Genetic evaluation trial reveals virtues of White Suffolks

Trompf-2

A White Suffolk cross lamb in the genetic evaluation trial at Northgate Park.

White Suffolk genetics have performed well in a maternal evaluation trial in north east Victoria, ranking the highest for sucker turn off, carcass value, lambs marked on the first lambing and weaning weight.

The trial is being undertaken by Dr Jason Trompf, JT Agri-Source, on his family’s 450ha “Northgate Park’’, at Greta.

A base flock of 1000 composite ewes were joined to five sire groups in January 2015, with each sire group selected on key performance traits using breeding values (maternal White Suffolks, maternal composite, terminal, NZ composite, a meat Merino and a maternal-terminal composite).

The wether lambs were slaughtered at four months of age in October 2015.

White Suffolk sired lambs had an average liveweight of 52.5kg, carcass weight of 26.2kg, dressing percentage of 50, lean meat yield 56.7, fat score of 3.4 and a carcass value of $136.50.

Dr Trompf said the carcass value was almost $10 higher than the average of the other sire groups.

All ewes born from the trial in 2015 were retained and mated to lamb in August 2016 at 14 months of age.

The White Suffolk sired ewe lambs at joining ranked the highest on scanning and marking rates, and the weaning weight of their lambs.

They recorded a marking at first lambing of 108 per cent and weaning weight of first lambs of 29.6kg.

During 2017, the trial ewes were measured for both fleece value and meat production.

Although the White Suffolk-cross ewes ranked lowest for wool value, they were ranked second for total meat and wool production

($200.24).

Their average weight at the second joining (19 months) was 68kg at condition score 3.4 and they had a lamb marking of 123 per cent.

Dr Trompf outlined the maternal trial results to date at the Australian White Suffolk Association conference at Creswick, Vic, on February 12-13.

Under his own production system, Dr Trompf has been a long-term user of the White Suffolk as a maternal breed but selection is based on a specific focus.

“When focused on a balance of performance traits, the White Suffolk can be both a great terminal and maternal breed, however this requires targeted selection for an animal with appropriate growth for its production environment, balanced with finishing ability, high number of lambs weaned, worm resistance and lower mature weights,’’ Dr Trompf said.

“With the right selection emphasis on key traits, White Suffolk-Merino cross ewes no longer have to be the poor man’s first-cross ewe.

“Bred well, fed well and target managed, they can compete well with any first-cross ewe, especially when you consider the stocking rates that a tough, high carcass merit ewe, with rapid lamb turn-off, can be run under.’’

Dr Trompf aims to drive kilograms of lamb weaned per hectare on Northgate Park.

Last year, his flock scanned at 150.4 per cent or 3233 foetuses from 2145 June-lambing adult ewes, and marked 2895 lambs.

This represented a marking percentage of 135, and stocking rate of eight ewes per hectare.

Records are maintained on ewe scanning, lamb survival and ewe fleece values, while lamb performance and carcass feedback are collected.

Ewes are confined to containment areas in April-May before lambing to strategically manage pastures.

Single bearing ewes are managed to lamb at 2.7-3 condition score and are allocated lower legume content pastures for lambing.

“We are trying to breed the easiest doing ewe we can possibly find, that can carryover spring feed on her back, minimise supplementary feed requirements in autumn and be highly productive at the same time,’’ Dr Trompf said.

In July/August, he measures the five key banks – the cash bank, supplementary feed on-hand, condition score, pasture available and soil moisture levels.

He also examines the southern oscillation index in winter for indications of a dry spring.

“With sheep plus cattle, our stocking rates are well over 20 dse/ha with an average rainfall of 650mm so we need animals that are target bred and proactively managed,’’ Dr Trompf said.

“We keep an eye on muscle and fat, worm egg counts, lamb survival and growth rates, plus the adaptability of our ewes.

“This year we intend to use sensor technology to link lamb to dam at birth, track maternal behavior on the birth site, measure relative feed intake, and also assess ewe body composition to inform appraisal of total productivity and profitability.’’