Studies on intestinal digestion in the sheep. 3. Net movement of certain inorganic elements in the digestive tract on rations containing different proportions of hay and rolled barley.
TL;DR: In all instances there was an extensive net secretion of Na and P between mouth and small intestine, net absorption of K and P from the small intestine and of Na from the large intestine, and in five of the six observations there was a smallnet secretion of Ca and Mg during passage of the digesta through the reticulo-rurnen, omasurn and abomasurn.
Abstract: 1. In each of three experiments, two sheep were given diets consisting of hay, or two parts hay to one part barley or one part hay to two parts barley. Each sheep was equipped with a cannula into the rumen and re-entrant cannulas into the proximal duodenum and the terminal ileum. The rations containing barley were supplemented to adjust the intake of calcium, phosphorus, magnesium, sodium and potassium to a level similar to that in the all-hay ration. Paper impregnated with chromic oxide (Cr2O3) was given twice daily by rumen fistula.2. Amounts of crude ash and the five minerals entering and leaving the small intestine and excreted in the faeces were measured. The amounts passing through the re-entrant cannulas were adjusted to give 100% recovery of chromic oxide. The values were used to calculate the direction and net movements of the elements through the walls of the three main parts of the alimentary tract.3. In all instances there was an extensive net secretion of Na and P between mouth and small intestine, net absorption of K and P from the small intestine and of Na from the large intestine.4. The net movements of Ca and Mg were small and rather variable. In five of the six observations there was a small net secretion of Ca and small net absorption of Mg during passage of the digesta through the reticulo-rurnen, omasurn and abomasurn. Net secretion of Ca and Mg apparently occurred in the small intestine and net absorption of Mg in the large intestine.5. The only between-diet differences were small differences in net movements of Na and K.
Citations
More filters
TL;DR: C O N T E N T S I N T R O D U C T I O N .
Abstract: C O N T E N T S I N T R O D U C T I O N . . 125 E N D O G E N O U S S E C R E T I O N I N T O T H E G A S T R O I N T E S T I N A L T R A C T . 126 SITES A N D M E C H A N I S M S O F G A S T R O I N T E S T I N A L P i A B S O R P T I O N . 126 N O N R U M I N A N T S . . . 126 Small intestines . . 126 Large intestines . . 128 RUMINANTS . . 129 Forestomach and abomasum . . . 129 Small intestines . . 129 Large intestines . . 130 H O R M O N A L R E G U L A T I O N OF P H O M E O S T A S I S . . 130 CONTROL OF EPITHELIAL P , TRANSPORT . . . 131 I N T E R A C T I O N S B E T W E E N P A N D ca HOMEOSTASIS . . . 131 D I E T A R Y P D E F I C I E N C Y I N R U M I N A N T S : E F F E C T S O N M I C R O B I A L M E T A B O L I S M I N T H E G A S T R O I N T E S T I N A L T R A C T . . 133 C O N C L U S I O N S . . 134 R E F E R E N C E S . . . 135
172 citations
Cites background from "Studies on intestinal digestion in ..."
...1 g P, net absorption ranged between 2 and 30% of the P amount entering the hind-gut (Bruce et al. 1966/67; Pfeffer et al. 1970; Grace, 1972; Grace et al. 1974; Ben-Ghedalia et al. 1975, 1982; Greene et al. 1983; Breves et al. .1985; Thewis & FranCois, 1985; Wylie et al. 1985)....
[...]
...It has clearly been shown that as in single-stomach animals, the small intestines are the major site for net P, absorption in ruminants (Bruce et al. 1966/67; Pfeffer et al. 1970; Grace et al. 1974)....
[...]
TL;DR: It was concluded that the poor protein anabolism in the ALI sheep was caused by an induced mineral deficiency resulting from parasitic damage in the small intestine.
Abstract: Four groups of eight lambs, 4 months of age and reared parasite-free from birth, were used to investigate the effect of the intestinal parasite Trichostrongylus colubriformis on the intake and efficiency of utilization of food, using balance trial and comparative slaughter techniques. One group (CI) was killed initially as control. Two further groups (ALC and ALI) were offered ad libitum a complete ruminant diet. The ALI group was dosed orally each day for 14 weeks with 2500 infective larvae. Sheep in a further group (PF) were individually paired to members of the ALI group, and given the same amount of food as their pair. Balances of nitrogen, Ca and P and the digestibility of dry matter and energy were determined for the ALI and PF groups during weeks 6–7 and 12–13 and after 98 days of infection the sheep were killed. The bodies of these and the CI and ALC sheep were analysed for water, fat, nitrogen, Ca and P contents.Parasitism reduced food intake over the whole experiment by 9%, but had no effect on the digestibility of energy or nitrogen. At the first trial the N balances of the ALI group were inferior to those of the PF group due to increased urinary N excretion, but there was no difference at the second trial. Ca and P balances of the ALI group tended to be inferior to those of the PF group at both trials. The weight gain of the ALI sheep was only 50 % of that of the PF sheep with the same digestible energy and protein intakes. The protein content of the gain in empty body weight of the ALI sheep was 80 g/kg compared with 112 and 124g/kg in the ALC and PF groups, respectively. Possible causes of the poor protein anabolism are discussed.The gross efficiency of utilization of metabolizable energy for growth was calculated to be 13·3 % in the ALI sheep, compared with 26·2 and 24·2 % respectively, in the ALC and PF groups. It was not possible to determine whether this was due to change in maintenance requirement or in efficiency of fattening.The Ca and P content of the skeletons of the ALC and PF sheep increased by 55 % during the 98-day period, while no net change occurred in the ALI sheep. It was concluded that this was caused by an induced mineral deficiency resulting from parasitic damage in the small intestine.
150 citations
TL;DR: The cause and prevention of milk fever and the downer cow syndrome will be discussed, focusing on the role of diet cation–anion difference and use of low calcium diets.
126 citations
TL;DR: Hypocalcemia is a clinical disorder that can be life threatening to the cow (milk fever) and predisposes the animal to various other metabolic and infectious disorders.
Abstract: Hypocalcemia is a clinical disorder that can be life threatening to the cow (milk fever) and predisposes the animal to various other metabolic and infectious disorders. Calcium homeostasis is mediated primarily by parathyroid hormone, which stimulates bone calcium resorption and renal calcium reabsorption. Parathyroid hormone stimulates the production of 1,25-dihydroxyvitamin D to enhance diet calcium absorption. High dietary cation-anion difference interferes with tissue sensitivity to parathyroid hormone. Hypomagnesemia reduces tissue response to parathyroid hormone.
124 citations
TL;DR: Mg absorption becomes more and more independent of ruminal K with increasing Mg concentration, which can be considered as an explanation for the well-known prophylaxis of hypomagnesemia by increasing oral Mg intake.
Abstract: Hypomagnesemic tetany is a disorder of magnesium metabolism in ruminants, affecting goats, sheep, beef, and dairy cattle. This disease exhibits a variety of clinical signs characterized by excitability, grinding of the teeth, salivation, ataxia, recumbency, and tetanic muscle spasms. This article summarizes recent knowledge of the pathogenesis of hypomagnesemia and the clinical consequences for the afflicted animals, primarily focusing on magnesium absorption from the gastrointestinal tract, pathogenesis of clinical signs, and renal magnesium excretion.
119 citations
References
More filters
TL;DR: The present experiments describe the weight and histological appearance of the salivary glands in sheep and calves and provide data on the rate of secretion and composition of parotid, submaxillary, sublingual, inferior molar and palatine saliva.
Abstract: Sheep and cattle secrete large volumes of alkaline and well buffered saliva that serve to stabilize the pH and water content of the fermenting digesta contained in the rumen. A large fraction of this saliva is supplied by the parotid glands, which have been studied by many workers (Colin, 1886; Scheunert & Trautmann, 1921; Coats, Denton, Goding & Wright, 1956; Denton, 1957b; Kay, 1958). The parotid glands secrete rapidly and continuously, but the submaxillary glands secrete little except during feeding periods (Colin, 1886; Scheunert & Trautmann, 1921). In addition, considerable quantities of saliva are secreted continuously by the small glands of the mouth (Scheunert & Krzywanek, 1929; Phillipson & Reid, 1958; Kay & Phillipson, 1959) but the glands which contribute to this secretion have not been examined in detail. Sheep parotid saliva consists of a solution of sodium, potassium, bicarbonate, phosphate and a little chloride (McDougall, 1948), and the relative proportions of these salts are affected by the rate of secretion (Coats & Wright, 1957) and by sodium depletion (Denton, 1956). Relatively little is known of the composition of submaxillary and sublingual saliva or of the secretions of the small glands of the mouth. More information concerning the non-parotid salivary secretions is required before a balanced knowledge of ruminant saliva can be gained. The present experiments describe the weight and histological appearance of the salivary glands in sheep and calves and provide data on the rate of secretion and composition of parotid, submaxillary, sublingual, inferior molar and palatine saliva.
194 citations
TL;DR: In this paper, the use of chromic oxide (Cr 2 O 3 ) as an indigestible marker for studies on intestinal digestion in sheep has been examined, based on 7-day collection periods, and the mean recovery for all seven experiments being 99.6 ± 0.7%.
Abstract: 1. The use of chromic oxide (Cr 2 O 3 ) as an indigestible marker for studies on intestinal digestion in sheep has been examined. The sheep used were equipped with a cannula into the rumen and a re-entrant cannula in the proximal duodenum; some also had a re-entrant cannula in the terminal ileum. The marker was administered twice daily in the form of Cr 2 O 3 -impregnated paper, through the rumen cannula. 2. Recovery of Cr 2 O 3 in the faeces, based on 7-day collection periods, was satisfactory, the mean recovery for all seven experiments being 99.6 ± 0.7%. In seventeen 24 h collections of digesta entering the proximal duodenum, the mean recovery of the daily dose of marker was 83.7% (range 63.6-148.4%); in eleven such collections at the terminal ileum the mean recovery was 77.3% (54.0-90.0%). 3. Detailed examination of the concentrations of Cr 2 O 3 in dry matter was made with individual samples taken during single 24 h periods for five duodenal and three ileal collection periods. There were always marked variations in these concentrations. It is concluded that use of short collection periods to give mean values for the flow of digesta throughout the 24 h, at particular points along the tract, may lead to large errors.
155 citations
TL;DR: In seven experiments sheep were given diets ranging from all-hay to all-barley, and also a diet comprising one part hay to two parts flaked maize, and some values for a fraction designated non-glucose reducing polymer for cellulose and for gross energy were obtained.
Abstract: 1. In seven experiments sheep were given diets ranging from all-hay to all-barley, and also a diet comprising one part hay to two parts flaked maize. Each sheep was equipped with a cannula into the rumen and a re-entrant cannula in the proximal duodenum; six of the ten also had a re-entrant cannula in the terminal ileum. Paper impregnated with chromic oxide (Cr2O3) was given twice daily by rumen fistula. 2. Amounts of α-linked glucose polymer entering and leaving the small intestine and excreted in the faeces were measured. Some values for a fraction designated non-glucose reducing polymer for cellulose and for gross energy were also obtained. The amounts passing the proximal duodenum and the terminal ileum were adjusted to give 100% recovery of Cr2O3 and the values were used to measure the extent of digestion in various parts of the alimentary tract. 3. When rolled or whole barley was given alone or was the major feed constituent the amount of α-linked glucose polymer entering the small intestine was 6.0±0.76% of that ingested (range 2.6–8.1%). The value was significantly lower than that found for the diet of hay and flaked maize (10.4±1.3%, range 8.0–13.6 %).The α-linked glucose polymer which entered the small intestine was almost completely digested there. 4. The digestibility of the non-glucose reducing polymer, which included much of the hemicelluloses present, ranged from 51 to 73% and almost all the digestible fraction (93–97%) was digested before the small intestine when hay or predominantly hay diets were given. On high-cereal diets only 71–85% of the digested fraction disappeared before the small intestine and appreciable amounts were digested in the large intestine. 5. On the all-hay diet 91% of the digestible cellulose and 67% of the digestible energy were lost before the small intestine, 0 and 21% in the small intestine and 9 and 12% in the large intestine. 6. Mean digestibility coefficients determined in sheep fed solely on either whole or rolled barley were: for dry matter 88.1 and 87.9%, for nitrogen 83.5 and 82.1%, for crude fibre 53.7 and 56.6% and for gross energy 87.7 and 88.0%.
138 citations
90 citations
90 citations