Record Details
A comparison of in vivo and in vitro techniques for the evaluation of varying roughage-concentrate rations
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | A comparison of in vivo and in vitro techniques for the evaluation of varying roughage-concentrate rations |
| Names |
Klett, Ramon Hollis
(creator) Ralston, A. T. (advisor) |
| Date Issued | 1966-04-28 (iso8601) |
| Note | Graduation date: 1966 |
| Abstract | The objective of this study was to compare the total collection (in vivo), nylon bag, and in vitro digestibility techniques under standardized conditions. Twin steers were used simultaneously to measure the digestibility of five rations consisting of the following ratios of alfalfa hay to steamed roller barley: 4:0 (I), 3:1 (II), 2:2 (III), 1:3 (IV), and 0:4 (V). One trial was completed in the in vivo study using a six day collection period, whereas two trials were run for each of the other two techniques. Fermentation periods of 24, 48, and 72 hours or 12 and 24 hours were used for the nylon bag and in vitro studies, respectively. In vivo energy, crude protein, ether extract, and dry matter digestibility and TDN increased as the roughage: concentrate decreased from 4:0 to 0:4. The inverse relationship was noted for cellulose and crude fiber digestibility. The variability in dry matter digestibility, as measured by standard deviations and coefficients of variation, was highest in the nylon bag and lowest in the in vivo procedure. The difference between trials, using dry matter digestibility as the criterion, was generally non-significant for both the nylon bag and in vitro techniques. It was concluded that repeatability between trials is not a factor when using these techniques if sufficient replications are used. Differences between animals within rations were greater than expected; however, when the data were pooled across all rations, the steers were not significantly different. The rate and variability of nylon bag and in vitro dry matter and cellulose digestion was greatest in the first digestion period in each of the five rations. However, as the rations included concentrates, the rate of nylon bag dry matter and cellulose digestion decreased in the same period. A comparison of the three techniques,using the mean dry matter and cellulose digestion coefficients,showed the in vivo dry matter digestion to compare closely with the 48 hour nylon bag and 24 hour in vitro digestion. The nylon bag and in vitro cellulose digestibility underestimated the in vivo digestion of cellulose. The nylon bag dry matter digestibility at 48 and 72 hour fermentation periods and in vitro dry matter digestibility at 12 and 24 hours was significantly correlated with the in vivo digestibility of ether extract, energy, dry matter, cellulose, and crude fiber. Similar correlations were obtained when nylon bag and in vitro cellulose digestion was correlated with in vivo digestibility of the chemical components. Correlation coefficients between the nylon bag and in vitro techniques, using dry matter and cellulose digestion as criteria, showed a close relationship at the longer digestion periods. Regression equations developed from these correlations showed no significant (P < .01) difference between the predicted and actual in vivo dry matter digestibility of eight substrates when using equations developed from the nylon bag and in vitro dry matter digestibility in this study. The effect of inoculum source on substrate digestion was studied using the in vitro technique. The data showed that all-roughage and all-concentrate substrates are digested more completely with inoculum from animals maintained on the same diet. However, when measuring the digestibility of a mixed substrate (roughage and concentrate), the most accurate results, as measured by a standard, were obtained when using an inoculum from donor animals maintained on a mixed diet, regardless of the proportion of roughage and concentrates. |
| Genre | Thesis/Dissertation |
| Topic | Digestion |
| Identifier | http://hdl.handle.net/1957/47596 |
