THE EFFECT OF FASCIOLOSIS ON THE WOOL PRODUCTION OF MERINO SHEEP

The wool production of 20 Merino sheep, artificially infected with Fasciola hepatica, was compared with that of 20 uninfected controls. Sheep of two different ages, 6 months and 4 years, were fed in pens ad lib on two different diets giving high and low planes of nutrition. The midside tatooed patch technique was used to measure the wool production over periods of 6 weeks prior to the infection date, and 0–6, 6–12, 12–18 and 18–24 weeks after this date. Infection with F. hepatica caused a significant reduction of 20–39% in wool production from 6 weeks after infection, irrespective of the age of the sheep or the plane of nutrition. It was found that a reduction in wool production may occur without symptoms of fasciolosis being apparent.     

THE EFFECT OF EPERYTHROZOON OVIS INFECTION ON THE GLUCOSE LEVEL AND SOME ACID-BASE FACTORS IN THE VENOUS BLOOD OF SHEEP

Eperythrozoon ovis infected sheep have low venous blood glucose levels and correspondingly increased blood lactic acid levels as compared with control sheep. Acid-base studies showed that these changes were accompanied by significant falls in venous pH, and standard bicarbonate as well as a negative base excess. All these changes were considered to result from the increased alvcolytic activity of infected erythrocytes. The acidosis and hypoglycaemia associated with E. ovis infection, while not having any apparent effect on young, well-fed sheep, could be potentially serious in pregnant ewes and in sheep on a low plane of nutrition.     

SQUAMOUS-CELL CARCINOMA OF THE VULVA IN MERINO SHEEP

Squamous-cell carcinoma of the vulva was observed in 3.1% of Merino ewes up to 3 years old. It is suggested that this high incidence of tumours was related to increased exposure of the perineal region to direct sunlight. It occurred in a group of sheep where short docking of tails and a radical surgical procedure to reduce cutaneous myiasis (Mules' operation) both led to greater exposure of the perineal region. The perineum was also subject to scarring from the operation and to application of organophosphate compounds to control cutaneous myiasis.