ASBVs for breech attributes well underway

Development of Australian Sheep Breeding Values (ASBVs) for breech attributes could fast track the production of animals with improved natural resistance to breech fly strike due to the relatively high heritability of the genetics involved.

The development of these Breech ASBVs (BVs) is a significant step towards breeding sheep that are better able to withstand breech flystrike without mulesing. Although the BVs are currently in prototype format, the first of the breech ASBVs – breech wrinkle – is moderately heritable so genetic change can occur relatively quickly over successive generations.

Wool growers can help fast track their selection for this important trait by submitting breech scores of their lambs to Sheep Genetics.  Australian Wool Innovation (AWI) funded research into breeding sheep with a natural resistance to fly strike is showing that animals with lower breech wrinkle scores are better able to withstand breech fly strike.
Reducing dag is the second most important factor with an emphasis on reducing breech cover a final consideration after wrinkle and dag.

A visual breech scoring system that allows scoring of breech indicator traits for fly strike, including breech wrinkle, cover and dag, has been available for the past three years, helping breeders identify animals that are naturally more likely to withstand fly strike.

This visual breech score data is now provided to Sheep Genetics through its members and research flocks and analysed to produce BVs, which can be downloaded from the Sheep Genetics website.  The use of more accurate BVs not only allows identification of sheep with low flystrike risk, but also enable growers to benchmark their breech attributes against industry.

New England seedstock producer Andrew Burgess is undergoing trials to breed for desirable breech attributes both in his stud and commercial flocks and has been impressed with the heritability of the traits.
Andrew and his wife Carol Watson operate the Ruby Hills Merino Stud on their Walcha property, NSW. The stud began in the early 1970s and was registered in the mid-80s.

Andrew has used Estimated Breeding Values since 1992 to help improve four traits – Clean Fleece Weight, Fibre Diameter, Worm Egg Count and Staple Strength. He has since used ASBVs when introduced five years ago.
“We originally used EBVs to help with breeding more worm resistant sheep but it soon became clear they were useful in determining other traits as well,” Andrew said.

Research has indicated that breech strike correlates to the amount of wrinkle on a sheep so Andrew artificially inseminated a portion of his flock to a sire with a low breech wrinkle score.
There was a noticeable change from the one joining. The low wrinkle sire produced lambs with a wrinkle score approximately 1 score less than the other progeny.

When it came time to replace some older sires, Andrew purchased them from studs that utilise ASBV figures. He took his usual balanced approach to selection, ensuring none of the figures were too extreme.
Although none of the studs had figures for breech values, Andrew used the figures for production traits relevant to him and visually scored the rams for wrinkle.

“We haven’t had lambs from the new sires but I am hopeful that we will see similar positive results,” Andrew said.
“We are working to breed sheep that are naturally resistant to flystrike, while still maintaining their fibre and other positive health attributes”. The breeding program at Ruby Hills is based on developing robust sheep with high fleece weights and long, bright wool measuring 17 to 17 ½ micron.

Andrew believes the evolution of the BVs will be similar to the development of the worm resistance (WEC) ASBVs, however is hopeful that it may occur at a faster pace because of their higher heritability.  “Improving the WEC involved some trial and error to start with and this will be the same but as more people submit data to MERINOSELECT the more accurate it will be.  “It’s not a difficult trait to score once you have the lambs in the cradle.”

More information:  http://www.sheepgenetics.org.au

Carcass value an opportunity for wool breeders

As the focus on improving the carcass quality of Merino sheep increases, the NSW Department of Primary Industries has released a timely study.

In a massive number crunching exercise, fourteen production characteristics were analysed from more than 110,000 sheep records gathered over 30 years.

A key finding is that there are no major antagonisms between breeding for wool and meat in Merinos, meaning that breeders can improve both characteristics using an appropriate selection index.

The study, led by NSW Department of Primary Industries research scientists, combined data from seven Australian Merino research flocks across Australia including three owned by NSW DPI.

NSW DPI’s Dr Alex Safari said that until this study was undertaken, accurate estimates of genetic correlations among most production traits were not available.

There was little information about the correlations between genes for:

•    wool, with carcass, reproduction and feed intake

•    growth, with carcass, reproduction and feed intake and

•    within carcass traits.

“Earlier work showed there were huge gaps in information about the impact of breeding for some specific groups of traits”, Dr Safari said.

“The good news is that we can now develop more complex and diverse breeding objectives with increased certainty of outcome.

“This is particulary important when it comes to breeding Merinos for both meat and wool in the current very difficult production and economic environment.”

Sheep Genetics Australia (SGA) is already incorporating the genetic correlations relating to growth, reproduction and wool into their genetic evaluation systems.

Dr Safari said relationships are now being investigated between carcass and meat quality traits and other production traits, within carcass and meat quality traits and between feed intake and other production traits.

The research was undertaken in conjunction with the Australian Sheep Cooperative Research Centre (CRC), CSIRO, University of New England and South Australian and West Australian state government departments.

Findings from this major study of 110,000 records were published recently in international scientific journals.

Cost of production calculator

Compare the health of your business annually with other lamb producers and find out if there is scope for improvement or if your enterprise is already performing well.

Developed by MLA, the cost of production (CoP) calculator is measured in cents per kilogram, and is an indication of the outlay required to produce each kilogram of lamb. The calculator allows you to improve the performance of your lamb enterprise as well as develop a good understanding of the current health of your business. Calculating your cost of production is an important step in assessing flock performance and a first step to making change.

» Click here to improve your lambing enterprise.

Dipsticks take on worms

Sheep farmers could soon welcome a quick and easy test for barber's pole worm thanks to research from the Australian Sheep Industry Cooperative Research Centre.

The test, which detects blood in the sheep's faeces to identify whether barber's pole worms are present and to what level, is going into a field validation phase in Spring 2007 and producers who have had problems with barber’s pole worm are being encouraged to participate in the trial.

The breakthrough for a new test came when Drs Leo le Jambre and Ian Colditz, Senior Research Scientists with CSIRO Livestock Industries in Armidale, asked, "Why don't we just test for blood in the sheep's faeces rather than count worm eggs?" The scientists have since devised a method to do just that.

Unlike other sheep intestinal worms, infections with barber's pole worm can rise very rapidly resulting in deaths only weeks after a drench due to massive blood loss from these blood-sucking worms. This test can detect dangerous burden’s of barber’s pole worm before the traditional worm egg count test, which relies on the worms being old enough to lay eggs.

Dr Brown Besier, Principal Veterinary Parasitologist from DAFWA and Parasite Management Program Leader for the Sheep CRC said, "In southern Australia this is a sporadic event happening in some years when the combination of rain and temperature is just right. It often catches farmers off-guard in early summer and late autumn, when there can be considerable sheep losses. However, in the summer rainfall areas of Queensland and northern NSW, barber’s pole worm is responsible for many sheep deaths every year."

The new test will involve farmers collecting 1 or 2 pellets of fresh dung from the ground from up to 20 sheep in each mob – a simple job and most farmers will be familiar with this from taking samples for worm egg counts. Some simple mixing and measuring steps follow with no microscopes or special skills needed. By the time the producer then has a cuppa, the samples are ready to read using a dipstick that detects blood. Supporting information will be provided to assist the sheep producer with decisions on whether to drench now or how soon to retest the mob.

In less than an hour, and at a much lower cost than conventional worm egg counting and larval differentiation tests, a sheep producer can have results of the level of barber’s pole worm infection for about half a dozen mobs without having to leave the farm or handle the sheep.

On-farm testing will dramatically reduce the time taken for results on barber’s pole worm burdens to be known from over a week to less than an hour. With such affordability and ease, many more producers will be able to know the barbers pole worm burden in more of their mobs, leading to fewer sheep deaths and less unnecessary drenching.

Producers interested to participate in the validation trials, by providing dung samples, should contact Deborah Maxwell on (02) 6773 3597 by mid-August.