It is estimated that approximately 47% of the world’s ruminant meat and milk is produced in tropical and subtropical regions, with pasture comprising the main food base of these animals. Nitrogen fertilisation is an essential practice for the maintenance of pasture productivity, considering that a deficiency of this nutrient is a primary factor in triggering pasture degradation. In addition to directly influencing the photochemical and biochemical phases of photosynthesis, nitrogen stimulates enzyme activity and the synthesis of enzymes responsible for fixing CO2 (Rubisco in C3 plants and phosphoenolpyruvate carboxylase in C4 plants), thus increasing the efficiency of atmospheric CO2 capture. All of these physiological processes are easily observed macroscopically in the characteristics of forage plants. This review examines the impact of nitrogen fertilisation in tropical pastures on the main components of production systems (soil, plants and animals), describes the results obtained in different situations and highlights the most efficient ways of producing meat without environmental impacts.

The slaughtering process has been the target of criticism, and the sanity of the facilities for not providing the necessary hygiene for the slaughtering and meat storage procedure. The objective was to expose the level of knowledge of the people involved in the slaughter process and meat consumers in Itabi / SE municipality through a form with directed questions that aimed to expose the degree of knowledge of them. Of the marchers 54.0% remain in the activity due to lack of opportunity, 63.0% of the total interviewed believe that working conditions are adequate and only 36.4% do not agree with the way animals are treated during the whole process. until the slaughter. Consumers prefer meat sold at the fair (65.7%), of the total respondents 88.24% would be willing to pay a higher price for meat where the animal was slaughtered in a stress-free environment for the animal, as 80% confirmed that they reduced consumption if they learned that slaughter practices were used. The educational level directly influences the degree of knowledge about the risks of contaminated food consumption, as well as the lower the educational level the lower the precaution to the animal integrity, the whole procedure and also after slaughter in the meat handling.

Objetivou-se avaliar o efeito da dieta líquida no desempenho de bezerros leiteiros e nos custos operacionais da fase de cria. O experimento foi conduzido, entre os meses de novembro e dezembro de 2015. Foram utilizados 10 animais, distribuídos em delineamento inteiramente casualizado com dois tratamentos (leite integral bovino ou sucedâneo) e cinco repetições. As variáveis de desempenho avaliadas foram: peso, ganho médio diário (GMD), ganho de peso total (GPT), e medidas biométricas (altura de cernelha, comprimento corporal, perímetro torácico, largura de garupa e de peito). Os indicadores econômicos analisados foram: os custos totais com a dieta líquida, com o concentrado e os custos com a mão de obra. Foi avaliado os encargos e impostos, despesas diversas, receita bruta, custo de oportunidade, lucro operacional e lucro total. Foi observado efeito da dieta liquida para peso final, GMD e GPT, os animais que receberam leite integral tiverem GMD 38% superior. Não houve efeito de tratamento para as medidas biométricas. O item de maior participação nos custos de produção foi a dieta 75% e 70% para leite e sucedâneo, respectivamente, seguido pelo custo com mão de obra, o leite tornou o sistema mais oneroso. A receita bruta estimada foi maior para os animais que receberam leite integral (548,5 vs 353,5 US$). O balanço econômico foi negativo para ambas as dietas. Bezerros leiteiros recebendo leite bovino na fase de cria na dieta líquida, apresentam um desempenho superior aos que recebem sucedâneo. Mesmo com desempenho superior, o leite integral tornou o sistema mais oneroso.

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.

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.

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.

Para a produção de pequenos e grandes ruminantes em regiões de clima tropical, torna-se necessário buscar fontes de alimentos que supram a necessidade dos animais em pastejo ou plantas forrageiras suplementares, agindo como uma forma estratégica de potencializar a produção animal nessas regiões. O sorgo apresenta características favoráveis para regiões de clima tropical, pois exibe rápido estabelecimento, resistência ao déficit hídrico e, comparado às demais culturas, apresenta baixa exigência em fertilidade do solo, sendo uma excelente alternativa para regiões de clima tropical, em que há baixos níveis de fertilidade natural, além da estacionalidade de produção de forragem. Apesar de ser uma cultura de ampla aptidão, o potencial do sorgo é pouco explorado, pois é possível encontrar linhagens com potencial para a produção de grão, materiais forrageiros para silagem e pastejo. Diante disso, foi elaborada uma revisão com os aspectos relacionados ao potencial forrageiro do sorgo. O sorgo apresenta bons índices para a produção de animais a pasto, assim como em situações que almejam a utilização como fonte de forragem suplementar, no entanto, ainda há necessidade de maiores incentivos para a utilização desse material forrageiro na alimentação animal.

Resumo. O Brasil possui diversas espécies de capins tropicais que podem ser ensiladas. Esses capins apresentam alto potencial de produção de forragem. Todavia, a maior produção dessas gramíneas ocorre nos períodos de maior disponibilidade de fatores abióticos, o que promove à estacionalidade na produção forrageira, sendo necessário o uso de tecnologias de conservação de forragens para manter alimentos de maior qualidade em tempos de escassez. A ensilagem de capins tropicais no Brasil tem sido limitada por fatores operacionais e por questões inerentes à própria planta, pois, invariavelmente essas plantas apresentam baixos teores de matéria seca e de carboidratos solúveis, além de uma alta capacidade tamponante no momento ideal do corte. Para contornar esses problemas, temse utilizado alguns aditivos com resultados bem interessantes; porém, esta prática pode onerar ainda mais o processo produtivo. Portanto, pretende-se com esta revisão, discutir os principais entraves da produção de silagens a partir de capins tropicais, os fatores que podem alterar a qualidade da silagem e as implicações ao inserir esse tipo de volumoso na dieta de ruminantes.