Using DSEs and carrying capacities to compare sheep enterprises

How to use Dry Sheep Equivalents (DSEs) to compare sheep enterprises

Sheep enterprises cannot be selected simply on the basis of gross margin per head or gross margin per breeding ewe because each enterprise requires differing amounts of feed. For example, larger framed sheep need more feed than smaller sheep and pregnant or lactating animals eat more than non-reproducing animals.

In measuring the energy requirements of livestock, we use a 50 kg wether as the standard. Other areas use a 45 kg wether. A 50 kg wether maintained at constant weight has a dry sheep equivalent (DSE) rating of 1. Animals requiring more feed have a higher rating and animals requiring less feed have a lower rating. The DSE rating of all classes of stock is based on the feed requirements of the animals. The DSE requirements of different sheep are shown in Table 1.

From the figures shown in Table 1, we can calculate the DSE rating for each sheep enterprise by estimating the numbers of sheep in each class (pregnant and lactating ewes, lambs, replacement ewe hoggets and rams) and estimating the DSE rating of the flock.

Remember, the DSE ratings are based on a number of assumptions about weights, growth rates and lambing percentages. There will be some variation in these figures from region to region and from farm to farm, so the figures in Table 1 are estimates. But they do give a good idea of the general differences between types of animals.

In planning the livestock activity, it is often valuable to estimate DSE requirements on a more frequent basis using the estimated numbers of livestock in each month or quarter. Depending on the climatic pattern and pasture type, the animal requirements in the most limiting feed period can be identified. The number of animals also to be carried in this period will provide a guide to the maximum stocking rate for the activity. This information is also useful in determining whether supplementary feeding should be undertaken.

Be aware that cattle and sheep may have different grazing efficiencies. In some cases animals may selectively graze pastures. Pasture composition may also be important in terms of farm management considerations. A clover-dominant pasture may cause bloat problems in cattle and a grass-dominant pasture can cause grass tetany. A farmer with a mix of livestock types and ages can also achieve better worm control through rotation of livestock over paddocks.

In periods of drought, and in the drier western country, direct comparison between livestock enterprises on a DSE basis may be inaccurate. Sheep and goats can forage better than cattle in dry times and when feed is short. In areas that regularly receive dry seasonal conditions the safe number of cattle to run on an area may be less in terms of total DSE requirements than with sheep or goats. Note, however, that environmental factors and concerns of pasture failure must also be considered.

Carrying capacities and returns per hectare

The budgets presented give gross margin information on:

• a ‘per head’ basis;
• a ‘per dry sheep equivalent (DSE)’ basis; and
• a ‘per hectare’ basis.

Per hectare returns are based on improved country that can carry 10 DSE per hectare. An annual cost of $46 per hectare has been allowed for each hectare of improved pasture to cover, fertiliser costs and spreading costs.

Farmers wishing to compare livestock enterprises with cropping on a gross margin per hectare basis should estimate their own carrying capacity and calculate per hectare returns. As outlined in more detail in the section titled “Adjusting the budgets for your area”, this is achieved by multiplying the gross margin per DSE figure by the average stocking rate in terms of DSEs per hectare to estimate a gross margin per hectare figure.

Table 2 contains estimates of long-term stocking rates. The figures for the northern slopes and tablelands were based on a survey of district agronomists whose responses were remarkably consistent, but the remainder are estimates and are not based on trial work (except intensive lucerne). Note that there are many variables that can affect the ultimate pasture performance so these figures can be used only as a basic guide for normal seasonal conditions.

Table 2. Estimated carrying capacities for pasture types in NSW

Source: W. McDonald, previously Program Leader Pastures (North), Tamworth and Dr P. Orchard, previously, Program Leader Pastures (South), Wagga Wagga