Saturday, March 30, 2024

Cropping milk yield has downsides

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Cropping has produced more milk in trial work comparing feeding maize silage, turnips and fodder beet with a pasture-based system and one using palm kernel.
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But while this was higher at 1049kg milksolids (MS)/ha compared with 1028kg for the palm kernel farmlet and 870kg for the pasture-based farmlet, for the 2015-16 season, operating profit was lower.

At a $3.90kg MS payout it was $446/ha compared with $788/ha for the palm kernel farmlet and $821/ha for the grass-only farmlet. Cropping had the highest total working expenses at $4.19/kg MS compared with $3.86 for the palm kernel farmlet and $3.65 for the pasture-based farmlet.

The additional capital required for infrastructure, machinery and livestock reduced operating profit to $300/ha for the cropping farmlet, compared with $626 for the palm kernel farmlet and $789 for the grass-only system.

Results from the first year of the trial done at the Northland Agricultural

Research Station (NARF), just north of Dargaville were presented to farmers at a field day in late May. Chris Boom from AgFirst Northland said the trial funded by DairyNZ, the Ministry for Primary Industries’ Sustainable Farming Fund and the Hine Rangi Trust was not being approached from an anti-palm kernel perspective. But there was a concern about the reliance many dairy farmers now had on imported feed.

“So the question was, ‘How do we make a pasture-based system work in the modern world?’” he said.

The trial, which started on June 2 last year, got off to a flying start with good grass growth through to the end of November. On November 18 the palm kernel farmlet was in the lead, having produced 519kg MS/ha and 191kg MS/cow. This meant it outpaced the cropping farmlet at 515kg MS/ha and 189kg MS/cow and the grass-only farmlet at 452kg MS/ha and 181kg MS/cow.

The grass-only farmlet had a lower stocking rate of 2.5 cows/ha with 71 cows having calved on 28ha. For the other two it was 2.7 cows/ha with 78 cows on the same sized area.

The cropping farm grew 23% of its area in crops, 2ha of turnips, both Barkant and Green Globe varieties, 2ha of fodder beet and 2.5ha of maize silage. The palm kernel farmlet imported this supplement as required, based on grazing residuals, to optimise profit from pasture.

Paddocks in each farmlet are not adjacent to each other but have been balanced so they all have the same resource and effluent application capability. At the trial’s start there was the same pasture cover on all three. The herds were made up of similar-aged cows with matching condition scores. All young stock were grazed off from November but no cows went off unless there was an animal welfare issue.

All farmlets could make hay or silage with the cropping farmlet starting with 70 tonnes drymatter (DM) of maize silage available. It also started with more new grass paddocks as it will have a greater amount of pasture renovation done following cropping.

Mulching and oversowing Italian ryegrass will be used on the kikuyu-based pastures and up to 200kg nitrogen can be used strategically on each farmlet.

Additional labour required for tractor time and moving cows and fences was calculated at 413 hours for the cropping farmlet and 293 for the palm kernel system.

Computer modeling using Farmax software predicted that milk production would be 6% higher on the palm kernel farmlet than the cropping farmlet and 41% high than the grass-only system.

At a payout of $4.70/kg MS the cropping farmlet was expected to be slightly more profitable at $707/ha. But at a $6/kg payout farm operating profit would be higher at $2129/ha on the palm kernel farmlet and even more so at a $8 payout with a farm operating profit of $4194/ha.

But actual results showed instead of the palm kernel farmlet leading the way at 380kg MS/cow, the cropping farm achieved 384kg. The grass-only farmlet also performed better than expected at 347kg MS/cow compared with the model’s estimated 297kg.

Because of good weather pasture covers were higher than expected and that meant lower than envisaged use of supplements. Calculations made by using a rising platemeter before and after grazing estimated total annual pasture growth of 17.4t/ha for the season compared with historical annual production of 13.7t DM/ha.

“Topping was occurring and we were struggling with pasture growth which was more than the stocking rate could cope with,” Boom said.

Farm manager Karla Frost agreed, saying it had been an exceptional year.

“We don’t think we’re going to get one like that again.”

This clearly showed the value of the trial running over three consecutive seasons.

On the grass-only farmlet pasture covers were 400kg DM/ha higher than predicted at 2000kg DM/ha, so 2.5ha of silage was able to be made in mid-October with another 3ha shut up in early November and cut in December. In April 99kg DM/cow was fed out rather than the Farmax model’s prediction of 309kg, giving a total of 11.7t DM/ha eaten.

The cropping farmlet was able to use 6ha of new grass paddocks without damage and feeding maize silage in June and July helped maintain pasture covers. In October 6.5ha was taken out for crops, increasing the stocking rate to 3.5 cows/ha. But pasture covers were kept at a higher level than that predicted.

This farmlet started with maize silage on hand and fed just 630kg DM/cow by mid-November compared with the model prediction of 705kg DM/cow. With harvests estimated at 22t DM/ha made at a cost of 13.1 cents/kg DM 55t was able to be taken through to the 2016-17 season.

Turnips planted in late October yielded only 9t/ha, which was regarded as very low. Their estimated cost was 7.7c/kg DM and 123kg DM/cow were fed from January 5 to February 15, compared with the model prediction of 336kg. The herd was offered 4-6kg/day.

Fodder beet was sown in early November but harvests were disappointing at 15.5 t/ha. This crop, grown at an estimated cost of 26.2c/kg DM, was fed from February 6 to May 3 with cows being fed about 6kg/day. A total of 404kg DM/cow was fed compared with the model’s predicted 558kg making up an overall figure of 13.3t DM/ha feed eaten.

There was a lot of discussion at the field day as to why crop yields were so low as it had been a good growing season. The suggestion was made that they might have been grazed earlier than ideal, but Boom said as time went on the fodder beet bulbs didn’t increase in size but were “hammered by insects”.

On the palm kernel farmlet less supplement than predicted was used with just 469kg DM/cow fed, not half the 1047kg predicted by the model. Grass silage was made on 6ha during October and December making up, along with pasture, 12t DM/ha of the 13.3t of total feed eaten. Mating results placed the grass-only farmlet first with a three-week submission rate of 96% and an empty rate of 6% and the cropping farm poorest at 83% and 13% respectively. But the differences were not considered to be a consequence of the farm treatment.

Once-a-day milking was used on cows in the herd with body condition scores (BCS) of less than 3.5 from two weeks before mating. With BCS assessed every two weeks light conditioned cows were dried off on all farmlets from early April then the remainder on the grass-only farm on May 3 and the other two farmlets 10 days later.

In mid-May the average BCS was about 4.2 while the ideal would have been 4.5 to get them to 5.0 at calving.

Sponsor, BNZ, is helping to analyse the financials for the trial.The other sponsors are FarmSource, LIC, Ballance and Ecolab.

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