Back to Corriedale origins

One Romney wool fining project is using finer-woolled Corriedale rams in its breeding programme. Jo Cuttance reports. Photos by Nathn Trethowen.

A trial to improve the quality and increase the value of wool in crossbred sheep is underway by a group of Corriedale sheep breeders.

The trial, started in 2021, involved mating Corriedale rams with Romney ewes, then assessing the wool of the offspring, along with how the lambs developed.

Project convenor John Booker said the idea had been in the making for a few years, borne from observing low prices for coarse crossbred wool. The idea was to see if having a finer micron wool on crossbred sheep helped farmers see a better return for their wool clip.

“It appears breeding has gone full circle. Romneys were one of the parent breeds of the Corriedale,” Booker said.

There was more to consider than just crossing a Corriedale ram and Romney ewe and looking at the wool, he said. Other factors needing consideration included: could commercial farmers develop a flock of sheep that could handle a wide range of New Zealand areas; what would the progeny be like; and would lambs be able to be fattened in a reasonable time?

Booker, who is Corriedale NZ Sheepbreeders Association vice-chairman, said there was no scientific modelling or trials that he knew of that used Corriedales to lower the wool micron in crossbred sheep, which was why the group were making a start in the hope that it might get the attention of others who would like to take the project further.

The five rams used in the trial were provided by five different Corriedale stud breeders with a wool micron ranging from 24 to 28. Booker said three of the five rams were at the fine edge of the micron and there were genetic differences between the rams.

Duncan and Tina Mackintosh from White Rock Mains, Loburn, Canterbury, provided 200 randomly selected four-tooth Romney ewes with Landcorp/ Pamu sheep genetics. The ewes offered were from a high-performing flock, Booker said.

The ewes were artificially inseminated and tagged according to sire. There were also 40 home-bred ewes mated to a Pamu ram as a control flock.

The lambs were weaned in January. There was a range between 22 and 49 lambs per sire with an average weaning weight of 32.81kg. After weaning, ram lambs were grazed at a farm in North Canterbury until autumn when they were dispatched to the meat works. The Pamu lambs had an advantage in carcase weight.

The ewe lambs were run on Charles and Emma Miller Brown’s farm in Waipara. The lambs were weighed in April and those 36kg or more were put to a terminal Southdown ram. The scanning percentage was 80%.

The lambs would be shorn as hoggets and wool samples taken then.

Booker said this would also give an individual feel for the progeny of each sire.

The group would shear the hoggets in November. Wool samples would be taken from the first cross animals and the control, and valued.

“It is important that anyone considering cross breeding should look at the value of the fleece now, and at a long-term five-year and 10-year price relativity of crossbred and mid-micron wool,” Booker said.

Looking at a long-term price would help farmers decide if there was any benefit in fining-up crossbred wool.

At this stage the plan was to retain the first-cross ewes and mate to a Corriedale sire, then evaluate the second-cross lambs, so there would be at least one more mating.

The group was funding the project themselves, and they were all pitching in with the work.

“We are incredibly grateful to Datamars for their assistance with identification tags,” Booker said.

The idea was to start the ball rolling. It might be up to farmers themselves to get more trials done because at this stage there was no data available for crossing a Corriedale with a Romney.

“The data from the Corriedale rams will also be very helpful in establishing linkages between the Corriedale sires and our own Goldmark Performance Group,” Booker said.

This is the basic data to see what is possible.

It was anticipated a Field Day would be held in early December for farmers to view the progeny, their lambs, and also some fleeces. Details are still to be decided.