The Effect of Ensiling on Crop Digestibility

Abstract

The digestibilities of 22 herbages, and of the silages made from them, were measured with sheep: in two experiments batches of the same herbage were ensiled by several different methods. In every case the digestibilities of herbage and of the corresponding silages were found to be very similar, and no significant effect of method of ensilage on digestibility was found. The importance of using the true dry-matter content of silages (i.e. corrected for losses of volatile constituents during drying) is emphasized; a depression in the digestibility of herbage during ensilage is likely to be estimated unless this correction is made. These experiments have shown that silage of high digestibility (>80%) can be made from highly digestible herbage; however the intakes, both of dry matter and of digestible dry matter, from such silages were found to be much lower than expected. If the potential for animal production of high digestibility in silage is to be exploited, intakes must be increased; two possible measures, viz. the wilting of herbage before ensilage, and the use of high-digestibility forages of high soluble carbohydrate contents, are discussed. INTRODUCTION It is widely recognized that the digestibility of herbage decreases as it becomes more mature, and that this is reflected in a decreasing digestibility of the corresponding conserved crops. Studies at a number of centres have indicated that it should be possible to predict the digestibility of cut herbage from inforniation on the herbage species and variety, the date of cutting and the previous management (13,21). Such information would be of particular use in conservation practice if it were possible also to predict the digestibility of the conserved products made from the cut herbage.Investigations of haymaking methods (23) have shown that the digestibility of the cut herbage has a major effect on the digestibility of the resulting hay, but that the latter is also affected by the efficiency of the conservation process. Similar quantitative evidence is however lacking for silage, particularly in regard to the digestibility of silages made from highlydigestible immature herbage. Clearly two effects must be studied: first the overall relationship between the digestibility of herbages and that of the resulting silages, and second the possible modifying effect of the 204 method of ensilage. An effect of herbage digestibility was reported by Dodsworth and Campbell (9) who found that delay in the date of cutting of herbage led to lowered digestibility of silage. Sears et al. (22) found that herbages of different digestibilities gave ensiled products which also differed in digestibility. Most available evidence suggests that the effect of ensilage method on silage digestibility is not marked. Watson and Ferguson (25) found that the digestibilities of herbage ensiled without additives, or with molasses or mineral acids, were very similar, and also similar to the digestibility of the original herbage. Camburn et al. (5) found similar digestibilities for silages...

The Feeding Value of Silages Made From Whole‐crop Barley

“…This observation agrees with the higher intakes of forages conserved by drying, rather than ensiling, which have been reported on numerous occasions (13,14,19).…”

Effect of formaldehyde treatment on the chemical composition and nutritive value of silage

“…Compared with feeding fresh pasture, ensiling herbage by conventional methods causes a marked reduction in voluntary intake (Harris & Raymond 1963;Bryant & Lancaster 1970). However, the dry matter intake of HCHO-treated silage in this experiment was similar to that found in other experiments when fresh pasture of comparable digestibility was fed to sheep of the same breed and age (3.07% of live weight; Barry unpublished), suggesting the HCHO treatment process used here had not caused a reduction in intake.…”

“…Less dry matter is consumed as silage than when the same herbage is fed as fresh pasture (Harris & Raymond 1963;Bryant & Lancaster 1970) or is conserved as hay (Gordon et al 1961).…”

BROWN MIDRIB-3 VERSUS NORMAL CORN PLANTS (Zea mays L.) HARVESTED AS WHOLE PLANT OR STOVER AND FROZEN FRESH OR PRESERVED AS SILAGE FOR SHEEP

“…silage, lignin, corn stover, sheep Lignin is known to decrease digestibility et al 1977) a greater growth, intake and of plants (Ely et al 1953; Dehority et Gordon and Neudoerffet 1913; tibility of plants by breeding for less lig- Keith et al 1979 Lechtenberg et al 1972). In ad-bn versus normal corn silage (Rook et (Demarquilly and Jarrige 1970;Harris and corn plants (Colenbrander et al I972, Raymond 1973). However, this reduction 1973However, this reduction , 1975Frenchick et al 1976).…”