Aspectos epidemiológicos de la criptosporidiosis en becerros de rebaños lecheros

Abstract

Two groups of 200 dairy calves, from calving to the 60th days of life, with and without diarrhoea were selected by clinical examination of 930 calves from 30 collective calf boxes, and 13 with individual boxes, chosen at random, in the State of Sao Paulo, Brazil. Feaces smears from the calves were stained by the modified Ziehl-Neelsen technique. A semi-quantitative score of oocysts numbers in feaces was done. The occurrence of diarrhoea was higher during the 2nd week of life, but cryptosporidiosis was similarly found in calves from the 1st - 3rd week of life. Diarrhoea and cryptosporidiosis were less frequent in older calves. Calves with cryptosporidiosis excreted more oocysts and were more frequently found (38%) than asymptomatic calves (11.5%). Most of these later calves were two-weeks old. Calves shedding Cryptosporidium oocysts were seen in 58% of the farms studied, being more prevalent in those farms that kept calves in collective boxes.