HIGH FLEECE WEIGHT SHEEP HAVE LOWER PLASMA GLUCOSE AND INSULIN

摘要

In previous experiments, we had found that plasma insulin concentrations were lower in high fleece weight sheep, but fleece weight was poorly correlated with plasma glucose concentrations. The study reported here tested the glucose/insulin relationship with an adrenaline challenge, since adrenaline is known to affect plasma glucose concentrations. Four groups each of 10 ewes aged 20 months were selected from the Western Australian Department of Agriculture Katanning Base Flock. Animals were selectedprimarily on their estimated breeding value for high or low clean fleece weight (CFW) and also for their high or low fibre diameter (FD). The experiment was a 2x2 factorial design. The ewes were fitted with bilateral jugular catheters and 24 hours laterwere infused with a bolus dose of adrenaline (Adrenaline Injection~(R), Astra) at 10 μg/kg liveweight. The dose we used (10 μg/kg) was within the physiological range. Three blood samples were collected before the challenge, and then at 10, 20, 30, 40,50, 60, 90, 120 and 180 min. All infusions and associated blood samplings were carried out before feeding the daily ration.