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| Author(s): |
Guilherme Aparecido Fim Júnior
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Jaboticabal. 2016-02-17. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal |
| Defense date: | 2015-12-17 |
| Advisor: | Luiz Francisco Zafalon |
| Abstract | |
This study aimed to establish the infectious etiology of subclinical mastitis in two different stages of lactation and the frequency of this disease in different breeds sheep. Furthermore, we sought to define the diagnostic characteristics of somatic cell count (SCC) for the diagnosis of subclinical mastitis in these sheep breeds, adopting different classes of SCC, and establish a screening value for SCC as diagnostic method. The experimental work was carried out in a herd composed of 407 sheep of Santa Inês, Texel, Ile de France and Dorper breeds, located in the Embrapa Southeast Livestock, São Carlos, São Paulo. The California Mastitis Test (CMT) was performed for a preliminary diagnosis of mastitis. After antisepsis of the teats, milk samples were collected in early lactation and weaning in two consecutive calvings for confirmation of infectious etiology of the disease by microbiological analysis and the determination of SCC. For each breed, CCS values were divided into four classes. We investigated 1,457 mammary glands, from which 203 (13.9%) had subclinical mastitis. Coagulase-negative staphylococci (CNS) were the etiological agents with higher occurrence isolated or in an association, 58.1% and 60.6%, respectively, followed by Streptococcus spp. (19.7%). Among the CNS, the most frequent species was Staphylococcus xylosus (87.7%).The Santa Inês breed had a significantly higher number of cases of subclinical mastitis (p < 0.05). Good and excellent concordances to the association between CMT and SCC were obtained for all breeds except Ile de France. Different cutoff points to SCC were determined for the studied breeds in both stages of lactation. Higher sensitivity and specificity of SCC cutoff points were obtained for the Ile de France and Dorper breeds during lactation, where as weaning stood out the Texel and Dorper breeds. There were no complete concordances to compare CMT and SCC reactions to the screening of subclinical mastitis. The test results varied according to the breed of sheep. The SCC can be used for screening of subclinical mastitis in sheep according to the prevalence of the disease in each breed, assisting technicians and producers to improve the control of the disease in herds. (AU) | |
| FAPESP's process: | 13/23054-9 - Somatic cell count of healthy mammary glands and with subclinical mastitis in sheep breeds Santa Inês, Texel, Dorper and Ile-de-France in early lactation and before drying |
| Grantee: | Guilherme Aparecido Fim Junior |
| Support Opportunities: | Scholarships in Brazil - Master |