Metaanalysis of subclinical mastitis prevalence in water buffaloes (Bubalus bubalis)

Water buffalo milk, compared to cow's milk, has a preferable composition in terms of health and nutritional value. Subclinical mastitis, one of the most important problems of the dairy industry, is as important of an issue in water buffaloes as in cows. In this study, it was aimed to evaluate the prevalence of subclinical mastitis in buffaloes by metaanalysis, and to calculate the pooled prevalence. For the metaanalysis of the prevalence of subclinical mastitis in buffaloes, a total of 382 publications 294 from Scopus, 31 from Medline Complete, and 57 from ScienceDirect were obtained as a result of the literature searches with the key words "Buffalo, Water buffalo, Nili Ravi, Bubalus bubalis, Asian buffalo, Jafarabadi, Italian Mediterranean buffalo, subclinical mastitis prevalence". Five repeating studies were excluded. The study material is made up of 53 subclinical mastitis prevalence data derived from the 51 studies in total that were conducted between 1989 and 2020. In this study, 10,996 water buffaloes (water buffalo-based studies) and 44,372 udder quarters (udder quarter-based studies) were included in the metaanalysis. Additionally, a total of 3292 agent identification results from 38 prevalence data obtained from 14 studies were used for metaanalysis of subclinical mastitis prevalence by isolates. A high level of heterogeneity (I2(%) > 75%) was detected amongst both the water buffalo-based studies and the udder quarter-based studies that were included in the analyses. At the end of the study, subclinical mastitis pooled prevalence was calculated to be 0.38 (95% CI: 0.32-0.44) in water buffalo -based studies and 0.28 (95% CI: 0.23-0.34) in udder quarter-based studies. In 38 studies with agent identification, the pooled prevalence according to isolates for Staphylococcus spp., Streptococcus spp., Bacillus spp., coagulase-negative staphylococci (CNS), and Escherichia coli (E. coli) were respectively calculated as 0.36; 0.26; 0.03; 0.39, and 0.11. With this study, the inconsistencies in individual studies regarding the magnitude of the effect of the prevalence of subclinical mastitis in water buffaloes in the population were eliminated by metaanalysis, enabling us to make a stronger and more precise estimation.