Tool 12.14 Calculate DSEs for your property

Tool 12.14 Calculate DSEs for your property

The dry sheep equivalent (DSE) is a standard unit used to compare the feed requirements of different classes of stock.

One DSE is based on the energy required by a 50 kg wether (i.e. a dry sheep) to maintain condition score (CS) 3 and body weight. Animals that have a higher feed requirement than 1 DSE (e.g., a lactating ewe or one weighing more than 50 kg) will have a higher DSE rating.

To estimate a DSE figure for stock, an estimate of standard reference weight (SRW) and the class of stock is required. SRW refers to the weight of a ewe that is not pregnant, in condition score 3, bare shorn (if not a shedding breed), with no gutfill – tool 10.7 in MMFS Module 10 Wean More Lambs will assist you in performing the SRW calculation for your flock. Standard DSE tables then assist in determining the relevant DSE value for each class of grazing stock.

Use the following tables to calculate the total number of DSEs you are running on your property. You can further refine these calculations to determine how many DSEs are in different parts of the property, and at different times of the year.

Further analysis of this information is possible to enable you to relate DSEs to rainfall, and, with time and practice, determine when critical decisions need to be made regarding stocking rates.

DSE ratings for Merino ewes (adult)

Source: Alchin et al 2008, adapted by AWI and MLA

DSE ratings for Merino weaners

Source: Alchin et al 2008, adapted by AWI and MLA

DSE ratings for goats

Source: MLA Going into Goats, adapted by AWI and MLA

DSE ratings for cattle

Source: MLA, adapted by AWI and MLA

Complete the following table using the tables on the previous pages to get a DSE rating for each class of stock:

• Write down each class of stock in the table below;
• Weigh a representative sample (at minimum, weighing the whole class of sheep would be better);
• Record each class of animal’s status (dry; pregnant – single; pregnant – multiple);
• Record the DSE rating of each class of livestock
• Record the number of stock in each class;
• Multiply the DSE rating by the number of stock in each class to get a total DSE rating for that class of stock; and
• Add up the total number of DSEs for your property.

Make sure you include any grazing pest species in your DSE figures to help you understand total grazing pressure – refer to tool 12.13.

Once the average DSEs are known, the daily DSE figure for a paddock can be determined by multiplying the total number of stock by the DSE figure, e.g. 500 ewes x 1.5 DSE (pregnant – single, 65 kg bodyweight) = 750 DSE daily grazing pressure.

Use the following tables to understand the different nutritional requirements that sheep have over the year, as well as the approximate energy and protein levels in some common rangeland species.

Understanding the requirements of sheep at different times throughout their breeding cycle, as well as the quality of the feed, and its energy and protein content, will be a starting point to begin a basic fodder budget for your business. This exercise will allow you to gain a greater understanding of the extent of any surplus or shortfall in animal requirements that exists, and from this information you can make further decisions regarding management of these animals.

Nutritional requirements of sheep based on their reproductive status

Source: LifetimeWool and National Research Council, adapted by AWI and MLA

Protein and energy levels of common rangeland feed species

Source: Franklin-McEvoy, 2005, adapted by AWI and MLA

Tool 12.14 More information – nutritional value of pastoral grasses

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Nutritional value of common pastoral grasses to livestock

This factsheet has nutrition information for 10 common grasses growing in South Australia’s rangelands and considers the extent to which they meet nutrient requirements for livestock.