Study on the possible survival of Staphylococcus chromogenes through the dry period in dairy ewes

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• 作者：E. Kiossis ; C.N. Brozos ; E. Petridou ; A. Zdragas ; Th Papadopoulos ; C. Boscos
• 关键词：Ewes ; Udder ; Staphylococcus chromogenes ; Dry period ; Mastitis
• 刊名：Small Ruminant Research
• 出版年：October, 2013
• 年：2013
• 卷：115
• 期：1-3
• 页码：124-129
• 全文大小：525 K

文摘

CNS (Coagulase-Negative-Staphylococci) in dairy ewes are the most commonly isolated microorganisms during subclinical mastitis and are related to milk loss. The objective of this study was to investigate whether CNS can survive during the dry period, despite the use of drying-off treatment, and persist during the subsequent lactating period in dairy ewes. 47 primiparus dairy Chios ewes were used. All animals were sampled during the last milking before drying-off and they were then randomly assigned into one of two groups. Ewes of the treated group (n = 21) were administered a dry period intramammary preparation (Nafpenzal^庐), and ewes of the control group (n = 26) received no drying-off treatment. Immediately after lambing and once every month until the end of lactation, milk samples were collected for microbiological examination and for the determination of SCC. Daily milk yields were also recorded during the sampling days. Twelve out of the total 47 animals were found to carry the same microorganisms during 2 subsequent milking periods (pre and post partum). Staphylococcus chromogenes was the most commonly identified CNS species (7 animals). All 25 isolated Staphylococcus chromogenes strains were subjected to pulsed field gel electrophoreses in order to identify the presence of the same or different clones of the bacteria. Two clones were identified. Both clones were isolated before drying-off and re-isolated during the subsequent lactation period (>90% similarity). Apart from the first month of lactation, mean milk yield of treated group was higher than that of the control group, but the difference was significant only after the third month of lactation (P < 0.05). Results from the present study suggest that drying-off treatment is beneficial for milk production, but is not advantageous for the elimination of Staphylococcus chromogenes infections.