THE EFFECT OF NUTRIENT COMPOSITION ON THE VOLUNTARY INTAKE AND APPARENT DIGESTIBILITY OF FIRST- AND SECOND-CUT GRASS HAYS PREPARED IN PRINCE EDWARD ISLAND

1982 ◽  
Vol 62 (4) ◽  
pp. 935-939 ◽  
Author(s):  
P. NARASIMHALU ◽  
K. A. WINTER ◽  
H. T. KUNELIUS ◽  
K. B. McRAE

Hays prepared in Prince Edward Island from the primary growths of Rise reed canarygrass, Tardus orchardgrass, Saratoga bromegrass, Itasca timothy, and Trader meadow fescue cut in mid- to late June, and from their regrowths cut 7–8 wk later, were studied for the interrelationships among cell wall components, in vitro dry matter disappearance values, and in vivo determined values of voluntary intake of digestible energy (DEI) and apparent dry matter digestibility (DMD). The in vivo values for each hay were measured on four wether lambs during a 24-day feeding trial. Simple correlation coefficients were calculated among neutral (NDF) and acid detergent fibers (ADF), lignification (= log10 (lignin/ADF)), two-stage in vitro dry matter disappearance (IVDMD), acid-pepsin solubility (APDMD), DEI, and DMD. The content of NDF was not correlated with either DEI or DMD value for the first-cut and second-cut hays (P > 0.10). First-cut hays showed correlations between lignification and DMD (r = −0.88, P < 0.05) and between APDMD and DEI (r = 0.87, P < 0.10). Second-cut hays indicated the following correlations: ADF with DMD (r = −0.98, P < 0.01), and IVDMD with both DMD (r = 0.97, P < 0.01) and DEI (r = 0.95, P < 0.05). Lignification showed promise as a predictor of DMD and APDMD could predict DEI for the first-cut hays prepared in this region. In the case of second-cut hays, the ADF or IVDMD could predict DMD, whereas APDMD or IVDMD may prove useful in predicting the DEI value of local hays.

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.


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.


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.


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.


1978 ◽  
Vol 26 (2) ◽  
pp. 203-215 ◽  
Author(s):  
Janet Z. Foot ◽  
A. J. F. Russel

ABSTRACTThe voluntary intake of two hays and one dried grass by 48 mature non-pregnant Blackface ewes was measured for 33 weeks. The apparent dry-matter digestibility coefficients of the diets in vitro were 59, 61 and 77% respectively for the hays and the dried grass. At the end of the first phase of the experiment each group of 16 ewes was split into two subgroups of five animals, each of which was subsequently given one of the other diets, and one subgroup of six animals which remained on the same diet. Food intake was measured for a further 8 weeks. Body fat was estimated at intervals from tritiated water space.The amount of variation in voluntary food intake that could be attributed to variation in live weight and fatness of the animals and in apparent dry-matter digestibility and cell wall constituents of the diet was calculated for various periods.The range of live weight and fatness increased during the experiment. Initially, and after the change in diets, variation in apparent dry-matter digestibility had an important positive effect on intake, but at the end of the 33-week phase its influence was negligible or, when fat weight was not considered, negative. The negative effect of fat weight on intake increased during the experiment.Within individual diets during short periods of time (1 to 5 weeks) the highest proportions of the variation in intake that could be attributed to variation in live weight and fatness of the ewes were 50, 94 and 65% respectively for the hays and the dried grass. Taking all three diets together all the variables considered could explain 75% of the variation for a few weeks at a time, but for longer periods seasonal influences, and other factors not included among the independent variables, probably operated.


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