How to use dry sheep equivalents (DSEs) to compare beef enterprises
Beef enterprises cannot be selected simply on the basis of gross margin per head or gross margin per breeding cow because each enterprise requires differing amounts of feed. For example, you can run more breeding cows on a farm if you turn off the progeny as yearlings than if all progeny is kept through until 2 years of age. In addition, it is known that large cows eat more than small cows and that pregnant or lactating animals eat more than non-reproducing animals.
In measuring the energy requirements of livestock, the standard animal against which all other animals are compared is a 50 kg wether sheep maintaining a constant weight.
By definition, a 50 kg wether 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 energy requirements of different cattle are given in Table 1, together with the ratio or rating of requirement compared with a 50 kg wether at maintenance. (Note: In some references the standard DSE is based on a 45 kg wether and not a 50 kg wether.)
From those figures we can calculate the DSE rating for an activity by estimating the numbers of cattle in each class (pregnant and lactating cows, calves, replacement females and bulls) and estimating the DSE rating of the herd.
Remember that the DSE ratings are based on a number of assumptions about weights, growth rates and calving 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.
Table 1. Comparative feed requirements of livestock
Change in DSE rating calculations
Prior to August 2008 DSE ratings for enterprises were estimated manually by calculating the number of animals in each of the categories in Table 1 on a quarterly basis, adding their DSE requirements and finally averaging by dividing by four. Beef-N-Omics (BNO) was used in August 2008 to more accurately calculate the feed demand.
The software provides the user with a feed budget report that provides feed demand estimates on a monthly basis in kg/day. The monthly demands were averaged and then multiplied by to get an estimate of the total year round demand for the year. Feed demand for a 50kg wether was calculated using the DroughtPack software contained in the StockPlan suite of software programs. The feed demand for 100 breeding cows or steers estimated in BNO was divided by 34,320, the number of kg required to maintain 100 dry sheep at for one year.
The DSE ratings have generally been adjusted upwards for most enterprises but usually adjustments have been less than 5%. However in four enterprises; specialist local trade, young cattle moderate growth, EU and Japanese Ox, the adjustments have been more than 10% higher.
Carrying capacity and return 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 were based on unimproved or natural pasture carrying 4 DSE per hectare and improved country carrying 8 DSE per hectare. An annual cost of $30 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. This is achieved by multiplying the ‘gross margin per DSE’ figure by the average stocking rate in terms of DSEs per hectare in order 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 for ‘intensive lucerne’). Note that there are many variables that can affect 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
