Fatty acids, vitamins and cholesterol content, and sensory properties of cheese made with milk from sheep fed rapeseed oilcake.

The aim of the present study was to evaluate the influence of rapeseed oilcake used for feeding sheep on the content of fatty acids (FA), tocopherols, retinoids, and cholesterol of milk and cheese, and on the sensory properties of cheese. Indoor animal feeding (in winter) is the highest cost of production for cheesemakers, and the inclusion of locally produced rapeseed oilcake in the concentrate feed formulation can reduce the cost of cheese production, as long as the quality of the cheese is not altered. The experiment was carried out in March (mid lactation) with 72 Latxa sheep from an experimental farm located in the Basque Country (northern Spain). Two homogeneous groups of animals (n = 36) were set to receive each a different diet based on commercial or rapeseed concentrate, respectively, and forage (Festuca hay). Animal production parameters were individually recorded for each feeding group, whereas bulk milk from each group was used for cheesemaking trials. The rapeseed concentrate had higher amounts of unsaturated FA (mainly C18:1 cis isomers, C18:2 cis-9,cis-12 and C18:3 cis-9,cis-12,cis-15) and tocopherols than the commercial concentrate. The inclusion of rapeseed oilcake in the diet of dairy sheep did not compromise animal production parameters or milk gross composition. Bulk milk and cheese from sheep fed rapeseed concentrate showed higher content of unsaturated FA and tocopherols than those from sheep fed commercial concentrate. No differences were observed in the content of retinoid in milk and cheese between feeding groups, whereas the cholesterol content was slightly lower in cheese made with milk from sheep fed rapeseed concentrate. Thus, milk and cheese from sheep fed rapeseed concentrate had a healthier lipid profile. In addition, the inclusion of rapeseed oilcake in the diet of sheep did not change the typical sensory attributes of Protected Denomination of Origin Idiazabal cheese. Therefore, rapeseed concentrate could be a good local resource for feeding sheep to improve the nutritional quality of dairy products and to provide higher returns to farms.

Microscopic and PCR findings in sheep after experimental infection with Ehrlichia phagocytophila.

Methods available for the diagnosis of Ehrlichia phagocytophila infection are limited and of low sensitivity. Since polymerase chain reaction (PCR) is a highly sensitive and specific method for the detection of infectious agents in animals, it was considered useful to develop a PCR method specific for this agent. An experimental protocol in which blood from 10 different flocks was inoculated into 10 naive 1 month-old lambs was carried out. Progress of the infection was monitored during 3 weeks by daily rectal temperature and blood samples. Eight lambs showed hyperthermia, presence of E. phagocytophila in blood, and lower growth rate while the other two never showed the agent in their blood or any clinical signs. This experimental infection, essentially designed to provide infected samples, also showed that flocks from areas previously thought to be free of E. phagocytophila were actually infected. PCR on blood samples allowed detection of the infection earlier than in case of microscopic examination. This was related to an increased sensitivity (87-91%). PCR yielded positive results on samples with as few as 1.08 infected neutrophils/µl (about 0.1%).