Growing and managing weaners is an essential part of sheep farming. Incorrect management of weaners or assuming that weaners 'will manage themselves' may result in high mortalities and high economic losses. Mismanagement of weaners can have a lifelong impact on the animals, reducing their ability to grow wool and meat.
Running weaners under sub-optimal conditions can slow growth rates and reduce production. Weaner mortality on poorly managed commercial farms can be as high as 27%. Being prepared on weaning day allows weaners a good start to life and makes management throughout the season easier and less stressful.
Weaning should take place by 12 weeks from the start of lambing, sooner if the season has been poor. Weaning at this time will help with the ewe's recovery and allow her to get back into shape before next year's mating. It is essential that weaners are provided with adequate nutrition to meet their growing needs. Feeding ewes while they have lambs at foot is a great way to 'imprint feed' lambs. The lambs will learn to feed more quickly and will take to grain/pellets easily at weaning.
Weaning weights will vary depending on the breed, frame and pre-weaning nutrition. It is important to aim for the heaviest weight possible at weaning. Even small increases in weaning weights can significantly influence the chance of survival. Aim for 40% of their expected mature liveweight by weaning. If animals are less than 40% of their mature liveweight, consider managing the tail of the mob separately, providing them with improved nutrition.
Growth rate after weaning is as important as actual weaning weight for survival of Merino weaners. A light weight, under-grown weaner at weaning time can have its chances of survival bolstered by having a good growth rate. Weaners under 40% of mature weight at weaning should grow at least 30 grams (g)/day with 50g/day being the recommended growth rate.
If hand feeding is likely to be required for the weaners post weaning it is important to ‘imprint feed' while they are still on their mothers. This means hand feeding with the grain or feed that the weaners will face later in the season. Imprint feeding needs to be done at least three times prior to weaning for the lambs to understand what the feed is and be able to seek it out. If lick feeders or self feeders are being used for weaning then these should be used during imprint feeding also.
On weaning day
On weaning day many things should already have been put in place such as deciding on and setting up the paddock that the lambs will be weaned onto (or the paddock that the ewes will be moved to), ordering the vaccine and imprint feeding of the weaners while still on their mums.
A good checklist is as follows:
- Vaccination: either a 5-in-1 or 6-in-1 vaccine to cover the main clostridial diseases. This should be the weaners' second vaccination. Weaners should be vaccinated against the main clostridial diseases (for example, tetanus, pulpy kidney) and cheesy gland. An initial vaccination should have been given at lamb marking and the second vaccination at weaning to ensure the development of long-term immunity. All sheep that will be retained in the flock should have annual booster vaccinations.
- Liveweight or condition score: animals should ideally be individually weighed to tag at weaning. This will provide good information for later selection, growth rate calculation for sale animals and summer management. If this is not practical, weigh a sample of 100 weaners and record the scores to determine the average liveweight as well as the range of weights. Weaners can also be condition scored at this time and this measurement will provide data on nutritional status which can be plotted for change in condition over the summer months. Weaners should be at least score 2. Weaners less than this either have nutritional stress or a health issue that needs to be managed. Consider drafting off the lightest 20% and managing separately.
- Drenching: all weaners should be monitored for worms using faecal egg counts. Weaners should be drenched at weaning or in early summer to prevent high worm burdens and decreased production. For information on drenching please see Sheep worm control in Western Australia.
- Flystrike: Checking for flies and lice regularly will increase weaner health. If animals are in the high risk category for flystrike it may be beneficial to use a preventive fly chemical at weaning, particularly if surveillance and yarding of weaners will be difficult over the following two months.
For more information on weaners refer to the Growing weaner sheep page.