Dorper Performance Testing

Why Dorper 21 ?

The flock farmer remains the most important client in any stud breeding business. Characteristics such as hardiness and adaptability are of great importance to the flock farmer. In his understanding he tries to generate a maximum income (adaptability) with minimum input costs (hardiness)

The most important components for hardiness and adaptability are:

  1. Breeding rate
  2. Growth potential
  3. Survival
  4. Quality of the animal (or Carcass)

The purpose of Dorper 21 is to identify the animals that excel in all the characteristics in order to be selected as the possible parents of the next generation. If the correct animals are selected then the nett income can increase with time. The real question is, how can it be applied practically? The income of the farming enterprise can be accurately predicted by 80% with a few basic norms. These basic norms are lambs weaned per ewe, growth rate (carcass weight and marketing age) and carcass quality. Breeding rate and survival is measured as the total kilogram lamb weaned per ewe per lambing chance and growth rate is measured as weaning weight with Dorper 21.

Take for example a production unit with 110% lambs weaned (per ewe mated), marketing weight of 35kg and a marketing age of 6 months. The gross margin is R228 per SSU with this simple scenario. The gross margin increases to R242 / LSU if the weaning percentage increases to 115% and the marketing weight increases to 36kg (age remains the same). This improved income can definitely be obtained by management and a better environment.

The purpose of Dorper 21 is to obtain a similar improvement in income by making use of breeding animals that produce more efficiently. Information about the animals’ growth ability (better growth of 2kg = marketing 1 month earlier) and also the breeding ability of the ewe or the rams’, ewe lambs must be available in order to manage this.

What Is Dorper 21?

Different levels of participation are available. The purpose of all the levels is to identify animals that are superior in spite of the characteristics that are measured. This does not mean that the animal is good in ALL characteristics, of course there are important characteristics that are not measured with Dorper 21. There must be a balance, as with everything in nature between the measured and non-measured characteristics maintained.


Level 3 (This is the most “simple” level of participation)


What is required?

An animal number, birth date, sex, weight and weaning date is required. Furthermore at least 20 animals must be weighed together so that they can be compared. This weight can be taken at any stage from weaning up to 12 months. These animals must be more or less the same age (born within 3 months) and have received the same treatment for the last three months.

What do you get?

A weight that is corrected for age and an index that is calculated. The animals in the group are thus compared to each other, 50% will be above average and 50% below average.


Level 2 (The level at which most breeders are participating)


What is required?

An animal’s number, the Dam’s’ number, birth date, sex, birth status, weaning weight and weaning date. All lambs must be born within 60 days from each other and have received the same treatment up to weaning age.


The Sires’ number and additional weights at 270 days and/or 265 days of both the rams and the ewes. A point (description) for conformation, fat (condition) and type.

What do you get?

For the Lamb, a weight that is corrected for age, birth status, Dams age and also an index. If more than one weight is taken a selection index (SI) is given which combines the 2 weights.

An Ewe Production Index is worked out for the Dam, which is based on the total weight of the lambs per lambing chance. The average index of the lambs over her lifetime is also calculated, top ewes (and on-hangers) can be identified. A Sire-summary of the weights is given if the Sire is also known. The ram which produced the heaviest lambs at weaning age can be identified.

BLUP breeding values for weaning direct (growth genes of the lamb that was calculated from all its relatives) and weaning material (his/her capability of weaning heavy lambs) is calculated. The breeding values for TWW (total weight of lamb weaned) are also calculated for all the animals. A breeding value is calculated if post-weaning weight is also taken. These breeding values are combined into a Relative Economic Value which is expressed in R/c per SSU per year. The growth ability and breeding rate is then taken into account in order to obtain a ranking through which an animal can be selected.


Level 1 (Full registration)


This level is similar to level 2, but the animals must fulfill the requirements of full registration. Dorper 21 is the beginning of making your breed competent compared to other breeds as well as breeders in other countries. The equipment is in place. It is in your hands as to how you are going to use the equipment.

Dr JJ Olivier – LNR
Livestock Business Unit
Tel: 021 808 5220