The effects of intake of lucerne (Medicago sativa L.) and orchard grass (Dactylis glomerata L.) hay on the motility of the forestomach and digesta flow at the abomaso-duodenal junction of the sheep

Reticular contraction frequency and ruminal gas dome development in goats do not differ between grass and browse diets

In investigations of differences between ruminant species feeding on browse or grass, it is often unclear whether observed differences are animal- or forage-specific. Ruminant species have been classified as 'moose-type', with little rumen content stratification, or 'cattle-type' with a distinct rumen contents stratification, including a gas layer. To which extent putative differences in forestomach motility are involved in these patterns is unknown. Using sonography, we investigated the frequency of reticular contractions and the stratification of rumen contents in goats fed exclusively on grass hay (n = 6) or dried browse (n = 5) directly after feeding, and after another 6 and 12 h with no access to feed. The frequency of reticular contractions decreased from immediately after feeding (1.8 ± 0.3 min^-1 ) to 6 h afterwards (1.2 ± 0.2 min^-1 ) and then remained constant, with no difference between diets. A gas dome became more visible over time, but neither its incidence nor its extent differed between diets. The results are in accord with classifying goats as 'cattle-type' in terms of their digestive physiology, and they add to a growing body of evidence that differences in digestive physiology between ruminant species are more due to species characteristics than different kinds of ingested forages.

Intestinal starch disappearance increased in steers abomasally infused with starch and protein

Steers (379 +/- 10 kg) with ruminal, duodenal, and ileal cannulas were used in a 5 x 5 Latin square digestion trial to quantify and evaluate the relationship between intestinal protein supply and intestinal starch disappearance. Treatments were infusions of 0, 50, 100, 150, or 200 g/d of casein along with 1,042 g/d of raw cornstarch. Abomasal infusions were accomplished by passing tubing and a pliable retaining washer through the reticular-omasal orifice into the abomasum. Steers were fed a 93% corn silage, 7% supplement diet that contained 12% crude protein at 1.65% body weight in 12 equal portions/d. Periods lasted 17 d (12 d for adaptation, 2 d of collections, and 3 d of rest). The quantity and percentage of organic matter and protein disappearance from the small intestine increased linearly (P < 0.03) with infused casein. Greater quantities of starch disappeared with increased casein infusion (P < 0.01). The infusion of 200 g/d of casein increased small intestinal starch disappearance by 226 g/d over the control. Casein infusion did not affect the quantity or percent of organic matter, starch, or protein disappearance in the large intestine. Treatments did not change ruminal ammonia N, ruminal pH, or plasma glucose concentrations. Starch disappearance from the small intestine was increased with greater protein flow to the duodenum of steers.

Duodeno-abomasal reflux in cows with abomasal displacement

The aim of this study was to investigate abomaso-duodenal digesta transport during abomasal displacement and after surgical correction of the abomasum, using intra-abomasal bile acid concentration. In healthy cows, bile acids were found in the abomasum, indicative of duodeno-abomasal reflux being a physiological event. In cows with left abomasal displacement (LDA), right abomasal displacement (RDA) and abomasal volvolus (AV), abomasal bile acid concentration was significantly higher than in healthy control cows. This was found to be true during surgery, on the first day as well as on the third day after surgery. Abomasal bile acid concentration was significantly different between LDA, RDA and AV, with LDA, RDA and AV showing lowest, intermediate and highest values respectively. In those with LDA and RDA, abomasal bile acid concentration significantly increased from surgery to first day after surgery, and decreased from first to third day after surgery. In AV cows, however, bile acid concentration declined constantly from surgery to third day after surgery. These findings indicate pathological duodeno-abomasal reflux during abomasal displacement and after surgical correction of the abomasum. Reflux seems to differ between forms of displacement (LDA < RDA < AV) and during recovery. Pathological duodeno-abomasal reflux is discussed as a consequence of functional and/or mechanical impediments on abomaso-duodenal digesta transport during abomasal displacement and after surgical correction of the abomasum.

Effects of cereal grain silages versus alfalfa silage on chewing activity and reticular motility in early lactation cows

Four early lactation Holstein cows fitted with ruminal and duodenal cannulas were used in a 4 x 4 Latin square design experiment to determine the effects of whole crop barley, oat, and triticale silages substituted for alfalfa silage in the forage portion of diets on chewing behavior and the relationships between attributes of reticular contractions and voluntary intake and digesta passage from the reticulorumen. Mean ad libitum DMI was 18.3 kg/d and was affected by diet. Duodenal flows of DM, NDF, and OM were not affected by diet. The frequency and duration of reticular contractions during eating, rumination, and resting were not influenced by diet. Amplitude of reticular contractions during eating was lower for cows fed alfalfa than for those fed barley silage. The NDF of alfalfa was transferred less efficiently than that of cereal silages at the duodenum. Cows fed alfalfa and barley silage diets transferred less NDF per unit of duration than cows fed oat and triticale silage diets. However, an equal amount of NDF was transferred per unit of amplitude of contraction, regardless of diet. Changes in DMI and digesta passage could be explained only partially by changes in chewing activity and attributes of reticular contractions required to transfer each unit of digesta from the reticulorumen.