Clinical and epidemiological studies on thin ewe syndrome

Abstract

Sheep represent an important source of meat and wool in Egypt. Egypt considered as one of the five tope sheep exporting Arab countries (Baghasa, 2006). Sheep industry is one of the developing and profitable industry in Egypt

their number estimated in 1976 to be 2 millions but recently it reached in 1996 to be 3.491 millions (Anon, 1976 and 1996). Now they number estimated in 2006 to be 5.2 millions (Celine, 2006).

Thin ewe syndrome is a loo .e name defined as a debilitating condition affecting mature ewes was found to be associated with the caseous lymphadenitis, chronic pneumonia, paratuberculosis and parasitic infestations and other infections. (Gates et al, 1977, Renshaw et al.,1979) Caseous lymphadenitis is a chronic suppurative disease that mainly affects goats and sheep. and can cause debility in animals, presenting itself in cutaneous and visceral forms. The disease is distributed worldwide, with cases being reported in Europe, Australia, North and South America, Africa and the Middle East (Dorelia et al., 2006). The diseased is caused by Corynebacterium pseudotuberculosis. It is non-motile pleomorphic rods (0.5-0.6 11m by 1.0-3.0 -tm) that are gram positive and tend to show a characteristic palisade or Chinese letter arrangement in smears (Baird and Fontaine, 2007). Caseous lymphadenitis causes considerable economic losses, which range from condemnation of skins and carcasses, due to abscesses, to expressive losses in reproductive efficiency, as well as in wool, meat and milk production. Subclinical infections are also important, because they allow C. pseudotuberculosis to disseminate within and between herds (Paton et al., 1994). Also, caseous lymphadenitis can become a public health problem as it is a zoonosis (Peel et al., 1997; Join-Lambert et al., 2006).

Sheep are usually more prone to internal parasites as they mostly depend on grazing. The situation could be more crucial in marshy areas where the internal parasites could more easily propagate as compared to relatively dry environment. Internal parasites could cause severe damages to sheep in terms of high mortality, reduced body weight gain, wool yield and birth rate (Ahmad, 1992). It is recognized that helminth infections of sheep cause major economic losses