GroundCover™ Supplement Issue: 129 | 15 Jun 2017 | Author: Phillip Barrett-Lennard
Michael Humphrey grazes twin-bearing ewes on crop ahead of lambing to improve their condition score.
PHOTO: Phillip Barrett-Lennard
As part of Grain & Graze research in Western Australia, growers from the Moora–Miling Pasture Improvement Group (MMPIG) and the Southern DIRT group explored the use of crop grazing to improve the productivity of twin-bearing ewes either before or during lambing in 2015 and 2016.
Their trials showed that cereal crops in early winter have high feed quality (metabolisable energy of 12 to 14 megajoules per kilogram) and an upright growth habit, which allows for high animal intake at low feed-on-offer levels.
This enabled pregnant twin-bearing ewes at the MMPIG sites to gain 0.2 to 0.5 of a condition score in three weeks on crop. By contrast, similar ewes run on annual pasture either lost condition or gained less condition during the same period.
For sheep producers who lamb in July, grazing pregnant twin-bearing ewes on crop in June makes a lot of sense. Lifetime Ewe Management research clearly shows that twin-bearing ewes with a higher condition score at lambing have significantly improved lamb survival, mostly due to an increase in lamb birthweights.
Putting the twin-bearing ewes on crop for three weeks in June also allows some pasture to be spelled, which increases the feed-on-offer levels at the start of lambing, leading to better lamb survival and growth rates. If the stocking rate of twin-bearing ewes grazing crop is reasonably low (perhaps two to five ewes per hectare), any negative impact on subsequent crop yield will be relatively small.
“We run our sheep at high stocking rates as this is a key driver of profit per hectare, but this isn’t conducive to high lamb survival in our twin-bearing ewes,” trial host Michael Humphrey says. “Over the past few years, as part of the Grain & Graze research, we have run some of our twin-bearing ewes on cereal crops both before and during lambing and we are very happy with the results.”
He says the ewes have been in much better condition at lamb marking and the grain yield losses due to grazing have been minimal.
“It’s too early to tell if we are seeing an improvement in lamb marking percentage, but I’m fairly confident this will come over time,” he says.
“Crop grazing has improved our ability to handle a tough season, but we will still need back-up plans in place for a year with a very late break, when both crop and pasture growth will be poor.
“On the flipside, if we get a good start, we are now more confident to sow an extra paddock or two to crop and increase the winter stocking rate, knowing that the twin-bearing ewes don’t need access to a pasture paddock in June and July (because they are on crop). If the season deteriorates we can always sacrificially graze out those extra cropping paddocks.”
GRDC Research Code FGI00010
Philip Barrett-Lennard, agVivo,
0429 977 042,