Yanco Agricultural High School

A quality secondary education in an historic rural setting

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Breeding objectives

The objective of the breeding program at Yanco has always been to produce hardy, easy lambing, structurally correct, highly fertile White Suffolk rams, suitable for use by commercial producers over a Merino base flock, whilst educating students on meat sheep production.

We have been using performance recording with Sheep Genetics Australia database Lamb Plan since the stud's inception, however an increase in focus on performance-based breeding objectives has seen us make significant progress in the last five years in improving genetic merit.

The mission statement of the stud is:

  • To produce a high quality, structurally correct ram for commercial producers, capable of producing first-cross lambs with high growth rates that when slaughtered for the domestic market produce a 18-22kg carcass, with high muscling, balanced fat coverage, high intramuscular fat and low shear force for high meat eating quality and a high value skin.
  • To provide a cutting edge, commercial and technologically advanced educational enterprise for the next generation of leaders in the sheep industry.

Using Lamb Plan to make consistent genetic improvement.

The Yanco breeding program is centered on a sound combination of genetic principles and practical experience with the aim of breeding modern, profit making sires for commercial lamb production.

Yanco uses Lamb Plan to provide accurate information on the genetic merit of individuals in our flock. In Lamb Plan, performance and pedigree information is combined to give Australian Sheep Breeding Values (ASBV). ASBV's are calculated from systematic combinations of performance information on individuals plus their relatives. They are expressed as the difference between an individual's genetic merit and the genetic base to which the animal is compared.

Australian Sheep Breeding Values are provided in this catalogue for nine main traits:

  • Birth weight (BWT): Estimates the genetic difference between animals in liveweight at birth.
  • Weaning weight (WWT): Estimates the genetic difference between in liveweight at 100 days of age.
  • Post Weaning Weight: (PWWT): Estimates the genetic difference between animals in liveweight at 225 days of age.
  • Fat: (PFAT): Estimates the genetic difference in GR fat depth at 45kg liveweight.
  • Eye Muscle Depth (PEMD): Estimates the genetic difference in eye muscle depth at the C site in a 45kg liveweight animal
  • Worm Egg Count: (PWEC): Estimates the genetic difference between animals in worm burden at 225 days of age.
  • Lean Meat Yield (LMY): Estimates the genetic difference in the percentage of lean meat at slaughter.
  • Intramuscular Fat (IMF): Estimates the genetic difference between the chemical fat percentage in the loin muscle of a lamb, and is often referred to as marbling. IMF has been shown to have a significant impact on the flavour, juciness, tenderness and overall likeability of lamb.
  • Shear Force (SHEAR F) Estimate the genetic difference in the force or energy required to cut through the loin muscle of lamb after 5 days of ageing, the ASBV is reported in deviations of kilograms of force.

Genetic improvement

The stud uses the eating quality index (LEQ) to gauge genetic progress. This is an index that combines the same traits as the Lamb 2020 index. For example, growth, birthweight, muscle, fat and WEC, however also include eating quality (EQ) traits, intramuscular fat and shear force.

The graph below indicates Yanco's genetic progress compared to the White Suffolk breed average and terminal sires for all animals measured by Lambplan for the traits detailed above and eating quality (LEQ index).

This is achieved by the full utilisation of technologies available to sheep producers. These include the following:

Electronic identification tags

Electronic idenification tags (EID) are used along with an EID bluetooth reader, indicator and software recording package for individual performance recording of all animals. These are used for weighing, pregnancy scanning, muscle and fat scanning, condition scoring, lambing and mothering up to record pedigrees and during the artificial insemination program. The students have become very adept at using these systems.

Artificial insemination

Our artificial insemination program is an annual event run by the Year 10 Animal Management (Sheep and Wool) class and gives the stud access to high quality sires. As part of the Superwhites Young Sire Improvement Group, the stud is allocated two young, high quality White Suffolk sires, which are used by other studs within the group for benchmarking purposes and to identify superior stock. Students, under the guidance of staff, select the remaining sires to be used in the program according to the stud's breeding objectives.

Embryo transfer

In 2016, the stud embarked on its first Embryo Transfer program, using several elite ewes identified by DNA testing. A total of 28 embryos were recovered from four ewes, resulting in 19 live lambs. Ewe lambs have now entered the breeding flock and rams were sold in the recent 2017 sale. One of the embryo transfer rams, Yanco 160003, sired by Farrer 140019 was selected for Series 22 of the Superwhites Young Sire Improvement Program. 


This is a program offered by Sheep Genetics Australia, which predicts mating outcomes and selects rams and ewes according to breeding objectives, balancing co-ancestry or flock inbreeding against performance gains, based on objective data. This has been used for the first time at the end of 2015 for selecting replacement ewe lambs, selecting donor and recipient ewes for the Embryo Transfer program, selection of semen sires and backup ram lambs, once any visual faults were removed. It is used each year to assist in selection decisions.


The stud has been involved with DNA testing since it became available to commercial producers and has tested 20% of the top ewes in the flock, 30% of top ram lambs and top ewe lambs in both the 2014 and 2015 lamb drop, until the data for eating quality became available on Lamb Plan. Our ongoing testing strategy is to test all selected ewe and ram lambs each year. These tests improve the accuracy of our ASBVs, particularly for those traits that are unable to be measured by any other means except slaughter, such as those corresponding to meat eating quality and lean meat yield as well as parentage verification. Al sires that are used also have genomic data. Lambs are sampled with the Tissue Sampling Units and sent away for genotyping.

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