Aug 23, 20234 min read

A Guide to Successfully Growing and Finishing Lambs...

Depending on your lambing time and system, you may already be selling lambs fat, or maybe considering options for the next few months to ensure you hit the markets when they suit your lamb type. Feeding and ensuring finishing lambs health can be a challenge but whatever you decide, it must be efficient.

Weaning

When to wean:

Lambs are usually weaned between 12 to 14 weeks of age.
Once a lamb reaches 8 weeks of age, grass intake provides more energy than milk intake does.
Lambs should be weaned once the lambs and ewes are competing for the available grass.

Where to put lambs:

Move the ewes but leave the lambs in the same place for 48 to 72 hours.
Once the lambs are over the stress of weaning, they should be moved to a low parasite burden pasture or a forage crop.
Ideally, do not graze finishing lambs on fields that have had ewes and lambs on in the same season.

Growth rates post weaning:

To achieve optimum growth rates after weaning: lambs should be turned onto grass with a sward height of 6 to 8cm if set stocked.
On a rotational grazing system: sward height should be 10 to 12cm pre grazing and 5 to 7cm when exiting the pasture.
The quality of the grass should be young and leafy.
From weaning to slaughter, the growth rate can be increased by 25% by grazing white clover pastures.

Parasite Burden

Parasite burden can be reduced at grazing by utilising other classes of stock or using fields for conservation. Faecal Egg Counts should be used to monitor any potential worm challenges. Batching lambs according to their weight can enable feed to be targeted more efficiently. A good target for grass-based systems is to ensure >70% of lambs are sold (finished or as stores) by tupping.

Feed

Introduce creep feed if lambs need support to ensure they perform as required.

Using a good concentrate with cereal, quality protein and good mineral package will encourage growth. Once you’re happy with the size and frame growth of the lambs then increase starch and decrease protein.

Male Lambs

Keeping male lambs entire can help with higher growth rates due to better feed conversion. They should be separated from ewe lambs by 5 months of age and their finishing should be planned to avoid any store periods. The meat quality can be affected if they are not finished by 8 months of age.

Store Lambs

Shearing store lambs means they eat more and finish quicker. The lambs need less lying area but their requirement for feeding space is NOT reduced. Shearing housed lambs reduces the risk of heat stress on high cereal diets. The lambs need to be housed for over a month to see the benefit and it is important to check there is no penalty at the abattoir for shorn lambs.

Avoiding issues with lamb feeding

Feeding lambs can present several challenges and we are all aware how easy it is to end up with some deaths due to lambs gorging on feed. There are certain situations in which the risk of this will be higher and there are management protocols we can use to minimise the risk.

The transition and change of environment or feed sources are the biggest risk times for resulting lamb illness or death. Housing, change of field, change of grazing type, and introduction of feed all pose a risk.

Lambs are grazing in a field with a reasonable amount of grass. Feed is introduced to the lambs in a hopper. In an ideal situation the lambs will gradually introduce themselves to the feed in the hopper but that is a risk being taken. Ideally use a feeder that can be restricted such as an Advantage feeder or feed restricted quantities for the first few weeks gradually increasing to ad-lib. Ensure clean, fresh, readily available water is accessible.
Housing lambs from a grazing and hopper situation will mean that the lambs know what the feed in the hopper is rather than the forage they meet when housed. This increases the risk of the lambs gorging and getting ill. Whenever lambs are housed for the first time, they should be given hay, haylage or fairly dry silage for the first 24 hours, ad-lib, to ensure they fill themselves up before the hopper is (re-)introduced. Ensure clean, fresh, readily available water is accessible.
Lambs being housed from just grazing, having not had access to hard feed, are likely to take a few more days to get onto a hopper fed concentrate and less likely to gorge BUT it is still possible. These lambs should be offered forage only for 24 hours to fill up before concentrate feed is offered. Ensure clean, fresh, readily available water is accessible.
Lambs grazing and moved to a field of different grass or forage crop. Adjustment should be accounted for. If the grazing is poorer quality to encourage concentrate feed, then ensure 24 hours in the new field before introducing the concentrate feed. If the grazing is much better quality, or has a lot of clover present, introduce for a few hours in the day and return to previous grazing for the rest of the day, gradually increasing the time on the new grazing area. If moving to forage crops from grass, ensure strip graze the forage crop and ensure a run back area onto grass is available.

It is important to ensure lambs are fully vaccinated for Clostridial disease and Pasteurella before a time of risk. For best uptake, these may need to be given separately. Also ensure fluke and worm doses have been administered as required.