In-vitro screening of Kalahari browse species for rumen methane mitigation

The nutritional value of browse foliage from the Thorny Kalahari Dune Bush veld of South Africa is not characterized. Most of this browse species is rich in tannin, but still palatable, and is consumed by ruminants during the dry season, as well as having a role to play in mitigating enteric methane emission from ruminants. In this study, the rumen methane mitigation potential of 19 browse species foliage collected from the Thorny Kalahari Dune Bush veld, was analyzed in terms of chemical composition, in vitro fermentation, digestibility and methane production. In vitro gas and methane production and organic matter digestibility (IVOMD) were determined by using rumen fluid collected, strained and anaerobically prepared. A semi-automated system was used to measure gas production (GP) from each browse species by incubating 400 mg samples in a shaking incubator at 39 °C with or without inclusion of 400 mg of polyethylene glycol (PEG). Data for all the parameters collected were statistically analyzed using the SAS (9.0) general linear model (GLM) procedure, and differences between foliage species were determined using Duncan’s multiple-range test. Acacia luederitziiand Monechma incanumshowed the best potential for decreasing methane production by up to 90 % after 48 h of incubation. The secondary components (mainly tannins) of the browse species appeared to have a significant effect on volatile fatty acids (VFA), methane and gas production as judged by the comparison of samples incubated with or without PEG inclusion. The substantial amount of crude protein (CP) content coupled with their anti-methanogenic effect during fermentation would make these browses a potential mitigation option for small scale farmers and pastoralists in sub-Sahara Africa. However, it is also very important that systematic and strategic supplementation in a mixed diet should be looked at as the way forward in terms of best utilization

Características bromatológicas, fermentativas e população de leveduras de silagens de cana-de-açúcar acrescidas de ureia e aditivos absorventes de umidade Fermentative and bromatological characteristics and population of yeast of sugarcane silage enriched with urea and with additive absorbent of humidity

Este trabalho foi conduzido com o objetivo de avaliar os efeitos da utilização de aditivos sobre as características fermentativas e bromatológicas e a população de leveduras da silagem de cana-de-açúcar. O experimento foi conduzido em delineamento inteiramente casualizado, com quatro repetições. Foram testadas diferentes quantidades de aditivos à cana-de-açúcar no momento da ensilagem (com base na matéria verde da forragem): 1,5% ureia; 0,5 ureia + 4% de milho; 0,5 ureia + 4% de mandioca desidratada; 1,5% de amireia e cana-de-açúcar controle. A cana-de-açúcar da variedade RB-72454, com 18 meses de rebrota, foi armazenada em silos experimentais de concreto com capacidade de 500 kg durante 180 dias. Foram avaliados os teores de matéria seca, proteína bruta, fibra em detergente neutro, fibra em detergente ácido, carboidratos não-fibrosos, cinzas, pH, nitrogênio amoniacal e lignina e a contagem de leveduras. O maior teor de matéria seca e o menor teor de fibra em detergente neutro são obtidos com a associação de ureia e milho, que melhora o padrão fermentativo na silagem.<br>The research aimed to evaluate the use of additives on the fermentative and bromatological characteristics and the population of yeast of the sugarcane silage. The experiment was carried out in a complete randomized design with four replicates. It was tested different amount of additives added to the sugarcane silage at ensiling (based on the forage fresh matter) which were the following: urea 1.5%; urea 0.5% + corn meal 4%; urea 0.5% + dehydrated cassava 4%; starea 1.5%; sugar cane only. Sugarcane variety RB-72454, at 18 months of regrowth was stored for 180 days in experimental concrete silos (500 kg capacity). Contents of ash, pH, dry matter, crude protein, neutral detergent fiber, acid detergent fiber, non fiber carbohidrate, ammonium nitrogen, lignin and count of yeasts were evaluated. The greatest contents of dry matter and the lowest contents of neutral detergent fiber are observed in the urea-corn meal treatment, which improves fermentative pattern of the silage

Parâmetros ruminais e desaparecimento da MS, PB e FDN da forragem em bovinos suplementados em pastagem na estação seca Ruminal parameters and DM, CP and NDF forage disappearance of supplemented steers under grazing, during the dry season

O trabalho foi conduzido com o objetivo de determinar o efeito de suplementos concentrados com diferentes degradabilidades da proteína (alta-70%, média-50% e baixa-30%) e o efeito da quantidade dos mesmos (0,5, 1,0 e 1,5 kg de MS/dia) sobre os parâmetros ruminais (pH e N-NH3) e o desaparecimento da MS, PB e FDN da forragem em bovinos pastejando Brachiaria brizantha cv. Marandu no período da seca. Foram utilizados 10 novilhos canulados no rúmen com peso médio de 354 kg em um esquema fatorial com três repetições (blocos). Não houve influência da degradabilidade protéica e/ou quantidade de suplemento sobre os valores de pH ruminal, que variaram de 6,38 a 6,91. As concentrações de N-NH3 ruminal foram crescentes com o aumento da degradabilidade do suplemento e quantidade de suplementação, sendo maiores uma hora após o fornecimento do suplemento e decrescendo até cinco horas. O tratamento-controle apresentou concentrações de N-NH3 consideradas adequadas para boa atividade microbiana. Não houve efeito da degradabilidade protéica do suplemento ou quantidade na degradação ruminal da MS, PB e da FDN da forragem, não diferindo do tratamento-controle. Quanto aos parâmetros de degradação ruminal da forrageira, os valores médios foram de 29% para a fração solúvel da PB e de de 47% para a insolúvel potencialmente degradável, com taxa de degradação de 4,88%. Para FDN, a fração potencialmente degradável foi de 56% e a taxa de degradação, de 4,33%.<br>The objective this work was to evaluate the effect of protein supplements with three degradability levels (high-70%, medium-50% and low-30%) at three levels (0.5, 1.0 and 1.5 kg/day) on the ruminal pH, N-NH3 and DM, CP, NDF degradability of forage fed steers grazing Brachiaria brizantha cv. Maradu, during the dry season. The experiment design was a randomized complete block with three replications (grazing periods) and the supplement treatments were arranged in a factorial 3x3. Ten rumen-fistuled steers with 354 kg live weight, were used. There was not effect of the protein degradability and/or level of supplementation on the ruminal pH values with variety from 6.38 to 6.91. The concentrations of N-NH3 ruminal increased as the degradability and levels of supplementation increased, and were higher one hour after feeding, and decreasing until five hours. The control showed N-NH3 concentrations within the limits considered adequate for a good microbial activity. There was no effect of the protein degradability and/or level of supplementation on the CP and NDF ruminal degradation of forage, and these values were not different from the control, where 29% CP constituted the soluble fraction and 47% was the insoluble potentially degradable, with the rate of degradation of 4.88%. NDF was 56% potentially degradable at the rate of 4.33%