Ewe preparation
In WA the average reproductive rate (foetus per 100 ewes joined) is 120%, however, flocks will vary and flocks across years will vary considerably. Nutrition and the ewe's condition score are the greatest determinants of reproduction rate. Therefore, take every opportunity when you have your ewes in the yards to condition score 25 sheep per mob, starting 56 days prior to the start of joining.
Tips for preparation
- Check ewe condition at least a month prior to joining to assess if feeding is required to maintain their condition.
- Check ewes for low condition, udders, poor feet and mouth condition – remove any affected ewes from the main flock.
- Ewes should be in condition score 3+ (good cover of muscle and fat over the short ribs).
- Tease ewes if mating prior to mid January.
- Join for 35 days (two cycles).
What condition should my ewes be in?
The higher the condition score of ewes at joining, the higher the potential number of lambs and the lower the number of dry ewes there will be in a flock. The average response is about 20 extra lambs per 100 ewes for an additional condition score at joining.
Remember it is cheaper to maintain condition rather than to feed supplements to put on weight. If joining is on dry feed, ewes will need to have reached optimum condition before the pastures deteriorate or stubbles are grazed out.
The higher reproductive rate is due to fewer dry ewes and more ewes conceiving twins. At condition score 3, there should be no more than 10% dry ewes in most Merino flocks and less than 5% dry ewes in cross-bred flocks.
In flocks scanning around 120%, half of the lambs born will be twins and less than 5% of the ewes will be dry. View the pregnancy scanning benchmarks in WA to see where your flock's reproduction rate sits.
The condition of the ewes should be maintained over the joining period to ensure optimum conception and profitability. Maiden ewes should reach at least 90% of their adult body weight prior to joining to maximise their chances of conception. Ewes less than condition score 2 should either be treated separately to gain condition prior to mating, or not mated at all. Those ewes conceiving in condition score 2 will be unlikely to gain condition over pregnancy and therefore be at risk at lambing.
Flushing or feeding lupins prior to joining
A method to stimulate reproduction rates is to feed ewes 500 grams per head of lupins daily from seven days prior to rams going in and continue for no more than seven days after rams-in. This method can be variable in its response and the cost of feeding lupins to the value of extra lambs needs to be taken into account. Note: ewes are more likely to respond to lupin feeding if they are less than condition score 3 and it is suggested that ewes be fed daily rather than twice weekly or join on ungrazed lupin stubbles. Be prepared to manage the extra twins generated – twinning ewes will need higher nutrition in pregnancy and lactation.
Any ewes stimulated to ovulate when in poor condition (< condition score 2) will be in below optimum condition at lambing and exposed to higher mortality risk.
A much more reliable strategy is to ensure at least 85% of ewes in each mob are above condition score 3 at the start of joining.