Sheep Ultrasound Pregnancy Diagnosis
Since 2002 the Department of Agriculture has been able to offer a Ewe Ultrasound Pregnancy Diagnosis (scanning) to farmers.
Worldwide, scanning is used as an important management tool. It allows producers to relatively accurately predict lambing percentage. These results are then used to alter or fine-tune management practises relating to nutrition, health and pasture use. This practise has therefore fitted neatly into the Farm Improvement Programme.
The scanning information can also be utilised as a financial forecasting tool: i.e. cash flow budgets, enabling better estimates of income and expenses.
The most basic way to use scanning as a management tool is to determine which ewes are pregnant and which ewes are not. This allows you to:
- Feed accordingly – while non-pregnant ewes should not be allowed to fall away completely (they will never get pregnant next season if they do), there is no point having a mob of mostly dry ewes on your swedes or re-seeds. Keeping the pregnant ewes in good condition means they can feed and raise lambs successfully and be in good enough condition to then get pregnant again next year. Ewes in good condition have a better chance of keeping lambs alive and maximising growth rates.
- See what your conception rates are compared to lambs born or lambs marked. If your conception rate (number of ewes getting pregnant) is 70% for example but your lamb marking percentage is 50% - where are you losing that 20%? Are the ewes aborting the pregnancies? Are the lambs being born but dying before marking due to poor nutrition?
- See if any particular ewes are consistently not producing a lamb.
Benifits to scanning are:
- Identifying multiples/pregnant/not-pregnant thus allowing you to use pasture and budget for feed accordingly for what the ewes require as opposed to wasting feed on dry ewes.
- Estimating conception rates and thus lambing percentage to enable you to forecast meat or wool income.
- Able to remove any ewes that continually do not get in lamb.
- Pens and race – a temporary race made out of pens/gates is fine. For optimum flow of sheep have the panels before the scanning crate solid or covered so the sheep cannot see the scanner.
- A continuous supply of hot and cold water – access to a working kettle is fine for the hot water supply.
- A reliable power supply.
- Sufficient workforce – 1 person to work the crate/drafting gates, 1-2 people to push sheep up the race and fill pens and 1 person to write tag numbers etc if required.
- Ideally we would scan in a shearing shed so there is easy access to water and power and the ewes can be brought in the day before and fasted overnight. However we can scan outside as we have a frame and tent for the scanner, we just need to know if we need to bring it. We also have portable pens so if need be we can scan right there, in your ewe camp, thus less gathering and moving of your ewes
- Ewes need to be off food and water overnight/twelve hours before scanning. Accurate scanning with a full rumen is both difficult and hard work.
- Having the ewes half bellied make the job much quicker and easier.
Naturally mated ewes:
- A short joining period of 34 (2 cycles) is advisable. This will mean that all pregnancies from the joining period can be accurately detected from 45 days after the rams were taken off. Added benefits of a short joining period are:
- a short and concise lambing period
- a shorter time period needed to be spent shepherding
- all lambs will be nearer in age for weaning/lamb marking
- Longer joining periods may mean that 2 scanning sessions are needed to accurately detect all pregnancies which will obviously be more costly and time consuming.
AI ewes and Cover Rams:
- Any ewes that don't conceive at AI should cycle and be fertile again 17 days after the AI attempt, therefore to ensure a concise lambing period put your cover rams out 2 weeks after the AI day for 35 days (2 cycles).
- It is important to have raddle or harnesses on your rams. Marked ewes can be assumed to be cycling and not to have conceived via AI so if they are scanned pregnant it can be noted that this is probably to the cover ram rather than the AI.
- Scanning should occur between 70-90 days after the AI date.
HOW TO BOOK YOUR SCANNING:
Please let us know the dates when the rams went in and off and how many ewes there are to scan.