Modeling digesta mean retention time in horses using a 2-compartment model

2019 ◽  
Vol 76 ◽  
pp. 88
Author(s):  
T.L. Hansen ◽  
J.M. Bobel ◽  
A.M. Adkin ◽  
K.J. Brinkley-Bissinger ◽  
E.L. Chizek ◽  
...  
1980 ◽  
Vol 31 (6) ◽  
pp. 1129 ◽  
Author(s):  
GJ Faichney

Knowledge of the fractional outflow rates of rumen digesta constituents is required for the quantitative prediction of rumen function. However, there are few data available for these parameters because of the problems associated with specific labelling of digesta constituents and with the need to ensure that samples are truly representative of rumen digesta. Methods are described here by which two markers can be used together to overcome the problem of representative sampling of the rumen, so eliminating the need for specific labelling, with 'ideal' markers, of digesta constituents. Thus, from the measurement of the amount and composition of true digesta in the rumen and the amount and composition of true digesta flowing from the abomasum, values for the fractional outflow rates (and its reciprocal, mean retention time) of rumen digesta constituents can be calculated. Appropriate application of these methods will allow the derivation of functions to predict fractional outflow rates. The results presented show that the fractional outflow rate of an adsorbable marker, 103Ru-P, was about half that of water but was about twice that of particulate matter; it was also greater than the net value for microbes. On the assumption that microbial material leaving the rumen is drawn from a free-floating microbial population and a population associated with particulate matter, it was calculated that 0.29 � SE 0.07 (range 0.09-0.49) of the rumen microbial population could have been free-floating.


2014 ◽  
Vol 92 (3) ◽  
pp. 1099-1109 ◽  
Author(s):  
J. G. L. Regadas Filho ◽  
L. O. Tedeschi ◽  
R. A. M. Vieira ◽  
M. T. Rodrigues

1987 ◽  
Vol 109 (3) ◽  
pp. 545-549 ◽  
Author(s):  
B. Fadlalla ◽  
R. N. B. Kay

SummaryThe suitability of stained food and [103Ru]phenanthroline-treated food as markers for measuring dietary retention time was examined in sheep. The digestibility of oat husk, assessed by incubation of samples contained in nylon bags in the rumen, was greatly depressed by staining with brilliant green, and slightly depressed by basic fuschsin. The latter effect appeared largely to be due to boiling rather than the stain itself.When milled hay treated with both basic fuschsin and [103Ru]phenanthroline was introduced into the rumen, the mean retention time estimated with the stain was about 40% longer than that estimated with [103Ru]phenanthroline.


1985 ◽  
Vol 53 (3) ◽  
pp. 559-567 ◽  
Author(s):  
J. E. Lindberg

1. Sheep were given a diet of 400 g chopped grass hay/d and 500 g crushed barley/d in three equal meals. The mean retention time in the whole gut (MRT) and the rumen retention time (RRT) of chromium-labelled feed particles and of water were estimated from marker concentrations in faecal samples.2. MRT of Cr-labelled hay (Cr-H), barley hulls (Cr-Bh), crushed peas (Pisum sativum) (Cr-CP) and rapeseed meal (Cr-RSM) were 53.5, 52.3, 44.3 and 37.0 h respectively when estimated from total faecal collections. The estimates obtained from spot samples of faeces were almost identical.3. RRT of Cr-H, Cr-Bh, Cr-CP, Cr-RSM (Expts 1, 2 and 3) and Cr-labelled cottonseed meal (Cr-CSM) was 35.9, 36.7, 25.3, 18.8, 19.8, 22.8 and 25.3 h respectively.4. The Cr-labelled feed particles showed marked variations in density in water (Dω). However, both MRT and RRT were closely related to Dω, (r—0.88 and —0.95 respectively).5. Rumen outflow rates of Cr-RSM in individual animals were related to the rumen outflow rates of water (r 0.76).


1990 ◽  
Vol 31 (1-2) ◽  
pp. 117-124 ◽  
Author(s):  
N. Silanikove ◽  
A. Brosh ◽  
Z. Holzer ◽  
D. Levy

1983 ◽  
Vol 23 (120) ◽  
pp. 14 ◽  
Author(s):  
NG Yates ◽  
RJ Moir

Oaten hay in either long or milled form, with or without a continuous intra-ruminal infusion of urea at the rate of 160 g/d, was offered ad libitum to four rumen fistulated steers in a 4 x 4 Latin square design experiment. Milling increased dry matter intake from 49.2 to 65.4 g/kg LW0 75.d (P< 0.001) and decreased mean retention time from 66.7 to 54.2 h (P< 0.001). Rates of cellulose digestion and dry matter digestibilities were similar for long and milled hay. Urea increased dry matter intake (from 49.0 to 65.6 g/kg LW0 75.d; P< 0.001), dry matter digestibility (from 58.1 to 65.3%; P< 0.01) cellulose digestibility (from 48.5 to 63.1%; P< 0.01) and the rate of cellulose digestion (P< 0.001), and decreased mean retention time from 65.3 to 55.6 h ( P < 0.01). Digestible dry matter intakes increased 29% with milling and 52% with urea and the effects were additive. Urea increased digestible cellulose intake to a greater extent with milled hay (91 %) than with long hay (64%). Digestible dry matter intake was closely related to liveweight change. When urea was given liveweight gain was higher for milled hay than for long hay (0.69 vs 0.11 kg/head.d) and without urea liveweight loss was less for milled hay than for long hay (-0.07 vs -0.45 kg/head.d). Nitrogen digestibility and balance were significantly higher when urea was given. Total volatile fatty acid concentrations were significantly higher and rumen pH significantly lower with urea compared with no urea and with milled hay compared with long hay. Urea increased rumen-ammonia concentration from 1.65 to 19.68 mg1100 ml (P< 0.001) and total free bacterial concentration (P < 0.05). The results demonstrate significant and additive benefits from the administration of urea to hay containing 0.8% nitrogen and from milling through a screen size of 7.6 mm.


2007 ◽  
Vol 109 (1-3) ◽  
pp. 27-29 ◽  
Author(s):  
A. Wilfart ◽  
L. Montagne ◽  
H. Simmins ◽  
J. Noblet ◽  
J. van Milgen

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