Anita O’Brien, Sheep and Goat Specialist, Ontario Ministry of Agriculture, Food, and Rural Affairs
(Previously published online as an OMAFRA publication: February 11, 2010)
The 
practice of increasing nutrient intake and body condition prior to and during breeding is called flushing. Its purpose is to increase the rate of ovulation and, hence, lambing rate.
The response to flushing is influenced by:
- age of the ewe (mature ewes show a greater response than yearlings)
- breed (prolific breeds are least responsive)
- body condition (thin ewes respond more than those in above- average condition)
- stage of the breeding season (greatest response is seen early and late in the breeding season).
Flushing is especially beneficial for thin ewes that have not recovered from previous lactation stress. There appears to be no response to flushing in ewes that are already in above- average condition.
It is best to flush ewes with condition scoring of 2 – 2.5 to increase their condition to 3 – 3.5. Ewes on a rising plane of nutrition drop more ova than ewes on a steady plane, i.e., condition scoring of 3 increased to 3.5. It takes about six weeks grazing on good pasture to improve the body condition of a ewe by one body score, and three weeks grazing on good grass to improve a half condition score. The following table indicates the required length of time necessary to bring ewes in below-average condition up to the ideal breeding condition.
| Ewe body score | Flushing period (weeks) |
|---|---|
|
1.5
|
9
|
|
2.0
|
6
|
|
2.5
|
3
|
|
3.0
|
2
|
Flushing is generally accomplished by providing ewes with fresh pasture, supplemental harvested forage, or up to one pound of grain per ewe daily, depending on environmental stress (time of year), availability of forage, and body condition of the ewes. Special feeding usually begins around 2 weeks prior to breeding and continues at least 2 to 4 weeks into the breeding season. The reason for carrying the plane of nutrition on after breeding is to decrease embryonic death loss. The extra feed ensures the fertilized eggs have a much better chance of attaching to the uterus wall, rather than being reabsorbed due to lack of energy from the ewe.
Flushing should not be continued too long after the breeding season, as an extended period of high feeding is unnecessarily costly, and provides no improvements in ewe performance and productivity over a maintenance level feeding program.