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Spring Lambing Complements High Performance Genetics

A switch to spring lambing, an injection of high performance White Suffolk genetics and improved nutritional levels have boosted profits for a prime lamb enterprise at Yarrawonga in the Murray Valley on the NSW/Victorian border.

Agronomist Graeme McInness, part owner of the Yarrawonga CRT store, said much of his agronomy work was with cereal growers who carefully monitor and measure input costs and he was applying the same principle to livestock production.

Graeme and his wife Meegan have doubled the number of lambs sold each season and have been able to run 20 to 25% more breeding ewes on their 250 ha property Pine Grove since switching to spring lambing.

Combined with better nutrition and management, this has created a 25 to 39% boost in the number of lambs weaned compared to late autumn-early winter lambing.

“The key production drivers, stocking rates and lambing percentages, rely on identifying when ewes require the best feed levels,” said Graeme.

“There is a five month window of opportunity to grow as much feed as cheaply as possible and produce as much lamb per hectare as possible off that feed’, he said.

The shift to August lambing meant the flock’s highest feed demand is now matched by the natural spring growth curve. It took a few seasons to gradually push the lambing period back.

Pine Grove’s 800 big framed clean pointed first cross ewes are sourced from NSW.

Ewes are flush-fed lupins via lick feeders to increase fertility and reach a 150% lamb weaning rate. While this is a cost, there is a solid return through fertility and production.

Last year’s eight week joining resulted in 99% pregnancy of mature ewes with a 154% weaning rate. The pregnancy rate in the maiden ewes, joined at 11 months, was 96% with 123% lambs weaned.

The aim is to unload by December off pasture 65-70% of their prime lambs as unshorn suckers at 22-24kgs carcase weight. Last year, despite the below average winter and spring rainfall, 57% of the lambs were sold as suckers and averaged 22.3kg carcase weight. That worked out at 133kg/ha carcase weight production.

“Research indicated that to be profitable we needed to produce at least 20kg/ha of carcase weight per 100 mm of rain which meant on 513mm we had a benchmark of 104kg/ha, explained Graeme.

During the favorable 2010 and 2011 seasons, sucker carcase weights were 25-28 kgs and production per ha peaked at 177 and 193 kg/carcase weights.

Lambs that don’t make the cut are weaned and either sold as stores or finished on the property’s 50ha centre pivot irrigation block or grainfed for an autumn turn-off, depending on seasons and markets.

White Suffolk rams with high growth and eye muscle figures are sourced from Almondvale, Urana, NSW.

“Using rams with high performance genetics really helps with growth and weight gains. We find the White Suffolk tends to lamb a bit easier and they are cleaner around the points, so we have a greater chance of selling more as suckers straight off the ewes without having to shear,” said Graeme.

“We recognised early that we had to grow better pastures and modify our existing feed curve to allow maximum feed supply between August and November and at the same time reduce the cost of production for every kilogram of lamb produced.

The move to more lucerne and clover based pastures was curtailed by the 2010 and 2012 floods but these are being replaced.

Purpose grown grazing crops are critical to the program, Wedgetail and naparoo wheat give the ewes good quality green feed before lambing and these are grazed for six weeks before locking up for grain production. Forage brassica and Italian-type rye grasses are used for crop rotation.  

 

 
 

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