The Coopworth breed had its origins in the 1950s and 1960s at Lincoln College on the south island of New Zealand. The Romney ewe was crossed with the Border Leicester ram to produce the F1 Border- Romney and their subsequent inter-breeding produced F2 and F3 generation progeny.
“An essential feature of the Coopworth breeding process was performance recording, with selection (and culling) on the basis of measured performance — number of lambs born or weaned, adjusted weaning weight, fleece weight and quality and easy care.”
Continuous recording and analysis monitored progress during the inter-breeding process.
To widen the range of environments used, F1 and F2 rams were distributed to first-cross breeders for assessment. By the late 1960s farmers involved in inter-breeding programs believed their stabilised inter-bred Border Romneys at the F3–F4 level were at least equal to the first-cross sheep and certainly superior in overall performance to the original Romneys used.
The Coopworth Breed Society
The Coopworth breed — named after Professor Ian Coop, the developer of the breed — was formally established with the formation of a breed society in 1968.
Since the 1970s the base of the Coopworth breed has been widened to include sheep bred from white-faced breeds other than the Romney, by continued top crossing with Coopworth rams.
The current (2008) definition of a Coopworth is:
a sheep of 75% Coopworth blood and 25% white-faced, white-woolled blood and with two generations of Sheep Genetics Lambplan recording system.
All sires must be performance recorded, either on Lambplan or NZ Sheep Improvement Limited (SIL).
Coopworth Society regulations have been formulated to guarantee genetic progress for economically important characteristics.
Top 10 Coopworth Attributes
- Coopworth ewes have excellent mothering ability, and are highly fertile, weaning up to 170% in the commercial situation.
- Coopworth ewes are attentive and protective mothers, with high milk production, and good udder and teat conformation.
- Coopworth progeny are keenly sought after as trade lambs which are ideally suited to modern lamb cuts.
- Lamb growth rates of 300–400 grams per day are achievable.
- The Lambplan genetic assessment program includes measurement for eye muscle depth (EMD) and fat cover.
- Surplus ewe hoggets command premium prices from the prime lamb breeders whether they are to be mated to Coopworth rams or terminal sires.
- Running a self-replacing ewe flock means the dangers of purchasing footrot, lice or drench-resistent worms with your prime lamb ewe replacements is eliminated.
- Ewes cut about 4.5kg of 32–35 micron wool, and can be shorn at 8 month intervals if management requires.
- Lambs are born with good levels of brown fat meaning they will survive well when born into cold wet conditions.
- Coopworths are an intelligent robust sheep, ideally suited to the modern, performance based, prime lamb enterprise.
The Coopworth concept is to produce sheep with higher performance and economic gain. The open flock book approach allows other breeds to be infused where required.
At Palmerston we have trialed various other breeds over our Coopworth sheep with varying degrees of success. More often than not the introduction of another breed to improve one trait can lead to the decline of another.
Our aim is to produce dual purpose sheep ideally suited to Tasmanian conditions. Strong enough to survive lambing in cold, wet weather, show resilience to internal parasites and have strong tolerance of footrot. And at the end of the day produce a lamb carcase ideally suited to the trade lamb industry.
In recent times we have been using semen from a flock of stabilised Coopworth X Perendale sheep. The property is situated well below the 46th parallell in NZ and endure 1600mm of rain annually. Their prime lamb enterprise is centred on a carcase yield basis from the viascan machine at the Alliance works.
We are very pleased with this line of sheep as they are suiting all our requirements.