Mating ewe lambs doubles output

BRINGING replacements ewes into mid-season system flocks adds a significant cost to the enterprise. Breeding ewe lambs has the potential to lower the cost of these replacements ewes and increase flock output.

Studies have shown that mating ewe lambs significantly increases lifetime ewe output by 10 to 20%.

There are a few criteria around joining ewe lambs that farmers need to be aware of.

Heat onset of ewe lambs is influenced by ewe lamb live weight, contact with rams, their breed and age. The most critical issue is the weight of the ewe lambs at joining with target weight being 60% of their mature ewe weight or a minimum weight of 45kg.

As oestrus is shorter in duration than in mature ewes it is recommended to use experienced mature rams.

Studies have shown that shearing ewe lambs increased the subsequent lamb birth and lamb weaning weight.

Apart from actual weight at joining the pregnancy rate of ewe lambs is positively influenced by condition score at joining and the subsequent litter size is positively influenced by weight of the ewe lambs at joining.

When considering breeding ewe lambs there are a few other management factors that should be considered.

Ideally ewe lambs should be vaccinated for abortion, in particular for toxoplasmosis.

As the ewe lambs are still maturing it is necessary to begin pre-lambing supplementation earlier than for the main flock. These yearling ewes can be susceptible to worms and parasitic gastro-enteritis post lambing due to not having developed the worm resistance found in older ewes.

For this reason worm dosing of the yearling ewes is important. The ewe lamb flock should be managed as a separate group both prior to and after lambing.

The main perceived drawback of joining ewe lambs is the difficulty in returning them in lamb the following season.

This issue is mostly related to poor body condition recovery following their first lambing. To avoid this situation the yearling ewes will need supplementation post-lambing in addition to longer supplementation pre-lambing.

Their lambs should also be weaned on or maybe slightly earlier than the recommended 15 weeks of age in order that the yearling ewes can increase in weight and improve in condition for the subsequent mating season.