Recovery of pasture seed ingested by ruminants. 1. Seed of six tropical pasture species fed to cattle, sheep and goats

Abstract

This study examined the effects of different species of ruminants and pasture plants on the passage of ingested seed. Penned cattle, sheep and goats were fed a basal diet of 80% lucerne hay and 20% milled wheat. After 14 days on the basal diet a mixture of known numbers of pasture seeds (Brachiaria decumbens, Axonopus afinis, Neonotonia wightii cv. Tinaroo, Trgfolium semipilosum cv. Safari, Stylosanthes hamata cv. Verano and S. scabra cv. Seca) was fed on 1 day. Faeces were collected for 6 days after feeding the seed while animals remained on the basal diet. Seed samples of each species were tested for germination and hardseededness (or dormancy) both prior to feeding and on seed washed from a subsample of the faeces. Other subsamples were kept moist and emerging seedlings were removed over a 104 week period. Cattle digested less seed than did sheep and goats, but the germination characteristics of the recovered seed were similar for the different animals. The mean recovery of viable seeds ingested was 42, 10 and 19% for cattle, sheep and goats, and 39, 39, 23, 21, 12 and 8% for Safari, Tinaroo, Seca, Axonopus, Brachiaria and Verano. Most of the seeds excreted were recovered on the second and third days following feeding. For sheep and goats, the percentage recovery of ingested legume seed as emerging seedlings was similar to recovery calculated from washing out seed followed by germination testing. However, there was a lower recovery, as seedlings, for the seeds ingested by cattle. This was partially due to the larger number of hard seeds remaining in cattle faeces after the 104 week germination period.