An outbreak of tuberculosis in Lleyn sheep in the UK associated with clinical signs.

This case report describes an outbreak of Mycobacterium bovis infection a Lleyn sheep flock associated with clinical signs of illthrift. There was no known direct contact with tuberculous cattle although bovine tuberculosis (bTB) is endemic in the area. The spoligotype isolated from the diseased sheep was the local spoligotype. The repeated use of the comparative intradermal tuberculin test, and the subsequent removal of reactor animals, resulted in apparent elimination of bTB from the flock. Lesions caused by M bovis in sheep may contain very few acid-fast bacilli, and gross lesions may resemble those found in cases of Caseous Lymphadenitis. Routine meat inspection may, therefore, not always easily detect this notifiable disease.

[Somatotropin: endocrinological aspects]. / Somatotropine: endocrinologische aspecten.

Bovine somatotropin (BST) is a polypeptide hormone produced by the pituitary gland. Its release is regulated by hypothalamic hormones such as the Growth Hormone Releasing Factor (GRF) and the Somatotropin Release Inhibiting Factor (SRIF). Unlike somatotropin, GRF en SRIF are not species-specific. Somatotropin is released into the blood, and then bound to receptors which are present in various tissues but not in those of the mammary gland. Binding of somatotropin to receptors of hepatocytes results in the synthesis of somatomedins which are mediators of somatotropin. Receptors for somatomedins were recently found to be present in mammary gland tissue. The release of somatotropin is pulsatile and is influenced by steroids, genetic factors, nutrition and pregnancy. The effect of BST is dependent on its average concentration in the plasma and not on a particular pattern in this concentration. The effect of administration of BST prior to peak lactation is variable, but subsequently continuous to be positive. It therefore is advisable to start treatment after day 90. In the future, administration of recombinant-BST will be performed through slow-release preparations.