Effect of cadmium on the rumen protozoan population in sheep

The effect of increased cadmium doses on the rumen ciliate population in sh eep was investigated. The experiment was carried out on 18 adult Merino she ep fed a diet composed of meadow hay and barley meal for 3 weeks prior to a nd during the experiment. The cadmium content of the diet (control value) w as 0.09 mg/kg dry matter of feed (DM). Increased doses were 5 mg Cd/kg DM a nd 10 mg Cd/kg DM. Protozoa in the ruminal fluid of sheep were examined thr oughout seven weeks. Entodinium spp., Dasytricha runinantium, Isotricha spp ., Ophryoscolex caudatus tricoronatus, Polyplastron multivesiculatum and th e total number of ciliates were counted. Short-time supplementation of cadm ium (day 20) increased the total number of ciliates and the number of all p rotozoan groups examined. No significant effect on the protozoan population can be seen after long-term supplementation of the cadmium doses tested (o n day 47).