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This study was carried out to validate the efficacy of Spondias mombin, used locally as an anthelmintic, and to standardize the effective dose of the plant extract required for worm control in livestock. In vitro and in vivo studies were conducted to determine the direct anthelmintic effect of ethanolic and aqueous extracts of S. mombin towards different ovine gastrointestinal nematodes. A larval development assay (LDA) was used to investigate the in vitro effect of extracts on strongyle larvae. Another study was conducted in vivo to evaluate the therapeutic efficacy of the extracts administered orally at dose rates of 125, 250, 500 mg/kg to sheep naturally infected with gastrointestinal nematodes. Twenty sheep were selected on the basis of positive faecal egg counts (750 epg). The sheep were allocated randomly to a non-medicated control group (A) or to groups given 125 mg/kg (B), 250 mg/kg (C) or 500 mg/kg (D) of extract, respectively. Sheep in groups B-D were given extracts orally on two days. Individual faecal egg counts were performed on days 0, 3, 6, 9 and 12. The presence of S. mombin extracts in in vitro cultures of larvae decreased the survival of L3 larvae. The LC50 of the aqueous extract of S. mombin was 0.907 mg/ml, while the LC50 of the ethanolic extract was 0.456 mg/ml. This difference in LC50 was statistically significant (p > 0.05). The mean percentage faecal egg reduction of sheep drenched with 500 mg/kg S. mombin extracts was 15.0%, 27.5%, 65.0%, 65.0%, 100.0% against Haenmonchus spp., Trichostrongylus spp., Oesophagostomunm spp., Strongyloides spp. and Trichuris spp. respectively, on day 12. Extracts of S. mombin could find application in the control of helminths in livestock.

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IN most countries, the profitability of sheep breeding is low and farmers look for convenient, safe, efficient, broad-spectrum drugs to control parasites. It is desirable to limit the cost of treatment in parasite control initiatives in order to improve the overall profitability. Farmers in Nigeria commonly use fresh seeds of Leucaena leucocephala to deworm their animals. A paste made by pounding 50 to 100 seeds is administered orally, with 200 ml of water. In Senegal, the seed is also reported to be useful in expelling Ascaris species worms (Adebowale 1993).The seeds of L leucocephala are popular for their nutritive value, albeit limited by the toxicity of mimosine, a non-nutrient component of the seed. Chicken fed on meal containing 15 per cent L leucocephala seed powder for 12 days at one to five weeks of age show a reduction in feed intake and bodyweight gain regardless of their growing stage (Okonkwo and others 1995). This has been attributed to mimosine toxicity as evidenced by experimentation with male broilers. Reverting to feeding on a normal diet rapidly reduced the stored mimosine in the birds' tissue (Kamada and others 1997). A feed containing 15 per cent L leucocephala seed given to crossbred cows for 240 days was responsible for the maintenance of good health and these cows were free from reproductive disorders. Nutrient intake, digestibility of nutrients and nitrogen, phosphorus and calcium levels were not affected by the treatment. The rumen pH, total volatile fatty acids and the concentration of total nitrogen fractions in strained rumen liquor of an experimental cow were unaffected (Talpada and others 1997).Documentation of the true value of the claimed use of the extract of L leucocephala is of interest and practical relevance, because of the well-known toxicity of the mimosine component of the seed. This short communication describes an assessment of the anthelmintic effect of an aqueous extract of L leucocephala seed on the infective larvae of strongyles from sheep with a naturally acquired infection using a larval development viability assay (LDVA). The larvae were identified as predominantly Haemonchus contortus.L leucocephala is a shrub that is freely available in Ibadan, south-west Nigeria. Dry pods and seeds of the shrub were collected in the morning from near the University of Ibadan. Voucher specimens, that is, samples of the plant used for reference at the herbarium after taxonomical identification, were deposited at the herbarium of the Department of Botany and Microbiology, University of Ibadan.A sample of dried, powdered seed (10 g) was dispersed in 100 ml distilled water. The dispersion was stirred with a glass rod for 10 minutes and filtered using a previously weighed filter paper. A dark brown filtrate was obtained. The residue was dried in an oven at 125°C for one hour, weighed again, and the difference in weight gave the amount of powdered seed dissolved in water (0·58 per cent w/v). Appropriate aliquots of the aqueous extract was taken and diluted to prepare graded doses of t...