Comparative effects of three seasons on seed population and viability of cattle, sheep and goat dungs in South-West Nigeria

Résumé

An experiment to determine the effects of seasonal variations on population and viability of seeds in the faeces of ruminant animals was conducted between April to December 2001 using two breeds of cattle, sheep and goats. Three samples were collected per breed from three animals that were tagged for uniformity of data collection. Sampling took place weekly, in the mornings before the animals were taken out for grazing. The highest (P<0.05) total number of seeds, seeds/g dry weights and total number of viable seeds were recovered from cattle, while the least were from goats, but the reverse was the case for percentage viability. The weights of the faeces were significantly (P<0.05) higher in the rainy season than the dry season. The weights of the faeces reduced gradually as the dry season sets in. Likewise, there were more seeds in the early rain than in the late rain and early dry season, with the percentage viability higher in the late rains and early dry season than the early rainy season. There were more broadleaved weeds and sedges in the early rain than late rain and early dry season but the reverse was the case for grasses. In conclusion, although there were more faeces and consequently more seed production in the rainy season, however, but the viability was lower than in the dry season. Also, seeds of broadleaved plants were more in the rainy season while those of grasses were more in the dry season. More seeds and number of viable seeds were recovered from the faeces of cattle than sheep and goats in all the seasons due to the higher weights of faeces but the percentage viability was higher for sheep and goat than cattle.