Flushing Ewes Before Breeding: More Lambs from Better Feed

Flushing is one of the oldest tricks in sheep husbandry and one of the few that still earns its keep. The idea is simple: put ewes onto a rising plane of nutrition in the weeks before the ram goes in, and more of them will shed more eggs at ovulation. More eggs means more twins, and more twins means more lambs weaned per ewe put to the ram.

It works, but not on every ewe, and not by as much as the folklore suggests. Knowing who to flush, and when, is what separates a genuine lift in scanning percentage from a fortnight of wasted feed.

What flushing actually does

Ovulation rate in the ewe is sensitive to two things: how much body reserve she is carrying, and whether her energy intake is going up or down. Flushing targets both.

• Static effect. A ewe in better body condition ovulates more eggs than a thin ewe of the same breed and age. This is the larger of the two effects.
• Dynamic effect. A short-term rise in energy intake immediately before and during mating gives a further, smaller lift on top of whatever condition she already carries.

The practical consequence is that flushing is not a rescue plan. You cannot take a ewe from body condition score 1.5 to a respectable ovulation rate in a fortnight of good grass. Condition takes months to build; flushing sharpens what is already there.

Who benefits, and who does not

This is where most of the money is won or lost.

Ewe group	Response to flushing
Thin ewes (BCS 2.0-2.5)	Largest response, clear lift in ovulation rate
Moderate ewes (BCS 2.5-3.0)	Useful response
Ewes already at target (BCS 3.0-3.5)	Small to negligible response
Over-fat ewes (BCS 4+)	No benefit, and fat ewes can have poorer conception
Ewe lambs / hoggets	Modest response; growth rate matters more than flushing
Prolific breeds already scanning 190%+	Diminishing returns

The lesson: condition score before you spend anything. Draw the flock into groups, feed the thin ones preferentially, and leave the fat ones alone. Blanket-feeding the whole flock feeds the ewes who need it least.

Timing

The standard, and well supported, approach is:

• Start 3-4 weeks before the ram goes in. Ovulation is influenced by nutrition over roughly the preceding cycle, so you need a lead-in.
• Continue through the first cycle (about 17 days) with the ram in. Ewes served on the second cycle still benefit.
• Do not stop abruptly at ram-out. A sharp drop in intake immediately after mating is the last thing a newly implanting embryo needs. Taper down over a week or two.

Total commitment is therefore roughly six to seven weeks of better feeding, not two.

How to flush in practice

Flushing does not require concentrates. It requires a rising plane of energy.

• Good grass is the cheapest option. Shift ewes onto a clean, well-rested pasture with plenty of leafy cover. Save a paddock for it.
• Legume-rich swards (clover, lucerne) are excellent for condition, though very high-oestrogen clover stands are best avoided right at mating.
• Brassicas and forage crops work well where they are established, but introduce them gradually over 7-10 days to avoid digestive upsets.
• Concentrates, around 250-500 g/head/day of a cereal-based feed, are a reasonable option when grass is short. Introduce gradually.
• Minerals matter. Ensure adequate cobalt, selenium and iodine status, guided by local knowledge or blood testing, as deficiencies suppress fertility regardless of how much energy you feed.

Avoid sudden dietary lurches. Rumen microbes need time; a ewe with acidosis is not a ewe who is ovulating well.

The knock-on effects on lambing

Flushing succeeds by increasing twins and triplets. That is a benefit with a bill attached, and you should plan for it:

• Multiples arrive earlier. Ewes carrying twins or triplets typically lamb one to two days ahead of singles. Gestation still averages 147 days with a normal range of 142-152, but the peak shifts forward slightly.
• Triplets need management. More triplets means more fostering, more artificial rearing, and more demand on late-gestation feed.
• Late-gestation nutrition becomes non-negotiable. A ewe carrying triplets on a thin ration is a candidate for twin lamb disease.

Once the ram is out, put your service dates into the Sheep Gestation Calculator to get the expected lambing date and the 142-152 day window, then work backwards to schedule scanning, vaccination and the step-up in late-gestation feed.

A simple flushing plan

1. 10-12 weeks out, condition score the flock. Identify ewes below target and cull the ones that will not recover.
2. 6-8 weeks out, start correcting condition in thin ewes; this is condition building, not flushing.
3. 3-4 weeks out, move the target group onto the flushing sward or start the supplement. Rams in with raddle harnesses.
4. Through the first cycle, hold the plane of nutrition steady and high.
5. After mating, taper down gradually. Avoid stress, handling and long transport in the first three weeks after service, when embryo losses are most likely.

Common mistakes

• Flushing fat ewes. No response, and you make them fatter.
• Starting too late. Two weeks before the ram is barely enough to register.
• Stopping too early. Cutting feed on the day the ram goes out risks early embryo loss.
• Ignoring the rams. A well-flushed flock and an infertile or lame ram is a very expensive lesson. Fertility-check rams eight weeks out.
• Chasing prolificacy you cannot house. Extra triplets on a farm without the labour to rear them is not a win.

Flushing is cheap, it is repeatable, and on a flock with a genuine spread of body condition it is one of the best-value interventions in the breeding calendar. Score first, target the thin ones, keep the plane rising through the first cycle, and record every service date so the Sheep Gestation Calculator can tell you exactly when the extra lambs will arrive.

This article is general husbandry guidance, not veterinary advice. For decisions about a specific animal or flock, speak to your vet.

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Plan your lambing dates: use the free Sheep Gestation Calculator to turn a breeding date into an expected lambing date, a 142–152 day window and a full milestone timeline. Estimates only, always consult a veterinarian for animal-health decisions.

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