KANGAROO Island sheep producer Rick Morris has started treating his pastures similar to how a graingrower would, which is helping him to improve grass growth rates, increase pasture utilisation and ultimately increase his carrying capacity.
Mr Morris, with wife Annie, have just under 5000 Coopworth-based composite breeding ewes lambing this season on 920 hectares at Karatta on the south of the island, where they average about 560 millimetres annual rainfall.
Most of the ewes are joined back to Cashmore Oaklea composite rams, with 20 per cent mated to Ella Matta White Suffolk rams as terminals.
Usually 30-50pc of the wether portion are sold as trade lambs with the remainder as stores usually on auctions-plus, surplus maternal ewe lambs are offered locally or also through auctions plus.
His stocking rate is about 13 dry sheep equivalent/ha, but he is aiming to lift numbers to 5500 ewes lambing or 15DSE/ha.
“But I need my pastures to improve before I can get there, theres scope for increasing dry matter production out of the annuals and also introducing more perrenials,” he said.
One way Mr Morris aims to improve utilisation of pastures is through using the Pastures from Space mapping technology.
The program through Landgate provides estimates of pasture production during the growing season by means of remote sensing.
Satellites (NDVI technology) are used to quantitatively estimate pasture biomass, or feed on offer, and combined with climate and soil data, produces pasture growth rate estimates.
“Currently we only have access to the low resolution PFS but we’re looking forward to being able to utilise high resolution (30x30m pixels) in the future for improved accuracy,” Mr Morris said.
“I’m also keen to see what’s coming out in terms of hand held or drone-mounted NDVI technology for improved accuracy.
“As an extension to PFS, with help from local PIRSA employee Lyn Dohle, we were able to obtain some average total dry matter production maps through Landgate, similar to what the croppers would produce as a grain yield map.
“These average total dry matter maps are pretty exciting and immediately highlighted some problem areas.”
From this information, Mr Morris started to ground truth and figure out why his poorer paddocks were underperforming,
“We had some pH mapping conducted by Brendan Torpy and his team from Precision Ag,” he said.
“It turned out that some of the poorer performing areas were too acidic and needed liming, which I have since carried out using variable rate application with a local contractor.
“Other poorer performing areas were those that waterlog during winter.”
Mr Morris said it was the first time they had tried VR technology, via a contractor, but if future fertility mapping showed enough variability, we would soon be modifying our own machinery.
“We are now embarking on more fertility mapping through Precision Ag, which will not only map pH but also phosphorus (P), sulphur and potassium, but I’m most interested in mapping P with the chance of spreading P using variable rate in the future, P is our biggest input cost.
“The first trial paddock we mapped for P was selected for its variable soiltypes and showed a huge range from 140ppm down to 23ppm (Colwell P), so it would be a no-brainer to spread that paddock with VR technology.
“The contractor is coming back again this month to map another 100ha, so it will be interesting to see what the P variation will be on more uniform soiltypes, this will help us to decide whether to adapt our own machine with VR instead of contracting the work out.”
Mr Morris also uses the PFS program to make flock management decisions based on progressive data through tracking the season and food on offer.
“I can remotely analyse pasture growth and create feed budgets,” he said.
Mr Morris said the stored data not only allow the user to compare previous seasons, “it’s also putting some figures on our rough rules of thumb in terms of stocking rates when we set-stock out for lambing”.
“For example I used to put twinning ewes out for lambing at 2.5/acre into a good looking pasture (3-4cm high),” he said.
“Having completed the Lifetime Ewe Management course I now know my twinners need at least 1300kg/ha FOO growing at at-least 25kgDM/ha/day in order to provide them enough energy and maintain DM/ha.
“The single-bearing ewes may only need 1000-1200kg/haDM and are set out at 3-4 ewes per acre.”
Pastures are mainly sub-clover based annuals with about 10pc of the property seeded to kikuyu.
“My philosophy with our pastures is that we’ll be most profitable by fully utilising our existing annual pastures, however, as stocking rates approach our targets we may have to invest in more perennials, possibly phalaris or the like,” he said.
"Kikuyu has been seeded into anything looking a bit scaldy to manage rising water tables, it has a real niche in smaller paddocks where stock can be locked up for confinement feeding giving the rest of the farm a chance to get away at the start of the season prior to lambing (mid-June).“
They have been using kikuyu with success for five years, but Mr Morris says it takes a bit of managing in order to ensure clover comes through it in winter.
“Frosts in early June this year put a real stop to kikuyu growth which opened up an “opportunity” to do some winter cleaning with Simazine and re-seed some legumes, including balansa clover, later in winter,” he said.
“Normally we just keep throwing nitrogen at the kikuyu and it keeps growing through winter given our coastal climate and relatively warm winters.
“I guess if we have to lock it up for 1 winter every 4-5 years in order to clean up the weeds and top up the legumes it’s not too bad.
“It has so many other benefits, particularly for providing that small pick of green during autumn for young stock. But I think 10-15pc of the farm to kikuyu will be enough, as the annuals are so productive through winter and spring.”
Mr Morris said that fortunately the season was tracking on average (404mm to the end of Aug), timely rain in May and June just kept clover alive which is so important for finishing stock and getting weight back on the ewes prior to summer.
“According to PFS, we are not too far below average in terms of total dry matter production and tracking on average for current food on offer (many paddocks at 1500-1800kg/ha) and growth rates (currently around 35kg/ha/day late August),” he said.
Mr Morris scans his ewes to be able to split the mob into singles and twins.
“We are still rejoining drys at this stage to get our numbers up, but eventually drys will be culled along with any dry ewe lambs,” he said. “This will start our true selection pressure for fecundity.”
Up to 1200 replacement ewe lambs are selected from the twinning portion in order to capture some of the twinning genetics, with the surplus ewe lambs are ideally sold to local producers.
“But I’m looking forward to the new blue-tooth matchmaker technology being developed to link ewes with their lambs on a commercial scale,”Mr Morris said.
“I’ll then get into electronic tagging in order to be able to identify and keep superior genetics, such as twinning composites that grow like mushrooms and are off the place before Christmas.
“We also use breeding values in our ram selections from Cashmore Oaklea, with the main profits drivers being number of lambs weaned, growth rates and worm resistance along with positive eye muscle and fat and wool cut while trying to bring adult ewe size down.
“This is proving to be a real challenge, you want the early growth rates in order to improve conception in the ewe lambs but don’t want the massive adult size.
“We’ve been selecting Cashmore Oaklea “curve benders” as an attempt to achieve this.”