Most farmers use insecticides to control insect pests on their farms. However, there are concerns among farmers that insecticides residue may be left on crop residues such as cowpea haulms that are often used to feed ruminants and could negatively affect the health of these animals. Experiments were conducted in 2013 and 2014 cropping seasons to evaluate the effects of insecticides spray on cowpea yield and residual effects of the insecticides left on the haulm used as fodder on the health of sheep. Three spraying regimes were used [calendar spray (cs), monitored spray (ms) and farmersípractice (fp)]. The cowpea cultivar Padituya was used and agro-chemical sprayed was Lambda-cyhalothrin (a synthetic pyrethroid insecticide) as Lambda Super 2.5% at the rate of 0.65 L/ha. Twelve sheep were fed with the cowpea haulm harvested from the three insecticide spray regimes in each year. The result showed that cs and ms spray regimes significantly lowered population of insects and damage caused by insects including aphids, Maruca vitrata and pod-sucking bugs was also lower in cs and ms resulting in higher yields compared with the fp. Haulm yield was significantly different (P
Key words: Insect pests, insecticide spray regime, cowpea haulm, toxicity, sheep haematology.