An in situ technique was adopted to investigate the time-dependent ruminal degradation of chloroplast compared with recombinant DNA of Bt176 corn using conventional and quantitative PCR assays. In parallel, the Cry1Ab protein content and fragment sizes were determined by ELISA and immunoblotting techniques. Triplicate nylon bags filled with 5 g of each substrate (whole-plant isogenic, whole-pla...

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The objectives of this study were to evaluate the effects of high-moisture corn (HMC), either whole or ground, fed separately from concentrate and straw on feeding behavior, rumen fermentation, whole tract digestibility, and nitrogen balance. Twenty-four Holstein heifers (199 ± 5.5 kg BW and 157 ± 6.9 d age) housed in individual pens were assigned to 3 treatments: 1) whole (unprocessed) HMC fed...

Seventeen 350 lb (159 kg) Holstein steers were utilized to determine stability of rumen pH postmortem. Cattle were randomly assigned to two whole-corn ration treatment groups: 1) limit-fed (7.5 lb; 3.4 kg) or 2) fed ad libitum (9.5 lb; 4.3 kg). Calves were humanely euthanized, rumen fluid was collected, and pH measurements were taken at 0, 1, 2, 3, 6, 12, and 24 hours postmortem. A subset of fi...

To assess the relative contributions of microbial groups (bacteria, protozoa, and fungi) in rumen fluids to the overall process of plant cell wall digestion in the rumen, representatives of these groups were selected by physical and chemical treatments of whole rumen fluid and used to construct an artificial rumen ecosystem. Physical treatments involved homogenization, centrifugation, filtratio...

Strategies to manage metabolic hydrogen ([H]) in the rumen should be considered when reducing ruminant methane (CH4) emissions. However, little is known about the use of dietary treatments to stimulate rumen microorganisms capable of capturing the [H] available when CH4 is inhibited in vivo. The effects of the phenolic compound phloroglucinol on CH4 production, [H] flows and subsequent response...

Considerable difficulty and uncertainty can be associated with sampling through cannulas from the reticulo-rumen of the sheep. The contents are by no means homogeneous, and for some purposes relatively large samples have to be withdrawn from various places within the organ and mixed in an external container before a subsample is taken for analysis and the unused portion returned to the rumen. I...

Direct microscopic examination of the rumen and its contents shows microbial populations largely attached to feed particles in the digesta. Most feeds contain a surface layer that is resistant to attachment and therefore to digestion. Infiltration of these recalcitrant epidermal layers through damage sites or through focused enzymatic attack is essential for initiation of the digestive process....