Lamb Nutrition

Lamb nutrition can be fairly simply split into two parts – the Ewe and the Lamb. Tom Jackson talks us through the basics…

The Ewe

During the first six weeks of life a lambs growth is provided almost entirely by the ewe’s milk.  This is therefore influenced by a number of factors including the milk yield of the ewe, the number of lambs suckling and the ability of an individual lamb to compete for its share.

This demand means that the energy requirements of the ewe can increase by up to 70% from late pregnancy to early lactation. It is vital to safeguard ewe body condition scores (BCS) in order to maintain milk production. This is particularly important for Ewes that have two or three lambs at foot and are subsequently at a greater risk of body fat mobilisation and post-partum problems such as ketosis and metritis if not provided with adequate nutrition.

This can be achieved by feeding high-quality ad lib forage and by using a concentrate containing up to 20% rumen undegradable protein (such as rumen protected Soya). Having said that, be careful not to use excessive amounts of concentrates as this can decrease forage intakes and increase your total costs. Concentrates should be fed for the first three to four weeks of lactation before being gradually decreased to zero by six weeks. Aim to have 90% of ewes at target BCS, and strive to avoid any BCS loss greater than 0.5 points during lactation.

The Lamb

From birth to roughly 35kg liveweight, the protein requirements of the lamb are met solely by milk which bypasses the rumen to be directly digested in the small intestine. Following this point, forage should take over as the primary source of protein to fuel growth.

Up to eight weeks, growth rates should exceed 250g per day (predominantly from milk); if growth rates dip below 200g per day this should trigger weaning. Plan to wean lambs at 12-14 weeks old, and wean on to high quality pasture with a sward height of 6-8cm and a low level of parasitic challenge. Weigh all lambs and sort in to three groups, monitoring fortnightly. Bear in mind that a growing lamb eats 4% of its bodyweight as dry matter every day (eg a 30kg lamb on decent forage consumes 1.2kg dry matter per day).

Research into different feed types has shown that exposing growing lambs to varying sources of nutrition (such as Red Clover, Chicory or cereals) can help them to perform better when they are placed on these food sources post-weaning. It can take the rumen up to three weeks to adapt to a new feed so take care when changing onto a new diet.

Creep feeding is something that can play an important part in lamb nutrition and growth under certain circumstances, but does not necessarily always make economic sense!

Reasons for creep feeding:

• Increase suckling lamb nutrient uptake
• Maintain growth despite inadequate grass supply
• Meet target weight for a specific high-price market, for example, Easter
• Decrease the risk of gastrointestinal parasitic infection
• Allow an increased stocking density without adversely affecting growth rates

If a good amount of grass is available – sward height greater than 5cm – then creep feeding will not necessarily improve performance but will certainly increase costs! As an alternative, forward creep-grazing can reduce the need for creep feeding by giving lambs access to the best pastures before the ewes follow on.

On restricted grazing (sward height less than 3.5cm) creep feeding can be profitable; Lambs with a limited amount of creep feeding will gain 1kg live weight per 5-6kg of creep feed when compared to un-supplemented lambs.

When home-mixing creep feed, whole barley plus 15% Soya bean meal should provide 12.5 MJ of metabolisable energy per kg of dry matter. For long-term use, including a lamb suitable mineral at 2.5% is advisable (no added Copper, Magnesium or Phosphorous).

Take care to introduce concentrates to older lambs gradually in order to reduce the risk of gorging and acidosis.

Creep feeder design for optimum lamb nutrition:

• Easy access for lambs but not ewes
• Sheltered
• On hard-standing to avoid poaching
• Keep surroundings clean and dry to decrease risk of transmission of coccidiosis (apply lime if necessary)

Mineral and trace element deficiencies occur reasonably commonly in sheep. If you suspect a deficiency is affecting performance at any point, discuss with your vet and consider taking blood samples to identify and rectify the potential cause. Following supplementation, monitor performance to confirm a positive response.

Sources:
Hybu Cig Cymru / Meat Promotion Wales – Practical Sheep Nutrition 1
AHDB Beef and Lamb – Sheep BRP Manual 5 – Growing and Finishing Lambs for Better Returns