Summary :The aim of the present study was to estimate the prevalence of Cryptosporidium parvum infection in goats maintained under semiextensive feeding conditions in the southeast of Spain. Four farms took part in the study. Samples were obtained during the autumn and spring kidding seasons. The goats were divided into three groups: group I (0-15 days), group II (> 15 days-2 months) and group III (> 2 months-9 years). Faecal specimens were concentrated and smears of the sediment (25 µl) were stained by the modified Ziehl-Neelsen acid fast technique. Parasite oocysts were identified in all the farms; of the 582 goats, 111 were found to have the parasite in their faeces, i.e. the prevalence was 19.1 %. The frequency distributions of the Cryptosporidium oocyst counts according to the age categories were 10.4 %, 13.4 % and 25.2 % for groups I, II and III respectively. With respect to the kidding season, no differences were found. The present study revealed the high prevalence of Cryptosporidium infection in goats in the studied zone. or arid and semi-arid regions of the Mediterranean zone, livestock farming based on extensive or semi-extensive feeding conditions is proposed as the option offering greatest productive possibilities. In this context, the goat is a species of choice because of its ability to adapt to these climatic conditions and thanks to the high value of caprine products, milk and meat (Boza, 2005). However, goats are among the farm animals that are most affected by cryptosporidiosis, and farmers suffer considerable financial losses on this account. Cryptosporidium infection may have an important economic impact on farmers because of high morbidity and sometimes high mortality rates among farm animals (Casemore et al., 1997). This mortality increases when the disease in associated with concurrent infections or deficiencies in nutrition or husbandry (de Graaf et al., 1999). Moreover, Cryptosporidium oocysts excreted with the faeces of infected farm animals can be a source of human infection, and there is a high incidence of the disease in AIDS patients, against which there is no consistently effective treatment (Tzipori, 1998). In goats, infection was first described in Australia in a 2-week-old kid with diarrhoea (Mason et al., 1981). Since then, the infection has been diagnosed in outbreaks of diarrhoea and prevalence in goat kids has been reported in several European countries (Majewska et al., 2000). In Spain Cryptosporidium infection in small ruminants was first diagnosed in 1985 (Rojo Vázquez et al., 1985); subsequently, cryptosporidiosis was reported from different geographical areas (Rojo Vázquez et al., 1987; Matos-Fernández et al., 1993;Castro-Hermida et al., 2007). Taking into account this background and its relevance, the aim of the present study was to estimate the prevalence in relation to age and kidding season of Cryptosporidium infection in goats at randomly selected farms in the southeast of Spain. RésuméArticle available at http://www.parasite-journal.org or http://dx.doi.org/10.1...