Growth and Rumen Characteristics of Holstein Steers Fed Pelleted or Conventional Diets

Abstract

Holstein steers were group-fed a pelleted complete feed or a ration of long hay and concentrate between ages 18 and 32 wk. Eight of each group were slaughtered at 32 wk; four of each were continued to 36 wk on the control diet. The pelleted diet was higher than control in acid detergent fiber and lignin and lower in protein and in vitro dry matter disappearance. Steers fed pellets consumed 6.0 kg dry matter/kg gain and controls, 5.0. Gains in weight, height, and chest circumference were identical. Rumen walls of the experimental group were thinner than those of controls; papillae were longer, poorly attached, often large and paddle shaped with crusted or eroded tips. Rumen contents were greater in volume, higher in density, and appeared foamy in the pellet-fed group. There was moderate hyperkeratosis in six of eight pellet-fed rumens at age 32 wk, none in controls. Four steers converted from pellets to control diet from age 32 to 36 wk tended toward reversal of effects on the rumen and approached controls. Control steers had higher blood and rumen acetate, lower rumen propionate, and similar blood (β-hydroxybutyrate, glucose, hematocrit, and packed cell volume compared with those pellet-fed. Carcass measurements were similar. © 1980, American Dairy Science Association. All rights reserved.