Abstract

Regurgitated and reswallowed rumination boli from 6 diets were collected from oesophageal fistulated sheep. After wet sieving, large particles retained on the 4mm sieve were treated with propan-2-ol and examined under a binocular microscope for types of structural damage. Particle types were identified as leaf, stalf, endodermis and cuticle. Bolus particle composition was different for each diet and for regurgitated and reswallowed material. The overall effect of rumination chewing on bolus composition was to increase the number of stalk particles retained on the 4mm sieve. Surface area (length x width) of particles was determined. Individual red clover leaf particles were markedly larger than all other particle types. Significant differences in individual particle surface area occurred in 2 ways after rumination chewing. For immature and mature ryegrass diets, surface area in stalk and leaf particles increased respectively but red clover, meadow hay and lucerne chaff showed decreased surface area of stalk particles.

GJ, Piggot

Proceedings of the New Zealand Society of Animal Production, Volume 48, , 219-224, 1988