SCANNING ELECTRON-MICROSCOPY OF RUMINAL PAPILLAE IN CALVES FED VARIOUS AMOUNTS AND FORMS OF ROUGHAGE

  • 1 January 1976
    • journal article
    • research article
    • Vol. 37  (5) , 497-508
Abstract
Neonatal calves (20) were fed milk plus 1 of 4 rations ad lib: pelleted concentrates plus alfalfa hay, pelleted concentrates plus ground alfalfa hay, pelleted concentrates alone or pelleted concentrates containing whey. Eight calves were killed at 4 wk of age, and 12 calves at 6 wk. The ruminal mucosa was examined grossly, by light microscopy and by scanning EM. Well-developed differences among groups were evident in calves at 6 wk of age; changes at 4 wk were similar, but less developed. In 6 wk old calves fed concentrates plus alfalfa hay ad lib, papillae were flattened and tongue-shaped on the ventral floor of the atrium ruminis (cranial sac). Calves fed concentrates plus ground alfalfa had tongue-shaped, rounded and finger-like papillae. Calves fed concentrates alone or concentrates plus whey developed small, nodular, branched papillae which were cauliflower-shaped, severely parakeratotic and arranged on transverse folds on the floor of the atrium ruminis and on zigzag folds elsewhere in the rumen, except on the dorsal wall in contact with the gas bubble. The transition from tongue-shaped to nodular-shaped papillae under the influence of ration occurred last on the floor of the atrium ruminis. In 6 wk old calves, that site generally is not typical of changes in most ruminal papillae.