Cropping

Gassed silage is a viable options

By Alana Christensen

When it comes to feeding cows, rice straw silage isn’t normally the first thing that springs to mind.

But with high feed prices taking their toll in another tough year, dairy farmers around the region are turning to the novel feed as part of their feed budget.

Retired hay contractor Ashley Dempster has been a strong advocate for rice straw silage for more than a decade.

And while rice straw silage is never something that’s used in a normal year, it provides a useful stop gap in drought years according to Mr Dempster, who says it can help maintain the weight of cattle and livestock.

‘‘It all comes back to price in a year like this,’’ he said.

‘‘It’s something to use in a drought, it’s a substitute.

‘‘In a good year you get it for nothing in NSW.’’

This year, as feed and water prices continued to skyrocket, use across the region has increased.

And while rice straw silage in its simplest format may not deliver all the nutritional benefits farmers hope for, there is a solution — gassed silage.

While untreated silage carries 3.1 per cent protein of dry matter and 5.9 MJ/kg DM of energy, rice straw silage treated with anhydrous ammonia sees the protein results improve more than three-fold to 9.7 per cent of dry matter, while energy is improved to 7.4 MJ/kg DM, according to feed testing.

By gassing the rice straw, Mr Dempster says the protein value can be artificially increased, with the more times it’s gassed, the greater the improvement.

A recent feed test of twice-gassed rice straw returned protein results of 14.9 per cent of dry matter and metabolisable energy of 8.0 MJ/kg DM.

Mr Dempster estimates about a dozen farmers around the Goulburn Valley region have used rice straw this season, with the product also travelling as far south as Romsey, about 30km west of Kilmore.

A number of those have used rice straw silage in the past, including Wyuna dairy farmers Harold and Tom Montgomery.

Having first used rice straw silage more than a decade ago during the millennium drought, they have been using one-and-a-half times gassed rice straw silage as part of their feed program for their 200-strong herd.

‘‘This year feed has been hard to come by,’’ Harold said.

‘‘We’ve ordered about 300 rolls (of rice straw silage) and there’s more to come.’’

While it can take a few days for cows to get used to the taste of the gas treated rice straw silage, Tom said the proof was in the paddock — when you looked around you could see there was not much left.

Ideally the rice straw is harvested between three and 10 days after its been stripped by the header and must still be green when cut.

The greener the straw the more moisture is retained and ultimately the better quality of the final product.

Bales are then wrapped in plastic twice, with black plastic used on the outside to preserve the heat within the bale and encourage the chemical reaction.

During the gassing process a probe is inserted into the centre of the bale, with the gas pumped into the wrapped bale where it is trapped and pickles the silage.

Before feeding to the herd, Mr Dempster said the bales would be opened up about 24 hours before, and then later spread in the paddocks and allowed to air before the cows ate the silage.

And although it might be a unique idea to many, there’s plenty of positives to the feed, which can be kept for months without being affected by mould or mice.

‘‘The longer you leave it the better it gets,’’ Mr Dempster said.

Because it’s preserved in ammonia it can last two years.

‘‘It’s amazing what we can do with something that would normally be waste,’’ he said.