The need to apply vaccines in different species – small ruminants
2012 • 1 10 Foot and mouth disease (FMD) has been successfully controlled and eliminated in many parts of the world using conventional disease control measures, including vaccination of domestic animals. Potent vaccines have also been the mainstay in controlling outbreaks in non-enzootic regions. Several characteristics of FMD complicate the use of vaccines to control the disease. Not only are there seven serotypes, with little cross-protection between the serotypes, but genetic and antigenic variants occur within these serotypes. In addition, FMD virus can infect over 70 cloven-hoofed species, many of which are free-living wild animals. The role of sheep and goats in the epidemiology of the disease is poorly understood and perceived differently in different parts of the world. This perception is reflected in the vaccination policies applied in these countries. Cattle are generally the species of choice in vaccination programmes, while sheep and goats are vaccinated in only a small number of countries, and then mostly either for strategic purposes or as part of a routine disease control programme. The general assumption is that sheep and goats do not play a significant role in the spread of the disease or as sentinel animals to detect clinical disease. However, this assumption does not hold true for all circumstances or under all epidemiological conditions. This paper describes the potential circumstances under which the vaccination of small livestock should be considered to mitigate the risk of viral spread or to contain an outbreak of the disease. The need to apply vaccines in different species – small ruminants
The role of small ruminants in the epidemiology and transmission of foot-and-mouth disease.
Despite representing the largest part of the world's foot-and-mouth disease (FMD)-susceptible domestic livestock, sheep and goats have generally been neglected with regard to their epidemiological role. This is partly due to the often inapparent nature of the disease in these hosts. Nevertheless, their ability to become carriers represents a reservoir for further infection and spread of disease, and so trade of live sheep and goats present a major risk of entry of FMD to disease-free countries. Research and epidemiological studies continue to be necessary in order both to prevent the entry of the virus and to assist in control should the disease reoccur. This review concentrates primarily on more recent studies relating to sheep and goats and, in particular, considers the importance of these hosts in the overall epidemiology of FMD.
Spray drying of dairy products: state of the art
Milk is extremely perishable, and yet, for a number of reasons, it has to be preserved for later consumption. The removal of water prevents the growth of micro-organisms and facilitates pres- ervation and storage of milk constituents. Spray drying is one of the most convenient techniques for producing milk powders and for stabilizing milk constituents. Before spray drying, the milk under- goes several processes (such as heat treatment, cream separation, membrane processes, vacuum evap- oration and homogenization). The chemical, physical, technological, nutritional, functional and microbiological properties of final products are influenced by a number of factors such as operating conditions, properties of the dairy products and storage conditions. The aim of this review is to de- scribe the process of spray drying of dairy products and to review the present and recent advance- ments of knowledge on the properties of spray-dried milk products, on modelling and water transfer simulation (drying and rehydration), dairy powders and the spray drying equipment and energy con- sumption.