Chrome Sheep Studs genetics boost lamb survival

Based at Hamilton in western Victoria, Matt and Tanya Tonissen established their stud in 2004 with Poll Dorsets, and have gone on to develop several specialised composite sheep breeds, becoming one of the largest suppliers of prime lamb rams in southern Australia.

"Our aim is to breed a moderate-framed ewe with moderate adult weight, I think a body weight of 70 to 80 kilograms at condition score three is where they need to be," Mr Tonissen said.

"In recent years our breeding goals have been to increase fertility, eye muscle depth and fat depth which provide good reserves for the tougher times of the year."

Although the Chromedale maternal rams are the backbone of the stud, Mr Tonissen said demand for their ICON Southie rams, which are predominantly a 75 per cent Southdown and 25pc Poll Dorset-cross, has significantly increased due to more commercial producers choosing to mate ewe lambs.

This year, the Tonissens have carried out an extensive embryo transfer program to accelerate the rate of genetic gain in their stud flocks.

Based on performance measurements and visual assessment, 30 elite ewes across the different breeds were selected, including for the first time, several ICON Southie ewes.

"The ICON Southie is an easy lambing terminal sire, but still produces a sheep that matures early and has a good carcase shape at a younger age," Mr Tonissen said.

Chrome Sheep Studs will offer more than 800 rams in this year's selling season. They pride themselves on the additional support provided to clients, with free ram delivery, a structural soundness guarantee, and to help volume buyers, every sixth ram is free at their sales.

For Pigeon Ponds prime lamb producer Craig Grant, making the change to a maternal composite flock has boosted lamb survival rates by more than 40pc and improved overall ewe resilience and hardiness.

Mr Grant, his wife Jacinta and their family run a self-replacing flock of 5500 composite ewes across two properties in south west Victoria and have been using Chromedale rams since the stud began 16 years ago. They also own the Lindsay Murray Grey stud, joining about 160 cows each year.

"Originally we ran fine wool Merinos and as the meat industry became more appealing, we moved into first-cross ewes," Mr Grant said.

"We then decided to trial the Tonissen's Chromedale rams over our first-cross ewe base so we could start a self-replacing flock.

"We kept all the Chromedale-cross ewe lambs and very quickly worked out how maternal and productive they were."

They now join two-thirds of their composite flock to Chromedale maternal rams to supply replacement breeders, while the two oldest age groups of ewes are mated to terminal Poll Dorset sires, also sourced from the Tonissen family.

"The result that did it for me the most was that we were scanning 120pc in lamb in our Merinos, but still only marking 70pc," Mr Grant said.

"The first-cross ewes were better, but there was still a real fall out of potential foetuses that we weren't bringing back to the lamb marking cradle.

"Once we started getting into the composite sheep, we were scanning 140 to 145pc and still marking 125 to 130pc, that lamb survival is critical and all adds up to how tough and robust they are."

This season, the maiden ewes have scanned at 145pc and the adult ewes averaged 155pc, with their lambs just starting to hit the ground now.

The Grants have established a strong market for their composite ewe lamb replacement breeders, which are keenly sought by repeat buyers.

About 2000 ewe lambs are kept each year, with half retained in their flock and the remainder sold through the Chrome Genetics ewe sale and a special sale at Casterton, Victoria, in January, topping this year's market at $350 per head.

They aim to sell most of the wether lambs over the hooks by December at a dressed carcase weight of 22 to 24kg. Some lambs are also kept to finish on summer crops.

"Not only are we getting bang for our buck from the maternal side, the wether lamb portion is also becoming a high value product, the lambs we feed on are extremely good doers and yielding very well."