scholarly journals Role of rumen protozoa in nitrogen digestion in sheep given two isonitrogenous diets

1986 ◽  
Vol 56 (2) ◽  
pp. 407-419 ◽  
Author(s):  
K. Ushida ◽  
J. P. Jouany ◽  
P. Thivend

1. The effect of protozoa on digestion in the rumen was studied using either defaunated or faunated sheep.2. Six wethers, each fitted with rumen and simple duodenal cannulas, were given two isonitrogenous diets containing either lucerne (Medicago sativa) hay (diet L) or sodium hydroxide-treated wheat straw (diet S). The diets were given in eight equal portions per day at 3-h intervals. The mean intake of dry matter, 53 g/kg body-weight0.75per d, was similar for the two diets and each diet had a similar digestible organic matter content. Diet L promoted a large protozoal population and was rich in nitrogen sources of low rumen-degradability, while diet S supported a smaller protozoal population and was rich in rumen-degradable N.3. Digesta flow at the duodenum was estimated by means of a dual-marker technique using chromium-mordanted lucerne hay and polyethylene glycol as markers. The microbial flow at the duodenum was estimated using diaminopimelic acid (DAPA), nucleic-acid purine bases (PB) and35S incorporation simultaneously. The different microbial markers were compared in the defaunated sheep. Protozoal N contribution was estimated in faunated sheep.4. Defaunated sheep had lower rumen ammonia concentrations and molar proportions of butyric acid than faunated sheep, but they had higher molar proportions of propionic acid.5. Rumen organic matter digestion was reduced by defaunation, but this decrease was compensated for by increased intestinal digestion.6. There was a net increase of N flow (approximately 10 g/d) between mouth and duodenum in defaunated sheep. This was explained by increases in both microbial and dietary N flows from the rumen compared with faunated sheep.7. The influence of protozoa on solid- and liquid-phase retention times in the rumen is discussed, as well as the protozoal contribution to microbial N flow in the duodenum of faunated sheep.

1973 ◽  
Vol 24 (6) ◽  
pp. 889 ◽  
Author(s):  
RF Thornton ◽  
DJ Minson

Eight grasses and six legumes were fed ad libitum at hourly intervals to wethers fitted with large rumen fistulas to determine voluntary intake, apparent digestibility, and the apparent retention time of organic matter in the rumen, as well as the quantity of rumen digesta and the organic matter content of the rumen digesta. The voluntary intake of legumes was 28% higher than that of equally digestible grasses. This difference was caused by a shorter retention time (17%) and a higher amount of organic matter (14%) in the rumen digesta from legume diets than from grass diets. The weight of wet digesta in the rumen of sheep fed on legumes was 7% lower than from those fed on grass. Neither the quantity of digesta nor the quantity of organic matter in the rumen was related to the voluntary intake, digestibility, or retention time of organic matter in the rumen. Number of jaw movements each day and rate of cotton thread digestion were not related to the retention time of the diets either. Daily intake of digestible organic matter (DOMI, g/day) was closely correlated with retention time (RTOM, hr) for the feeds in this study (r = –0.93) and the same relation applied to both temperate and tropical feeds, viz. DOMI = 1276–50.7 RTOM (r=0.96) Differences in voluntary intake between grasses and legumes were attributed to differences in retention time and the density to which the food was packed in the rumen.


1968 ◽  
Vol 8 (33) ◽  
pp. 401 ◽  
Author(s):  
P McInnes ◽  
PJ Austin ◽  
DL Jenkins

At the end of 23 weeks the mean daily dry matter intake of Merino weaners was 190 g of poultry litter and 235 g of wheat. The mean weekly body weight gain, 210 g per sheep, was not significantly different to weaners that consumed a mean daily dry matter intake of 365 g of wheat grain and gained 180 g weekly. The mean digestible organic matter content of wheat and poultry litter were calculated to be 88 and 31 per cent respectively. Weaners fed wheat only were not supplemented with limestone (1.5 per cent) for 13 weeks by which time two of the eight weaners had serum calcium levels below 8 mg per 100 ml. One of these weaners had gained weight, the other had lost weight and died three weeks after limestone supplementation. The addition of limestone did not increase the mean serum calcium levels significantly, but at the end of the trial all weaners had levels above 8 mg per 100 ml. ' Serum glutamate oxalacetate transaminase and bilirubin concentrations were higher for weaners fed wheat-litter mixture, but below levels normally associated with liver dysfunction. Reasons for caution in the use of poultry litter in the manufacture of commercial feedstuffs for ruminants are discussed.


1980 ◽  
Vol 20 (107) ◽  
pp. 674 ◽  
Author(s):  
D Hamilton ◽  
JJL Maden

Steers of 252 kg initial mean liveweight were fed 0.44 kg of hay dry matter (DM)/head day-1 plus five rates of whole oats, crushed wheat or whole wheat, with the crushed wheat rations providing 0.7 to 1.3 times the estimated energy for maintenance. All-grain rations at these energy levels had been attempted, but resulted in digestive upset, and were abandoned. The results obtained, listed in the order of the above grains, were : 1 ) grain in ration to maintain liveweight: 1.31, 1.41 and 1.85 kg DMIhead day-1 ; 2) additional grain for each 10 kg improvement in liveweight over I2 weeks: 434,466 and 61 3 g DMIhead day-1 ; 3) mean digestible organic matter content (DOM) of rations, tested at the highest and lowest rates of grain : 69.4, 84.5 and 68.3%. The DOM of the oat rations declined by 8.1 units from the lowest to highest rate of grain. The relative liveweight change on oats could not be explained by the DOMs. Nevertheless, the results suggest, for similar conditions to those applying in our experiment, that: 1) whole oats may be at least as good a feed as crushed wheat, and both will be much better than whole wheat; 2) the feed requirement for maintenance may be about 20% less than standard recommendations; 3) even a little hay in the ration, compared with grain only, may greatly reduce the likelihood of digestive upset


1996 ◽  
Vol 1996 ◽  
pp. 41-41
Author(s):  
A.T. Adesogan ◽  
E. Owen ◽  
D.I. Givens

Estimates of the metabolisable energy (ME) content of whole crop wheat (WCW) derived using measured energy losses as methane (ELMm) are lacking due to the cost of measuring ELMm. Published ME values of WCW are largely calculated using predicted energy losses as methane (ELMp, Blaxter and Clapperton, 1965) or digestible organic matter content (DOMD) in vivo. However, there appears to be no published information about the accuracy with which DOMD in vivo or ELMp predicts the ME content of WCW. Therefore, this study assessed the validity of such ME predictions by comparing them with ME contents calculated using ELMm.


1988 ◽  
Vol 28 (4) ◽  
pp. 439 ◽  
Author(s):  
DW Hennessy ◽  
PJ Williamson

In the coastal subtropics of New South Wales, pasture growth occurs mainly in summer, when 500-600 mm of rain is expected. During winter, pasture quality declines, with digestible organic matter content as low as 374 g/kg DM in August and nitrogen down to 6.5 g/kg DM. Growth and reproduction of British breed cattle is also low so that, in an attempt to increase these attributes, protein meal supplements were offered to Hereford heifers and cows over 5 years. Heifers without supplements lost liveweight during their first winter and none calved after being mated at 15 months of age to Hereford bulls during a 9-week joining period. During their second winter, 58% of the heifers calved and, over 5 mating seasons, their mean annual calving rate was 48%. Supplemented heifers gained liveweight during their first winter and 95% of them calved, after first-joining at 15 months of age. Over 5 years their mean calving rate was 85%. Delaying first-joining to 27 months of age, as determined by a second group also supplemented with protein meal, did not increase production or mean calving rate (81%) over 5 years. The 230-day adjusted liveweight of calves weaned from non-supplemented heifers was 138 kg, significantly (P< 0.01) less than the 179 �10 kg (mean � s.e.d.) for calves weaned from the supplemented early-calving group, or 198 kg for the supplemented late-calving group. The results highlight the limitation to cattle production imposed by the low levels of nitrogen and poorly digestible pasture, and emphasise the important role of protein meal supplements with added minerals in increasing production of breeding herds grazing unimproved pastures in the subtropics.


1977 ◽  
Vol 25 (3) ◽  
pp. 397-400 ◽  
Author(s):  
M. E. Castle ◽  
W. C. Retter ◽  
J. D. Metcalfe

SUMMARYGrass silage with a dry-matter content of 20·7%, and containing 18·9% crude protein and 67·0% digestible organic matter in the dry matter was self-fed to 20 lactating dairy cows for 18 weeks. In addition, 9 kg of brewers' grains with a dry-matter content of 28·8% was offered to each cow daily. The two supplement treatments were a barley mix and a groundnut cube containing 11·9 and 33·5% crude protein in the dry matter respectively. The barley was given at the rate of 4 kg/10 kg milk, and the groundnut at 1·5 kg/10 kg milk. The mean daily yields of milk were 18·9 and 19·4 kg/cow on the barley and groundnut treatments respectively and did not differ significantly.


Geoderma ◽  
2013 ◽  
Vol 209-210 ◽  
pp. 177-187 ◽  
Author(s):  
E.S. Vogelmann ◽  
J.M. Reichert ◽  
J. Prevedello ◽  
C.O.B. Consensa ◽  
A.É. Oliveira ◽  
...  

Author(s):  
D I Givens ◽  
Jeannie M Everington

Despite its importance, relatively few measurements have been made of the metabolisable energy (ME) content of fresh herbage. Changes in the nutritive value of spring herbage are commonly described in terms of its digestible organic matter content (DOMD) either measured in vitro or predicted from a fibre fraction. ME is normally assumed to be directly proportional to DOMD.Energetic studies of herbage such as those of Armstrong (1964) and Beever et al (1985) have been restricted to pure species and one location. The purpose of the present experiment was to examine changes in DOMD and energy values with increasing maturity in vivo using sheep in commercial swards over several years.


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