A number of studies have been carried out to identify reliable reference genes in specific tissues in various species [34] [35] [36] [37] [38] . In sheep, analyses of expression stability of candidate reference genes are limited to a restricted range of tissues [5] [6] [7] [8] and data on ovine whole blood were still lacking. However, peripheral whole blood is attractive because of its accessibility and usefulness in monitoring several physiological and pathological conditions. As regards disease status, blood certainly represents the best tissue for in vivo test development since collection is non-invasive and easy to perform. For example, the identification of differentially expressed genes acting as indirect in vivo markers in blood would represent a major breakthrough for the diagnostics of non-conventional agents (like prions) which currently cannot be detected by standard methods as the diagnosis still rely on post mortem investigations. This study provides a panel of optimal control genes for use in qRT-PCR studies in sheep whole blood. The two softwares tested, based on different algorithms and analytical procedures, produced highly comparable results. SDHA and YWHAZ represent good reference genes for gene expression studies in sheep peripheral whole blood, unaffected by disease status and heat stress conditions, and the geometric mean of these two stable genes is an accurate normalization factor [1] . Our results may be useful for the identification of genes differentially expressed in a readily accessible tissue, with the potential of discovering new physiological and disease markers and as a tool to improve production traits (e.g., by identifying expression Quantitative Trait Loci (eQTLs) [39, 40] . Normal variation in thermal radiated temperature in cattle: implications for foot-and-mouth disease detection BACKGROUND: Thermal imagers have been used in a number of disciplines to record animal surface temperatures and as a result detect temperature distributions and abnormalities requiring a particular course of action. Some work, with animals infected with foot-and-mouth disease virus, has suggested that the technique might be used to identify animals in the early stages of disease. In this study, images of 19 healthy cattle have been taken over an extended period to determine hoof and especially coronary band temperatures (a common site for the development of FMD lesions) and eye temperatures (as a surrogate for core body temperature) and to examine how these vary with time and ambient conditions. RESULTS: The results showed that under UK conditions an animal's hoof temperature varied from 10°C to 36°C and was primarily influenced by the ambient temperature and the animal's activity immediately prior to measurement. Eye temperatures were not affected by ambient temperature and are a useful indicator of core body temperature. CONCLUSIONS: Given the variation in temperature of the hooves of normal animals under various environmental conditions the use of a single threshold hoof temperature will be at best a modest predictive indicator of early FMD, even if ambient temperature is factored into the evaluation. Foot-and-mouth disease (FMD) is a highly infectious viral disease of cloven-hoofed animals, both domestic and wild. The disease is caused by a small RNA virus, which is 28 nm in diameter and exists as seven serotypes. The disease is characterised by fever, and blisters in the mouth, on the feet and on the teats and these rupture and are associated with slobbering and lameness. Adult animals may suffer weight loss and milk production can decline significantly. Though most animals eventually recover from FMD, the disease can lead to myocarditis and death, especially in newborn animals [1] . FMD is found regularly in parts of South America, Africa, the Middle East and other parts of Asia and periodically spreads to affect normally disease free countries. It is a significant impediment to trade in livestock and their products as countries with the disease face restrictions for exporting to disease free regions. Moreover, the disease is difficult and costly to control and eradicate. The Royal Society [2] estimated that during the 2001 epidemic in the UK, in which some six million animals were culled, the losses to agriculture and the food chain were £3.1 billion and some £2.5 billion was paid by the UK Government in compensation for slaughtered animals and clean-up costs. Losses were also experienced in tourism and business directly affected by tourism; it has been estimated these were between £2.7 and £3.2 billion [3] . Two other epidemics highlight the global impact of the disease; the first a major epidemic in Argentina in 2001 and the second in Japan during 2010; in the first two thousand five hundred and nineteen herds were infected [4] and in the second two hundred and fifty (Office international des épizooties-World Organisation for Animal Health, 2010. Follow-up report Early identification of animals infected with FMD virus is vital if disease outbreaks are to be rapidly diagnosed and controlled. Thorough screening to identify signs of FMD is time consuming and labour intensive since it requires the capture and restraint of suspect animals for clinical examination. This can be particularly difficult in some situations, for example where animals are at pasture, are difficult to handle or are present in very large numbers. Animals with FMD often develop a fever with temperatures in excess of 40°C and vesicular lesions around the coronary band, in and around the mouth and on the mammary gland. The vesicular lesions are associated with local inflammation giving rise to an increase in skin temperature which can be detected by palpation [1] . On their own, these temperature changes are not pathognomonic for FMD but can be used to select animals that warrant closer examination to detect more definitive signs and/or enable sampling for confirmatory testing.