Abstract This study assessed the association between encapsulated nitrate product (ENP) and monensin (MON) to mitigate enteric methane (CH4) in vitro and possible effects on ruminal degradability, enteric fermentation characteristics, and microbial populations. Six treatments were used in randomized complete design in a 2×3 factorial arrangement with two levels of MON (0 and 2.08 mg/mL of buffered rumen fluid) and three levels of ENP (0, 1.5 and 3.0%). The substrate consisted of 50% Tifton-85 hay and 50% concentrate mixture (ground corn and soybean meal). ENP replaced soybean meal to achieve isonitrogenous diets (15% CP). No ENP×MON interaction was observed for any measured variable (P > 0.05) except for the relative abundance of F. succinogenes (P = 0.02) that linearly increased in diets with MON when ENP was added. The ENP addition decreased CH4 production (P < 0.01) without affecting (P > 0.05) truly degraded organic matter nor the relative abundance of methanogens. Hydrogen production was reduced with MON (P = 0.04) and linearly decreased with ENP inclusion (P = 0.02). We concluded that use of nitrate is a viable strategy for CH4 reduction, however, no additive effect of ENP and MON was observed for mitigating CH4 production.

ABSTRACT. Feeding behavior analysis provides information about the relationships between animals and pastures. Therefore, this review aims to describe some aspects of the feeding behavior profiles of both sheep and goats in grazing systems. The structure of the pasture is a key factor in the feeding behavior of grazing animals. The amount of feed consumed in a given period of time is affected by the number of meals, duration and velocity of swallowing, changes in grazing time, bite rate, bite weight, and quality of ingested forage. The different phenological stages of forage also influence the animals’ strategies to optimize their intake, which consequently changes their behavioral activities. Sheep and goats tend to be more selective than cattle, and young animals are more selective than older animals; this selectivity characteristic is one of the most important aspects to be observed in pasture management. According to the degree of selectivity, the animals will intake forages of higher or lower nutritive quality. In addition, the intensity and distribution of their daily activities (grazing, ruminating, and resting) are influenced by several factors, such as the availability and nutritive value of the pasture, its management, the animal activity in the group, and the predominant climatic conditions of the region.

Resumo O objetivo deste estudo foi avaliar os efeitos da infecção por Trichostrongylus colubriformis nos parâmetros hemato-bioquímicos, digestibilidade aparente dos nutrientes e balanço de nitrogênio de cordeiros Santa Inês. Dezoito cordeiros Santa Inês, de três meses de idade e castrados (16,9 ± 1,43 kg de peso corporal), foram distribuídos aleatoriamente em dois tratamentos experimentais: infectados com T. colubriformis (I, n = 9) e não infectados (U, n = 9). O grupo I recebeu um total de 45.000 larvas L3 de T. colubriformis (5.000 larvas infectantes, três vezes por semana, durante três semanas). Durante o período experimental, foram avaliadas as variáveis sanguíneas, digestibilidade e balanço de nitrogênio. Os cordeiros I apresentaram redução de eritrócitos, hemoglobina, hematócrito, volume corpuscular médio e proteínas totais, além de aumento de plaquetas e eosinófilos, quando comparados ao grupo U (p< 0,05). Contudo, exceto para proteínas totais, os valores estavam dentro do intervalo normal para a espécie. Além disso, a digestibilidade da matéria seca e da matéria orgânica foi menor no grupo I de cordeiros (p = 0,08). Os presentes achados destacam que a infecção por T. colubriformis teve potencial para prejudicar alguns parâmetros hemato-bioquímicos, bem como a digestibilidade aparente da dieta, o que poderia afetar a produtividade dos cordeiros.

Abstract This study aimed to evaluate the effects of Trichostrongylus colubriformis infection on the hemato-biochemical parameters, feed digestibility, and nitrogen balance in Santa Inês lambs. Eighteen three-month-old Santa Ines castrated male lambs (16.9 ± 1.43 kg of body weight) were randomly distributed in two experimental treatments: infected with T. colubriformis (I, n = 9) and uninfected (U, n = 9). The I group received a total of 45,000 L3 larvae of T. colubriformis (5,000 infective larvae, three times per week, for three weeks). During the experimental period, blood, feed digestibility, and nitrogen balance were evaluated. The I lambs showed a reduction in erythrocytes, hemoglobin, hematocrit, mean corpuscular volume, and total proteins, as well as an increase in platelets and eosinophils compared to those in the U group (p < 0.05). With the exception of total protein content, these values were within the normal range for the species. Furthermore, lower dry matter and organic matter digestibility were observed in the I lambs (p = 0.08). The present findings highlight that T. colubriformis infection has the potential to impair some hemato-biochemical parameters as well as feed digestibility in lambs, which could affect their productivity.

Resumo: O objetivo deste trabalho foi avaliar três espécies de gramíneas tropicais quanto à produção de metano (CH4) in vitro e à degradabilidade da matéria orgânica, para determinar as relações entre a qualidade nutritiva das gramíneas e a produção de CH4. O capim-colonião (Megathyrsus maximus), o capim-braquiarão (Urochloa brizantha) e o capim-decumbens (Urochloa decumbens) foram avaliados. O capim-braquiarão apresentou os maiores teores de matéria orgânica, fibra em detergente neutro, fibra em detergente ácido e lignina, e o menor teor de proteína bruta. O capim-decumbens apresentou os maiores teores de hemicelulose e de nitrogênio em fibra de detergente neutro, além do menor teor de celulose. O capim-colonião e o capim-decumbens apresentaram maior produção total de gases do que o braquiarão. Além disso, o capim-colonião apresentou maior produção de CH4, e o capim-braquiarão, menor degradabilidade verdadeira da matéria orgânica e reduzido fator de partição, em comparação ao capim-decumbens. Maior produção de CH4 foi verificada em casos em que os valores de hemicelulose e fator de partição foram menores. A qualidade nutricional e a produção de CH4 das forragens avaliadas podem ser utilizadas como parâmetros a serem empregados, que visem a sustentabilidade da produção de ruminantes.

Abstract: The objective of this work was to evaluate three tropical forage species for their in vitro methane (CH4) production and organic matter degradability, in order to determine the relationships between forage grass nutritive quality and CH4 production. Guinea grass (Megathyrsus maximus), palisade grass (Urochloa brizantha), and signal grass (Urochloa decumbens) were evaluated. Palisade grass showed the highest organic matter, neutral detergent fiber, acid detergent fiber, lignin, and lower-crude protein content. Signal grass had the highest values for hemicellulose and neutral detergent fiber-nitrogen, and the lowest-cellulose content. Guinea grass and signal grass showed a higher-total gas production than palisade grass. Besides, Guinea grass showed an increased CH4 production, and palisade grass showed lower value for truly degraded organic matter, and reduced partitioning factor, in comparison to signal grass. An increased CH4 production was observed in cases of lower hemicellulose and paratitioning factor. The nutritive value and CH4 production of forages may be employed as parameters, aiming at the sustainability of ruminant production.

RESUMO: A adubação com Selênio (Se) em pastagem para a biofortificação de alimentos de origem animal tem sido realizada em solos com baixo Se. O objetivo foi avaliar o aumento no conteúdo de Se na biomassa de Brachiaria spp. com aplicação de ureia revestida com Se. O experimento foi conduzido em casa de vegetação em Latossolo Amarelo. O delineamento foi em blocos casualizados com quatro repetições em esquema fatorial com dois cortes e seis doses de Se (0, 10, 20, 40, 80 e 160gha-1). A Brachiaria brizantha demonstrou ausência de mudanças em altas e perigosas doses de Se sem alterar a atividade da enzima antioxidante glutationa peroxidase. Com isso, concluiu-se que seu enriquecimento com ureia revestida é obtida com 34,5gha-1 de Se.

ABSTRACT: Selenium (Se) fertilization in grazing to biofortification of animal products have been carried out in low Se soils. The objective of this study was to increase the Se content in the biomass of Brachiaria spp.with urea coated with Se. The experiment was performed in a typical Hapludox soil under greenhouse conditions. A completely randomized block design with four replicates in a factorial structure with two cuts and six Se doses (0, 10, 20, 40, 80, and 160gha-1) was used. The Brachiaria brizantha demonstrated the absence of changes in higher harmful doses without modifying the activity of glutathione peroxidase enzyme. We concluded that enrichment of Brachiaria brizantha with coated urea is obtained with 34.5gha-1of Se.