The effects of pregnancy of the passage of food through the digestive tract of sheep

1962 ◽  
Vol 13 (5) ◽  
pp. 894 ◽  
Author(s):  
Graham N McC ◽  
AJ Williams

The rate of passage of food residues through the digestive tract of pregnant and non-pregnant Merino ewes was measured at four levels of feeding. The passage of digesta became more rapid as the level of feeding was increased, or, the intake being constant, as pregnancy advanced. The mean retention time fell by 3 hr per 100 g increase of food intake, and by 1 to 1½ hr per 100 g increase of estimated weight of concepta at constant intake. The digesta increased by about 150 g dry matter (depending on level of feeding) per 100 g increase of daily food intake and fell by about 150 g per 1000 g increase of estimated weight of concepta. Two alternative explanations of the changes of rate of passage during pregnancy are discussed. While reduction of the quantity of digesta by the increasing bulk of the uterus would tend to curtail appetite, increase of the flow of digesta as a physiological side-effect of pregnancy would tend to enhance appetite. In either case, more rapid passage of digesta would depress the digestibility of some rations and so contribute to undernutrition in late pregnancy.

1969 ◽  
Vol 9 (40) ◽  
pp. 493 ◽  
Author(s):  
JL Lamberth

In two experiments using twin heifers with one of each pair pregnant, the effect of advanced pregnancy on the voluntary food intake, dry matter digestibility and rate of passage of food residues, was studied. In the first experiment sorghum silage was fed ad lib. In the second experiment lucerne chaff was fed at ad lib. and restricted levels and, in addition to the measurements listed above, the quantity of reticulo-rumen contents was determined in each animal. In both experiments each of the pregnant heifers ate less than their non-pregnant CO-twins, and, on analysis of all the data on ad lib. feeding, the differences were significant (P<0.01). The mean coefficients of dry matter digestibility for the pregnant heifers were significantly (P<0.01) less than those for non-pregnant heifers. This caused a significantly (P<0.01) lower intake of digestible dry matter by the pregnant heifers. Measurements of the contents of the reticulo-rumen and the rate of passage of food particles gave inconclusive results. These experiments demonstrated that there was a depression of voluntary intake in late pregnancy the cause of which is not known. This would be nutritionally significant only when the quality and voluntary intake of food were marginal.


1970 ◽  
Vol 24 (1) ◽  
pp. 291-296 ◽  
Author(s):  
R. J. Bawden

1. The mean retention time of stained food residues was longer in sheep maintained on a chopped straw ration than in sheep maintained on a chopped lucerne ration.2. Infection of sheep with 1500 infective Oesophagostomum columbianum juveniles was associated with increased mean retention times.3. The extent to which the mean retention times were increased was associated with the diet and mode of infection of the sheep.4. It was noted that an increase in mean retention time following infection was associated with a general decrease in food intake per kg live eight0.75.5. The results are discussed in relation to the pathogenesis and survival of O.columbianum infections in sheep.


1973 ◽  
Vol 30 (2) ◽  
pp. 231-240 ◽  
Author(s):  
W. L. Grovum ◽  
V. J. Williams

1. Three groups of sheep receiving 400, 800 and 1200 g lucerne chaff/d in equal hourly meals were killed. The large intestines were removed and divided into segments 15 cm long to provide information on the amounts and dry-matter contents of digesta and on the rates of passage of digesta and absorption of water along the large intestine.2. With increasing intakes of food, increases were observed along the entire large intestine in the amounts of wet digesta present, in the transit rates of digesta and in the rates of absorption of water. The mean retention time of digesta in the large intestine decreased with increasing food intake, being 1737, 1056 and 692 min respectively.3. Four patterns of sodium and potassium concentrations in digesta water along the large intestine were found.


2014 ◽  
Vol 41 (2) ◽  
pp. 141 ◽  
Author(s):  
B. D. Cooke

Context Although the daily food intake of wild rabbits is broadly known, precise field estimates have not been made. Moreover, regressions based on metabolic body size and food intake of grazing herbivores in general are too imprecise to provide close predictions. Using such values could result in substantial errors when estimating grazing equivalents to sheep or cattle and resultant economic losses, or estimating the numbers of rabbits per hectare based on rates of deposition of faeces. Aim To re-analyse previously collected data on estimated food digestibility and food intake of rabbits, and provide a framework for better estimating economic and conservation losses attributable to wild rabbits. Methods Food intake of wild free-ranging rabbits was calculated from past measurements of water turnover obtained from dilution of injected tritiated water and estimates of the water content and digestibility of the food eaten. Key results During spring, male rabbits were estimated to eat 65.7 ± 12.5 g dry matter per corrected bodyweight (W–0.75) per day and lactating females ate 97.0 ± 19.4 g dry matter W–0.75 day–1. Similar results were obtained on repetition of trials at a second field site and from wild rabbits held in captivity. Conclusions The estimates of food digestibility and intake obtained, although not precise, are an improvement on theoretical expectations alone and help put previously published data in better perspective. Implications Improved estimates of food consumption provide more confidence in estimates of rabbit grazing pressure. Even moderate densities of rabbits (5 rabbits per ha) could remove about half the pasture produced in an average year in Australia’s arid-zone.


1971 ◽  
Vol 25 (2) ◽  
pp. 259-272 ◽  
Author(s):  
M. F. Fuller ◽  
A. W. Boyne

1. Twelve castrated male pigs were kept at each of three temperatures and given food at one of three levels of intake. The temperatures and daily food intakes (expressed as g/kg0.73) were 23° (80, 100, 120), 13° (100, 120, 140), 3–5° (120, 140, 160). Growth and nitrogen metabolism were measured during growth from 20 kglive weight until slaughter at gokg live weight, when the body contents of N and fat were estimated.2. Growth rate increased with each unit of daily food intake (I g/kg0.73 live weight) by 7.73 ± 0.74 g/d. This value did not vary significantly with temperature. Daily growth rate was depressed by 17.8 ± 2.3 g for each I° fall of temperature.3. Daily N retention estimated by the balance method exceeded by 2.59 g/d that estimated by the comparative slaughter technique. Both results led to the same conclusion, which echoed that found with growth rate, that there was no significant effect of temperature on the response of N retention to increasing food intake. Taking the mean of the two estimates, N retention at a constant food intake fell by 0.38±0.055 g/d for each I° fall of temperature.4. The N content of the ingesta-free carcass at slaughter fell with each increase in daily food intake by 0.007±0.002%, and the fat content rose correspondingly by 0.116±0.027%. These regressions did not vary significantly with temperature. When considered at a constant food intake, body composition did not alter significantly with temperature.


1972 ◽  
Vol 79 (3) ◽  
pp. 397-407 ◽  
Author(s):  
B. F. Fell ◽  
Rosa M. Campbell ◽  
W. S. Mackie ◽  
T. E. C. Weekes

SUMMARYThe food intake, the apparent digestibilities of dry matter, and of nitrogen were measured in housed Blackface ewes during late pregnancy, lactation, and after the lambs were weaned. The ewes were slaughtered serially together with non-breeding controls, and the liver, ruminal mucosa, intestines, CNS and carcass were weighed. In association with differing reproductive status marked changes occurred in the content of dry matter and protein in the alimentary organs, but not in the CNS, and the mean weight of DNA in the CNS for all the animals was 130 ± 20 (S.D.) mg.All of the alimentary organs became hypertrophied during lactation, and regressed after weaning. Maximum values for the liver and ruminal mucosa occurred in the sixth week of lactation, and were maintained until weaning. The small intestine reached maximum weight after 4 weeks of lactation.


1960 ◽  
Vol 32 (1) ◽  
pp. 39-51
Author(s):  
Aarne Mäkelä ◽  
Liisa Liakka

The retention times of dry matter and its constituents in the digestive tract of cows on hay+sugar beet pulp (5 cows) and cows fed on hay+swedes (8 cows) are compared with the retention times pertaining to cows fed on hay+concentrate or hay only. The following conclusions were reached; On a hay+sugar beet pulp diet the mean retention time of dry matter in the reticulo-rumen, and the retention times of lignin in the reticulo-rumen, in the whole digestive tract, and in the digestive tract following the reticulo-rumen are of the same magnitude as the corresponding retention times on a hay+concentrate diet (figs. 1, 2, 5, and 6). The mean retention time of membrane substances in the reticulo-rumen seems to be shorter and that of valuable N-free nutrients in the reticulo-rumen longer than the corresponding retention times on a hay+concentrate diet (figs. 3 and 4). On a hay+swede diet the mean retention times of dry matter and membrane substances in the reticulo-rumen are of the same magnitude as on a hay+concentrate diet (figs. 1 and 3). The mean retention time of valuable N-free nutrients in the reticulo-rumen and, in abundant feeding, the retention times of lignin in the reticulo-rumen, in the whole digestive tract, and especially in the digestive tract following the reticulo-rumen are shorter than on the hay+concentrate diet (figs. 2, 4, 5, and 6). On the hay+sugar beet pulp and the hay+swede diets the retention times are in general of the same magnitude. However, the retention time of membrane substances in the reticulo-rumen is shorter and that of the valuable N-free nutrients considerably longer on a hay+sugar beet pulp than on a hay+swede diet. Replacing a certain amount of hay by concentrates, sugar beet pulp or swedes on a dry matter basis seems to have no effect on the mean retention time of dry matter in the reticulo-rumen. However, a retarding effect on the rate of passage of typical hay constituents (lignin and membrane substances) and an accelerating effect on that of valuable N-free nutrients characteristic of concentrated foods was observed. The said replacing accelerates the rate of passage of lignin in the disgestive tract following the reticulo-rumen on a hay+swede diet.


2001 ◽  
Vol 72 (1) ◽  
pp. 209-221 ◽  
Author(s):  
E. Molina ◽  
A. Ferret ◽  
G. Caja ◽  
S. Calsamiglia ◽  
X. Such ◽  
...  

AbstractTwo experiments were carried out with pregnant (experiment 1) and lactating ewes (experiment 2), to compare dry-matter (DM) intake, and total tract apparent digestibility, digesta kinetics and weight of digestive tract contents of Lacaune and Manchega sheep, with the aim of explaining possible differences between the breeds in voluntary food intake. In experiment 1, 20 3-year-old single-bearing pregnant ewes, 10 Manchega and 10 Lacaune, were permanently housed for the last 10 weeks of pregnancy. The diet used consisted of lucerne hay, offeredad libitum, supplemented with 0·3 kg/day of concentrate. DM and digestible DM intake per kg M0·75were higher (P< 0·01) in Lacaune than in Manchega sheep. Breed did not affect total tract apparent digestibility, fractional rates of passage, transit time, total mean retention time, or weight of digestive tract contents. Changes in body weight and body condition score were similar between breeds. In contrast, Lacaune lambs tended (P= 0·09) to weigh less than Manchega lambs, suggesting genetic differences in the energy utilization between breeds in late pregnancy. Higher DM intake observed in Lacaune sheep may have been related to a higher energy demand for mammary development. In experiment 2, 32 3-year-old lactating multiparous ewes, 16 Manchega and 16 Lacaune, were permanently housed during the first 12 weeks of lactation. The experimental diet used was based on a mixture of maize silage and dehydrated lucerne (10: 1, fresh weight basis), offeredad libitum, and supplemented with 0·8 kg/day of concentrate. Milk, fat and protein yield as well as DM and digestible DM intake in Lacaune ewes was higher (P< 0·01) than in Manchega ewes. DM intake was constant in Lacaune sheep with advancing lactation, while in Manchega sheep DM intake decreased. Throughout this period Lacaune ewes lost 0·5 kg of body weight while Manchega gained 4·4 kg. Breed did not affect either apparent digestibility of DM, organic matter and neutral-detergent fibre, or fractional rates of passage, transit time and total mean retention time. The weight of total tract digestive contents was greater (P< 0·05) in Lacaune than in Manchega sheep, particularly in the reticulo-rumen. Results suggest that the scheme of selection in Lacaune dairy sheep has increased milk yield together with voluntary food intake, the latter being associated with an increase in the rumen fill capacity. The higher milk yield of Lacaune ewes cannot be attributed to the higher DM intake only; other factors, i.e. mobilization of fat reserves, are required to support this higher milk output.


2001 ◽  
Vol 204 (11) ◽  
pp. 1947-1956 ◽  
Author(s):  
M. S. Johnson ◽  
S. C. Thomson ◽  
J. R. Speakman

SUMMARYTo determine whether mice were limited in their capacity to absorb energy during late lactation, we attempted to increase the energy burden experienced by a group of female mice during late lactation by mating them at the postpartum oestrus, hence combining the energy demands of pregnancy and lactation. These experimental mice were therefore concurrently pregnant and lactating in their first lactation, and were followed through a normal second lactation. In a control group, females also underwent two lactations but sequentially, with the second mating after the first litter had been weaned. Maternal mass and food intake were measured throughout the first lactation, second pregnancy and second lactation. Maternal resting metabolic rate (RMR) was measured prior to the first mating and then at the peak of both the first and second lactations. Litter size and litter mass were also measured throughout both lactations. In the first lactation, experimental mice had a lower mass-independent RMR (F1,88=5.15, P=0.026) and raised significantly heavier pups (t=2.77, d.f.=32, P=0.0093) than the control mice. Experimental mice delayed implantation at the start of the second pregnancy. The extent of the delay was positively related to litter size during the first lactation (F1,19=4.58, P=0.046) and negatively related to mean pup mass (F1,19=5.78, P=0.027) in the first lactation. In the second lactation, the experimental mice gave birth to more (t=2.75, d.f.=38, P=0.0092) and lighter (t=−5.01, d.f.=38, P&lt;0.0001) pups than did the controls in their second lactation. Maternal asymptotic daily food intake of control mice in the second lactation was significantly higher (t=−4.39, d.f.=37, P=0.0001) than that of the experimental mice and higher than that of controls during their first lactation. Despite the added burden on the experimental females during their first lactation, there was no increase in their food intake, which suggested that they might be limited by their capacity to absorb energy. However, control females appeared to be capable of increasing their asymptotic food intake beyond the supposed limits estimated previously, suggesting that the previously established limit was not a fixed central limitation on food intake. As RMR increased in parallel with the increase in food intake during the second lactation of control mice, the sustained energy intake remained at around 7.0×RMR.


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