Suchergebnisse

The aim of the current study is to assess three integrated systems presenting different eucalyptus tree densities due to animal and forage production. The following integrated systems were assessed: crop-livestock-forest with 357 eucalyptus trees ha-1 (ICLF1); crop-livestock-forest with 227 eucalyptus trees ha-1 (ICLF2); and crop-livestock with 5 remnant native trees ha-1 (ICL). The randomized block experimental design was applied in a split-plot scheme with four replicates. The Average Daily Gain (ADG, g animal-1day-1) and the live-weight gain per area (LWG, kg ha-1) were applied to analyze animal performance, which was set by weighing the animals every 28 days (the animals previously fasted for 16h). Forage yield was higher in ICL during fall and winter; in summer, it did not differ from ICLF2. There was no forage yield difference between the ICL and ICLF2 systems in any of the assessed seasons; summer was more productive in ILPF1 than other seasons. The highest leaf crude protein contents (CP) in summer was recorded in systems ICLF1 and ICLF2, and the highest value recorded in fall was found in ILPF1; the lowest was found in ILP. On the other hand, the highest leaf NDF contents in summer were found in ILP. The highest ADG were found in summer. The highest LWG values recorded for the ICL and ICLF2 systems were collected in summer and fall; there was no difference in any of the three systems in winter. The LWG was higher in all system in summer. The ICLF2 emerged as the system (with trees) most appropriate for beef cattle production. Despite the shading interference on forage production, such condition is compensated by the best nutritional contents such as CP. The ICLF2 system allowing an annual LWG of 83% in relation to the ICL system during the fifth year of establishment of the systems.

With the objective to evaluate different frequencies of supplementation on the performance and ingestive behavior of Nellore calves kept on Urochloa brizantha cv. Marandu pasture, 56 animals with initial average body weight (BW) of 174.5 kg were submitted to the following treatments: no supplement and 1x, 3x, and 7x supplementation per week. The supplement was provided in the amount of 3.5 g kg-1 of BW day-1. BW and evaluation of behavior were assessed every 28 days. The randomized block's design with two repetitions was used. The analyses of variance were carried out by the GLM procedure in the SAS software, and the means were compared by the Tukey's test at 5% significance. The supplementation increased the average daily gain (ADG; P ? 0.05); however, it did not differ between frequencies (0.005, 0.190, 0.183, and 0.177 kg head-1 day for the no supplement treatment and 1x, 3x, and 7x per week, respectively). The animals in the no supplement treatment showed longer grazing time (P ? 0.05) compared to those receiving the supplement. However, results did not differ between frequencies (10.44, 8.57, 8.32, and 8.59 hours day-1 for no supplement treatments and 1x, 3x, and 7x per week, respectively). Thus, the frequency of supplementation can be reduced to once a week without reducing animal performance.

This study aimed at evaluating carcass traits and meat quality of Nellore steers on pasture submitted to different dietary supplementation strategies. The 32 Nellore animals tested (8 ± 0.6 months) were raised under rotational grazing on Brachiaria brizantha cv. Piatã (syn. Urochloa brizantha cv. Piatã) pasture and distributed in four treatments: supply of mineral salt ad libitum in the growth and finishing phases (MSGF); concentrate supplementation only during the growth phase (CG); concentrate supplementation only during the finishing phase (CF) and concentrate supplementation the growth and finishing phases (CGF). The concentrated supplement was supplied at 0.5% of body weight and mineral ad libitum. The steers were slaughtered when more than 50% of the lot of each treatment reached 450 kg body weight. The mean the hot and cold carcass weight and subcutaneous fat thickness did not differ between treatments (P > 0.05). The calves the treatment CF and CGF showed a larger rib-eye area and higher ether extract levels in the Longissimus dorsi muscle than in MSGF and CG (P < 0.05). Mean shearing force was similar between treatments (P > 0.05). The use of feeding strategies on pasture with concentrate supplementation in the growth and finishing phases of Nellore cattle anticipates slaughter in 92 days and produces carcasses and meat with satisfactory traits.

Animal nutrition needs simple methodologies to be applied under field conditions, providing valid estimates of consumption and digestibility that can be used by both farmers and animal input industry. Thus, the search for new substances, provided in a practical way, quantified by simple and low-cost analytical methodologies, replacing external indicators (chromic oxide used as reference) would be well accepted by the scientific community. In this context, the aim of this study was to assess the supply of chorionic oxide by esophageal route or mixed in the diet and the use of kaolin as an indicator, under the same forms of administration, to estimate fecal production and digestibility using four castrated male Holstein cattle. The experimental design was a 4 × 4 Latin square design, with four experimental periods of 12 days and six-day intervals between periods. Treatments consisted of supplying chromic oxide by esophageal route (COer), kaolin by esophageal route (Kaoer), chromic oxide mixed to the diet (COdiet), and kaolin mixed to the diet (Kaodiet). The treatment Kaodiet allowed obtaining estimates of fecal production similar to the treatment COer. The treatment COdiet did not differ from the treatment COer (p > 0.05) considering all the assessed parameters, evidencing that the indicator chromic oxide can be supplied mixed directly in the diet without damaging the estimates of fecal production and digestibility. Under the studied conditions, kaolin was not an effective indicator to obtain accurate estimates of fecal production and further studies are needed to adjust the analytical techniques of aluminum extraction as well as to resolve some doubts regarding its digestion process.

The present work aimed at evaluating models that predict the proportion of bone, muscle, and fat in ewe lamb carcasses using in vivo data obtained from the 9th to 11th rib section and from the 12th rib. A study population of 30 wooled ewe lambs, derived from Texel breed crosses, were fed with different concentrate levels (0%, 20%, 40%, 60%, and 80%) and slaughtered at a weight of 37.70 ± 10.23 kg. Carcass fat content (FC%) and muscle content (MC%) were estimated from models using the proportion of muscle and fat in the 9th to 11th rib section or in the 12th rib, with or without additional data regarding subcutaneous fat thickness (SFT mm) or carcass ribeye area (RA cm2). Carcass bone content (BC%) was predicted based on the proportion of bones in the 9th to 11th rib section or in the 12th rib. Modeling with in vivo data included fasting body weight (FBW), withers height (WH), and ultrasound measurements of SFT and RA. The FC% could be estimated from the carcass SFT and fat content in the 12th rib. The MC% was more accurately predicted from the proportion of muscles in the 9th to 11th rib section and from carcass RA. The 9th to 11th rib section provided the most accurate data for the prediction of BC%. To determine FC% and MC% from in vivo inputs, the model must include FBW and WH. In vivo FBW measurements alone allow for the estimation of BC%. We recommend the use of 12th rib composition for the accurate estimation of carcass fat content, and the use of the 9th and 11th rib section for the prediction of carcass muscle and bone content. Models using in vivo data for the prediction of fat, muscle, and bone in ewe lambs should incorporate FBW and WH.

This study aimed to assess the performance, carcass traits, and non-carcass components of feedlot finished Texel crossbred lambs from different residual feed intake classes (RFI). Forty-seven uncastrated male Texel crossbred lambs (¾ Texel + ¼ Pantaneira) tested here were 4-month-old with an initial weight of 29.9 ± 5.5 kg. The lambs were confined for 70 days for individual dry matter intake (DMI) and average daily gain (ADG) assessment. The diet containing corn silage was provided as roughage, while the concentrate consisted of corn grain, soybean meal, urea, and mineral mixture with a 40:60 roughage to concentrate ratio and 76.34% total digestible nutrients (TDN). After confinement for 70 days, the lambs were slaughtered to assess carcass traits and non-carcass components. Based on the RFI, lambs were divided into three classes according to the standard deviation (sd): Positive RFI (inefficient, 0.5 above the mean), Negative RFI (efficient, 0.5 below the mean), and Medium RFI (intermediate). Classes with Negative (efficient) and Positive RFI (inefficient) showed no differences in ADG (0.321 vs 0.306 kg; P > 0.05). Dry matter intake (g d-1), and percentage of body weight (BW) differed significantly between the RFI classes (P < 0.05). Compared to lambs in the inefficient class, those in the efficient class (Negative RFI) showed a 9% reduction in DMI and had the same ADG. The lambs in either Positive or Negative RFI classes showed no weight differences between non-carcass components (P > 0.05). The RFI classes showed no differences in shrunk body weight, hot carcass weight, hot dressing, and weight of commercial cuts (P > 0.05). They showed no differences in neck, shoulder + shank, loin, rack, flank steak, rack cap off, and leg weights (P > 0.05). Our results indicate that improvement in feed efficiency, as a function of the RFI index, does not compromise performance and carcass traits of Texel crossbred lambs.

This study aimed to evaluate the growth of body components in crossbred ewe lambs fed increasing levels of dietary concentrate and to determine the optimum level of supplementation for finishing ewe production. Thirty crossbred (½ Pantaneira × ½ Texel) wool ewe lambs fed Tifton 85 hay (Cynodon spp.) and different dietary concentrate levels (20, 40, 60, and 80% DM basis) were selected for study. At the beginning of the study, six animals were slaughtered for determination of initial body composition. The remaining animals were slaughtered at approximately 48 kg live weight. The growth of body components in relation to body growth was estimated from the allometric model BC = a × (FBW)b, where BC is body component weight, a and b are growth equation parameters, and FBW is fasted body weight. Carcass, muscle, bone, and gastrointestinal tract were late maturing (b < 1, P < 0.01). Carcass and carcass fat growth was positively affected (linear, P < 0.05) by concentrate level. Total fat weight increased with increasing concentrate level (P < 0.05). The addition of up to 60% concentrate in growing ewe lamb diets is recommended for production of carcasses with early deposition of muscle and fat. The addition of 20% concentrate in ewe lab diets is sufficient for production of carcasses with maximum deposition of muscle and no excess fat.

The aim of this study was to evaluate the effects of aging on meat quality of crossbred heifers. Qualitative and quantitative evaluations of carcasses and meat of 148 crossbred heifers with an average age of 13 months and 407.5 ± 29.22 kg body weight at slaughter were performed. After cooling for 24 h, the carcasses were evaluated for hot carcass weight, pH, conformation, physiological maturity, finishing, fat distribution, and length. Characteristics, such as pH, color, marbling, exudation, as well as cooking losses, percentage of ether extract, and shear force were evaluated in meat at time zero and after seven days of aging. The carcasses displayed satisfactory results for parameters such as pH at 24 h of cooling (pH24), finishing, distribution of fat, and subcutaneous fat thickness (5.58, 3.27, 2.40, and 6.62 mm, respectively). The meat had a low marbling score (5.08) and percentage of ether extract (1.71), indicating that the meat was relatively lean. Exudation and cooking losses showed similar results at zero and seven days of aging. The meat subjected to seven days of aging showed higher lightness and hue (40.98 and 0.77, respectively) and tenderness of 5.25 kg. These results indicated that aging affected meat color and shear force parameters; the meat of cross-heifers was softer but less red after maturation.

The study evaluated the effects of dietary protein-energy supplementation on feed intake, ingestive behavior, rumen parameters and nutrient digestibility in lambs. Four castrated lambs with 31.9 kg mean body weight and fistulated rumen were tested. distributed into latin square design (4x4), four treatments were tested over four periods of time: no supplementation (control) or with supplementation at 8, 16 and 24 g kg-1 body weight. The supplement (soybean meal, soybean hulls, ground corn and minerals) was provided with roughage (Tifton Bermudagrass, Cynodon spp., hay), which was offered ad libitum once a day, at 8h00. In treatments receiving 0 (control), 8, 16 and 24 g kg-1 supplementation, dry matter intake was 685.26, 742.86, 842.51 and 1013.33 g day-1, crude protein intake was 80.18, 95.98, 118.64, 150.14 g day-1 and metabolizable energy intake 1.55, 1.91, 2.31 and 2.98 g day-1, respectively. Treatments receiving the highest supplementation levels spent less time with rumination and feeding and rested for longer (P < 0.05). Protein-energy supplementation level did not affect rumen parameters. Average rumen pH was 6.3 and rumen ammonia nitrogen 165 mg dL-1; both were affected by sampling time. Supplementation levels until 24 g kg-1 BW improves feed intake and nutrient digestibility linearly and changes ingestive behavior, lowering rumination time without affecting rumen parameters.

To maximize economic gain in sheep production systems it is critical to adjust feedlot diets to maximize performance while minimizing feed, and especially concentrate, waste. Little information is available on ideal diets for crossbred ewe lambs. Therefore, this study aimed to evaluate the performance of feedlot crossbred ewe lambs, and the digestibility of diets, with increasing levels of concentrate during the growing and finishing phases. Twenty-four crossbred Texel × Pantaneira Texel ewe lambs were confined and fed Tifton hay with increasing levels of concentrate in the diet (20, 40, 60 and 80%) for individual evaluation of dry matter intake (DMI), digestibility of diets, average daily gain (ADG) and feed efficiency (FE). Animals were slaughtered at 47 kg. In the growing phase, the inclusion of concentrate in the diets (1176 g.kg-1) did not change DMI (p > 0.05). Concentrate levels had a quadratic effect (p < 0.05) on the dry matter digestibility coefficient (DMDC) and on total digestible nutrients (TDN) during the growing phase. In the finishing phase, there was a negative linear effect of concentrate levels on DMI (p < 0.05), but TDN intake was similar among the experimental diets (p > 0.05). DMDC and TDN values displayed a quadratic behavior (p < 0.05), plateauing at 60% concentrate. ADG and FE increased as concentrate was added to the diet in the growing phase (p < 0.05). During the finishing phase, lamb performance was similar (p > 0.05) for different diets. Thus, the use of 60% concentrate in the confined crossbred ewe lamb diet during growing and 20% concentrate during finishing is recommended.