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.

Factors contributing to the loss of seed from the seed‐bank of Trifolium balansae and Trifolium resupinatum over summer

“…because a large proportion of the seed passes unchanged through the animal, although this may also depend on the type of animal (Simao Neto et al 1987).…”

Recuperação e resposta germinativa de sementes de leguminosas passadas pelo trato digestório bovino

“…Tais alterações estão relacionadas, entre outros fatores, ao período de retenção no intestino, tamanho da semente, dureza do tegumento e estágio de maturidade dos propágulos (Janzen 1985). Segundo Simão Neto et al (1987), sementes grandes ou com tegumento totalmente permeável são mais propensas a danos causados pela mastigação, ao passo que sementes menores atravessam o trato digestório com maior velocidade do que as grandes, diminuindo assim seu período de exposição às condições potencialmente estressantes nesse ambiente (Simão Neto et al 1987).…”

The seed coat as a modulator of seed-environment relationships in Fabaceae

“…Hardseededness increases the survival rate of seeds in its passage through the digestive tract of many animal species (Simão Neto et al 1987) which, in consequence, act as agents of spatial seed dispersal. Rapid recolonization of burned areas by certain species is made possible by soil-accumulated hard seeds, rendered permeable by fire (Dell 1980).…”