The effect of urea on the absorption of volatile fatty acids from the rumen of sheep fed on oat straw

1968 ◽  
Vol 19 (5) ◽  
pp. 803 ◽  
Author(s):  
GJ Faichney

The effect of a urea supplement on the utilization of a diet of poor quality oat straw plus minerals, fed to sheep, was investigated. The supplement of urea was responsible for a highly significant (P < 0.01) increase in dry matter and energy intake and a highly significant ( P < 0.01) decrease in body weight loss. There was a significant (P < 0.05) increase in nitrogen balance and in the rate of passage of food residues through the alimentary tract. A tendency for the digestibility of dry matter, energy, crude fibre, and cellulose to be higher when the urea supplement was given was not significant. There was a significant (P < 0.05) increase in the VFA absorbed from the rumen reflecting the increase in intake, but there were no differences between diets in the contributions of acetic, propionic, and butyric acids to VFA absorption. The mean values obtained for the proportion of the digested energy accounted for by the VFA on the straw plus urea diet and the straw diet (with the standard error of the mean) were 31.4 (± 2.5)% and 38.1 (± 5.6)% respectively.

1965 ◽  
Vol 16 (3) ◽  
pp. 429 ◽  
Author(s):  
JZ Foot ◽  
B Romberg

Two roughage diets, lucerne hay and oat straw, were given to three Corriedale sheep and three red kangaroos. Dry matter intakes, nitrogen balances, and body weight changes of the animals were compared, and the digestibilities of each diet by each species and the retention times of the food residues in their alimentary tracts were estimated. The kangaroos were less affected by the quality of the diet than were the sheep. The sheep ate nearly the same amount of lucerne hay and less oat straw than the kangaroos, after adjustment for body weight differences. Digestibility coefficients were higher for the lucerne hay when fed to the sheep, but apparent dry matter digestibility coefficients for oat straw were about the same for sheep and kangaroos. The mean retention times of food residues were lower in the kangaroos, and dietary nitrogen was retained to the same or a slightly lesser extent than in the sheep. The kangaroos maintained weight on the poor quality diet and appeared to be even better adapted to utilize this type of roughage than the sheep.


1970 ◽  
Vol 18 (3) ◽  
pp. 247 ◽  
Author(s):  
DK Forbes ◽  
DE Tribe

The utilization of good-quality and poor-quality roughages (lucerne hay and oat straw) by red and grey kangaroos, Megaleia rufa and Macropus giganteus, compared with sheep was investigated by means of digestibility trials in individual metabolism cages. On average the kangaroos ate slightly less per unit metabolic body weight than the sheep when fed ad libitum, but the differences were not significant. They digested a similar percentage of lucerne dry matter but digested straw much less well, mainly because of their poor ability to digest crude fibre. When nitrogen intakes were low, with the straw diet, the kangaroos retained nitrogen less well than sheep although the digestibility of the crude protein was similar for kangaroos and sheep. The kangaroos appeared to have relatively low energy and nitrogen requirements, probably because of their low metabolic rate, and their weight losses were similar to sheep on the poor-quality diet despite much lower digestible dry matter intakes per unit metabolic body weight. There were no differences between red and grey kangaroos in dry matter digestibilities, nitrogen metabolism, or rate of passage.


1963 ◽  
Vol 61 (3) ◽  
pp. 341-348 ◽  
Author(s):  
I. H. Bath ◽  
J. A. F. Rook

1. A study was made of the effects of feeding regimen and the composition of the diet on the ruminal production of V.f.a.'S in cattle.2. The day-to-day variations in the pattern of rumen fermentation in cows given a diet of hay and concentrates indicated that within-cow differences in the molar proportions of the acids from diet to diet are of significance if they exceed about 3% (of the mean value) for acetic acid, about 10% for propionic and butyric acids, and about 25% for valeric acid. The results emphasized also the important differences to be found between cows given the same diet.3. A change in the frequency of feeding from once to four times daily at a constant daily drymatter intake had little effect on the daily mean values for pH, concentration of total V.f.a.'S, or the molar percentages of the individual acids, but almost invariably decreased the range of values observed between feeding.4. With diets of hay and of hay and concentrates an increase in daily dry-matter intake was associated with a fall in pH and an increase in the concentration of total V.f.a.'S; with the diet of hay and concentrates there was a considerable decrease in the molar percentage of acetic acid and a corresponding increase in N-butyric, but there was little change in the molar percentages of the acids with the diet of hay.


1966 ◽  
Vol 20 (2) ◽  
pp. 229-244 ◽  
Author(s):  
R. C. Campling ◽  
M. Freer

1. Two experiments were conducted to examine the effect of grinding and pelleting roughages on the voluntary intake of food, digestibility, time of retention of food in the digestive tract, amounts of digesta in the recitulo-rumen and eating and ruminating behaviour of adult, non-lactating, non-pregnant cows. The first experiment was with artificially dried grass and the second with oat straw; also, with a diet of ground, pelleted oat straw the effect was studied of giving a daily intraruminal infusion of 150 g urea. The size of the particles of the ground roughages are given. 2. The mean voluntary intakes of long and ground dried grass were similar, the voluntary intake of ground, pelleted oat straw was 26% greater than that of long straw and the daily infusion of urea increased the voluntary intake of ground, pelleted oat straw by 53%. 3. The digestibility of the ground roughages was lower than that of the long roughages, the lower digestibility of the ground roughages was due mainly to the poor digestibility of crude fibre in the reticulo-rumen. The rate of disappearance of cotton thread placed in the ventral sac of the rumen was slower with ground than with long roughages. 4. The mean times of retention of ground roughages were shorter than those of long roughages when equal and restricted amounts of each food were given; with food offered ad lib. there was little difference between the mean times of retention of long and ground roughages in the alimentary tract. 5. On average, the mean amounts of digesta dry matter in the reticulo-rumen immediately after a meal were about the same with long and ground dried grass, with long and ground oat straw the amounts of dry matter were similar, but when the intraruminal infusion of urea was given the amount of dry matter increased by 49%. 6. The rate of eating (min/kg food) ground, pelleted roughages was much faster than that with long roughages; when the cows received ground roughage rumination did not occur but during short periods triple reticular contractions were seen. 7. The relationship between the voluntary intake of food, the amount of digesta in the reticulo-rumen and the rate of disappearance of digesta from the alimentary tract is discussed.


1941 ◽  
Vol 31 (4) ◽  
pp. 488-499 ◽  
Author(s):  
Grahame Williamson

The digestibility coefficients of old barley straw fed with a basal ration of oats, bran and maize to two adult horses and of the same straw after treatment by Beckmann's method were ascertained. The coefficients of the nitrogen-free extractives and the crude fibre of the untreated straw were 33·23 and 38·24 respectively and of the treated straw 54·14 and 63·71. There was a reduction in the digestibility of the small quantity of protein and fat.Taking into account the 14·5% of dry matter lost during treatment, the starch equivalent value of the treated material was somewhat higher than that of poor quality meadow hay.The digestibility coefficients were considerably lower for an immature horse previously maintained entirely on fresh grass.


1972 ◽  
Vol 25 (6) ◽  
pp. 1377 ◽  
Author(s):  
RFH Dekker ◽  
GN Richards

The dry matter digestibility (DMD) of poor quality roughages such as spear grass (Heteropogon contortus) by sheep and cattle has been shown to increase on addition of sulphur to the diet. The sulphur is added most frequently as inorganic sulphate, either alone (Playne 1969) or supplemented with urea (Bray and Hemsley 1969; Kennedy and Siebert 1972; Siebert and Kennedy 1972) or gluten (Playne 1969). These supplements have also increased feed intake in sheep (Playne 1969; Kennedy and Siebert 1972; Siebert and Kennedy 1972) and cattle (Siebert and Kennedy 1972), and have improved the nitrogen and sulphur balance (Moir, Somers, and Bray 1967; Bray and Hemsley 1969; Playne 1969; Kennedy and Siebert 1972) within the animal. Sulphates have been shown to increase the in vitro rumen digestion of starch (Kennedy, Mitchell, and Little 1971), crude fibre (Bray and Hemsley 1969), and acid-detergent fibre and cellulose (Barton, Bull, and Hemken 1971).


1965 ◽  
Vol 16 (2) ◽  
pp. 159 ◽  
Author(s):  
GJ Faichney

An experiment was carried out on sheep to investigate the effect of supplementary energy, in the form of sucrose, on the intake and utilization of a diet of oat straw supplemented with urea. The sucrose supplement had no significant effect on the dry matter intake, although there was a tendency for the intake of straw to decline with an increase in the sucrose supplement. There was no significant effect on the digestibility of dry matter or crude fibre, but the digestibility of crude fibre tended to decrease when the sucrose supplements were fed. This may explain an increase in faecal nitrogen excretion, which was reflected in a significant (P < 0.05) decrease in the apparent digestibility of nitrogen on the diets supplemented with sucrose. There were no significant differences between the diets in rate of passage, rate of cellulose digestion in the rumen, nitrogen balance, body weight gain, rumen pH, or concentrations of volatile fatty acids and ammonia nitrogen in the rumen. It was concluded that the lack of a supplement of readily available energy was not a limiting factor in the sheep's utilization of the diets used.


1961 ◽  
Vol 28 (1) ◽  
pp. 67-74 ◽  
Author(s):  
M. E. Castle ◽  
A. D. Drysdale ◽  
R. Waite

SummarySince grassland conservation crops are normally bulky fibrous feeds and often limit the appetite and nutrient intake of dairy cows, a feeding trial was made in which a basal ration of hay and grass silage was compared with similar rations containing roots. Three rations were compared in a 12–week winter feeding trial using twelve Ayrshire cows. Ration A consisted of 8 lb of hay and 65 lb of grass silage daily, whilst rations B and C contained 30 and 60 lb of fodder-beet, respectively, in addition. With all three rations concentrates were given at 3½ lb per 10 lb of milk. The total weights of dry matter consumed per day were 29·1, 32·5 and 35·4 lb, respectively, for rations A, B and C and were significantly different. For every 1 lb of additional fodder-beet dry matter eaten the decline in the amount of basal feeds consumed was 0·45 lb. The largest effect was on the silage which fell from 10·8 lb of silage dry matter per day for ration A to 8·8 lb for ration B and 6·8 lb for ration C.The weight of starch equivalent (S.E.) given per day increased significantly from 18·1 lb for treatment A to 22·2 lb for treatment C, whilst at the same time the total weight of crude fibre and lignin eaten decreased significantly in the rations containing fodder-beet.The mean daily milk yields for rations A, B and C were 37·4, 39·2 and 38·5 lb, respectively, with a response of 0·9 lb milk per 1 lb of extra S.E. given between rations A and B but no further response between rations B and C. The fat percentages of the milk were not significantly different for the three rations whereas the solidsnot-fat (S.N.F.) varied significantly from 8·58% for ration A to 8·77% for ration C— a response of 0·05% S.N.F. for each additional 1 lb of S.E. The change in the S.N.F. was mainly in the protein fraction of the milk. The cows were significantly heavier when on ration C than when on ration A.The effect of feeding roots on the appetite of the cow and on the resulting milk quality, and the problems of growing roots on intensively managed grassland farms are briefly discussed.


1973 ◽  
Vol 29 (3) ◽  
pp. 347-355 ◽  
Author(s):  
B. Eskelandt ◽  
W. H. Pfander ◽  
R. L. Preston

1. Glucose, and acetic, propionic and butyric acids, the major energy sources available to ruminants, have been comparatively evaluated as energy sources for growth in lambs. The energy sources were administered intravenously at 2·092 and 2·510 MJ metabolizable energy per 24 h for periods of 9–12 d. Nitrogen was given in excess of requirement so that growth rate was limited by energy, as indicated by the increased N retention after intravenous administration of energy.2. The N-balance results from the trials showed that propionic acid promoted a significantly (P < 0·01) higher N retention than acetic acid. In some of the experiments there were no significant differences between propionic and butyric acids, and in others, no significant differences between acetic and butyric acids. Compared with isoenergetic glucose infusion, all volatile fatty acids were less efficiently utilized than glucose. The mean values for N balance (g/d) were 2·31 during control infusion, 6·53, 5·71, 5·48 and 4·59 during glucose, propionate, butyrate and acetate infusions, respectively.3. All energy sources reduced the faecal N excretion significantly. The greatest reduction was observed during butyrate treatment. The mean values for faecal N excretion (g/d) were 4·24 for control, 4·00 for acetate, 3·89 for propionate, 3·83 for glucose, and 3·76 for butyrate infusion. The reduced faecal N excretion after butyrate infusion partly accounts for the increased N retention with that treatment.


1993 ◽  
Vol 56 (1) ◽  
pp. 85-92 ◽  
Author(s):  
D. Cardenas Garcia ◽  
C. J. Newbold ◽  
H. Galbraith ◽  
J. H. Topps ◽  
X. B. Chen ◽  
...  

AbstractThe effect of including 14 g urea with either 75 g dry matter (DM) from sugar cane molasses (UM) or Colombian rice polishings (RP) at three levels, 68 (RP1), 137 (RP2) or 203 (RP3) g DM on grass hay DM intake and on rumen fermentation was investigated. An incomplete Latin-square design was used and each experimental period was divided into 12 days for adaptation to each diet followed by 9 days in metabolism cages when all measurements were made using five adult sheep.Pooled mean values for rumen metabolites (five samples per day) were calculated. Rumen pH was not affected by the nature of the supplements. Concentrations of volatile fatty acids (VFA) (UM 92·8, RP1 84·2, RP2 86·4, and RP3 84·0 (s.e.d. 3·4) mmol/l) and lactate (UM 2·0, RP1 1/6, RP2 1/7, RP3 1/8 (s.e.d. 0·014) mmol/l) (UM v. RP, P < 0·05 and P < 0·10 respectively) were lower when RP were given, while concentration of branched and longer chain VFA (26·5, 34·0, 31·1 and 33·5 (s.e.d. 1·6) mmol/mol total VFA, UM v. RP, P < 0·01) and ammonia (98, 131, 141, 137 (s.e.d. 16·1) mg/l, UM v. RP, P < 0·05) were increased. Numbers of rumen protozoa (1·6, 3·2, 2·7, 3·3 (s.e.d. 0·75) × 105 per ml, UM v. RP, P < 0·20) tended to be higher 2 h after feeding when RP rather than UM were given. However, hay DM intake (1050, 960, 960, 880 (s.e.d. 45·3) g/day, UM v. RP, P < 0·05), and microbial protein supply (11·7, 9·3,11·1,10·8 (s.e.d. 0·59) g N per day, UM v. RP, P < 0·05), estimated from urinary purine excretion were reduced by feeding RP instead of UM.At the levels of inclusion tested RP did not increase the efficiency of rumen fermentation and were not as effective a supplement with urea as was molasses for a low-quality forage diet.


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