Straw top-up stretches stricken silage stocks
By Jessica Buss
OAT straw is being included in the milking cow diet to stretch the silage stocks through to turnout next spring on one Staffordshire unit.
Herd manager Chris Howe and Genus senior consultant Ian Browne have planned the winter ration to overcome a forage shortfall while ensuring cows are fed a consistent diet. Sudden changes to the diet in other years have proved detrimental to the performance of the 180-cow herd at Broad Heath Farm, Eccleshall.
Mr Howe has 8.5t a cow of good quality first-cut silage in the clamp, analysing at 11.1MJ/kg ME, 13% crude protein, with a D-value of 70, and 20% dry matter. However, he has been feeding his second-cut as a buffer and will have finished it by housing in late September. He hopes to make enough maize silage for 3-4t a cow but still forage will not last all winter.
To eke out supplies Mr Howe is topping up the forage box-fed diet with 2kg a cow a day of chopped oat straw. The arable enterprise grows both oat and barley straw but he opted to feed oat straw, as it is higher in energy than the barley.
It is chopped using a big round bale chopper also used for bedding. It does not need to be chopped short but the process stops cows leaving long bits of straw in the trough.
As well as helping replace forage in the diet Mr Howe believes straw aids rumen digestion. This is based on his experience last year when the ration included 6kg a cow of whole-crop wheat, equivalent to 4kg of grain and 2kg of straw. When the whole-crop was taken out of the ration the milk dropped and daily dry matter intakes. Although with the whole-crop a lot of cereal grain passed through the cows, and he considers it wasteful, he admits the straw in the material did open up the feed and improve digestion.
Every mouthful counts
"Straw works to condition the rumen and with a nice open ration the cows will keep eating it," adds consultant Ian Browne. "It is the last few mouthfuls of forage that make the cheap litre of milk."
Mr Browne aims for 45% dry matter, 18.5% crude protein and an energy density of 12MJ/kg DM in the total ration.
He figures straw added to wet silage, such as the first-cut at Broad Heath Farm, can achieve a good dairy cow diet.
The oat straw will cost about £40/t, it would normally be £25-30/t, but the price has to be lived with, says Mr Browne. "Without straw in the ration it would be very difficult to feed the cows, so price is almost irrelevant."
He formulates a ration for a 40-litre cow, including an 18% protein cake fed to yield in the parlour and in out-of-parlour feeders to a maximum of 4kg a cow a day.
He stresses that cow intakes are often under-estimated. Mr Howes cows ate an average of 23kg dry matter a day last winter, although some of the high yielding cows must have eaten 25kg of dry matter, claims Mr Browne.
The year-round calving cows are milked three times a day and housed in two groups, with the high yielders fed a ration for maintenance plus 27 litres and the lower yielders fed for maintenance plus 19 litres.
Even with 2kg of straw in the ration it is possible to get maintenance plus 27 litres from the outside ration. "You can secure a high yielding ration with simple feeds," he says.
In addition to the 18% protein concentrates, straights are layered on top of the silage in the forage box. This years ration will be balanced with soyabean meal, rapemeal and maize meal, with some wheat included if the price is low enough.
Rapemeal is included as a source of rumen degradable protein. "Rumen degradable protein is often the limiting factor, when you get that right everything works," says Mr Browne. *
• Avoid sudden diet changes.
• Plan the ration ahead – balance wet silages with straw and dry silages with moist feeds.
• Aim for a diet of 45% DM and 18.5% crude protein with an energy density of 12 MJ/kg DM.
• There may still be a flush of grass this autumn, make use of it and extend the grazing period.
• Potatoes are likely to be too expensive for feeding to cows and it is hard to balance the ration, so cows may get fat.
• Ensure you get enough rumen degradable protein, for example rapemeal, for the ration to work.
• It is cheaper to feed cows straights out of the parlour than compounds in the parlour.
• Farm size: 616 ha (1522 acres). Owned by Lord Lichfield and managed as Anson Farms.
• Cows: 180 Holstein Friesians; plus dairy replacements and 90 beef calves.
• Stocking rate: 1.1 acres/livestock unit (0.45ha/LSU)
• Forage: 162ha (400 acres) grass, including parkland, 18.6ha (46 acres) maize.
• Cropping: Cereals 344ha (850 acres); potatoes 65ha (160 acres), sugar beet 26ha (65 acres).
• Performance: Milking three-times a day gives a yield of 8415 litres, and a yield from forage 3339 litres, off 2.37t/cow to leave a margin over purchased feed £1614/cow and 19.18p/litre.
Genus consultant Ian Browne (left) has advised Chris Howe to include straw in the dairy ration to eke out silage stocks.