Pregnancy scanning (real-time ultrasonography) of ewes is one of the most impactful management tools available to sheep producers. By identifying single, multiple, and non-pregnant ewes before lambing, targeted nutrition and management dramatically improves both ewe and lamb welfare outcomes.
Why Scan?
Ewes carrying twins or triplets have significantly higher nutritional requirements in late pregnancy than those carrying singles. Without scanning, mixed-pregnancy groups receive average nutrition — inadequate for multiple-bearing ewes and potentially excessive for singles. The consequences of miscalculation include:
- Pregnancy toxaemia (twin lamb disease) in underfed multiple-bearing ewes
- Large, oversized singles leading to dystocia in overfed single-bearing ewes
- Hypocalcaemia and poor colostrum quality from nutritional mismanagement
- Unnecessary feed costs from overfeeding singles
Timing and Technique
Scanning is typically performed 70–90 days after the end of mating — early enough to allow nutritional adjustment while providing reliable fetal counting. A real-time ultrasound scanner (3.5–7.5 MHz transducer) is applied to the right inguinal area with the ewe restrained in a cradle or against a wall. Skilled scanners achieve 95%+ accuracy for twin detection; triplet detection accuracy is lower. Scanning should only be performed by trained, competent personnel.
Management Groups Post-Scanning
Ewes should be sorted into management groups immediately after scanning:
- Barren ewes: Consider culling economics; maintain basic welfare nutrition pending sale or slaughter
- Singles: Moderate concentrate supplementation (200–300g/day) in last 6 weeks
- Twins: Higher concentrate supplementation (400–600g/day) in last 6 weeks
- Triplets: Highest supplementation (600–800g/day); consider fostering a lamb at birth
Welfare Benefits
Scanning and targeted nutrition reduces:
- Pregnancy toxaemia incidence by up to 50% in properly managed flocks
- Perinatal lamb mortality (lambs from well-nourished ewes have higher birth weight and colostrum)
- Dystocia rates (appropriate body condition in singles reduces oversized lambs)
- Ewe mortality from metabolic disease
Scanning as a Positive Welfare Indicator
Adoption of pregnancy scanning is an indicator of good farm welfare culture. It requires investment (equipment or scanner hire, labour for restraint, sorting facilities) but delivers welfare and economic returns that substantially exceed costs. Farms not scanning multiple-bearing ewes are missing a fundamental welfare management opportunity.