THE growing global demand for protein and natural fibres is behind a decision by the NSW Department of Primary Industries (DPI) to kick off a new program, Top Lamb Crop, later this year to counter low sheep numbers and reproductive rates.
DPI Dubbo district sheep officer Edward Joshua said the national flock reproductive rate had been at just 77 to 78 per cent for lambs weaned per ewes joined for the past 50 years.
While the national flock had bounced back from a low of 71.6 million head in 2009, he said the smaller flock and current rates were limiting.
Mr Joshua said the Top Lamb Crop format was based loosely around the Top Crop Australia concept, which kicked off in 1995.
The Top Lamb Crop project will include producer groups of about a dozen local growers who would participate in six half-day meetings throughout the year where management and nutrition would be discussed with a focus on reproductive rates and lamb survival.
Mr Joshua said the program would start around the common weaning time for the group, with the other sessions timed for pre-joining (including ram management), joining, pregnancy, lambing and marking.
The idea was to work with producers through the annual reproductive cycle of their flocks with the focus beginning with ewe fat score at weaning, he said.
Mr Joshua said a fat score increase of 1 was indicative of seven to eight kilograms of body weight and each 1 score increase in body condition was worth 13pc to 14pc more lambs weaned.
“Therefore, there’s a 28pc difference between fat score 2 and 4,” he said.
He said weaning was an ideal time to assess the ewes for wet or dry, as they were already in the yards for weaning.
By knowing the fat score of a mob of ewes, as well as a joining date, it allowed the producer to determine the nutritional needs and set a management program to achieve peak ovulation rate at joining.
In the approach to joining, ewes should be on a rising plane of nutrition, with 10 to 12 megajoules of energy and 12pc to 16pc protein daily intake.
Most Central West pastures at the moment were at about 6MJ of energy and 4pc protein, which meant any ewes lambing or lactating now without supplementation would be losing condition.
A dry ewe needed at least 8MJ of energy and 8pc protein for maintenance, he said.
“People look out the window and think ‘look at that feed’,” he said, but in reality the dry grass was often short of the ewe’s requirements.
Most producers were using supplementary feeding to make up the shortfall in energy and protein, otherwise the sheep were “pulling it off their back”.
In the Dubbo area, the next stage for many producers was lambing.
“Ewes that are below a 2 fat score have a very high risk of dying in the lambing process,” Mr Joshua said.
This was due to the high demands of growing the lamb to a high enough birthweight, colostrum production, as well as the energy required to push a lamb out.
“There is an opportunity after scanning to put condition on without putting too much into the lamb’s size,” he said.
In the first two trimesters it was possible to put condition on the ewes without significantly increasing the birthweight of the lamb, which was of particular concern with single lambs.
However, ewes with twins could be fed right through, as any increase in twin lamb birthweight was beneficial to twin lamb survival, and the ewe can use the extra energy for milk production, he said.
Therefore, it was beneficial to know which ewes were bearing twins.
“Because they’ve got so much conceptus in their abdomen it restricts their intake, even if they’re on a lush oats crop,” he said.
He said the necessary feed availability for twin-bearing ewes was 1200 kilograms a hectare of green dry matter, plus about a cup (250 grams/ head/day) a day of lupins for the eight weeks before lambing.
“Then when they’re due to lamb, put them in a paddock with about 2500kg/DM/ha, and a self feeder with lupins,” he said.
Single bearing ewes, however, only needed about 900kg/ha of green dry matter.
“Basically you want them on a bit of a diet – a bit of Jenny Craig for the singles,” he said.
He said if ewes with single lambs received too much nutrition the lambs grew too large and could suffer brain damage during parturition from oxygen deprivation.
Mr Joshua said producers could put single lamb bearing ewes onto better feed once they saw the first single lamb appear, but it was important to have separated the ewes which became pregnant on their second cycle to prevent their lambs growing too large.
“Put the second cycle single ewes on to the good feed in the lambing paddock two weeks after the first cycle single ewes, to prevent their lambs growing too big on the good feed,” he said.
Producers interested in joining Top Lamb Crop can contact Sheep Connect NSW, or their local NSW DPI Livestock officer (sheep and wool).
Cost was yet to be finalised, but was expected to be known within the next month.
Contact Sheep Connect (02) 6391 3954, sheep.connect@industry.nsw.gov.au, or Edward Joshua 0428 285 987.
