Shelters for dairy cattle on farms where rainfall is high could become more common in Taranaki because they reduce nitrogen leaching and feed wastage.
Stratford Demonstration Farm supervisor and PGG Wrightson agricultural consultant Graeme Pitman says farms where wet soil causes pugging and substantial nutrient leaching would benefit from covered feed pads and stand-off areas.
Dairy farmers considering shelters for their cattle will benefit from research being conducted at the Stratford Demonstration Farm.
Nearly $200,000 has been spent at the farm on a shelter for feed pads and stand-off pads. The cost - at about $1200 per cow - includes site works, feed bins, drainage, peelings and bark, fencing and an effluent storage.
"But whether the benefits will balance the costs, you probably could argue forever," says Pitman.
"The more we use it the better the return will be as the high capital cost will be spread over more feed used. Using it to obtain high per-cow production levels is also important."
About half the cost was for the 60m long building which features two bays 9.5m wide divided by a central accessway containing the feed bins.
The structure has room for 150 friesian cows or 170 jersey cows, who stand on 400mm-deep wood on a 600mm base of bark peelings.
The wood chip will be raked and turned over regularly and will be used on the farm as fertiliser at the end of the season when new wood chip will be laid.
Even though the structure occupies 0.3ha of prime land on the 51ha farm, it's handy to its two main races and is readily accessible for trucks bringing in woodchips and feed.
Pitman said the project would generate information for farmers about the costs of building and operating covered feed pads and stand-off pads and of developing suitable feed systems. It would also determine whether nutrient management improved.
The farm, east of Stratford, is mostly flat and has free-draining volcanic ash soil. At an altitude of 300m, it has average annual rainfall of 2050mm.
Managed for the last six years by Lyndon Muggeridge, it has 172 cows which produced 62,000kg milksolids (MS) last season. Calving for the new season has begun.
Finishing touches are still being made to the shelter, which has been in use since early June. An April start to the project - later than planned - has limited its use so far.
Pitman said the farm committee decided to establish the shelter to better manage the high-input herd in a feed trial started last season.
The trial on equal size farmlets is comparing the efficiencies, economics and environmental impact of high- input and low-input feed systems. The high-input trial has 100 cows at a stocking rate of 3.9 cows/ha and there are 72 cows in the low-input trial for a stocking rate of 2.8 cows/ha.
In past trials on the farm, high- stocked herds were dried off early or wintered elsewhere, but the current trial had a long lactation with the aim of achieving higher production. Milking continued until late in May, requiring the high-stocked herd to be wintered off the farm or the cheaper option of buying more feed.
"Wintering off is expensive and hard to find in Taranaki," said Pitman. "There is high demand for it and low supply. The quality is dubious at times and it's not a practical option if large numbers of farmers were to do it.
"Covered feed pads have been discussed for years, especially after wet winters, and a number have been built in Taranaki in recent years."
Pitman said justifying the shelter economically was a struggle, but there were still enough potential positives to proceed. "So we decided to build it in the name of science."
Using the composted woodchip as fertiliser would help offset the cost and the farm would also have to use cheaper feeds and achieve better feed utilisation and pasture growth. Pasture damage also had to be reduced.
Pitman said the cows could be housed in the shelter 24 hours a day in wet weather, if necessary. So far it had been used only overnight, with the herd grazing in the paddocks during the day.
"At the moment its use is variable - we're still working our way into it."
The structure is fairly weatherproof, although heavy rain can penetrate the windproof screens that create the walls. The clear plastic roof lets sunlight dry the effluent and the wood chip base also absorbs moisture from the effluent.
Any remaining effluent drains to a storage tank and can be sprayed on the paddocks. "But if the system works well, I'm not expecting much effluent in the tank."
Pitman expects the feed pad to be used extensively at the start and end of each season.
Last season the two herds in the trial produced 363kg MS, a little below the target of 375kg - partly because they dried off earlier than planned.
The high-input herd produced 1425kg MS/ha, 39 per cent more than the low- input herd's figure of 1025kg MS/ha.
Little supplement was harvested on the high-input farmlet and 4880kg dm/ ha, or 150kg supplement per cow, was brought in. The supplement was mainly palm kernel expeller, although hay and silage were fed last winter. Maize silage is being fed this winter.
The herd consumed 33 per cent more feed, making it 6 per cent more efficient than the low-input herd. Its labour costs were higher.
A high level of supplement - 410kg dry matter/ha - harvested on the low- stocked farmlet was fed to the low-input herd during the season.
Standard fertiliser dressings were applied to both farms, but less could be applied on the high-input farmlet because the feed brought in had a better fertiliser value.
The low-input herd had a lower environmental impact per hectare than the other herd, which had less effect per kg/MS because of the effect of brought- in feed.
Based on a $6 payout, Pitman's interim calculations show the high-input herd performed slightly better, with a $60/ha advantage over the other herd. "A higher payout would favour the high-input herd and vice-versa, depending on feed cost."
The stand-off pad would reduce nitrogen leaching in winter so its effects could be similar to the low-input system. Its use meant less waste and the cows would probably eat less because they were warmer and drier. It would also reduce pasture damage so more grass would grow.
"Once the system is up and running, it should make winter management easier and less stressful.
"The farmer can lie in bed on a wet day and know his cows are comfy and happy and not making a big mess. It's also great for calving because the cows are sheltered. Wind chill is a big issue when cows are wet." The Stratford Demonstration Farm, operated by an incorporated society and governed by a committee of farmers, veterinarians and agricultural consultants, was established in 1917 to develop and promote improved methods.
- © Fairfax NZ News
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