Sheep Pregnancy Scanning: Management Tips

Agdex#:	433/22
Publication Date:	09/02
Order#:	02-061
Last Reviewed:	15 April 2010
History:	Original factsheet
Written by:	Anita O'Brien - Sheep and Goat Specialist/OMAFRA

Table of Contents

1. Introduction
2. Reasons Producers Use Realtime Ultrasound Scanning
3. Protocol For Success
4. What is the Cost-Benefit of Pregnancy Scanning?
5. Savings in Lamb Mortality:
6. Conclusion
   

Introduction

When scanning is performed within the recommended time frame, accuracy of identifying animals that are not pregnant and counting number of fetuses is very high. Accuracy decreases when animals are above or below this time window, and with increasing number of fetuses. One of the services available to sheep and goat producers in Ontario is pregnancy detection (scanning) using realtime ultrasound equipment.

Reasons Producers Use Realtime Ultrasound Scanning

• To identify, and manage accordingly, those animals that are open (not pregnant).
• To use fetus count to improve feeding management.
• To improve newborn survival through appropriate feeding management.
• To determine appropriate dry-off time in dairy animals.

For producers to get the maximum benefit from using pregnancy scanning, factors affecting accuracy need to be well understood. According to the scanners that are certified to offer this service to Ontario producers, some of the factors that seem to be involved with reduced accuracy in sheep flocks include:

• full rumen (fresh off pasture)
• dirty sheep (in the crutch-udder area)
• fat animals
• prolific animals (lots of triplets, quads, etc.)
• extra-wild, jumpy lambs or yearlings
• too much variation from the 78 day ideal (below 55 and above 100 days)
• too many operations (marking, hand recording animal ID, drafting off scanned animals) and not enough staff.

Protocol for Success

• Book appointment as early as possible.
• Know date of ram (buck) entry.
• Know date of ram (buck) removal.
• Aim to scan between 70 and 90 days.
• Ask the scanner what their protocol is.
• Take sheep off feed, etc.
• Have adequate labour available.
• Do NOT plan to do other "jobs" while scanning.
• Provide some means of equipment cleanup.

With good setup, a throughput of more than 75 ewes or does per hour is possible.

What is the Cost-Benefit of Pregnancy Scanning?

To demonstrate the cost-benefit of scanning, consider the example of a group of 200 ewes, with a typical open rate of 5%. Those that are determined open at scanning can be culled immediately, taking advantage of seasonally strong cull prices, or moved into the next breeding group and exposed again for breeding. For the purposes of this example, cost of scanning is assumed to be $2.00 per animal. In many instances, the cost will be less than this, depending on travel distance and whether other flocks in the same area are being scanned at the same time.

Cost: 200 ewes at $2.00 each = $400

Income from sale of culls:
5% open = 10 ewes at 145 lb/average weight and $0.60/lb = $870

Feed Savings can be calculated using the following formulas:
Number of open ewes x number of days to lambing x pounds hay / ewe / day.
Number of open ewes x number days on grain x pounds grain / ewe/ day.

Feed saved compared to normal culling time.

Hay:
10 ewes x 60 days x 5 lb/day = 3,000 lb
(1.36 metric tonnes) at $80/tonne = $109

Grain:
10 ewes x 45 days x 1.5 lb/day = 675 lb
(0.31 metric tonnes) at $165/tonne = $51

 

Savings in Lamb Mortality:

Through better feeding management, singles will be smaller and multiple lambs will be larger. If lamb mortality is reduced to 10%, from 12%, this will result in an extra 6 lambs in this sample flock. At today's market prices, this reflects an extra $600 to $720 in gross income.

Conclusion

Ultrasound pregnancy scanning can be used as a cost-effective management tool to improve breeding program management, feeding management, and newborn survival.