Effects of the inclusion of Moringa oleifera seed on rumen fermentation and methane production in a beef cattle diet using the rumen simulation technique (Rusitec).

Moringa oleifera seeds are currently being used as a livestock feed across tropical regions of the world due to its availability and palatability. However, limited knowledge exists on the effects of the raw seeds on ruminant metabolism. As such, the rumen stimulation technique was used to evaluate the effects of substituting increasing concentrations of ground Moringa seeds (0, 100, 200 and 400 g/kg concentrate dry matter (DM)) in the diet on rumen fermentation and methane production. Two identical, Rusitec apparatuses, each with eight fermenters were used with the first 8 days used for adaptation and days 9 to 16 used for measurements. Fermenters were fed a total mixed ration with Urochloa brizantha as the forage. Disappearance of DM, CP, NDF and ADF linearly decreased (P<0.01) with increasing concentrations of Moringa seeds in the diet. Total volatile fatty acid production and the acetate to propionate ratio were also linearly decreased (P<0.01). However, only the 400 g/kg (concentrate DM basis) treatment differed (P<0.01) from the control. Methane production (%), total microbial incorporation of 15N and total production of microbial N linearly decreased (P<0.01) as the inclusion of Moringa seeds increased. Though the inclusion of Moringa seeds in the diet decreased CH4 production, this arose from an unfavourable decrease in diet digestibility and rumen fermentation parameters.

Predicting fecal nutrient concentrations and digestibilities and growth performance in feedlot cattle by near-infrared spectroscopy.

Fecal nutrients and apparent total tract digestibility (ATTD) were predicted using near-infrared spectroscopy (NIRS) of feces collected from the pen floor or the rectum of feedlot cattle in 2 studies, and pen floor samples were assessed for their ability to predict NE, ADG, and G:F. In study 1, 160 crossbred beef steers in 16 pens (4 pens per treatment) were fed dry-rolled barley or wheat (89% of diet DM) processed at 2 levels. Study 2 utilized 160 crossbred beef steers in 20 pens (5 pens per treatment) that were fed dryrolled barley with 4 levels of barley silage (0%, 4%, 8%, and 12% of diet DM). Both studies fed steers to a target weight of 650 kg. Differences in composition of feces collected from the rectum and the pen floor of a subset of steers (3 to 7) were examined. Fecal pats from the pen floor of each pen were collected throughout the feeding period and composited by pen. Except for DM, which was higher ( 0.01) in pen floor than rectal fecal samples, there were minimal differences in fecal constituents between collection methods. In study 1, interactions between grain type and processing index ( ≤ 0.05) were observed, with a reduction in DM, OM, and starch and an increase in NDF and ADL concentrations being associated with more extensively processed wheat than barley. As grain was more extensively processed, ATTD of all nutrients increased ( 0.01). In study 2, fecal ADF and ADL linearly increased ( 0.01) with increasing silage in the diet, whereas fecal DM and N linearly decreased ( 0.01). Digestibility of all nutrients except starch linearly decreased ( 0.01) with increasing silage. Apparent total tract digestibility of GE predicted using NIRS was related to NEg of the diets as estimated by performance for the wheat-fed steers in study 1 ( = 0.58, = 0.03) and those fed increasing silage in study 2 ( = 0.43, < 0.01). Similarly, observed ADG could be predicted using NIRS for steers fed wheat in study 1 ( = 0.48, = 0.05) and silage in study 2 ( = 0.40, < 0.01), but G:F could not. Using NIRS of feces collected from multiple cattle off the feedlot pen floor demonstrated potential for predicting growth performance of finishing cattle. However, grain type and stage of maturity of the cattle impacted the predictability of equations. Increasing the sample size and sampling frequency may be necessary to improve predictions.