EIMERIA INFECTION IN CALVES UNDER LOCAL FARMING SYSTEM IN AND AROUND ASELLA, OROMIA REGIONAL STATE, ETHIOPIA

Bovine coccidiosis is one of the most common livestock diseases worldwide, and usually affects cattle under one-year-old. High infection rates occur from environments that were already contaminated with infected animals. A study on the prevalence, species and risk of occurrence of Eimeria species in calves was conducted at Asella, Oromia Regional State, Ethiopia. Management systems, breed, age, sex, and site were considered as variables for the surveillance. For this, fecal samples were collected from 384 randomly selected calves of age less than or equal to 12 months. Sporulation was applied at room temperature for 10-14 days. The flotation technique was applied on fecal samples and these were examined using direct microscopic examination to detect presence of Eimeria species. Eimeria oocysts weredetected in 72.4% of the total samples with ranges of 68-100% prevalence in all factors considered. Ten different Eimeria species were identified: E. bovis (44.5%), E. zuernii (26.3%), E. auburnensis (10.9), E. canadensis (9.4%), E. ellipsoidalis (5.7%), E. subspherica (6.5%), E. cylindrical (3.1%), E. alabamensis (2.6%), E. wyomingensis (2.6%) and E. bukidnonensis (2.1%) in decreasing order of prevalence. Of the 278 positive calves, 52.2% were infected with single species, while 47.8% were infected with 2-4 of identified species. Significantly lower prevalence in calves fed colostrums (71.2%) than those not fed colostrum (100%) (χ2 = 6.3; p <0.05) were observed in early birth. However, no statistical association in infection was observed within all other risk factors considered (p >0.05). Infection with one or more species was found to be insignificant in sex, feeding system, and cleaning frequency (p >0.05). The present finding showed the role of early colostrum feeding in a remarkable reduction of coccidiosis. However, the majority of assessed factors had a great contribution for the contamination and maintenance of Eimeria on the farm and its primes at 68.4%-100%, with high risk of infection to subsequent calves. Moreover, the occurrence of infection, with single (52.2%) to multiple of four (1.4%) pathogenic Eimeria spp. in positive cases, indicated the downside of substandard management systems, making calves prone to subclinical cases thus hampering growth and health, with considerable economic losses. Therefore, early feeding with sufficient amount of colostrum, practicing good management in calves and implementation of proper hygienic measures in their environments should be recommended to reduce direct and indirect economic losses from the infection.

Keywords
Eimeria; epidemiology; prevalence; calves; infection; sporulated oocyst; Asella