Epidemiology and economics of mastitis in smallholders dairy farms in southeast of Brazil

• Ano de defesa: 2020
• Autor(a) principal: Silva, Aline Callegari
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Animal health economics; Custo da mastite; Economia da saúde animal; Fatores de risco; Mastitis cost; Medidas preventivas; Preventive measures; Risk factors; Transição para orgânico; Transition to organic
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/10/10134/tde-06052021-100703/

The specific objectives of this study were a) analyze the risk factors associated with mastitis in smallholders dairy farms in the Southeast of Brazil, b) present the main economic methods applied to analyze the cost of mastitis in dairy herds, and c) analyze the total cost of mastitis in conventional and in transition to organic smallholders dairy farms. The tese are structured in 3 chapters referent to 2 studies and 1 review. In chapters 1 and 3, the studies were developed from data collected and provided by 10 smallholders dairy farms (7 conventional and 3 in transition to organic), visited 4 times, during the period of May 2018 to June 2019. At the first visit were applied a questionnaire that contained information about general farm data and individual cows details. In all visits, a combination of udder clinical examination and the Tamis (screened mug) test were applied to observe clinical mastitis(CM), and California Mastitis Test to determine subclinical mastitis (SCM). Chapter 1, a logistic regression analysis was applied to investigate associations between cow and herd- level risk factors with the presence of CM and SCM. The total of 4567 quarters was tested, 107 (2.3%) had CM, while 1519 (33.2%) had SCM. At the cow level, CM risk was highest in mid-lactation (50-150 DIM), while SCM was highest in late lactation (>150DIM) and lower in primiparous than multiparous cows. At the herd level. using drying off treatment (OR 4.23, 95% CI 1.42-12.62) was associated with CM risk. Milking clinical (OR 0.37, 95% CI 0.24-0.56) and subclinical cases last (OR 0.21, 95% CI 0.09-0.47) and clean milk parlor (OR 0.27, 95% CI 0.15-0.46) had decreased odds for SCM, while herds with optimized feed had greater odds for SCM (OR 9.11 , 95% CI 2.59-31.9). In chapter 2, we presented a review that identifies the different methods and mathematical models used in the literature to perform the calculation of the cost of mastitis, allowing future reflections on methodological standardization and to provide information to guide future work. In chapter 3, the total cost of mastitis( failure and preventive) was calculated for conventional and transition’s smallholders dairy farms. The total cost of mastitis identified was variable in conventional with a mean of U$ 434.07 per cows (ranging from U$ 68.76 - U$931.76) and in organic transition with a mean of U$ 580.42 per cows (ranging from U$362.48 U$ 1010.83) for the period of 2017 to 2018. The mean total costs per milk production per year were U$ 0.1018 (U$ 0.03 - U$ 0.23) for conventional farms and U$ 0.1231 (U$ 0.07 U$0.18) for the transition to organic’s farms. In conclusion, we identified some risk factors for mastitis on smallholder farms, but further research on more farms across more areas of Brazil is required to develop targeted control programs for mastitis on smallholder farms. Also, the analyzes resulting from mastitis cost showed that its total cost is influenced by a combination of factors such as the animal’s health status, milk production and farm management.