Fecal excretion and germination of forage legume seeds ingested by sheep

The effects of species and gastrointestinal retention time in the recovery and viability of forage legume seeds voided in sheep feces were determined by feeding 30,000 seeds of red clover (RC), white clover (WC) and subterranean clover (SC) to 3 adult Merino x Romney rams confined in metabolic cages which permitted complete collection of feces; direct emergence of seedlings from recovered feces was also measured. Three fecal collection periods of five days, each preceded by three days of adjustment and a new administration of seeds, were used in a latin square design. Germination and viability of seeds recovered from fecal samples were determined. RC seeds were more recovered (P 0,05) than WC seeds, SC being intermediate (10.21, 1.12 and 5.98%, respectively). Excretion of viable seeds as a percentage of ingested viable seeds, showed a similar trend. Recovery of hard seeds as a percentage of hard seeds ingested was 42.52%, 20.15 and 20.17%, for RC, WC and SC, respectively (P 0.05). Mean daily recovery % among species, for the entire period was 26.30, 52.16 15.42, 4.21 and 1.91%, for day 1 to 5, respectively. Highest recovery was obtained on day 2 and lowest on days 4 and 5, (P 0.05). Hard seeds accounted for the main proportion of excreted seeds. Accordingly, per cent daily recovery of germinable seeds was 5.70, 9.05, 2.55, 0.34 and 0.07% of total recovered seeds, for days 1 to 5 respectively. Of the total seeds excreted, a higher percentage of germinable seeds from RC (4.62%) and WC (4.77%) than SC (1.24%), was recovered. Seedlings emerging directly from feces collected on different days after seed intake, were affected by day and forage species. As a percentage of total seed recovery, emergence of seedlings from feces per day of collection, average over the 3 species, was: 5.14, 3.64, 1.51, 0.19 and 0.09%, for feces collected on days 1 to 5, respectively. Seedling emergence by species, as percentage of all recovered seeds for the entire period, was 2.18% (RC), 3.24% (WC) and 0.92% (SC). It is concluded that dissemination of viable seeds by sheep is dependent on plant species and retention time in the gastrointestinal tract