Robots find their way into nz grazing system _fginsight. com – vip – fg insight
Milking 300 mainly Friesian autumn and spring calving cows with the help of one full-time employee and his wife, who rears the calves, David McConnell has built an impressive set-up by anybody’s standards.
Four robotic units handle the milking, but grazing, which is still the main forage, is backed by meal fed during milking and a mixed buffer ration in the cubicle barn.
The cubicle barn itself is flush washed with recycled water, topped with solar panels and features
another robot to push up the silage.
However, it is the fact Mr McConnell’s farm is based in the Waikato region of New Zealand’s North Island, just outside the town of Hamilton, that makes it really stand out. In a country where rotary parlours and spring calving are the norm and cubicles are a rarity, Mr McConnell set out to achieve double the national average lactation yield, which stands at around 350kg milk solids (MS), or 4000 litres/cow at 8.75% MS.
“There were quite a few reasons why I chose this type of set-up,” explains Mr McConnell. “Mainly, I like a challenge. I was also still enjoying farming, but getting tired of milking cows, and I like developing systems from the ground up.
“Having moved back to the Waikato – where I was brought up – after selling our previous dairy unit in the South Island, I was looking for something that would keep me interested.”
Bought in 2012, the unit originally housed a 20:20 herringbone parlour in a typical New Zealand open-sided milking ‘shed’. The pit was filled in and the first three robotic milking units installed in August of that year. A fourth unit followed 16 months later.
The 150-160 cows milked on the farm in the first year expanded to 180, then 230, reaching 300 at the start of 2014. Yields were immediately 20% higher than the national average at 420kg MS, rising to 520kg MS by the second year and hitting 600kg MS during the 2014-15 season.
“Around 75 cows per robot is the target, and the aim is to produce 210,000kg MS from 300 cows, rather than the 600 cows most New Zealand farms would need,” Mr McConnell adds. “We’re doing that off 70ha of grazing here, plus a 25ha support block growing maize and annual grass for silage.”
Cows are fed to yield for the first 100 days of lactation, receiving up to 6kg/day of meal during milkings, which is then reduced to a flat rate of around 3kg/day. The buffer ration is adjusted to main-tain around 1450kg DM/ha post-grazing grass cover, with a typical example shown in Table 1.
The result is an overall diet supplying 11.2 MJ ME/kg DM at 17.7% crude protein when 3kg of concen-trates is fed, with a total digestible fibre (NDF) content of around 37%. In addition, up to 200kg/cow of palm kernel – along with extra grass silage – is fed each year to bulk up the buffer ration as and when needed to reduce grazing pressure and rebuild grass cover.
“We feed out the ration once-a-day in the morning, and that is when we reset the robot unit that pushes up the feed,” Mr McConnell explains. “It does this automatically 10-12 times during the day, moving in 200mm with each pass, and we turn it off overnight.
“The cows have access to the 300 cow-space cubicle shed and feed passage whenever they’ve passed through the milking units, and it’s up to them when they move on to the next paddock. They tend to loiter in the shed longer during hot days, for example, and we only ever shut them in over night to protect the pasture when the weather is really bad.”
The cubicle shed itself is flushed washed with ‘green’ water from the effluent lagoon, with solids removed by a separator unit. Solids are spread onto the maize ground, with the effluent spread onto the grazing block through an irrigation system.
The farm buildings are situated towards one end of the farm, and the single original race, which provided access to broadly uniform sized paddocks off to the left and right, has been supplemented by two additional tracks running parallel. These split all the paddocks in half to create the necessary network of smaller paddocks needed for the robotic milking system to operate. The additional paddocks created have no water.
“Cows are free to wander back from the paddock when they want, then after milking they have access to both the mixed ration in the cubicle shed and the next paddock along another race,” says Mr McConnell.
“Once all cows have been milked, we switch the gates around and set up the next paddock.”
Daily feed intake (kg/cow) Fresh weight Dry matter Grazed grass 34.0 8.5 Meal (fed to yield) 3.0-6.0 2.6-5.2 Buffer ration*: Straw 0.7 0.6 Maize silage 16.1 5.0 Grass silage 16.1 4.5 Molasses 0.5 0.4 Total 70.4-73.4 21.6-24.2
Replacements are reared to weaning by Mr Mc-Connell’s wife Glenys, and are then grazed off-farm on contract until returning to calve at two years of age. Cows not in-calf are sometimes carried over into the next calving group, an advantage of calving in spring and autumn.
The final innovation is the 40 kilowatt solar system on the roof of the cubicle shed. Although an increasingly common site in the UK nowadays, it is surprisingly unusual in New Zealand, despite the additional sunshine hours most years.
“The panels generate enough power to run everything during the day, most days, and we’re just drawing additional power from the grid when we need it. We don’t export any excess power, it’s just not worth it.”
With the system well set up and heading towards target in terms of yield, David was open to the idea of a yeast trial when it was suggested by Philip Harrison of AgriFeeds, which supplies most of the farm’s bought-in feeds.
The farm was identified as an ideal location for a farm-scale trial into the benefits of including a live yeast in the diet, with the ability to collect individual data across 300 cows, sieve manure samples from the cubicle shed and produce results relevant to both grazing-based systems and those relying more heavily on mixed rations.
The result was a 30% improvement in dry matter digestibility, an average rise in daily milk yield of 2.1 litres/cow, and up to 20kg increase in cow liveweight (LW) in just five weeks.
“I had no expectations when we started, it was just an interesting opportunity to see what the yeast would do,” he explains. “The extra milk yield was obvious from early on, and although it was most noticeable in the fresh calvers, there did seem to be a useful increase from most of the cows.”
Monitoring changes in overall diet digestibility was critical to understanding where the improvement in milk yield came from. To provide the necessary data, manure samples were collected and sieved using a standard NASCO sieve set for five days each week (Monday to Friday). This was done before the yeast (Vistacell at 4g/cow/day) was added to the ration, throughout the five-week trial, and for two weeks after the yeast was removed.
The results showed a rise in daily milk yield over the course of the trial (2.1 litres/cow) and an increase in cow liveweight (up to 20kg) which were matched by a 30% rise in dry matter digestibility. As feed material was more thoroughly digested into smaller particles, a greater volume was able to pass through the progressively finer sieves.
“To see the extra milk produced without the cows losing any body condition, and actually gaining weight, was impressive,” Mr McConnell says. “The drop-off when we took the yeast out of the ration was also easy to see from the data coming into the computer each day.”
The improved digestibility when feeding the yeast also had a noticeable effect on the manure solids volume coming off the separator.
“We usually have to push up the pile of solids every three days, but after the yeast was added, this extended out to around once every couple of weeks,” he adds. “The cubicle barn was also easier to flush, with less sticky manure, and the volume of solids definitely increased again when we took the yeast out.
“When we put the yeast back in, the cows responded just the same as they’d done first time around, and we’ve been using it ever since.”