Abstract

The relationships between sward height, bite dimensions and bite weight for one-year-old Friesian steers and bulls were examined. Eighteen turfs of uniform area of each of 3 pasture heights (5, 10, 15 cm) were cut from a ryegrass dominant sward in early spring and placed in polystyrene boxes. Sward height was measured prior to grazing and swards trimmed where necessary so that height in the surface horizon was uniform. The turfs were offered over 3 days to 3 bulls and 3 steers in a latin square design so that each animal had 20 bites of a turf of each height daily. Turfs were weighed to the nearest 0.1g before and after grazing. The height of grazed tillers was measured and all pasture was then removed above this height. The turf was then reweighed. Bite weight, depth, volume and area were then calculated for the steers and bulls. There was no significant difference between bulls and steers in bite dimensions. Sward height, which determines bite depth, appears to be the major determinant of bite weight and consequently of daily intake. The technique described has proved to be extremely useful in the study of specific sward structures and their effect on intake.

DL, Johnson, AL Rae, and JN Clarke

Proceedings of the New Zealand Society of Animal Production, Volume 49, , 197-202, 1989