Suchergebnisse

O objetivo foi avaliar a cinética de degradação ruminal in vitro de dietas contendo diferentes níveis de proteína da torta de crambe em substituição à proteína do farelo de algodão pela técnica de produção cumulativa de gases. Foram avaliados os alimentos e as dietas contendo diferentes níveis de torta de crambe (0, 250, 500, 750 e 1000 g kg-1). No fracionamento de proteínas foi observado que o farelo de algodão e a torta de crambe apresentam a maior parte dos compostos nitrogenados na fração de proteínas rapidamente degradáveis no rúmen, entretanto, a torta de crambe apresentou a maior fração A e a menor fração B3 quando comparada ao farelo de algodão. As dietas experimentais, apresentaram elevadas proporções de frações "A" e B1+B2. No fracionamento de carboidratos, a torta de crambe apresentou valor inferior da fração A+B1 e superior da fração C quando comparado ao farelo de algodão. A torta de crambe apresentou valores de carboidratos potencialmente degradáveis, superior aos do farelo de algodão. As dietas apresentaram poucas variações nas frações de carboidratos rapidamente degradáveis e na fração de degradação lenta. Observou-se uma diminuição da fração A1+B1 com o aumento dos níveis de torta de crambe em substituição à proteína do farelo de algodão. Observou-se homogeneidade na produção cumulativa de gases durante a incubação in vitro das dietas em função do tempo de incubação. Após 144 horas de incubação, a dieta contendo 1000 g kg-1 de torta de crambe apresentou o maior volume final da produção cumulativa de gases e a ração com 250 g kg-1, o menor volume. O volume final de gases produzidos pela fermentação dos carboidratos fibrosos apresentou efeito linear decrescente (P<0,05) em função dos níveis de inclusão da torta de crambe, entretanto, as outras variáveis não foram influenciadas (P>0,05). A utilização de proteína da torta de crambe em substituição à proteína do farelo de algodão não influencia a cinética de degradação de carboidratos e proteínas no rúmen, promovendo melhor disponibilidade na dieta. Assim como, não interfere na cinética de fermentação ruminal in vitro dos carboidratos não fibrosos.

The objective of this study was to evaluate the carcass traits of crossbred Santa Inês lambs fed with increasing levels (0, 300, 600, and 900 g kg-1 on a dry matter basis) of cactus pear cv Mexican elephant ear (Opuntia stricta Haw) as a replacement for Tifton-85 hay. Forty-eight male lambs (noncastrated), averaging 21.0 ± 2.93 kg body weight (BW) at the beginning of the study, were used in this trial. Replacement levels of Tifton hay by cactus pear affected the hot carcass and cold carcass weights and the carcass compactness index linearly (P < 0.05), but did not influence the yield of hot carcass and cold carcass, the loin eye area, conformation, finishing, and subcutaneous fat thickness, the yield of commercial cuts and tissue composition of the leg (P > 0.05). The averages of tissue components yields were: muscle 64.94%, bone 16.92%, fat 14.92%, and other tissues 2.71%. There was also no effect (P>0.05) of treatments on other measurements in Longissimus dorsi. However, there was an increasing linear effect on ether extract content (P<0.05). It can be concluded that the Mexican Elephant Ear cactus pear can be used to feed finishing lambs, replacing up to 900 g kg-1 of the dry matter of the roughage, with a consequent increase in carcass weight, loin, shoulder, and leg, as well as, in the percentage of ether extract of the meat. However, it does not alter the other carcass traits and physical-chemical characteristics of the meat.

The goal of this study was to evaluate different levels of crambe meal (0, 330, 670 and 1,000 g kg-1 dry matter [DM]) as a replacement for soybean meal in diets supplied to feedlot lambs, and their effects on performance, carcass traits and non-carcass components. Twenty-four castrated lambs weighing 18.2 kg at the beginning of the experiment were allocated in a completely randomized design. Diets were formulated to meet the requirements of the lamb for an average daily gain of 0.200 kg. The roughage:concentrate ratio was 60:40, using Brachiaria dyctioneura hay as roughage. Dry matter intake, feed conversion, average daily gain, carcass traits and non-carcass components were evaluated. There was no effect of different levels of crambe meal replacing soybean meal on performance, carcass traits and non-carcass components, except heart weight. Replacement 1,000 g kg-1 DM of soybean meal protein by crambe meal protein does not affect the performance, carcass traits, or non-carcass components.

The objective of this study was to evaluate ingredients and diets containing increasing levels of crambe cake protein replacing soybean meal protein, with in vitro ruminal fermentation parameters using a gas production technique. Diets were formulated for feedlot lambs and contained different levels of crambe cake protein (0, 250, 500, 750, and 1000 g kg-1) replacing soybean meal protein. Corn silage was used as roughage. Carbohydrate digestion rates were estimated using the in vitro gas production technique and the cumulative gas production kinetics were analyzed using the bicompartmental logistic model. The parameters values of ruminal degradation kinetics were generated using the R statistical program with the Gauss-Newton algorithm and then subjected to analysis of variance and regression (when necessary) according to a completely randomized experimental design with five treatments and five replications. Upon carbohydrate fractionation of ingredients and experimental diets, it was observed that corn grain and corn silage presented the highest levels of total carbohydrates (TC), with values of 128.3 and 464.8 g kg-1 dry matter (DM) in fraction B2, respectively. Lower TC content was found for soybean meal and crambe cake (CC). There was a predominance of fractions A + B1 in the ingredients and experimental diets. The B2 fraction decreased in the diets with the inclusion of the CC protein, and CC presented the highest C fraction. Protein fractionation (g kg-1 DM and g kg-1 crude protein - CP), the ingredients and diets showed a higher proportion of fractions A and B1 + B2. In in vitro degradation, the diet without CC (0 g kg-1 DM) showed the highest final cumulative gas production (365.04 mL g-1 of incubated DM), while the CC presented the lowest volume (166.68 mL g-1 of incubated DM). The gas volume of non-fibrous carbohydrate fermentation and fibrous carbohydrate degradation rate exhibited a quadratic effect according increasing levels of CC (Pmax = 265.8 g kg-1 DM and Pmin = 376.3 g kg-1 DM, respectively). The lag time and final gas volume showed a decreasing linear effect with increasing levels of CC protein. The degradation rate of non-fibrous carbohydrates and the final volume of fibrous carbohydrates did not differ. Replacing soybean meal protein with CC protein at the level of 250 g kg-1 of dry matter in diets formulated for feedlot lambs leads to good profiles of ruminal fermentation kinetics with respect to the degradation of fibrous and non-fibrous carbohydrates.

The reduction in the quality, consumption, and digestibility of forage can cause a decrease in animal performance, resulting in losses to the rural producer. Thus, it is important to monitor these characteristics in forage plants to devise strategies or practices that optimize production systems. The aim of this study was to develop and validate prediction models using near-infrared spectroscopy (NIRS) to determine the chemical composition of Tifton 85 grass. Samples of green grass, its morphological structures (whole plant, leaf blade, stem + sheath, and senescent material) and hay, totaling 105 samples were used. Conventional chemical analysis was performed to determine the content of oven-dried samples (ODS), mineral matter (MM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), cellulose (CEL), hemicellulose (HEM), and in vitro dry matter digestibility (IVDMD). Subsequently, all the samples were scanned using a Vis-NIR spectrometer to collect spectral data. Principal component analysis (PCA) was applied to the data set, and modified partial least squares was used to correlate reference values to spectral data. The coefficients of determination (R2) were 0.74, 0.85, 0.98, 0.75, 0.85, 0.71, 0.82, 0.77, and 0.93, and the ratio of performance deviations (RPD) obtained were 1.99, 2.71, 6.46, 2.05, 2.58, 3.84, 1.86, 2.35, 2.09, and 3.84 for ODS, MM, CP, NDF, ADF, ADL, CEL, HEM, and IVDMD, respectively. The prediction models obtained, in general, were considered to be of excellent quality, and demonstrated that the determination of the chemical composition of Tifton 85 grass can be performed using NIRS technology, replacing conventional analysis.