Castor bean cake for the control of parasites in pasture-finished sheep

The purpose of this study was to evaluate castor bean cake as alternative input in the control of gastrointestinal parasites in sheep raised on irrigated pasture under continuous stocking. The treatments consisted of sheep supplemented with standard diet and pasture fertilized with urea; sheep supplemented with alternative diet and pasture fertilized with urea; sheep supplemented with standard diet and pasture fertilized with in natura castor bean cake; and sheep supplemented with alternative diet and pasture fertilized with in natura castor bean cake. A randomized complete block design (CBD) was used, with 16 replications (sheep), with repeated measures over time, the plots being the treatments, and the subplots the collection times. Infective nematode larvae in the pasture (L3.g DM^-1), number of eggs per gram of feces (EPG), globular volume (GV), and total plasma protein (TPP) were evaluated. For adult gastrointestinal parasite counts, CBD was also used with six replications. Except for FAMACHA^© grade, all variables had effect (P < 0.01) of the time factor. The average number of L3.g DM^-1 and EPG were 126 and 841, respectively, with no effect (P > 0.05) of the treatment factor. The values observed for GV and TPP were higher than 25.9% and 6.4 g·dL^-1, respectively, which were considered normal. As organic fertilizer, the fractionated application of in natura castor bean cake does not reduce the contamination of pastures by nematode larvae. The evaluated feeds improve the resilience of the sheep to infection by gastrointestinal parasites. The treatments using castor bean cake reduced the adult parasites present in the abomasum of sheep.