Factors limiting the intake of feed by sheep. I. The significance of palatability, the capacity of the alimentary tract to handle digesta, and the supply of glucogenic substrate.

1966 ◽  
Vol 17 (6) ◽  
pp. 939 ◽  
Author(s):  
RH Weston

Voluntary feed consumption (VFC) decreased when a quantity of the diet being consumed by the sheep was introduced into the rumen. On diets of lucerne hay, lucerne hay plus maize, wheaten hay, and wheaten straw, the decreases in VFC ranged from 90 to 110% of the quantity introduced intraruminally when this quantity varied from 20 to 60% of the VFC during control periods. When sheep consumed wheaten straw ad libitum, and a quantity of coarsely ground wheaten straw equal to 140% of the VFC during a control period was given intraruminally, VFC ceased and digesta accumulated in the rumen. VFC decreased when indigestible materials were introduced into the rumen. The voluntary consumption of lucerne hay decreased by 15% when sawdust was introduced into the rumen at a rate equivalent by weight to 17% of the VFC during a control period ; decreases of 7 and 9% were found when finely ground polyvinyl chloride was introduced at rates equivalent by weight to 25 and 50% respectively of VFC during control periods. The voluntary consumption of wheaten hay decreased by 16 and 19% when sawdust was introduced into the rumen at rates equivalent by weight to 25 and 18% respectively of VFC during control periods. Intraruminal infusions of acetic acid, propionic acid, or a mixture of acetic, propionic, and butyric acids providing 290–510 kcal of energy daily were accompanied by decreases in the voluntary consumption of lucerne hay and wheaten hay; the decreases ranged from 0.29 to 0.86 g dry matter per kcal of energy infused; similar decreases were obtained when propionic acid was infused into the abomasum of sheep given lucerne hay. The intake of lucerne hay was 9% higher when given alone than when supplemented with 6% propionic acid. The results are discussed in relation to factors limiting the intake of lucerne hay and wheaten hay.

1969 ◽  
Vol 73 (3) ◽  
pp. 355-363 ◽  
Author(s):  
A. M. Raven ◽  
T. J. Forbes ◽  
J. H. D. Irwin

Summary1. An experiment consisting of two separate trials was carried out to study the utilization by beef cattle of high concentrate diets containing different amounts of milled barley straw and of protein. For each trial twenty-four Friesian steers, initially weighing about 270 kg, were divided into three groups and the animals within each group then allocated at random to eight dietary treatments. The treatments were based on an all-concentrate diet and three others containing 10, 20 and 30% of milled (1 in screen) barley straw. Four of the treatments consisted of giving the same concentrate mixture with each level of straw, and the other four involved giving concentrate mixtures with increasing levels of protein so that the percentage of protein in the diets was maintained. All the diets were fed ad libitum until slaughter.2. Performance in terms of live-weight gain was considered as the net result of a number of factors, notably the total intake of dry matter, the digestibility of the dry matter, the efficiency of utilization of the end products of fermentation in the rumen and the composition of the live-weight gain. The inclusions of 20 and 30% of straw in the diet were associated with lower rates of gain than on corresponding all-concentrate and 10% straw treatments but the differences obtained did not attain significance. Total intakes of dry matter were greater on treatments containing 10 and 20% of straw than on corresponding all-concentrate treatments, but then declined with further increase in level of straw to 30%. This trend was significantly curvilinear (P < 0·01), the equation for the relationship beingY = 5·881 + 0·131X - 0·004X2,with Y being the daily intake of dry matter (kg) and X the percentage of straw in the diet. The maximum intake of dry matter was calculated to occur with a level of 16·4% straw in the diet and represents an increase in total dry matter intake of 18·2% over that on an all-concentrate diet. Food conversion ratio, expressed as total dry matter consumed per kg live-weight gain, tended to increase with increasing proportion of straw in the diet.3. The mean digestibility of organic matter fell sharply with the inclusion of 10% straw in the ration, the decrease being 8·2% where the protein level was not maintained and 9·1% where it was maintained. Further reductions in digestibility occurred on the 20 and 30% straw diets, but the magnitude of the reductions were considerably less than those brought about by the initial introduction of straw into the ration.4. The molar percentage of acetic acid in the steam volatile acids of rumen liquor increased markedly, and that of propionic acid decreased sharply from the all-concentrate to the 10% straw treatment with a similar level of dietary protein. Increase in the level of straw to 30% gave rise to a further increase in the proportion of acetic acid and reduction in that of propionic acid. Analysis of samples taken at 3, 6, 9 and 12 h after feeding showed appreciable differences in pattern between treatments.5. Effects of treatment on killing-out percentage were different for each trial. In trial 1 the inclusion of straw in the diet did not cause any reduction in killing-out percentage, but the maintenance of protein level gave rise to a significantly higher killing-out percentage than was obtained with the lower protein groups. In trial 2 the killing-out percentages showed a significantly linear (P < 0·01) decrease with increasing proportion of straw in the ration, and maintenance of protein level did not give any improvement.


2018 ◽  
Vol 39 (1) ◽  
pp. 253
Author(s):  
Marcos Rogério Oliveira ◽  
Antônio Vinícius Iank Bueno ◽  
Guilherme Fernando Mattos Leão ◽  
Mikael Neumann ◽  
Clóves Cabreira Jobim

We aimed to evaluate nutritional quality, fermentation profile, aerobic stability, and dry matter losses in corn (Zea mays) and wheat (Triticum aestivum 'BRS Umbu') silages. Treatments included uninoculated and inoculated (Lactobacillus plantarum and Pediococcus acidilactici, 1.0 × 105 UFC g-1) wheat silage, corn silage from a conventional hybrid and a transgenic hybrid. Nutritional quality and fermentation profile variables were tested in a completely randomized design. Means were compared using Tukey’s test at 5% significance. An aerobic stability trial was conducted in a factorial design with two silages (wheat × inoculated wheat; conventional hybrid corn × transgenic hybrid corn) and two temperatures (ambient temperature × controlled temperature at 24°C). Data were submitted to ANOVA and means were analyzed by the F test at 5% probability. Inoculation of wheat silage increased dry matter, organic matter, and total carbohydrates, but reduced crude protein by a dilution effect. Regarding the fermentation profile, inoculation reduced acetic acid and butyric acid content, whereas it increased propionic acid in wheat silage. Bt corn hybrid silage showed higher dry matter and lower neutral detergent fiber, whereas transgenic corn silage showed lower content of acetic acid, propionic acid, alcohol, and ammonia. Conversely, Bt hybrid silage showed higher butyric acid. Transgenic corn silage showed higher temperature than the conventional hybrid silage during aerobic exposure. Inoculated wheat silage experienced larger deterioration and dry matter losses during the aerobic stability trial. Temperature control worsened aerobic stability in all treatments, increasing dry matter losses and heating.


1987 ◽  
Vol 67 (4) ◽  
pp. 1129-1131 ◽  
Author(s):  
R. S. BUSH ◽  
J. W. G. NICHOLSON

Calves fed ad libitum whole milk plus formic acid, propionic acid or formalin consumed less than calves fed untreated milk and grew comparably slower. At weaning the control group was consuming up to 25% of their body weight in milk daily without significant scouring. Key words: Acidification, milk, calves


1971 ◽  
Vol 13 (3) ◽  
pp. 473-484 ◽  
Author(s):  
E. K. Poutiainen ◽  
C. R. Lonsdale ◽  
G. E. Outen

SUMMARY1. Young cattle were fed on four types of wafer containing chopped or coarsely-milled dried grass, with or without 50% of barley.2. At slaughter, the alimentary tract of each animal was removed and the contents of each part were weighed and sampled to determine the extent and site of digestion. Chromic oxide was used as an indigestible marker.3. The form in which the grass was processed had no effect on any of the parameters measured.4. The dry-matter content of the digesta in all parts of the alimentary tract was significantly higher when barley was included in the wafers. The inclusion of barley decreased the proportion of acetic acid and increased the proportion of butyric acid in the rumen liquor. The proportions of propionic and valeric acids were unaffected. Barley also appeared to reduce the proportion of digestible dry matter which disappeared in the forestomachs (31·44%) compared with that when grass was given alone (42·59%).5. With grass alone about 70% of the apparently digestible cellulose disappeared from the forestomachs, but the technique used did not allow a good estimation of these proportions when mixed diets were given. The retention time of dry matter in the forestomachs was not affected by the diet but the inclusion of barley in the wafers increased the retention time of cellulose in the forestomachs.6. Of 1·6·1·9 kg of starch ingested in mixed diets, 92-96% was apparently digested in the forestomachs, and only 80-130 g per day escaped rumen fermentation. The intake of starch on diets of grass alone was negligible and almost all the soluble sugars were digested in the forestomachs.7. More N was recovered at the omasum than was ingested, but the different diets had no effect on the site of digestion of N.


2021 ◽  
pp. 395-410
Author(s):  
Tânia Mara Becher Ribas ◽  
◽  
Mikael Neumann ◽  
Egon Henrique Horst ◽  
Fernando Braga Cristo ◽  
...  

The objective was to evaluate the efficiency of two bacterial inoculants, 11CFT and 11C33, with different genera of lactic acid bacteria on the chemical and fermentation composition of the silage, and the temperature and pH behavior of the silage during the feed out period. The experimental design used was randomized blocks, with three treatments: corn silage without inoculant (control); corn silage with 11CFT inoculant (consisting of strains of Lactobacillus buchneri and L. casei); and corn silage with 11C33 inoculant (consisting of strains of L. buchneri, L. plantarum and Enterococcus faecium). The use of both inoculants increased the concentration of lactic acid in the silage (22.42 g kg-1 for control against 36.00 and 33.33 g kg-1 for 11CFT and 11C33, respectively) and reduced aerobic dry matter losses. The silage treated with 11C33 obtained a higher concentration of acetic acid (17.44 g kg-1) and propionic acid (2.08 g kg-1). The 11CFT inoculant provided a lower concentration of ethanol, however, without differing from the silage with 11C33 (0.70 and 1.61 g kg-1, respectively). Even without variations in temperature and pH at silage unloading, the use of the 11C33 inoculant generated a higher concentration of acetic and propionic acid, providing better aerobic stability days after unloading. Both inoculants also improved the in situ ruminal digestibility of corn silage compared to control silage. They provide an increase in the content of lactic and propionic acids, which assist to reduce dry matter losses and ethanol production. There were no variations in temperature and pH at the silo unloading, however, the use of the 11C33 inoculant generated a higher concentration of acetic and propionic acids providing better aerobic stability after exposure to air.


1968 ◽  
Vol 19 (6) ◽  
pp. 963 ◽  
Author(s):  
RH Weston ◽  
JP Hogan

Ryegrass harvested at various stages of maturity was dried and offered to sheep either ad libitum or at approximately 90% of the ad libitum intake. Feed consumption and the times spent by the sheep in ruminating and eating were measured when the forages were offered ad libitum, and several aspects of digestion were studied when the level of feeding approached 90% of ad libitum intake. The chemical composition of the grasses and the apparent digestibility of the constituents showed the usual changes with maturity. As the grass matured, there was a tendency for: (i) the rate of flow of digesta from the abomasum to increase relative to the flow from the rumen, (ii) the concentration of organic matter in digesta leaving the abomasum to decrease, (iii) the quantity of nitrogen leaving the stomach in digesta per unit intake of dietary nitrogen to increase, and (iv) the sheep to spend more time in ruminating and eating per unit feed intake. No differences attributable to maturity were observed in: (i) the rate of flow of digesta from the rumen, (ii) the retention time of a water-soluble marker in the rumen, (iii) rumen volume, (iv) the distribution of the digestion of organic matter and carbohydrate between the stomach and intestines, and (v) the apparent digestion of nitrogen in the intestines. Although the quantity of nitrogen provided by 100 g of forage organic matter decreased with maturity from 4.3 to 1.2 g, the corresponding change in the quantity of nitrogen, in forms other than ammonia, apparently digested in the intestines was only 2.6 to 1.5 g. It was calculated, after making several assumptions, that the net energy value of the metabolizable energy derived from volatile fatty acids produced in the rumen and from amino acids digested in the intestines was little affected by the stage of maturity. On the other hand, after making assumptions about the energy costs of ruminating and eating, it was calculated that the proportion of the metabolizable energy used in ruminating and eating could increase from 5% with the immature grass to 13% with mature grass. Intraruminal infusion of propionic acid did not increase the sheep's intake of one forage that provided a relatively small quantity of propionic acid during ruminal digestion.


1985 ◽  
Vol 40 (2) ◽  
pp. 297-301 ◽  
Author(s):  
J. E. Vipond ◽  
E. A. Hunter ◽  
Margaret E. King

ABSTRACTTwo trials were undertaken to investigate the effect of rolling on the digestibility of barley and oat supplements offered to pregnant ewes at 0·43 kg dry matter per day. In the first trial, with ewes given a basal diet of grass silage ad libitum, rolling barley improved the apparent dry matter digestibility of the diet by 0·036 (s.e. 0·0115) and reduced the excretion of whole grains from 0·127 (s.e. 0·0190) of grain fed to almost nil. Method of storage (dried or treated with propionic acid) had no effect on utilization of whole or rolled barley. Grain excretion was lower with whole oats 0·049 (s.e. 0·0147) than with whole barley. In the second experiment, basal diets containing hay or roots ad libitum were supplemented with whole or rolled barley and oats. Excretion of whole grains was very low on the root-based diets and amounted to only 0·047 (s.e. 0·0177) for the whole barley and hay diet. Excretion of whole grains varied between animals and was shown to be a characteristic of the animal. It was concluded that in most situations grain should be given whole to ewes but that it may be advantageous to roll barley when it is given with silage.


1964 ◽  
Vol 44 (1) ◽  
pp. 58-67 ◽  
Author(s):  
J. W. G. Nicholson ◽  
H. M. Cunningham

Four experiments were conducted with sheep to compare the addition of sodium citrate and sodium propionate to pelleted and unpelleted rations and to determine the response to sodium citrate supplementation of different quality-hays. There were no significant differences in rate of gain or feed consumption of a ⅔ roughage −⅓ concentrate ration due to supplementation with sodium citrate or sodium propionate. Pelleting either the mixed ration or all-roughage rations increased feed consumption and rate of gain in all experiments. Pelleting the mixed ration decreased digestibility of dry matter, organic matter, and nitrogen in the one experiment in which this was determined. Pregnant and lactating ewes lost less body weight when fed a limited amount of long hay plus pelleted hay ad libitum than similar ewes fed a standard ration of long hay ad libitum plus 0.5 lb of concentrates per day. It was necessary to feed lambs 0.5 lb of rolled barley per day with long hay ad libitum to obtain gains equal to those of similar lambs fed pelleted hay ad libitum. The addition of sodium citrate significantly increased the rate of gain of lambs fed ad libitum a slightly moldy, weathered legume hay in the pelleted form together with 0.25 lb of long hay per head per day.The addition of sodium citrate to a mixed ration or to all-roughage rations did not usually alter the proportions of rumen volatile fatty acids. The addition of sodium propionate decreased the proportion of acetic acid while increasing that of propionic acid. In both experiments where this was determined, pelleting an all-roughage ration resulted in a decrease in the proportion of acetic acid and an increase in the longer chain volatile fatty acids in rumen fluid.


1973 ◽  
Vol 16 (2) ◽  
pp. 195-203 ◽  
Author(s):  
Hi Shin Kang ◽  
Jane Leibholz

SUMMARYAn experiment was conducted with 50 male Friesian calves between 5 and 11 weeks of age. Milled wheat straw (0·95 cm screen) was included in a pelleted all-concentrate diet at concentrations of 0, 15, 30 or 45 %. The nitrogen content of the diets was maintained by the addition of urea. The diets were given alone or with a chaffed lucerne hay or wheat straw supplement ad libitum. All diets contained 2 % sodium bicarbonate.The feed intake and weight gains of the calves were increased significantly by the inclusion of 15 % milled wheat straw, but were reduced by 30 or 45 % straw. The supplements of chaffed wheat straw or lucerne hay ad libitum did not influence the performance of the calves. The inclusion of wheat straw in the diets reduced their dry-matter digestibility but the digestibility of acid detergent fibre was maximal with 27 % straw. The digestibility of nitrogen was significantly increased by 15% straw but reduced by further increases in straw.The inclusion of wheat straw in the diets did not influence the pH of the rumen contents or the concentration of total volatile fatty acids in the rumen. Increasing the level of straw in the diet caused a significant linear increase in the proportion of acetic acid and decreases in butyric, propionic and valeric acids.


1971 ◽  
Vol 22 (3) ◽  
pp. 469 ◽  
Author(s):  
RH Weston

The voluntary consumption by lambs of a ground and pelleted diet containing 24.4% crude protein on a dry matter basis was studied over 25 days when a nutrient solution based on evaporated cows' milk and lactose was administered per abomasum. The lambs, initially 11-12 weeks old and weighing 26 kg, had been surgically prepared with permanent abomasal fistulae. Separate digestion experiments were conducted to determine (i) the digestible energy (DE) content of the basal diet and (ii) patterns of digestion of the basal diet in the stomach and intestines. The basal diet had a DE content of 3.39 kcal/g dry matter and provided 22 g crude protein digested in the intestines per 100 g digestible organic matter; the nutrient solution contained 7.2 g nitrogen/Mcal gross energy and the energy was 94% digestible. In the digestion experiments, the rates of flow of digesta from the rumen and abomasum were 9.9 and 14.4 l/day respectively; the ruminal digesta was at pH 5.7 and the concentration of volatile fatty acids was 138 mmoles/litre. Approximately 59% of the apparent digestion of organic matter and 78% of the digestion of acid detergent fibre occurred in the stomach. The supplemented and unsupplemented groups of lambs consumed similar amounts of feed in a control period; the daily intakes expressed in relation to body weight in kg0.75 (BWkg0.75) were 101 g dry matter and 341 kcal DE. When nutrient solution providing 836 kcal gross energy or 58 kcal DE/BWkg0.75 per day was administered per abomasum, voluntary feed consumption declined by 16 g dry matter/BWkg0.75 or 53 kcal DE/BWkg0.75. Thus on the basis of DE, the decline in dietary intake compensated for the nutrient solution administration to the extent of 91 %. The daily DE intake of the supplemented group during nutrient administration was 345 kcal/BWkg0.75 and the rate of body height increase was 306 g/day ; the corresponding values for the unsupplemented group were 340 kcal DE/BWkg0.75 and 290 g/day. The data indicated that caloric homeostasis was well developed in lambs of this maturity and that the diet probably contained sufficient essential nutrients to permit the lambs to exhibit maximum growth. The capacity of the lamb to consume feed and increase in body weight did not appear to be restricted by any feature of ruminal digestion.


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