Just as exciting though is the fact most cows haven’t lost any discernable weight since calving.
Cows hit the record 2.23kg milksolids (MS)/cow/day on September 10, having sat above 2kg MS/cow/day since August 20.
The vicious windstorm that hit Canterbury that evening knocked power out to the farm and meant cows missed one milking.
Average weekly production/cow dipped to 2.14kg MS the following week but the farm’s manager Peter Hancox was confident that for some cows still yet to peak 2.3kg MS/cow/day was on the cards and barring any further natural disasters the target of 480-500kg MS/cow was realistic.
A drop in pasture growth rates from highs of 80kg drymatter (DM)/ha/day in late August to 36kg DM/ha/day in early September with cooler weather and falling soil temperatures meant the farm had dropped into a small feed deficit situation in mid-September and, like many going into the second grazing round, was feeding out silage – albeit very high quality silage.
In the third week of September cows were getting about 5.6kg DM/cow/day of silage with average farm cover falling to 2227kg DM/ha.
Many are watching the farm’s progress closely this year as it sets out into uncharted territory to find out what impact the loss of eco-n will have on profitability and production while it strives to farm within a self-imposed nutrient cap limit.
South Island Dairy Development Centre executive director Ron Pellow said in 2011-12 and 2012-13 the farm operated with a leaching loss of 24-31kg N/ha as modelled in Overseer 6 and the aim is to maintain that level while improving further on profitability and productivity.
To maintain the leaching loss savings eco-n provided in the farm’s Overseer 6 nutrient budget it will have to find another way to knock out losses of 6-8kg N/ha.
Modelling has shown that this should be achievable if the farm continues to achieve its milk production targets while also cutting total nitrogen fertiliser use from 350kg N/ha to 260kg N/ha and limits any one application to 25kg N/ha.
Continuing use of diverse pastures that contain chicory and plantain will help, based on Lincoln University Research Dairy Farm findings, and an upgrade to variable rate irrigation will also help, although the farm was already capturing some of these benefits in Overseer because of its active soil moisture monitoring and irrigation scheduling.
Gibberellic acid (GA) is being used again this spring and this too will help as it stimulates growth and the plant uptake of nitrogen. It’s sprayed onto the pastures three to five days after grazing with nitrogen also applied following grazing.
Lincoln University research has found much greater responses to GA if nitrogen is applied at the same time to feed the additional growth and cell elongation the plant is driven to make.
At this early stage of the season the impact of the lower nitrogen regime hasn’t been felt but Hancox said it could be the second grazing round where things get a little trickier. The ability to use larger application rates to fill feed gaps won’t be there this year.
Weather variables
The higher early season milk production has been a result of above average July and August growth rates, good grazing conditions and the high quality first round pastures that came about due to the fact covers were driven down during winter.
The rainstorm that hit Canterbury in June and brought almost a third of the region’s annual rainfall in just three days meant young stock being grazed off had to come back home due to flooding at their grazing location.
“We were a bit worried about our covers here back then but as it’s turned out it was probably a good thing,” Hancox said.
The strong mid to late winter and early spring season growth meant the pastures recovered quickly and the lower covers in June meant high quality feed in early spring.
“Other years the feed we’ve carried through would have been showing up a bit yellow in the base but we’ve had none of that.”
In late August, to help improve intakes and ensure residuals were going to be met in early spring the farm mowed 9ha ahead of the cows. The milk tanker docket and the regular body condition scoring of cows is showing it worked. Use and intakes have both been up this year, Hancox said.
“Cows have to be eating more – they’re producing more than they have before and they just haven’t lost the weight we’d normally see come off them after calving.”
It’s not that the cows were calving earlier or in a tighter calving pattern. In fact they were a bit slow off the blocks and then took off towards the end of August to end up about where they’d typically be by the start of September. The farm’s intensive and accurate recording shows it used about 10% more area each week than it would have if it had stuck religiously to the spring rotation planner. That meant the first round finished five to seven days ahead of previous seasons.
Good growth rates through August, culminating in the high of 80kg DM//ha/day at the end of August, gave management confidence in the allocation decisions and the milk production prize was pretty good too. Over the years the farm’s management team had learned it was important to have flexibility in bringing cows back onto the platform during winter if needed to control covers and so it leased a nearby runoff block.
If the young stock hadn’t been forced back home later calving cows could have been used to manage the higher covers building through the winter.
Pasture recipe
Pellow said the farm also needs to adjust management given the increasing impact of more shoulder and cool season growth with cultivars such as Shogun and it may be a review of target covers is needed.
DairyNZ developer and member of the farm’s management team Steve Lee said Shogun is a hybrid tetraploid between a perennial and Italian ryegrass.
It has cool season activity and through winter grew three times as much pasture as the average pasture production across the farm. This spring it looked to have grown up to 20% more than other pasture cultivars recording 80-90kg DM/ha/day through the early spring.
But using the paddock well is a must as without good grazing management persistence is compromised. LUDF has 15.3 ha sown in the cultivar, one paddock sown in November 2012 and the other in December 2011.
This spring they’ve stitched more seed into the older Shogun paddock to at a rate of 15kg/ha along with 1kg/ha each of chicory and plantain to get another two years out of the paddock.
The wet conditions early in the spring meant some treading damage was done to about 1.2ha and that too has been repaired.
Hancox said cows went into the winter slightly lighter than he’d wanted at an average body condition score (BCS) of 4.3-4.4 but they were adequately fed through winter and almost all were at or above BCS 5 at calving, with the average 5.3.
Good BCS was maintained this year like never before and along with that had been improved cow health. By mid-September there were just five metritis cows compared with 38 last year and 19 the year before that. There had been just 12 cases of mastitis up until the power cut.
The farm has been running a two-herd system over the past two seasons to allow greater attention to be paid to lighter and younger cows.
This season, by mid-September there were only 135 cows in the small herd compared with 228 at the same time last year. Hancox said 119 of the animals in the small herd are heifers leaving just 16 light cows.
It’s a great start to the season but all eyes will be on the showcase farm to see how it copes with its nutrient limitations.
