By day 40 it is possible to detect pregnancy with 100 per cent accuracy and foetal number to 95 per cent or better. This accuracy is maintained between days 40 and 120. Experienced contractors with real-time scanning machines and specialised ewe restraining equipment claim to scan 4,000 ewes a day for pregnancy status. The number is reduced to 2,400 ewes a day when the number of lambs per ewe is required. Contract rates are calculated on a daily or per ewe rate.
Veterinarians are normally aware of contractors operating in their districts.
The advantage of real-time scanning over other pregnancy testing techniques is being able to identify ewes carrying more than one lamb. Twin-bearing ewes can be readily identified and so genetic selection for reproduction is more easy and accurate. The presence of a foetus is detected by feeling the ewe's abdomen. While the ewe is held in a sitting position, one hand is pressed against one side of the abdomen while the fingers of the other hand palpate the other side. The foetus is felt as a floating mass.