Early weaning

When seasonal conditions are tough and pasture availability is low over lambing, early weaning of lambs might be a useful management option. The benefits are the total feed requirements for the flock are less, because ewes and lambs can be fed and managed to their requirements.

It is inefficient to feed increasingly large amounts of supplements to ewes with lambs at foot when they are both competing for the feed.

Once lambs are weaned, the requirements of the ewes are significantly less and depending on their condition, a maintenance ration or poorer pasture may be adequate to maintain weight and halt weight loss.

Early weaning may also provide the opportunity to draft off the poorest ewes and differentially feed these to improve their condition before the next joining.

Whilst the recommended lamb weaning age is 12 to 14 weeks from the start of lambing, lambs can be weaned at 8 to 10 weeks or even earlier if appropriately fed and managed.

Train lambs before weaning (imprint feeding) as it will be much easier to get them on a ration.

Both research and farmer experience show they can be weaned as early as 5 weeks of age, if weaned onto high quality diets. The lamb’s rumen is fully functional by 8 weeks but is ‘functioning’ maturely by 5 weeks.

Interestingly, at the 2018 BestWool/BestLamb Conference, Rajneet Sohi from La Trobe University showed some observations of this using ‘Fitbit’ smart sensors to monitor ewe and lamb behaviour.

The time that lambs spent suckling from their mothers dropped steeply after 3 weeks but stabilised at 5 weeks of age and grazing and mature rumination peaked and stabilised at this age.

See the BestWool/BestLamb Conference videos or view Rajneet’s presentation on Fitbits for farm animals.

The challenge facing producers contemplating early lamb weaning is ensuring they have a high-quality ration, and they adapt to the new diet without developing acidosis or becoming ‘shy-feeders’.

Nutritional setbacks earlier in life (such as nutritional hardship) mean it is less likely they will recover later in life to reach full bodyweight and reproduction potential; so it is vital to get these lambs away from competing with their mothers for good feed, and onto quality fodder sooner, rather than later.

The younger and lighter lambs are, the better the quality ration and management to ensure they do grow and thrive adequately. Table 1 provides an indication of target weights for weaners at various stages and mature weights, which can be used to estimate appropriate weight gain targets.

Early weaned lambs require dense high-quality rations.

Early weaned lambs require dense high-quality rations so if good green pasture (that is 800 to 1000kg dry matter (DM) of good quality green pasture) is not available, they will need a supplement with 11–12MJ ME per kg DM and 14 to 18% crude protein.

Table 2 gives a guide to energy and protein requirements at different weights and growth rates, noting the aim may not be to optimise growth rates but to provide reasonable growth for survival and future production (rather than competing with mum for limited pasture feed or grain).

Table 1. Target weights for weaners

Source: Drought Feeding and Management of Sheep book, page 23.

Table 2. Energy and protein requirements of weaned lambs

(Adapted from Table 3.1 in the Drought Feed Management of Sheep book)

If not already feeding grain, train the lambs before weaning (imprint feeding) as it will be much easier to get them on a ration if they’ve learnt through copying their mothers.

It will take several feeds over a few weeks and you may need to muster the lambs onto the grain trail, but the amount doesn’t need to be much — just enough to provide a long enough trail for everyone to access.

If lambs are going into a feedlot situation they will require access to roughage. Good quality hay (legume or grass-legume hay) is useful whilst getting onto a full ration by slowly substituting the hay for grain.

If using self-feeders, care will be needed to ensure all lambs can access and use the feeders while not gorging and getting acidosis in the build-up phase.

In a paddock situation, feeding lambs less frequently than daily, (that is more grain at any feed), is the best strategy for dealing with shy feeders as this ensures these animals can get access to grain.

If lambs are very young and require optimal growth, feeding daily or with access to feeders will help with this — as long as shy feeders are identified and managed separately.

Calcium is essential for growing animals and can be supplied in limestone on the grain or with salt as a lick. If lambs haven’t been fed this before when on their mothers increasing the salt proportion can help them take to it.

Ensure you vaccinate for clostridial diseases (such as pulpy kidney — see Sheep and Goat Mortality Surveillance Project results) and drench lambs at weaning. Follow this up with frequent Worm Egg Count monitoring at monthly intervals throughout the winter.

Ensure early weaned lambs have access to good quality water — they have a lower tolerance of high salt levels than adult sheep. Where there is no access to green pasture (as in a stock containment area), administer Vitamins A and E.