This study evaluated the dry matter production and chemical composition of Brachiaria forage grasses in the offseason after corn harvest in integrated crop-livestock system. The experiment was conducted at the Federal Institute of Goiás, Rio Verde Campus, using a randomized complete block experimental design, with four replications. The treatments consisted of the forages: Brachiaria brizantha cv. Marandu; Brachiaria brizantha cv. Xaraes; Brachiaria brizantha cv. Piata; Brachiaria brizantha cv. MG-4; Brachiaria decumbens and Brachiaria ruziziensis, intercropped in oversown corn for implantation of integrated crop-livestock system. The results showed that intercropping corn with Brachiaria grasses favors the production of high-quality forage in the offseason, and the cultivars of Brachiaria brizantha and Brachiaria decumbens showed higher dry matter production. And cultivars of Brachiaria brizantha (Marandu palisadegrass, Xaraes palisadegrass and Piata palisadegrass) are the most suitable for presenting food of better quality, compared with Brachiaria brizantha cv. MG-4, Brachiaria decumbens and Brachiaria ruziziensis.

SUMMARY Sunflower as silage is an alternative to be used in the off-season, when water shortage makes traditional crops unfeasible. However, exclusive sunflower silages have levels above 70 g/kg DM ether extract, which may impair ruminal fermentation. Thus, ensiling sunflower with tropical forages can bring benefits to the quality of the silage. This study evaluated the fermentation profile and nutritional value of sunflower silage with cultivars of Urochloa brizantha in the off-season. This was a completely randomized experimental design with four replications. The treatments were composed of the sunflower silage with and without addition of cultivars of Urochloa brizantha in the ensiling process: sunflower silage; sunflower silage + 30% Marandu palisadegrass; sunflower silage + 30% Xaraes palisadegrass; sunflower silage + 30% Piata palisadegrass and sunflower silage + 30% Paiaguas palisadegrass, totaling 20 experimental silos. The addition of the cultivars of Urochloa brizantha to sunflower silage contributed to improve the fermentation profile and nutritional value of the silages. Silages with 30% Piata and Paiaguas palisadegrass showed higher levels of CP and lower levels of ADF and lignin, and these cultivars are the most recommended for ensiling with sunflower.

Os sistemas silvipastoris é uma modalidade dos sistemas agroflorestais, onde a produção animal, forrageira e árborea encontra-se em consórcio na mesma área, no mesmo tempo. A maior parte da produção da pecuária bovina no Brasil baseia-se na utilização de pastagens. No Brasil, há mais de 100 milhões de hectares com pastagens cultivadas, cerca de 80% dessas pastagens encontram-se em algum grau de degradação. Uma alternativa para a recuperação dessas pastagens de forma sustentável e o uso de sistemas silvipastoris. Entretanto os sistemas sombreados são muito dinâmicos e podem modificar a estrutura do pasto de forma significativa quanto a quantidade e a qualidade da forrageira produzida com reflexos na produção animal,  principalmente em razão da competição por luz, água e nutrientes.

Although belonging to the same species, different Brachiaria brizantha varieties used for pasture vary significantly in their morphological structure. Therefore, this study starts from the central hypothesis that the defoliation dynamics during the period of occupation by animals in pastures formed by Brachiaria brizantha under rotational stocking varies among cultivars during the year. The experimental design used was randomized blocks with three treatments and three repetitions, with the cultivars consisting of Brachiaria brizantha cv. Xaraés, BRS Paiaguás, and Ecótipo B4. The defoliation patterns during the grazing periods were estimated using the marked tiller technique. Despite alterations in the tiller and forage mass components in the wet and dry seasons, no variations were observed in the tiller defoliation dynamics and the respective structural components. In the wet season, the area grazed only once was greater for BRS Paiaguás compared to the other two cultivars, but the other areas representing the grazing horizons were equally exploited among the grass varieties during the year. Therefore, based on the defoliation dynamics of pastures in Brazil’s tropical climate, it is possible to suggest that pastures formed by grasses with different structures and growth habits can be submitted to similar management strategies without impairing the forage canopy exploitation by the animals.

The aim of this study was to evaluate the use of different mathematical models to describe the growth of lambs during the pre-weaning phase and the effect of sex on their growth curve. Data from 51 lambs (26 males and 25 females) with a genetic constitution of at least 50% Santa Inês breed were used. Lamb weight was monitored during the entire pre-weaning phase (91 days) by weighing the animals weekly on a scale suitable for sheep, to draw the body-weight growth curve. The adequacy of the models was evaluated by the coefficient of determination, simultaneous F-test for parameter identity, concordance correlation coefficient, root mean square error of prediction and decomposition of the mean square error of prediction. Pairwise mean square error of prediction analysis and delta Akaike information criterion were used to compare the models in terms of accuracy and precision. The evaluation of the adequacy of the tested models showed that the data predicted by the linear, quadratic and exponential models were similar (P > 0.05) to the observed data. In contrast, the monomolecular model generated predictions that could not be accepted as true. The linear and quadratic models showed better accuracy and precision. The first-degree linear model should be preferred over the other studied models to describe growth of sheep in the preweaning phase. Males and females exhibited distinct growth patterns.

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.

The present work aims to evaluate the morphological and structural characteristics of Brachiaria brizantha cultivars in the system of grazing in the intermittent stocking. The experiment was conducted at EMBRAPA -Beef Cattle. The experimental delineation used was a randomized block with three treatments and three repetitions. The treatments were constituted by grasses of the same species (Brachiaria brizantha) composed by cv. Xaraé s, BRS Paiaguá s, and the ecotype B4. On the heights of post-grazing, it was observed an interaction between seasons of the year and cultivars. It was observed that the leaf appearance rate (LAR) was higher in the cv. BRS Paiaguá s, in relation to the other pastures. The leaf elongation rate (LER) was higher in perforations of the ecotype B4. In the winter, it was registered the lowest values of leaf area index (LAI), LAR, and LER, and, as a consequence, impact in a higher leaf life duration. Although there were some structural variations between tropical climate pastures, it was possible to verify that the phenotypic plasticity of these pastures presented the same behavior, once it suffered a higher influence of abiotic factors. Therefore, all the pastures of B. brizantha converged to the same LAI indicating high phenotypic plasticity.

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