Comparative study of €œin vivo€ digestibility of forage grasses and com silage with sheep and cattle. I. €” Dry corn

Abstract

The digestibility of dry com and silage com was studied using two ruminant species, sheep and cattle. The trials were carried out using the conventional method (total feces collection). During the experiment sheeps were kept in crats and equiped with harness for feces collection; while the cattle was kept in individual stalls and also equiped with harness for feces collection. Each trial was divided into three periods: 1) adaptation, with 14 days of duration for both species; 2) adjustment with 7 days for ovine and 14 days for bovine; 3) collection, with 7 days for ovine and 12 days for bovine. The animals were fed ad libitum except for the last three days of the adjustment period and during the whole collection period when they were fed 80% of the ad libitum intake. The 5 experiments were: A €” com silage (1), B €” com silage (II), C €” whole ground mature com plant; D €” com silage III, E €” com silage (0.5% of urea added at ensiling time). In experiment A, digestibility coefficients were higher for bovine for dry matter, crude fiber, organic matter (P <0.05) and for gross energy (P < 0.01). In experiment B no differences were found between sheep and cattle, except for crud protein, which was digested better by bovine (P < 0.01). Sheep presented higher digestibility of dry matter, crude protein, nitrogen free extract, and organic matter (P < 0.01) and of grass energy (P < 0.05). In experiment D although total digestible nutrients were higher for cattle than sheep (P < 0.01). In experiment E, cattle digested dry matter, crude fiber, gross energy and organic matter better than sheep (P < 0.01). In experiment C, sheep had higher digestibility coefficients for nitrogen free extract (P < 0.05) and for ether extract (P < 0.01) than cattle.