How body condition, current nutrition and Finn gene status influence litter size in Norwegian White Sheep : a study in flushing and antiflushing

The effect of body condition, current nutrition and Finn gene status on litter size was studied using 111 ewes of Norwegian White Breed, in the age from 1.5 to 6.5 years. The last 11 weeks before mating in mid-November the ewes were divided into three groups, where one group was fed to increase their body condition (BC), one was fed to keep a constant BC, and the last was fed to decrease BC. All groups were offered forage ad libitum as the sole feed, where forages differed considerably in energy concentration. Forty-eight of the ewes were stalled individually, whereas 63 were stalled in group pens. In addition to using the well-known body condition score (BCS) from 1-5 to describe the fatness of each ewe, also Body Mass Index (BMI) was calculated for each individual. Of the 111 ewes there were 41, 59 and 11 ewes with Finn gene status 0, 1 and 2, respectively. The litter size was registered with ultrasound measurement in January. Results showed a significant effect of BMI at mating (P