March/April 1983 Sheep-breeding system should continue — Lincoln economist

An open nucleus sheep breeding system established by the Lands and Survey Department in the Rotorua Land Development District should be continued after the land is subdivided and sold to settlers, a Lincoln College economist, Dr A.T.G. McArthur, said recently.

The 9000-strong nucleus flock established by the department at Waihoro station should be maintained to supply rams to flocks within the district, and in other Lands and Survey districts, he said.

Dr McArthur, Reader in the Department of Agricultural Economics and Marketing at Lincoln College, said the Waihoro nucleus breeding system should be extended to other Lands and Survey Development Districts.

He said the Waihoro nucleus should continue selling rams to private breeders, particularly those in co-operative breeding schemes using Sheeplan.

Dr McArthur said objective experiments should be conducted to assess the genetic deviation between rams from Waihoro, and rams sold by the pedigree industry to commercial farmers.

He gave his views in a Research Report on the economics of sheep breeding operations of the Lands and Survey Department, recently published by the Agricultural Economics Research Unit at Lincoln College.

Efficiency

Dr McArthur said his evaluation pointed to continuation of the sheep breeding project on the grounds of greater economic efficiency.

Presently, the department flock at Rotorua had 290,000 Romney ewes, and, using the system, the additional benefit per ewe was expected to rise by $0.18 each year to $7.20 after 10 generations of selection, he said.

“This has an equivalent annual return per ewe of $3.75, amounting to $800,000 (in 1981 dollars) annually over the total ewes involved,” Dr McArthur said.

Superior

Until 1967, the Lands and Survey Department at Rotorua bought rams from pedigree breeders, but then changed breeding policy and established a nucleus flock at Waihoro Station by selecting superior ewes from department flocks in the district.

The Waihoro flock is improved by using the best rams and the best ewes from the nucleus.

Ewes with outstanding performance in other flocks are also promoted to the nucleus, in an organisation of selected ewes called an Open Group Nucleus Breeding System.

Dr McArthur says the selection objectives used by the department are very similar to those defined in the national recording scheme Sheeplan.

Sheeplan is intended to improve the genetic ability of ewes through four traits: the average number of lambs born per lambing, the weaning weight of lambs, the spring liveweight, and the hogget fleece weight.

The department has a minor variation of Sheeplan, selecting for numbers of lambs weaned rather than the number of lambs born.

Dalgety News March/April 1983