Udder health in dairy cows in Tajikistan – prevalence of mastitis and bacteriological findings

Sammanfattning: Agriculture, including dairy production, is one of the most important industries in Tajikistan, occupying more than 50% of the country’s population. Consequently, milk is an important source of income, but it also contains essential nutritional components. In Tajikistan, the majority of milk production is confined to small household farms, but large commercial (enterprise or dekhan) farms are multiplying as the country is becoming more and more selfsuppliant of dairy products. To increase milk production and maintain the nutritional value of the milk, it is of great importance to prevent diseases. Mastitis, inflammation or infection of the udder, is the most costly disease in dairy cattle worldwide. It leads to great economic losses and impaired milk quality, becoming a health and welfare problem to both humans and dairy cows. To prevent mastitis, measures should be implemented - different depending on what causative agent is creating the disease. The present study was executed in the urban and peri-urban area of Dushanbe, Tajikistan, where 351 dairy cows were sampled and the milk was evaluated with California Mastitis Test (CMT). The study was executed on both large and small household farms. Out of the 351 cows, 209 (59.5%) showed indications of an elevated SCC in one or more udder quarters. Of the 209, 26 cows (12.4%) where classified as clinical cases of mastitis, while the remaining 183 cows (87.6%) were classified as subclinical cases of mastitis. The results showed that production type (large or small household farm) was not a significant risk factor for mastitis, however, manner of milking (by hand or machine) was. The odds were 1.69 times higher that cows milked by hand were suffering from mastitis. From cows classified with mastitis (subclinical or clinical) an aseptic milk sampled was taken, cultivated and evaluated after 24 and 48 h. In 24% of the cases, negative growth was found. The most frequently found bacterial species was Corynebacterium spp. (18%), followed by mixed growth (14%) and coagulase negative staphylococci (CNS) (13%). Overall results showed a prevalence of 37% contagious bacteria (including Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae och Corynebacterium spp.). This was compared to environmental bacteria (coliform bacteria and Streptococcus uberis) that composed 9% of the findings. CNS can be transmitted both from cow-to-cow and via the environment, hence is classified on its own and was responsible for 13% of the cases of mastitis. To minimise the transmission of the most common group of bacteria, contagious bacteria, strict hygiene routines should be implemented during milking. A comparable distribution of bacteria was found when evaluating the results based on milking manner. When evaluating the results based on farm size, large farms also had a similar distribution of bacteria. In small household farms, however, the results deviated prominently. Here CNS was the most common type of bacteria with a prevalence of 37%, followed by Staphylococcus aureus (11%) and Corynebacterium spp. (9%). A theory for this deviation is the difference in the keeping of cows – small household farmers keep fewer cows and therefore there are different principal means of transmission.