Gastrointestinal protozoa in dairy calves: identification of risk factors for infection

Objective. This study aimed to evaluate the occurrence of gastrointestinal protozoa in dairy calves and to identify potential risk factors for this type of infection. Materials and methods. For this purpose, 243 fecal samples were collected from calves up to 60 days of age in 43 dairy farms located in the West region of Santa Catarina state, Brazil. Samples were examined by centrifugal-flotation technique. Results. As a result, Giardia was present in 26.75% (65/243) of all samples, Eimeria in 21.81% (53/243), and Cryptosporidium in 20.99% (51/243). Additionally, 46.50% (113/243) of the samples were negative for any protozoa, while 39.10% (95/243) and 14.40% (35/208) showed single and mixed infections, respectively. There was a higher association between Cryptosporidium and Giardia (6.99%) in cases of mixed infections. However, the triple protozoa association had the lowest prevalence in mixed infections (2.06%). Epidemiologically, a questionnaire was applied to determine risk factors for these parasitic infections. Based on the statistical model applied, some risk factors for Cryptosporidium infections were identified, highlighting feeding management, period of time that calves stayed with their mothers (cows), and contact with dogs; the risk of contracting Giardia increased according to the milk source, while the floor type bedding, and age were appointed as risks factors for Eimeria. Conclusions. Therefore, it is possible to confirm that Giardia, Cryptosporidium and Eimeria may infect dairy calves, and the knowledge of some risk factors associated to their infection in calves.