The focus was on residuals and getting cows to graze down to an even 1500kg drymatter (DM)/ha or seven clicks on the rising platemeter every time.
Sometimes that could mean putting cows back on their break if they hadn’t cleaned it up before milking, and shifting them in the evening.
Initially they took a little pushing but soon they became super-mowers leaving behind residuals and breaks akin to bowling greens that under centre pivot irrigation quickly returned to lush, high-quality milking fuel.
The stocking rate on the 160ha milking platform could get as high as 4.4cows/ha with 680 cows peak milked and paddocks taken out for regrassing. The farm’s management team described it as farming on a knife edge.
The feed wedge, produced each week, showed covers for every paddock and when arranged from longest to shortest as a bar graph it was clear where the next paddock to be grazed should be.
Overlaying it with the demand line meant any looming deficits or surpluses stood out clearly, allowing the team to make proactive decisions on whether to take silage or feed it out.
Sometimes both could happen within a few days such was the knife edge.
Bought-in feed began to creep up and in 2011-12 cows numbers were reduced to 632 peak milked.
That helped balance feed demand and supply a little more closely with the aim of pushing profitability.
But it was the advent of nutrient restrictions and a plan to test farmlet-scale research at a commercial farm level that saw LUDF make its biggest change yet.
Stocking rate was cut to 3.5 cows/ha or 560 cows peak milked, nitrogen capped at 150kg N/ha/year and bought in feed restricted to 300kg DM/cow silage.
Some aspects of the feed supply and demand knife edge were gone but so were the tools used to get out of a feed hole and the mouths to keep surpluses in check.
Peter Hancox is the farm’s manager and is responsible for grazing management decisions.
He has to work within the confines of the regime and says there isn’t a simple recipe to follow.
Maintaining pasture quality is still top of the list but feeding cows fully sits right alongside it.
With fewer cows and an aim of reducing nitrogen loss without cutting into profitability the high Breeding Worth cows at LUDF still need their rocket fuel pasture if they’re going to produce the targeted 500kg milksolids (MS) per cow needed to earn high milk income.
The aim is to fully feed them on high-quality pasture alone as much as possible and achieving that with the restrictions means monitoring and observation are even more critical.
“The biggest thing is observing the cows; making sure they’re settled but that they’re also hitting a good, even residual and leaving no clumps. We’re not pushing them as hard as we might have sometimes before but we’re not letting them dictate to us too much either,” he says.
“Quality drives production so we have to protect that.”
Spring
LUDF has used the spring rotation planner for the first grazing round although the management team has managed it proactively in light of very low growth rates because of cold soil temperatures.
The average pasture cover was almost 200kg DM/ha below the 2700kg DM/ha target at calving.
But the calving rate at the start of calving was a little slower, which meant the farm management team had the opportunity to hold the area grazed per day to reflect the number of cows rather than the absolute area initially allocated.
Peter says that’s where observation and monitoring are important, rather than relying on a set formula.
“We were dealing with colder conditions and a slower spring so we modified the plan,” he says.
The earlier calving heifers also made up more of the colostrum and milking herd at the start and their lighter appetites helped the farm team crib some area back.
As the weeks went by they combined the pasture monitoring information with what they were observing from the cows and continued to tweak the plan, slightly increasing the area allocated per cow or cutting out balage as soon as residuals began to rise but bringing it in when continued cold soil conditions through September kept growth down.
By September 15 they’d grazed 108ha of the 160ha milking platform, compared with the 130ha they’d budgeted to have grazed by then.
They had also used less balage than budgeted with cows offered 56kg DM/cow by September 15 rather than 67kg DM/cow.
With growth rates still sitting around 39kg DM/ha/day in early to mid-September, the decision was also made to hold the area of pasture allocated per cow rather than opening it up.
That tactic meant the farm management team would have that additional area in reserve so a larger area could be allocated if it rained and they needed to limit any treading damage.
It also meant LUDF didn’t finish its first round until the last week of September.
By early September cows were doing 2.36kg MS/cow/day.
Peter says one of the key things he aimed for to ensure cows milked well was to avoid getting into a feed pinch where he suddenly had to bump silage inputs up to 6-7kg DM/cow/day.
“What we’re trying to do is look further out and keep those inputs down at 2-4kg DM/cow/day. That helps keep us from falling into a big hole and means we don’t get into the situation where we are diluting the high ME (metabolisable energy) pasture diet with too much silage.”
The farm operated under the lower input regime last season and Peter says it’s fair to say the approach to pasture management is more conservative than it’s been previously.
“In the past, when pasture growth takes off, we’ve allowed the grazing interval to get down to as low as a 16-day round but we just can’t risk that anymore.”
Through September the round is 38-39 days and from October to November last season it was maintained at 23 days.
“We’re aiming to keep it at 22-23 days through to the end of February,” he says.
The slower first round and more conservative approach to round lengths for the rest of the season mean that, all up, the farm is grazed less frequently throughout the season.
Last season there were 9.5 grazing rounds from the beginning of September whereas previously the farm averaged 11.
Pre-grazing covers have been allowed to lift to ensure cows are well fed.
Last season from September to January pre-grazing covers averaged 3328kg DM/ha compared with 3118kg DM/ha in previous years.
Peter says some pre-grazing covers got up to 3800kg DM/ha through September this year but quality has been high because the winter-active grasses mean that higher cover has been grown rather than coming from pasture that’s been saved from the end of last season.
From February to April covers were allowed to rise further. It’s possible to do that through that period as the ryegrass component of the pasture is no longer in its reproductive phase and quality is less likely to be negatively affected by the increased pasture mass.
Through those autumn months last season the pre-grazing cover averaged 3625kg DM/ha compared with an historical average for the same period of 3435kg DM/ha.
Mowing
While there’s few tools to manage a deficit the reduced stocking rate means there’s even fewer tools of the four legged variety to help manage a surplus.
Any true surpluses are taken for silage as has happened in the past but on occasion, through the high-growth rate months, or through wet periods cows can struggle to get to the desired low and consistent residual of about 1650-1670kg DM/ha.
Because the management team isn’t pushing the cows hard to get that very last bite out of the paddock there are times when the residual is higher than desired. In contrast to LUDF’s earlier years that can see the mower come out.
Peter prefers to use it as a pre-grazing tool rather than tidying up behind the cows.
Initially pre-graze mowing was used when pasture drymatters were very low with the idea that mowing the paddock a few hours before cows came into it would allow the pasture to wilt a little and improve cow intakes.
The scientists aren’t convinced that intakes are improved but Peter says there does appear to be a benefit in the practice because back calculations to establish what the cows are consuming, based on production, suggest they’re eating 22-24kg DM/cow.
“And that doesn’t add up,” he says.
“But we’re getting cows averaging up to 2.4kg MS/cow/day on grass only maintaining body condition.”
LUDF’s experience is that more grass disappears when it’s mowed so there’s a big proviso when it comes to making the decision to mow.
“We’ve got to have enough grass ahead of them or even a slight surplus otherwise we can quickly get into a deficit.”
The main driver for using the practice on LUDF is to protect pasture quality.
If conditions have been wet or a higher pre-grazing cover means cows haven’t quite managed to get to the desired 7-8 click residual across the whole paddock, it’s a candidate for pre-graze mowing.
“If we feel the cows are struggling or taking too long to get to a reasonable residual and possibly not getting enough intake we will mow to help them,” Peter says.
“Quality at the next grazing is king here. We know how important it is to have ME’s right up there every time.”
If residuals weren’t quite right last time cows are unlikely to push past that the next time without being forced and that can be to the detriment of milk production.
Based on recent years’ experience Peter expects the whole farm would be mowed at least once through October and November. The benefits to quality have outweighed the diesel and running costs on the tractor.
Spring boosters
LUDF has used gibberellic acid (GA) to help kick-start grass growth through the cooler spring season but the management team has been selective in its use.
Farm manager Peter Hancox says they’ve applied the naturally occurring cell elongater to older diploid pastures because that’s where they’ve had the best responses.
LUDF has a pasture renewal policy of renovating the poorest performing paddocks, based on grazing records.
Cultivars used have included those that are more winter-active such as the hybrid tetraploid Shogun and they’ve performed well in the cool start to the season.
“We avoided paddocks with the more winter-active grasses because we’re going to get a lot more response from the older, more established pastures and the diploids,” he says.
The first application was in early September, once enough area was being grazed daily to warrant bringing in the contractor to spray it on.
Economic responses occur when applied within three to five days of grazing, and the best responses come when nitrogen is applied just before or with the GA to support the extra growth.
The GA works by elongating the cells in the stem and leaf while nitrogen increases tiller numbers.
Until late September LUDF applied nitrogen as ammonium sulphate (Ammo 31) so sulphur, some of which is lost to the soil in cold winters, could be replaced.
The farm has a self-imposed limit of about 150kg N/ha/year so its use is strategically targeted to get the best response.
It has been applied at an equivalent rate of 25kg N/ha.
Selection criteria for the first applications of nitrogen at the beginning of August included:
- Newer pasture (mostly Shogun- hybrid perennial ryegrass expected to give better cool season growth responses than perennial ryegrass pastures)
- Positive growth rates over the previous two weeks
- Cover less than 2400kg DM/ha so 4-6 weeks till due for grazing
- Predominantly drier, free-draining soils less prone to saturation
- Not paddocks at the bottom of the wedge because improving growth rates may see them lift in cover without additional nitrogen.
Once soil temperatures have warmed up nitrogen is applied as urea and continues to be strategically applied at a rate of 25kg N/ha.
Last season urea wasn’t applied through December and January but Peter says that hurt them in terms of growth so they intend to manage applications so it can still go on through that period this season.
