scholarly journals Effects of experimentally-impaired reticular contractions on digesta passage in sheep

1997 ◽  
Vol 78 (1) ◽  
pp. 97-110 ◽  
Author(s):  
M Kaske ◽  
A Midasch
Keyword(s):  
Particle Size ◽  
Feed Intake ◽  
Functional Role ◽  
Rumen Fluid ◽  
Fluid Volume ◽  
Additional Experiment ◽  
Mean Retention Time ◽  
Ad Libitum ◽  
Digesta Passage

The aim of the study was to evaluate the functional role of reticular contractions for digesta passage in sheep. Feed intake, mean retention time of fluid and plastic particles in the reticulo-rumen, rumen fluid volume, forestomach motility and particle size distribution in the faeces were determined in five rumen-fistulated sheep fed on hay ad libitum (Expt 1). The same variables were determined when reticular movements were impaired for 10 d by introducing a silicone-covered lead weight (500 g) into the reticulum (Expt 2). As feed intake dropped in Expt 2 by 27% compared with Expt 1, the sheep received in an additional experiment exactly the amount of feed which had been consumed during Expt 2 and measurements were repeated without impairing reticular movements (Expt 3). The introduction of the weight did not affect the frequency of A- or B-cycles, but elevation of the reticular floor in a cranio-dorsal direction during the biphasic contraction was markedly reduced. The pattern of marker excretion indicated a drastically changed composition of reticular outflow in Expt 2 compared with Expts 1 and 3. During Expt 2, rumen fluid volume was similar to that in Expt 1 but about 25% higher than that in Expt 3; the amount of large feed particles in the faeces was increased compared with Expt 1 ( + 49%) and Expt 3 ( + 76%). In at least two sheep, abomasal emptying was inhibited during Expt 2, as indicated by an enlarged impacted abomasum. In conclusion, the results emphasize the central role of reticular motility for the separation of particles in the forestomach, the outflow of digesta from the reticulo-rumen and transpyloric digesta flow.

EFFECT OF COLD EXPOSURE ON LIVEWEIGHT AND BODY FLUID COMPARTMENTS IN SHEEP

1980 ◽  
Vol 60 (1) ◽  
pp. 33-41 ◽  
Author(s):  
A. A. DEGEN ◽  
B. A. YOUNG
Keyword(s):  
Cold Exposure ◽  
Rumen Fluid ◽  
Tritiated Water ◽  
Fluid Volume ◽  
Interstitial Fluid Volume ◽  
Body Fluid Compartments ◽  
Ad Libitum ◽  
Fluid Compartments ◽  
Total Body ◽  
Water Space

Effects of cold exposure on liveweight and body fluids were studied in 12 six-month-old wethers. Six sheep were offered feed ad libitum and six sheep were restricted to a near maintenance level of intake of a pelleted concentrate ration. The sheep were individually caged in controlled temperature chambers for two preliminary and four consecutive experimental (I-IV) periods of 10 days each; the preliminary periods and period I at 21 °C air temperature, periods II and III at 0 °C and period IV at 21 °C. In general, the responses to the cold were more pronounced during period II than period III, and more pronounced in the sheep on restricted feed than in the sheep on ad libitum feed. The sheep receiving feed ad libitum were able to maintain or increase their liveweight and body solids throughout the experiment. The sheep receiving a restricted ration lost 2.53 kg during the first 8 days of period II. Their total body water (tritiated water space) was reduced by 1.68 L representing 66% of the weight loss, and their body solids were reduced by 0.85 kg. The reticulo-rumen fluid volume (51Cr EDTA space) was reduced by 1.32 L; the interstitial fluid volume (SCN− space-T-1824 space) by 0.39 L and the plasma volume (T-1824 space) by 0.13 L. There was no reduction in absolute intracellular fluid volume with cold exposure.

Nutrient metabolism and rumen micro-organisms in sheep fed a poor-quality tropical grass hay supplemented with sulphate

1990 ◽  
Vol 115 (2) ◽  
pp. 269-275 ◽  
Author(s):  
M. Morrison ◽  
R. M. Murray ◽  
A. N. Boniface
Keyword(s):  
Feed Intake ◽  
Rumen Fluid ◽  
Poor Quality ◽  
Nutrient Metabolism ◽  
Heteropogon Contortus ◽  
Molar Proportion ◽  
Group A ◽  
Ad Libitum ◽  
The Difference ◽  
Group B

SUMMARYA feeding trial was performed during 1986, in Townsville, Australia, to describe alterations in nutrient metabolism, and the coincident gross changes in rumen microbiology, when a sulphurdeficient diet was supplemented with inorganic sulphur. Eight Merino sheep were fedad libituma spear grass (Heteropogon contortus) hay of low sulphur content (0·4 g/kg DM), supplemented with all other essential minerals. Upon supplementation, daily sulphur intake was increased toc.0·75 g and four animals continued to be fedad libitum(group A) whilst the remaining animals were restricted in feed intake (group B). Sulphur supplementation caused a twofold increase in the feed intake of group A (P< 0·05). In both groups of animals, sulphur supplementation increased the fermentation of cotton thread cellulose (P< 0·05), as well as of ground plant dry matter (P< 0·05), suspended in the rumen in nylon bags for 24 and 48 h. The apparent digestibility of organic matter (AOMD) was also increased by sulphur supplementation; from 30·6 to 39·3% in group A (P< 0·05) and from 35·1 to 41·5% in group B (P> 0·05). The difference in AOMD between groups with sulphur supplementation was not significant, despite group B maintaining a longer retention of fluid digesta in the rumen (20·7 v. 25·3 h) with a significantly lowered rumen volume (4·68 v 3·67 litres,P< 0·05) and outflow of fluid digesta from this site (5·31 v 3·58 litres/day,P< 0·05). Sulphur supplementation increased the molar proportion of acetic acid in rumen fluid (P< 0·05) but lowered propionic and butyric acids in group A (P< 0·05). Only the molar proportion of propionic acid in rumen fluid was significantly lowered in group B (P< 0·05). In both groups of animals, counts of fluid-borne rumen bacteria, protozoa and sporangia of rumen anaerobic fungi (RAF) all increased significantly with sulphur supplementation (P< 0·05 in all instances), but no significant differences were observed between groups in microbial counts, despite the different feeding regimes. The increase in sporangial forms of RAF was most marked; no sporangial forms were detectable until the diet was supplemented with sulphate and measurable concentrations of rumen sulphide were observed. This is the first account of nondetectable concentrations of RAF brought about by the nutritional status of the diet.

Wheat bran and oat hulls have dose-dependent effects on ad-libitum feed intake in pigs related to digesta hydration and colonic fermentation

2019 ◽  
Vol 10 (12) ◽  
pp. 8298-8308 ◽  
Author(s):  
Vishal Ratanpaul ◽  
Dagong Zhang ◽  
Barbara A. Williams ◽  
Simon Diffey ◽  
John L. Black ◽  
...  
Keyword(s):  
Gastric Emptying ◽  
Food Intake ◽  
Wheat Bran ◽  
Feed Intake ◽  
Passage Rate ◽  
Colonic Fermentation ◽  
Oat Hulls ◽  
Ad Libitum ◽  
Digesta Passage ◽  
Dose Dependent

Undigested nutrients and fermentable fibre in the distal ileum and colon stimulate intestinal brakes, which reduce gastric-emptying and digesta-passage-rate, and subsequently limit feed/food-intake.

Factors limiting the intake of feed by sheep. 10. The effects of concentrate supplements on the voluntary consumption and digestion of a medium quality roughage

1988 ◽  
Vol 39 (2) ◽  
pp. 255 ◽  
Author(s):  
RH Weston
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Feed Intake ◽  
Alimentary Tract ◽  
Whole Grain ◽  
Feeding Frequency ◽  
C 23 ◽  
Medium Quality ◽  
Digesta Passage ◽  
C 30

Feed intake and digestion studies were conducted with sheep offered a medium quality roughage and given various concentrate supplements. The provision of supplements in amounts equal to c. 23% of voluntary roughage consumption always decreased roughage intake. The decrease with wheat-based supplements was little affected by supplement feeding frequency, by use of ground grain rather than whole grain or by the provision of additional essential nutrients, but its magnitude was reduced by c. 30% with use of buffer salts to prevent decline in rumen digesta pH. The supplements were associated with less digesta in the alimentary tract and less rumination. Supplements increased the rate of liquor outflow from the reticulum and the rate of marker clearance from the reticula-rumen. The rumen digesta and reticulum digesta differed with respect to particle size distribution and only some 30% of the organic matter in reticulum digesta was in particles too large to pass to the omasum. The data were considered to be consistent with a concept that the regulation of roughage intake involves an interplay between the animal's energy metabolism and the quantity of digesta in the reticula-rumen and to indicate (i) some discrimination against the larger particles in digesta flow from the rumen to the reticulum, (ii) appreciable discrimination on the basis of size of particle in digesta flow from the reticulum to the omasum, and (iii) regardless of state of subdivision, constraints applied to digesta passage to the omasum which could have affected the level of feed intake achieved.

scholarly journals Body weight and sex effects on digesta mean retention time in growing Saanen goats

2020 ◽  
Vol 4 (2) ◽  
pp. 883-900
Author(s):  
Marcelo Gindri ◽  
Rafael Fernandes Leite ◽  
Carla Joice Härter ◽  
Simone Pedro da Silva ◽  
Normand St-Pierre ◽  
...  
Keyword(s):  
Body Weight ◽  
Feed Intake ◽  
Retention Time ◽  
Fixed Effects ◽  
Pool Size ◽  
Neutral Detergent Fiber ◽  
Mean Retention Time ◽  
Saliva Secretion ◽  
Wet Weight

Abstract Despite the important role of digesta mean retention time (MRT) on digestive efficiency of ruminants, it is poorly investigated in total gastrointestinal tract (GIT) of growing ruminants, especially in goats. The objective of this study was to evaluate the effect of body weight (BW) and sex on GIT MRT of particles and solutes in growing Saanen goats. A dataset from two studies, comprising 103 individual records of castrated males (n = 36), females (n = 34), and intact males (n = 33) Saanen goats slaughtered at 15, 22, 30, 37, and 45 kg BW, was used. Goats were fed basically with total mixed ration composed by dehydrated corn plant (Zea mays) milled to pass a 10-mm screen, cracked corn grain, and soybean (Glycine max) meal. Variables evaluated were BW, feed intake, feed intake level, composition of ingested diet, wet weight of GIT tissues, wet digesta pool size, digesta composition (dry matter and neutral detergent fiber [NDF]), indigestible NDF:NDF ratio of ingested diet and GIT digesta, MRT of particles (MRTiNDF) and solutes (MRTCr), and reticulorumen selectivity factors (large particles/solutes). Reticulorumen, omasum, abomasum, small intestine, cecum, and colon–rectum segments were evaluated. The dataset was analyzed as mixed models considering sex, BW, and sex × BW interaction as fixed effects, and study and residual error as random effects. Sex did not affect MRTiNDF in any GIT segments. Females and intact males presented similar reticulorumen MRTCr (5.6 h; P = 0.92) and they presented lower reticulorumen MRTCr than castrated males (7.0; P ≤ 0.04). Total GIT MRTCr was similar between castrated males and females (15.7 h; P = 0.11) and between females and intact males (14.2 h; P = 0.76). Body weight (BW) did not affect MRTiNDF in reticulorumen and colon–rectum and total GIT MRTCr (P ≥ 0.11). Reticulorumen and omasum MRTCr increased as BW increased (P &lt; 0.01), and abomasum MRTCr decreased as BW increased (P = 0.02). Feed intake, and wet tissues and wet pool size of all GIT segments increased as BW increased, except abomasum wet pool size (P ≤ 0.01). The mechanism related to sex effect on MRT has to be elucidated. Reticulorumen MRTiNDF and total GIT MRTCr were modulated by intake and capacity of reticulorumen and GIT, respectively. On the other hand, reticulorumen MRTCr seemed to be regulated by reticulo-omasal orifice opening and saliva secretion.

The role of angiotensin II in the central regulation of feed intake in sheep

2001 ◽  
Vol 81 (2) ◽  
pp. 215-221 ◽  
Author(s):  
Katsunori Sunagawa ◽  
Richard S. Weisinger ◽  
Michael J. McKinley ◽  
Brett S. Purcell ◽  
Craig Thomson ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Water Intake ◽  
Feed Intake ◽  
Salt Intake ◽  
Control Treatment ◽  
Central Regulation ◽  
Artificial Cerebrospinal Fluid ◽  
Access To Water ◽  
Ad Libitum

The objective was to determine the role of Angiotensin II (ANG) in the central regulation of feed intake by ruminants. As a control treatment, artificial cerebrospinal fluid (CSF) was given (over a period of 98.5 h) as a continuous intracerebroventricular (ICV) infusion (0.2 mL h–1) into the lateral ventricle of ewes (n = 5). Approximately 9 d later, the infusion was repeated with the same ewes, but the CSF contained ANG (25 g μL–1). The ewes were fed dried alfalfa chaff for 2 h once daily and both water and a 0.5 M NaCl solution were available ad libitum (except that water intake was restricted on the first day of ANG infusion). Infusion of ANG resulted in severe thirst that persisted when water intake was restricted to an amount equal to voluntary intake during the control infusion. Furthermore, when ewes had ad libitum access to water, consumption during ANG infusion was 1.4 to 2.8-fold greater than that during CSF infusion (P < 0.01). Compared with CSF infusion, ANG infusion decreased eating rates by an average of 46.5% (range, 31.8–62.6%; P < 0.01) and feed intake by 25.0% (5.4–48.1%; P < 0.01), and increased salt intake by 273.8% (124.0–417.6%; P < 0.01). We concluded that ANG produced thirst sensations in the brain, resulting in excessive water intake that caused ruminal distension and significantly reduced feed intake. Key words: Angiotensin, brain, thirst, feed intake, sheep

Evaluation of feed additives for increasing wool production from Merino sheep. 2. Flavomycin and tetronasin included in lucerne-based pellets or wheaten chaff fed ad libitum

1989 ◽  
Vol 29 (3) ◽  
pp. 327 ◽  
Author(s):  
EM Aitchison ◽  
K Tanaka ◽  
JB Rowe
Keyword(s):  
Feed Intake ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Fibre Diameter ◽  
Feed Additives ◽  
Protein Diet ◽  
Merino Sheep ◽  
Wool Growth ◽  
Ad Libitum ◽  
Pelleted Diet

The feed additives flavomycin, a glycolipid antibiotic, and tetronasin, an ionophore, were evaluated for their ability to improve wool growth and liveweight gains in Merino sheep. Each was included in 2 diets: one was a pelleted mixture of (g/kg) lucerne (590), lupins (250) and barley (1 50); the other diet was wheaten chaff. Flavomycin was included in each diet at 10 and 20 mg/kg feed; tetronasin at 5 and 10 mg/kg feed. During an 8-week experimental period, the diets were fed ad libitum to weaner Merino wethers, with 15 sheep receiving each treatment diet at each level of additive inclusion, and 30 sheep receiving each diet without additives. Liveweight changes, feed intake and wool growth were measured over 2 consecutive 4-week periods, and rumen fluid samples were taken from all sheep after 6 weeks. Feed intake, liveweight gain and wool growth rate were all higher for animals eating the pelleted diets compared with those eating chaff. Rumen volatile fatty acids (VFA) and ammonia (NH3) concentrations were also higher with the pelleted diet. On the pelleted diet, flavomycin and tetronasin inclusion significantly increased liveweight gains during the second 4-week period (296, 277, 231 g/sheep.day for flavomycin, tetronasin and controls respectively, P<0.001), but neither additive had any significant effect on feed intake. The amount of clean wool grown during both measurement periods was greater for animals receiving flavomycin or tetronasin with the pelleted diet compared with control animals. Neither additive had any significant effect on liveweight gains or wool growth of sheep eating chaff. Fibre diameter (FD) was measured on wool clipped in the second period, and was not significantly altered by either additive: mean FDs for animal receiving pellets were 25.1 �m, compared with 18.5 �m for animals receiving chaff. Total rumen VFA concentrations were lower with flavomycin or tetronasin treatments on both diets, and ammonia concentrations were lower with both additives on the pelleted diet and with tetronasin on the chaff diet. It is concluded that both flavomycin and tetronasin were able to increase liveweight gains and wool growth in rapidly growing sheep eating a high-protein diet, but had little or no consistent effects with animals eating a lower quality, low-protein diet.

Digestion and Digesta Passage in the Brushtail Possum, Trichosurus Vulpecula (Kerr).

1981 ◽  
Vol 29 (2) ◽  
pp. 157 ◽  
Author(s):  
GA Wellard ◽  
ID Hume
Keyword(s):  
Retention Time ◽  
Brushtail Possum ◽  
Trichosurus Vulpecula ◽  
Passage Rate ◽  
Significant Differentiation ◽  
Mean Retention Time ◽  
High Fibre ◽  
The Mean ◽  
Digesta Passage

Digestion and digesta passage rate were studied in brushtail possums (Trichosurus vulpecula) fed on semipurified diets of 2 different fibre values. Increasing fibre in the diet from 17 to 41% neutral detergent fibre (NDF) depressed digestibility of DM (P<0.01), energy (P<0.001) and NDF (P<0.05). Within the high-fibre diets, but not the low-fibre diets, there were negative correlations between apparent digestibility of DM and DM intake (P<0.005) and between NDF digestibility and DM intake (P<0.001). Caecectomy had no effect on intake or digestion of DM or fibre. The average mean retention time in intact animals was 64 h for fluid and 71 h for particulate digesta. Caecectomy increased the mean retention time of fluid to 120 h (P<0.025) and of particles to 125 h (P<0.01). This increase in retention time was used to explain the lack of any significant effect of caecectomy on fibre digestibility. There was no significant differentiation in passage rate of fluid and particulate digesta. Results are discussed in relation to the role of the caecum in digestion in the brushtail possum.

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