatments: saline (S) on Days 7 and 16 (Group Control); S on Day 7 and FM on Day 16 (Group FM); bST on Day 7 and S on Day 16 (Group bST); bST on Day 7 and FM on Day 16 (Group bST + FM); hCG on Day 7 and S on Day 16 (Group hCG); hCG on Day 7 and FM on Day 16 (Group hCG + FM); bST and hCG on Day 7 and S on Day 16 (Group bST + hCG), or bST and hCG on Day 7 and FM on Day 16 (Group bST + hCG + FM). The aforementioned treatments were administered at the following doses: 2.2 mg/kg FM (Banamine®; Intervet Schering-Plough, Cotia, SP, Brazil), 500 mg bST (Boostin®; Intervet Schering-Plough), and 2500 IU hCG (Chorulon®; Intervet Schering-Plough). Pregnancy diagnosis was performed 40 days after TAI by transrectal ultrasonography. Pregnancy rates were not significantly different among treatments. However, there was a main effect of hCG treatment to increase pregnancy rates (63.0 vs. 55.4%; P = 0.001). Concentrations of P(4) did not differ significantly among groups on Day 7 or on Day 16. However, consistent with the higher pregnancy rates, hCG increased P(4) concentrations on Day 16 (10.6 vs. 9.6 ng/mL, respectively; P = 0.05). We concluded that hCG treatment 7 days after TAI improved pregnancy rates of lactating Nelore cows, possibly via a mechanism leading to induction of higher P(4) concentrations, or by reducing the luteolytic stimulus during maternal recognition of pregnancy.

T-shaped IUDs accommodate in their position during the first 3 months after insertion

The objective of this study was to observe the position dynamics of the T-shaped intrauterine device (IUD) in the uterine cavity, from insertion to 90 days of use. IUD position was evaluated in 214 women by vaginal ultrasound, measuring the IUD-endometrium, IUD-myometrium, and IUD-fundus distances. The 90th percentile of the IUD-endometrium distance was 5, 6, and 8 mm at time of insertion, 30 and 90 days of use; 7, 9, and 10 mm for IUD-myometrium distance; and 23, 24, and 27 mm for IUD-fundus distance, respectively. Seventeen IUDs were classified as misplaced at insertion by using the 90th percentile of the IUD-myometrium distance as standard. Of these, only 6 remained misplaced after 90 days of use. On the other hand, 21 IUDs were beyond the 90th percentile at the 90-day observation, only 6 of which were considered misplaced at insertion. We conclude that the T-shaped IUD accommodates its position in the uterine cavity during the first 3 months following insertion, and that ultrasound evaluation of its position is not a good predictor of future evaluation.