Prevalence of sub-clinical mastitis in Uruguay :

Abstract: Uruguay is a major milk producer and exporter of dairy products in South America with 1,423.5 million litres of milk being produced annually. Thus, the dairy industry is of great economic importance to Uruguay. Mastitis is an inflammatory reaction of the mammary gland, which has significant health and economic implications. It is the major health problem among dairy cows in Uruguay. Sub-clinical mastitis is a condition in which there is no detectable inflammatory change in the udder and no observable abnormalities in the milk. However, it reduces milk production and adversely affects milk quality. It can also be seen as a reservoir for bacteria that can later cause clinical mastitis, which has an even greater effect on health and economy. It has been shown that sub-clinical mastitis is responsible for 70% of the losses in milk production in Uruguay. The aim of this study was to determine the prevalence of sub-clinical mastitis in an area of Uruguay. By identifying these cases and the bacteria causing them, udder health can be markedly improved. Seven farms in the Paysandú area were selected. On each farm, samples were collected from each quarter and analysed; partly for somatic cell count (SCC) by the California mastitis test (CMT), and partly for bacteriology. Samples were also taken from the tank for five consecutive days and analysed partly for SCC by the Fossomatic method, and partly for bacteriology. Identification of Streptococci was made by the CAMP-test and SVA-strept. The catalase test was used to differentiate Streptococci from Corynebacterium bovis. Staphylococci was identified by the coagulase test. The prevalence of sub-clinical mastitis was found to be high. On a cow-basis it was 42.2% and on a quarter-basis 21.8%. A number of various factors could be the reason for this and several measures could be taken by the farmers themselves to reduce these infections. The mean value for the total number of bacteria in the bulk tank was 24,227 cfu/ml. These results, however, are accounted for in the degree project: “Comparison between bulk tank milk samples and individual milk samples from dairy herds in Uruguay” written by Anneli Axelsson.