After five years of automatic milking, Tasmanian dairyfarmer Nick Dornauf decided to test run a four-way grazing system, and so far he and his staff are happy with the results.
Mr Dornauf, and his partner Rebekah Tyler, milk up to 600 cows through a DeLaval Automatic Milking Rotary (AMR) at Gala farm in northern Tasmania. Gala is one of four dairy farms run by the Dornauf family; the others have conventional milking systems.
Three-way grazing is the current recommended best practice for Australian automatic milking systems (AMS). The successful operation of three-way grazing at Gala gave Mr Dornauf the confidence to think about options to refine the performance of his AMS.
"With a grazing-based AMS, voluntary cow movement is central to the system's performance," Mr Dornauf said.
"We are always aware of how the cows are moving around the farm because this determines utilisation of the robots, grazing intake and milk production. And voluntary cow movement is all about animal behaviour. Like most AMS farmers, over the years we have become keen observers of animal behaviour and the ways our management practices affect the cows."
He had noticed that across time, a small proportion ù about 5-10 per cent (depending on the stage of lactation) ù of cows would learn to wait at the dairy for gate changes to access the best of the fresh pasture when it became available. As the herd has grown, this small proportion of 'clever cows' has equated to bigger numbers ù up to 60 ù consistently waiting at the dairy at each gate change. This created queues at the dairy at certain times of the day. And these 'clever cows' were also getting preferential access to the fresh pasture breaks where they could selectively graze the best quality feed.
Other cows, arriving up to eight hours later, accessed relatively depleted pasture. There was less available to them and the quality was lower as the leafy material had been eaten by earlier cows.
One of the Dornaufs' main motivations to try four-way grazing was to improve animal welfare across the herd. "We wanted to reduce the time cows waited in the queue to be milked, and we wanted to reduce the time those 'clever cows' spent standing on concrete," he said. "We also wanted the other cows to have more equitable access to fresh breaks of pasture."
At FutureDairy's annual AMS gathering, several AMS farmers had expressed an interest in trying four-way grazing. The barrier was the cost of changing the farm layout (for example, an extra one-way gate) to allow for four-way grazing when the benefits were unknown.
The Gala Farm layout was already suitable for four-way grazing so Mr Dornauf decided to test the idea from the start of spring calving (August 1, 2015).
Gala Farm is split into four areas of different sizes, but each with equal proportions of irrigated and dryland pasture. Under three-way grazing the gate changes had been at equal, eight-hour intervals: 6am, 2pm and 10pm.
For four-way grazing Mr Dornauf deliberately set the gate changes at unequal intervals (5am, 11:30am, 6pm, 9:30pm), partly because the four famlets were different sizes and also to reduce the number of cows waiting at the dairy at when the queues were longest ù in the middle of the day and early evening.
To enable the desired rotation length to be maintained across the farm, he offered a different size of the pasture break in each area.
"The cows are still fully fed," he said. "But their daily pasture allowance is split across four meals."
Five months down the track, the Gala team is cautiously optimistic.
"We are really happy with the results and at this stage I can't imagine going back to three-way grazing," Mr Dornauf said. "But we are only mid-way through a season and it makes sense to see out the whole lactation before getting too excited.
"Initially four-way grazing added a little complexity to our grazing system but once I got my head around it, putting it into practice has been straightforward and all of our staff actually prefer four-way grazing."
Four-way grazing has involved a little more labour but not as much as expected.
"There's a fourth fence to set up each day, but we now fetch two areas at the same time," Mr Dornauf said. "There's fewer cows to fetch and the queue they join at the dairy is shorter. Plus we don't have the frustration of trying to encourage the 'clever cows' to leave the dairy after milking.
"It took less than a week to see the impact, most notably, a large reduction in the number of cows waiting at the dairy, especially at the hottest time of the day and at night.
"This has been accompanied by a reduction in the average queuing time by 25 per cent. We've all commented that the cows seem more content."
Records from the AMS show the distribution of milkings is now more evenly throughout the day and night. "We still see a drop off in cows visiting the dairy between 3:30am and 5am, but it is less than in the past. We are milking at capacity now (80 cows/hour and longer into the night) and I think four-way grazing has allowed us to achieve this."
While milk production is significantly up on last year, Mr Dornauf acknowledges multiple things have contributed to this. He estimates four-way grazing may have contributed about five per cent increase in milk production.
"I think it's lifted production of the lower-production cows because they are now getting more equitable access to fresh pasture breaks and therefore better quality feed," he said. "But four-way grazing was never about improving production. We saw it as a tool to improve voluntary movement and cow comfort and it has been very successful in achieving that."
The FutureDairy team and other AMS farmers are following with interest the Dornaufs' experience with four-way grazing.
FutureDairy project leader Associate Professor Kendra Kerrisk said that while three-way grazing was currently considered best practice for pasture-based automatic milking systems, four-way grazing could be more suitable for certain situations.
"As Nick said, it's early days but the results at Gala so far look promising," Assoc Prof Kerrisk said. "Four-way grazing may be a better option on farms where queuing becomes an issue, which is likely to be large herds or AMS running at close to capacity."
Contact: Associate Professor Kendra Kerrisk, mobile 0428 101 372, email Email email@example.com. FutureDairy's major sponsors are Dairy Australia, DeLaval and the University of Sydney.