Key points:
As summer progresses into autumn, dry feed will continue to naturally decrease in quantity but also lose its nutritional value. As stubble or pasture quality declines, it may no longer provide livestock with sufficient energy and protein to maintain body condition and therefore supplementary feeds will be required to bridge the gap.
To ensure supplementary feeding is optimal from an economic but also a livestock production perspective it is important not to make too many guesses. It is important to know both the nutritional and energy requirements of the target stock that you are feeding, as well as the quality of the supplementary feeds available. This allows you to match the requirements of the stock with the correct quantity and quality of supplementary feed. Keep in mind that it takes only 17 MJ of energy to maintain 1 Kg of liveweight but 65 MJ of energy to increase liveweight by 1 Kg.
The quality and nutritional status of supplementary feed (purchased or produced on farm) varies substantially and therefore should be tested to determine the nutritional value.
Feeding stock poor quality feed will not enable you to maintain or gain your target livestock weights or condition scores.
So given we have had a feed test on some barley how can we determine how much to feed? Working through a simple example - a dry ewe of 50 Kg requires 8.3 MJ/day to maintain body condition. If barley is available and has been tested at 12 MJ/kg DM (and assuming paddock feed is minimal) - how much supplement is required? Divide the ewe energy requirement by the energy available in the barley, giving 690 g/head/day of supplement being required.
Body condition scoring is another relatively simple tool for monitoring stock, providing a guide as to whether the optimum amounts of supplementary feed are being used. A random sample of 25 sheep from the mob will give an average condition score that can then be used to make decisions on feeding. Regular condition scoring, ideally fortnightly, should be conducted over the time period that supplementary feeding is being undertaken.
Condition scoring could occur during key management activities such as drenching, crutching (for early lambing ewes), drafting off sheep for sale or autumn shearing. This will allow you to actively monitor the condition of livestock to ensure that volumes of feed being supplied are at least maintaining body condition, especially if the nutritional status of the feed is unknown. Sheep can be drafted in to priority feeding groups based on condition score, allocating the best pasture or supplementary feed to priority groups.
Details on sheep requirements are available in the ‘Feeding and Managing Sheep in dry times’ bulletin. A simple feed budget calculator is also available on the Lifetime Wool website.
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