The Effects of Pregnancy and Nutritional Stress on Fat Partitioning in The Body of Ewes

Abstract

The present study was conducted to determine the effects of pregnancy and nutritional stress on fat partitioning in the body of ewes. Twenty pregnant and 20 non- pregnant, 3 to 4 year old Pappin Merino ewes were placed in individual pens in an animal house. The pregnant and non pregnant ewes were allocated to maintenance and weight loss treatment groups on the basis of their liveweight and placed in individual pens. To achieve the required 20% decrease in matemal body weight it was calculated that the low nutrition animals be oficred 58% of thc ration fed to the maintenace group. Afier adjustment to the same matcmal body weight, there was no effect of nutrition on the weights of body components. Pregnancy status of the ewe did affect body composition, whereby the  pregnant ewes had 0.75 and 0.25 kg less carcass muscle and bonc respectively, than non-pregnant ewes. Pregnant ewes had a greater weight of dissected fat in the subcutaneous depot (0, l6 kg) and less in the kidney fat depot (0.07 kg, P<0.05) than non-pregnant c\vcs. There was also a trend for pregnant ewes to have loss fat in the omcntal depot (0.09 kg), although this difference failed to reach significance (P=0.085). The nutrition effect interacted with total disscetiblc body fat weight. At the same total chemical body fat weight, pregnant ewes had 0.22 and 0.09 kg more chemical fat in the subcutaneous and intcnnuscular depots, respectively, and 0.05 kg less chemical fat in both the carcass muscle and skin depots, than non—pregnant ewes.