Charles Sturt University : Managing lambing ewes on dual purpose wheat

New research at Charles Sturt University (CSU) has shown that lambing ewes may safely graze on dual purpose wheat in southern NSW.

Dr Shawn McGrath is a lecturer in whole farm management in the School of Animal and Veterinary Sciences at CSU in Wagga Wagga. His PhD focussed on grazing late-pregnant and lambing ewes on dual-purpose wheat.

Dual-purpose wheat refers to crops that are sown earlier than usual with the aim of grazing livestock on crops during the vegetative phase prior to stem elongation. This is a means of managing the winter feed gap and allowing farmers to increase stocking rates. Livestock are then removed from the crop so that grain can be harvested at the end of the season.

The research by Dr McGrath, involving surveys and field trials, established that good livestock management, such as the supply of mineral supplements and having ewes in good condition, could assist to reduce or prevent metabolic disease.

Dr McGrath said, 'My research supports the hypothesis that grazing lambing ewes on dual-purpose wheat provides a strategy to manage the winter feed gap and can therefore increase returns for producers.

'Ewes grazing wheat forage during late pregnancy and lactation may be more susceptible to metabolic diseases such as hypomagnesaemia, hypocalcaemia and pregnancy toxaemia. This is due to the low calcium, high potassium and low sodium levels in wheat forage, which could result in ewe mortality and lower production.

'Therefore it is prudent to supply additional calcium, magnesium and sodium to ewes grazing wheat in the form of mineral supplements, and to manage ewes to minimise the risk of these metabolic diseases occurring.'

Dr McGrath has made several recommendations for mixed-farmers in southern NSW considering grazing ewes on dual-purpose wheat to increase the profitability of their sheep enterprise:

-Optimise stocking rates to maximise profitability

- Provide ewes during late-pregnancy and lactation with a loose-lick mineral supplement that includes calcium, magnesium and sodium

- Ensure ewes are in body condition score of ≥ 3 at lambing

- Use moderate stocking rates for ewes during late pregnancy and lambing, particularly if the starting biomass is low.