Prevalence and Risk Factors of Mastitis in Lactating Dairy Cows in Southern Ethiopia

Mastitis is the most complex and costly disease of dairy cows occurring throughout the world. In Ethiopia, the disease is not well investigated. A cross-sectional study to elucidate its magnitude, distribution, and associated risk factors in lactating dairy cows in Southern Ethiopia was carried out from February 2001 to March 2002 in a total of 974 milking cows using California Mastitis Test and clinical inspection of udder. Of the total animals examined, 34.9% (340) had mastitis, 11.9% (116) clinical and 23.0% (224) subclinical. Prevalence of mastitis varied significantly (χ = 54.5, P < 0.001) between the study sites. It was higher in Areka (54.7%; odds ratio [OR], 7.5; 95% confidence interval [CI], 5.5−10.0) and Arbegona (55.0%; OR, 7.5; 95% CI, 5.0− 10.9]) districts and lower (13.7%; OR, 1.0) in the Awassa district. Cows managed under semi-intensive husbandry practice were more affected (43.8%; OR, 2.0; 95% CI, 1.6−2.5) than those managed under extensive (25.8%; OR, 1.2; 95% CI, 1.0−1.4) and intensive (28.9%; OR, 1.0) systems. Prevalence of mastitis was significantly influenced by season (χ = 28.7, P < 0.001). During the long rain season, cows were at greater risk (OR, 2.6; 95% CI, 2.0−3.4) of acquiring udder Intern J Appl Res Vet Med • Vol. 3, No. 3, 2005 Intern J Appl Res Vet Med • Vol. 3, No. 3, 2005 190 lion Tropical Livestock Units (TLU); this includes 31 million cattle, 42 million sheep and goats, 7 million equines, 1.2 million camels, and more than 53 million chickens and immense bee and fishery resources. Cows represent the largest proportion of cattle population of the country. According to the Food and Agriculture Organization, 42% of the total cattle heads for the private holdings are milking cows. Milk produced from these animals provides an important dietary source for the majority of rural as well as a considerable number of the urban and peri-urban population. However, milk production often does not satisfy the country’s requirements due to a multitude of factors. Disease of the mammary glands known as mastitis is among the various factors contributing to reduced milk production. Mastitis is one of the most complex diseases of dairy cows that generally involves an interplay between management practices and infectious agents, having different causes, degrees of intensity, and variations in duration and residual effects. In Ethiopia, the disease is insufficiently investigated, and information relating to its magnitude, distribution, and risk factors is scant. Such information is important to envisage when designing appropriate strategies that would help reduce its prevalence and effects. This paper describes the results of an investigation made to elucidate the prevalence and risk factors of mastitis in lactating dairy cows in Southern Ethiopia. MATERIALS AND METHODS