On page 6, Ciaran Lynch discussed options for early lambing and factors to consider in finding a system that works best for you. Like any system, performance in early lambing flocks can be maximised by putting plans in place early.

Keeping a tight lambing spread works best for numerous reasons, including less chance of a build-up of disease, fewer groups for managing, uniform lambs for health treatments and fewer tail-end lambs to contend with. Flushing, the ram effect and sponging are all options that can be used to help tighten the lambing spread.

Flushing

Flushing delivers advantages with ewes responding to a lift in nutrition in the form of earlier cycling, higher ovulation rates and improved conception rates. This lift in energy intake is positively linked to higher litter size and subsequent higher weaning rates – key factors in maximising farm gross margin.

The flushing procedure works best when ewes are on a restricted diet previous to flushing. However, the mistake is often made of over-restricting ewes, causing weight loss, and thereby not achieving the full benefits of the practice.

To let ewes lose too much weight and drop below optimum mating condition (BCS 3.0) is inefficient. Instead, ewes should be fed to maintenance or allowed to drop down to the target condition score over a period of time.

The condition that is gained during mating will be invaluable later in the year when there are extra nutritional demands on the ewe’s system.

Ram effect

The ram effect can also be beneficial at breeding, but the result can be variable at times. The ram effect has the result of getting non-cycling ewes to cycle, which could reduce the lambing spread by up to two weeks. Because ewes are seasonal breeders, the ram effect works best for early lambing ewes (or ewe lambs) as at breeding there may be less of the ewes cycling than later bred ewes.

There are advantages to this method of synchronisation. Firstly, there is no cost when compared to sponging and secondly, lambing will generally take place over a two-week period as opposed to a one-week period if sponged.

As a ewe comes close to the onset of the normal breeding season, mixing mature rams with the ewes will result in pheromones from the rams bringing the ewes in heat quicker. If ewes are already cycling, then the ram effect will not work. This is why it is most suited to early lambing flocks. The ram effect will only work where ewes have not had contact with rams for at least 28 days prior to this.

Ideally, a ram should be added to the flock approximately three weeks prior to the target onset of breeding. All non-cycling ewes will normally start to cycle within the first seven days, but full heats will not be seen until three weeks later. Rams should be introduced 14 days after the first ram and a ratio of one ram per 20 ewes should be maintained.

Sponging

Sponging is the most common synchronisation method used on farms in Ireland. There are two types of intravaginal sponges available in Ireland, flourgestone acetate (FGA) – Chronogest – and Medroxyprogestrone acetate (MAP).

The sponging method is simple. The sponge is inserted with the applicator on day one. The sponge is left inserted for 12 to 14 days and then removed. On removal of the sponge, the ewe is injected with PMSG. Using this method, approximately 90% of the ewes will be in heat within 30 to 60 hours.

When selecting ewes for sponging, ensure that only fit ewes are selected and that their body condition is approximately 3.5. For hoggets, it is advised that rams be introduced from 36 hours post-sponge removal. For mature ewes, rams should be introduced 48 hours after removal. Where a farmer is synchronising ewes, there will be a high demand on rams. For this reason, Teagasc advise that a ratio of one ram to eight ewes be maintained during breeding.