Early weaning of lambs in a drought
24 October 2019
The feed requirements of ewes with lambs at foot are generally higher than when ewes and lambs are fed separately. In a difficult season with reduced feed supplies, it can be more economical to early-wean lambs from their mothers to lower feed costs and ensure that the ewes regain condition before joining.
This practice becomes even more important as the costs of feeds increase. Ewe's milk provides the main source of nutrition for lambs until about eight weeks of age.
Lambs will sample pasture from about two weeks after birth and by eight weeks of age, pasture overtakes milk as the major portion of their diet with milk contributing around 10 per cent of the nutrients lambs require therefore little nutritional benefit is gained by leaving them with their mothers after this time.
To wean lambs early
- Lambs should be 8-10 weeks of age, minimum of 10 kilograms (kg) liveweight.
- They should be marked and vaccinated. If they have been recently mulesed, allow four weeks to recover before weaning to avoid setback.
- ‘Train’ them to eat grain while still with their mothers (weaners should be well adapted in drought years due to the ewes being supplemented with grain during lactation).
Benefits of early weaning
- Feed cost savings – the requirements of a ewe with a lamb is higher, about three dry sheep equivalents (DSE), than the requirements of a ewe and lamb separately (1.8DSE).
- Flexibility for ewes – ewes can be fed maintenance rations, placed on poorer feed paddocks, sold or agisted.
- Ewes have a longer time to regain condition before next joining – ewes will take a month and a half to regain one condition score on pastures with a Food On Offer (FOO) of 1500 kilograms per hectare (kg/ha). Until the lambs are weaned, ewes will continue to lose weight on this level of feed. Ewes need to be in condition score 3 by joining to achieve optimum lambing percentages.
- Pastures have a better chance to re-establish and grow ahead of grazing stock.
- Worms – lambs have a lower worm burden, as worm control can be provided earlier and they won’t be grazing the pasture being contaminated by their mothers for as long.
Management of early weaned lambs
Weaners are often your replacements in the breeding flock. What happens to your weaners now will affect their lifetime liveweight, wool production and future reproductive performance. It is important to optimise conditions for your growing weaners.
To optimise future production from weaners, aim for crossbred lambs at 30kg liveweight and merino lambs at 20 kg liveweight before summer and attain a condition score of 2. During dry seasonal conditions, lambs under 20kg at weaning and those losing weight post weaning are at increased risk of mortality so its vital to optimise growing conditions for these stock to mitigate this risk.
Vaccinate at weaning for the main clostridial diseases, pulpy kidney, tetanus and cheesy gland; following label directions. It’s essential to provide this booster vaccine at weaning as the dose given at lamb marking won’t be effective without the booster. Pulpy kidney is probably the most threatening disease for a weaner, particularly when they are to be fed high grain supplements or grazed on unharvested crops. Cheesy gland and tetanus are also important.
Provide high energy and high protein feed to ensure lambs keep growing. Weaned lambs require about 11 megajoules (MJ) of energy and 16.5-20 per cent crude protein in the diet for maintenance and growth. This can be provided from high energy and high protein grain supplements or commercial lamb pellets. Lambs that are weaned early and appear weak may grow better on commercial milk replacer pellets until there is sufficient pasture available.
Provide small amounts of the feed (100 g/ewe) at least three times prior to weaning to ‘imprint feed’ the lambs while still on their mothers and train the lambs to consume the ration and allow the rumen to adapt to the new feed type. Closely observe all the lambs are eating the supplement prior to weaning, if not you will need to extend the imprint feeding period, which will depend on current pasture available, milk from the ewe and the type of grain being fed.
Weaners should be fed a minimum of two to three times per week. Initial feeding rates should start at 25 grams (g) per head/day and increased slowly to achieve a minimum growth rate of 1 to 2kg / month in the weaners. Weaners will benefit from grazing green feed for as long as possible during spring.
A paddock with a FOO of 800-1000kg/ha will be sufficient to provide growth (this equates to 80 per cent green cover at one centimetre or 50 per cent cover at 3-4 centimetres). Where insufficient pasture is available, continue to provide adequate supplement in the paddock.
Monitor your weaners
Weighing a group of 50 weaners from the mob every two weeks will give a good indication if the feeding rate is adequate. Weaners should be gaining at least 30g/head/day and up to a potential of 200g/head/day until the start of summer.
Weighing lambs at weaning and calculating the required daily body weight gain to reach 30 kg or above by the end of November will help to determine whether your feeding program will be sufficient to optimise weaner survival over summer. Lambs have a greater potential to gain weight when they are younger, so it is better to grow them as soon possible after weaning.
Feed types for weaners
Spring pasture growth should provide sufficient energy and protein for the weaners. Be aware that quality of pastures declines rapidly after flowering and continues to decline as the pastures 'hay off'.
After the pastures have dried, the quality is usually too low for weaner growth and they will need supplements to maintain growth. From wilting, start to feed weaners 25g/head/day of supplement to continue a gradual increase in liveweight. Continue to monitor a group of weaners for body weight gain.
Weaners around 15kg liveweight require a diet of 16.5 - 20 per cent crude protein and a minimum of 6.5 metabolisable energy (ME)/day for growth. Their requirements vary depending on the weight and target growth rate. High protein sources such as lupins, faba beans, pellets and some cereals are recommended.
Cereal grains can be used as part of the supplement if high protein sources are in short supply. For example, wheat can be fed as two thirds of the ration along with a high protein source. Feed testing is recommended to determine nutritive value of feed on-hand or purchased in.
Remember to introduce cereal grains gradually to all sheep to reduce the risk of acidosis. This can be achieved by increasing grain supplements in small increments of about 50g every two days over 14-21 days. Gradual introduction to different types of grains is also recommended (for example oats to barley or wheat). Provide the highest quality roughage available (pasture or hay) to stock during the process of introducing grain into their diet.
There are also some very good quality commercial pellets now available for weaners. Choose pellets with more than 12MJ of energy per kilogram of dry matter and more than 15 per cent crude protein for weaners to ensure their requirements for growth can be met.
Parasites can seriously reduce weaner growth rates and survival during the spring and summer months. Weaners should be treated for worms at weaning time, using an effective drench, before turning the newly weaned lambs onto a 'low worm' pasture. Worm egg counts after pasture senescence will determine if you need to drench your weaners again in summer.
Weaners also require a cool, clean water supply, especially as the pastures dry out and the hot summer months arrive. Salt levels in water must be below 6,000 parts per million (ppm), or 1100 milli Siemens per metre (mS/m) for weaners to drink. Lot fed or confinement fed weaners require better quality water, up to 900mS/m. Poor quality water will reduce water intake resulting in reduced affecting feed intake and growth.
Creep feeding of lambs provides an alternative to early weaning during difficult seasons and is especially important when the lambs are too young or weak to be early-weaned from their mothers.
This method of ewe and lamb management provides less flexibility for ewe management but may be necessary when the ewes are in poor condition during lactation and/or the lambs are too young or weak to wean off their mothers at an early age.
Creep feeding involves the provision of high energy and high protein feed supplements to lambs while they are still with their mothers. There are several quality commercial milk pellets on the market to suit young lambs. Creep feeders consist of enclosures with vertical bars that are constructed to allow lambs to access the high-quality feed, while denying access to their mothers.
The spacings of the vertical bars should allow access for the lambs but the spacings should be too narrow for the ewes to enter. Further security for the feed can be provided by placing a horizontal bar at a height taller than the lambs, but smaller than the height of the ewes.
Tips for creep feeding
- 'Training' the lambs to accept the feed is hastened by feeding some of the pellets initially in a trail with their mothers. The lambs will learn to recognise the pellets as a feed source much earlier if fed with their mothers.
- The creep feeder should be placed near the main campsite of the flock (and/or near the trail feed area for the ewes) so the lambs have constant access. It’s important to continue to supplement the ewes while creep feeding the lambs, as the lambs will still be obtaining some milk from their mothers.
- There may be some risk of soil erosion around the creep feeder, so gravel may need to be applied around the base.
- Creep feeding provides an alternative management strategy for feeding small, young or weak lambs and also assists the ewes by reducing the energy demands of the lambs.
Further reading: Drought Feeding and Management of Sheep, a guide for farmers and land managers 2018
Contact Name: Mel Curtis
Contact Number: 0402 001 853
Categorised under: Agriculture