We investigated the effects of nitrogen (N) fertilisation levels on structural, productive and morphogenetic traits, chlorophyll content, tiller number (TN) and macronutrient uptake capacity of three Panicum maximum cultivars (BRS Zuri, BRS Quênia and BRS Tamani). The experiment was laid out in a completely randomised design with five N doses (0, 50, 100, 200, and 400 mg dm ⁻³ ). The concentration of chlorophyll increase linearly with increasing N doses in BRS Zuri. There was a significant interaction effect between cultivars and N doses on forage mass (FM), forage yield (FY), TN and the uptakes of nitrogen, potassium, phosphorus, calcium, magnesium and sulfur. The BRS Zuri had the highest FY and FM independent of the applied N dose. In the dose range of 200 and 400 mg dm ⁻³ of N, there was no increase in the productive performance of BRS Tamani and BRS Quênia, which were similar to each other. N fertilisation increased TN. Higher N doses in the soil translated into greater N uptake by the grasses. Nitrogen application to the soil can increase the production and structural indices of Panicum maximum cultivars and increases grass growth, but its concentration must consider the productive capacity of the plant for this nutrient.

Therefore, the present study examines the hypothesis that biometric measurements can be used to predict live weight in crossbred lambs. The objective was to propose a mathematical model to predict lamb body weight based on biometric measurements.

The aim of this study was to predict carcass traits of Santa Inês lambs finished in tropical pastures by using biometric measurements. Data originated from two experiments involving 56 lambs (32 in experiment I and 24 in experiment II). In both experiments, the sheep were finished in that were finished in pastures of Panicum maximum and Brachiaria brizantha, experiment I being conducted in the rainy season and experiment II in the dry season. The following biometric measurements were recorded before slaughter: body length (BL), withers height (WH), rump height (RH), thorax width (TW), rump width (RW), chest width (CW), heart girth (HG), thigh circumference (TC), rump circumference (RC) and leg length (LL), in addition to live weight at slaughter (SW). After slaughter, hot carcass weight (HCW), cold carcass weight (CCW) and the weights of primal cuts (shoulder, neck, loin, leg and rib) were recorded. In the equations generated to predict SW, HCW and CCW, R² ranged from 0.58 to 0.91 and the measurements of WH, TC, CW, HG and RW were the most relevant. In the equations developed to predict the weight of primal cuts, in turn, R² ranged from 0.26 to 0.99. In these models, SW, BL, CW, TC, LL and HG explained most of the variation in the weight of primal cuts. Biometric measurements can be used to accurately and precisely predict HCW, CCW and the weight of primal cuts from the carcass of Santa Inês sheep finished in tropical pastures, since the equations presented R² and correlation coefficient and agreement above 0.8.

It was aimed to evaluate the use of cottonseed cake (CSC) as a source of physically effective neutral detergent fibre (peNDF) to replace corn silage (CS) in diet of feedlot‐finished cattle. The design used was completely randomised, with 2 treatments (30% CSC and 30% CS) and 12 replications. There was interaction between fibre source and nutrient in the material retained in the Penn State Particle Separator. The highest concentrations ( P = 0.0001) of peNDF and the in vitro digestibility of peNDF (DpeNDF) were for CSC. There was a higher ( p < 0.05) dry matter intake (DMI) and neutral detergent fibre (NDF) intake (NDFI) by the animals on the CSC diet. The CSC‐fed steers showed higher ( P = 0.0001) final body weight (BW) and total weight gain. The steers fed CSC showed a longer ( P = 0.0001) feeding time, feed efficiency, and lower rumination time ( P = 0.0001) and rumination efficiency ( P = 0.0001). There were positive correlations between the variables: rumination time × intake, rumination time × NDFI and peNDF × DpeNDF. It was observed that there was a negative correlation between the variables: rumination time × peNDF, rumination time × DpeNDF, NDFI × peNDF, and NDFI × DpeNDF. Cottonseed cake is an alternative source of peNDF for feedlot beef cattle.

This study examined fermentation rates and kinetics of sheep rations based on combinations of elephant grass hay, gliricidia (Gliricidia sepium) hay or silage, soybean meal and corn meal using in vitro techniques. Three rations were prepared, namely: Control (elephant grass hay + soybean meal + corn meal); gliricidia hay (elephant grass hay + soybean meal + corn meal + gliricidia hay); and gliricidia silage (elephant grass hay + soybean meal + corn meal + gliricidia silage). A fixed ratio of roughage:concentrate of 55:45 was maintained for all rations, which were isocaloric and designed to support sheep gains of 200 g/day. The gliricidia replaced 57.6% of the soybean meal in the rations containing gliricidia and 81.8% of the elephant grass hay. Fermentation rates and kinetics, in vitro dry matter digestibility (IVDMD) and degradability of the rations were evaluated. Rations containing gliricidia as both hay and silage had higher (P<0.05) IVDMD than the Control ration (67.8 and 66.2 vs. 59.8%). The degradability of the ration containing gliricidia hay was higher (P<0.05) than that of the gliricidia silage ration (57.8 vs. 50.5%), whereas the Control showed an intermediate value (54.4%). The ration containing gliricidia hay and the Control produced more gas in the first 24 h than the ration containing gliricidia silage, and the gliricidia hay ration showed the shortest colonization time. Peak gas production occurred for the ration with gliricidia silage later than for the other rations. The study showed that substituting soybean meal with preserved gliricidia can result in higher digestibility of sheep rations. Feeding studies with animals are now warranted to verify these laboratory findings.

This study examined the use of the Gompertz, Groot, monomolecular, Richards and two-compartment-logistic mathematical models to investigate the kinetics of in vitro gas production of diets composed of combinations of Gliricidia hay or silage. In addition, the effects of Gliricidia hay or silage inclusion on the in vitro cumulative gas production of these diets were evaluated. Rumen fermentation kinetics were analyzed by the in vitro cumulative gas production methodology. The model parameters were estimated using the Gauss Newton method, with the exception of the Richards model, which was used by Marquardt’s algorithm. Model fit was assessed using the determination coefficient, F test for parameters identity, concordance correlation coefficient, root mean square error of prediction, and decomposition of mean square error of prediction into mean error, systematic bias and random error. The models were compared for accuracy (pairwise mean square error of prediction) and precision (delta Akaike’s information criterion). All model evaluation and comparison statistics were calculated using Model Evaluation System software version 3.2.2. The Groot and Richards models did not differ from each other (P>0.05) and were the most precise and accurate (P<0.05). Therefore, the Groot model was selected due to its better accuracy and precision and easier access to the parameters. The inclusion of Gliricidia silage in the diet resulted in an increase in the time to obtain the maximum rate of degradation and in the time after incubation when half of the asymptotic level was reached. The Groot model is recommended to estimate the average curve. Dietary inclusion of Gliricidia silage alters the gas production curve due to the longer time required for the diet to reach the maximum rate of degradation, this can increase the time the diet remains in rumen and promote a reduction in the consumption.