printStock Journal Technical Column, September 2022
Author: Deb Scammell, Talking Livestock
Setting a target weight for weaners and managing them accordingly is the first step to a successful weaning result. An ideal target weight of at least 40 percent of the mature weight of the ewe, will give weaners the best chance at thriving post-weaning. Timely weaning is crucial to allow the ewe adequate recovery time to achieve a successful joining result the following season.
Weaning needs to carefully consider stress management for the lamb. Over the weaning period they are separated from their mother, milk, but often also move to different feed and a totally new environment. The more you can reduce stress the more successful the post-weaning result. Ideally lambs should be adjusted to the new environment, water, and feed type with their mothers, so they can quickly adjust post weaning and are more likely to achieve have high growth rates.
The rumen takes up to 14 days to adjust to new feed and develop the appropriate rumen bugs to process the feed successfully. So introducing lambs to some grain pre-weaning assists with rumen development. Grain consumption early will allow the rumen wall to develop raised papillae which will increase the surface area of the rumen wall allowing improved rumen efficiency and performance later in life on grain. Grain introduction prior to weaning will also allow some continuity of feed if weaners also have access to grain post-weaning. Using the ewes to train lambs to eat grain out of a feeder or from a trail will avoid neophobia when they are introduced to these practices post weaning. Lambs that are introduced to grain with their mother have been shown to eat considerably more grain later in life – even up to two years later which is extremely useful for lambs that will be finished in a feedlot or replacement ewe lambs that will become part of your flock.
To achieve high growth rates after weaning lambs need to be on a balanced ration high in energy and protein. High quality green feed will usually provide adequate nutrition, however if the feed is very high in moisture and low in fibre high quality hay needs to be provided. The protein requirement of a 30kg + weaner is around 15%, if weaners are lighter, green feed or supplementary feed ration needs to be much higher in protein.
Very highly digestible weaner feed containing a high legume content (i.e. lucerne, medics and clovers) can cause animal health issues such as red gut which can lead to weaner mortality. These pastures can be balanced out by allowing access to a small quantity of cereal grain and some high-quality fibre. Once feed quality decreases and fibre level increases in the paddock, supplementary feed will allow energy and protein targets to be met and ensure high growth rates continue especially for sale wether lambs. Replacement ewe lambs should grow at a minimum of 50g /day through to twelve months of age to avoid weaner mortality.
Animal health issues need to be avoided, ensuring lambs have had a marking and weaning vaccine is crucial, worm burdens should also be monitored, and an effective weaning drench given if required. Monitoring weaning weights, growth weights and weaner nutrition is crucial to ensure a successful result with your weaners.