The survival and transmission of oocysts of Eimeria alabamensis in hay.

From a permanent pasture where young cattle had contracted coccidiosis due to Eimeria alabamensis 2 years previously, hay was harvested and fed to six 2-4 month old calves 15 days, 4 months or 8 months after being harvested. The excretion of oocysts by these exposed calves was compared with that by five control calves of similar age which were housed in the same premises but fed hay from a 'coccidia-free' field. All calves fed the contaminated hay developed patent E. alabamensis infections and excreted 142000 to 4.2 million oocysts of this species per gram of faeces starting 8 days after the hay was first fed. Five of them had soft (porridge-like to gruel-like) faeces and/or poor appetite. The control calves excreted no or very few oocysts and had firm faeces and unaffected appetite. It is concluded that making hay from pastures contaminated with oocysts of E. alabamensis is unsatisfactory if the hay is to be used for feeding young cattle.