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

Abstract

P < 0.001) in prevalence of mastitis was reported between breeds. Holstein-Fresian cows were affected at a higher rate (56.5%; OR, 3.3; 95% CI, 2.5-4.4) compared with local zebu (30.9%; OR, 1.2; 95% CI, 1.0- 1.5) and Jersey cows (28.9%; OR, 1.0). Udder/teat injuries caused mainly by ticks were the major predisposing factors of masti- tis in Southern Ethiopia. Cows with repeated episodes of mammary glands infections were about 5 times (57.0%; OR, 4.5; 95% CI, 3.7- 5.5) at higher risk of re-infection than previ- ously uninfected ones (22%; OR, 1.0; χ ABSTRACT Mastitis is the most complex and costly dis- ease of dairy cows occurring throughout the world. In Ethiopia, the disease is not well investigated. A cross-sectional study to eluci- date its magnitude, distribution, and associat- ed 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 var- ied significantly (χ 2 = 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 sea- son (χ