Changes in feed intake and digestibility in sheep given virginiamycin

1996 ◽  
Vol 47 (4) ◽  
pp. 539 ◽  
Author(s):  
GR Thorniley ◽  
MD Boyce ◽  
JB Rowe

An experiment was conducted to investigate why virginiamycin reduces feed intake when it is first included in diets fed to sheep and cattle. Sheep were dosed daily with various amounts of virginiamycin, and measurements were made of both in vitro and in vivo dry matter digestibility and of blood gastrin concentrations. Virginiamycin decreased feed intake and there was some evidence that the effect was dose related. Dry matter digestibility was reduced by doses of virginiamycin >80 mg/day. Although highly correlated with feed intake, digestibility did not seem to be the sole factor influencing feed intake. Blood gastrin concentration was not significantly affected by virginiamycin and was not correlated with feed intake.

1971 ◽  
Vol 22 (5) ◽  
pp. 787 ◽  
Author(s):  
GD Brown ◽  
JC Radcliffe

Twenty experimental silages were made from seven pasture species at different stages of maturity. In vivo dry matter, organic matter, and energy digestibilities of the silages were determined at restricted and ad libitum intake levels on standardized pairs of Merino wethers. In vitro dry matter digestibility determinations were made on ground frozen silage and ground oven-dried silage with and without a correction for the loss of volatile compounds during drying. Corrected in vitro dry matter digestibilities of ground oven-dried silage for a 48 hr rumen liquor digestion time gave the most accurate prediction of in vivo dry matter (r = 0.88), organic matter (r = 0.86), and energy (r = 0.74) digestibilities for restricted intake levels. In vitro digestibilities of ground frozen silage more accurately predicted in vivo digestibilities than did in vitro digestibilities of ground oven-dried silage without the correction for volatile losses. In vivo dry matter and organic matter digestibilities were highly correlated (v = 0.97), but both were poorly correlated with in vivo energy digestibilities. In vitro digestion of ground oven-dried silage with a correction for the volatile compounds lost during drying is recommended as a suitable routine determination for predicting the in vivo digestibility of silage.


1973 ◽  
Vol 80 (2) ◽  
pp. 283-296 ◽  
Author(s):  
W. R. McManus ◽  
M. L. Bigham

SummaryFood intake prediction relationships were developed from in vitro dry-matter digestibility determinations on food and resultant faecal material for a number of diets ranging from low quality roughage to high quality irrigated pastures.The relationship between true digestibility in vitro and in vitro food dry-matter digestibility was curvilinear, although true digestibility of food dry matter in vivo was highly correlated with apparent digestibility of food dry matter in vivo. The latter relationship was linear.For 122 sheep observations on voluntary dry-matter intake incorporating 11 diet types, introduction of either of the terms, cell-wall concentration in food: cell-wall concentration in the resultant faeces (CWFo/CWFe), or its converse, into conventional faecal index relationships did not increase precision of intake prediction using faecal nitrogen as an indicator substance. However, significant intake prediction relationships using food:faeces cell-wall ratios were generated.Values for in vitro digestibility of food and resultant faeces dry matter expressed as either a ratio (R) or as a difference (delta) yielded useful prediction relationships. For ‘green’ and for ‘dry’ classifications of the feedstuff's investigated some of these new relationships were either equal to or superior to the predictive efficiency of conventional faecal index relationships.Reasons are discussed for use of maximum potential in vitro digestibility values for food and faecal dry matter in such relationships in future work rather than a conventional 48 h fermentation.


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).


2009 ◽  
Vol 49 (7) ◽  
pp. 563 ◽  
Author(s):  
David B. Coates ◽  
Robert J. Mayer

In a study that included C4 tropical grasses, C3 temperate grasses and C3 pasture legumes, in vitro dry matter digestibility of extrusa, measured as in vitro dry matter loss (IVDML) during incubation, compared with that of the forage consumed, was greater for grass extrusa but not for legume extrusa. The increase in digestibility was not caused by mastication or by the freezing of extrusa samples during storage but by the action of saliva. Comparable increases in IVDML were achieved merely by mixing bovine saliva with ground forage samples. Differences were greater than could be explained by increases due to completely digestible salivary DM. There was no significant difference between animals in relation to the saliva effect on IVDML and, except for some minor differences, similar saliva effects on IVDML were measured using either the pepsin–cellulase or rumen fluid–pepsin in vitro techniques. For both C4 and C3 grasses the magnitude of the differences were inversely related to IVDML of the feed and there was little or no difference between extrusa and feed at high digestibilities (>70%) whereas differences of more than 10 percentage units were measured on low quality grass forages. The data did not suggest that the extrusa or saliva effect on digestibility was different for C3 grasses than for C4 grasses but data on C3 grasses were limited to few species and to high digestibility samples. For legume forages there was no saliva effect when the pepsin–cellulase method was used but there was a small but significant positive effect using the rumen fluid–pepsin method. It was concluded that when samples of extrusa are analysed using in vitro techniques, predicted in vivo digestibility of the feed consumed will often be overestimated, especially for low quality grass diets. The implications of overestimating in vivo digestibility and suggestions for overcoming such errors are discussed.


2017 ◽  
Vol 48 (2) ◽  
pp. 63-69
Author(s):  
M. Joch ◽  
V. Kudrna ◽  
B. Hučko

AbstractThe objective of this study was to determine the effects of geraniol and camphene at three dosages (300, 600, and 900 mg l-1) on rumen microbial fermentation and methane emission in in vitro batch culture of rumen fluid supplied with a 60 : 40 forage : concentrate substrate (16.2% crude protein, 33.1% neutral detergent fibre). The ionophore antibiotic monensin (8 mg/l) was used as positive control. Compared to control, geraniol significantly (P < 0.05) reduced methane production with increasing doses, with reductions by 10.2, 66.9, and 97.9%. However, total volatile fatty acids (VFA) production and in vitro dry matter digestibility were also reduced (P < 0.05) by all doses of geraniol. Camphene demonstrated weak and unpromising effects on rumen fermentation. Camphene did not decrease (P > 0.05) methane production and slightly decreased (P < 0.05) VFA production. Due to the strong antimethanogenic effect of geraniol a careful selection of dose and combination with other antimethanogenic compounds may be effective in mitigating methane emission from ruminants. However, if a reduction in total VFA production and dry matter digestibility persisted in vivo, geraniol would have a negative effect on animal productivity.


1974 ◽  
Vol 57 (5) ◽  
pp. 1224-1226
Author(s):  
Surendra K Arora ◽  
Bhagwan Das

Abstract A simple device, a fibrometer, has been devised for measuring the bulk value of a forage sample. The bulk value obtained by using the fibrometer was significantly and negatively correlated with acid-detergent fiber and cellulose. It was also significantly and positively correlated with in vivo and in vitro dry matter digestibility. This method reduces the effort required to analyze a large number of breeding materials for nutritional value and is also economical.


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