Dairy goat farming was significantly different to dairy cow farming, particularly when it came to feeding and total forage supply, AgResearch farm systems senior scientist Dr Warren King said.
“Most dairy goats are housed indoors and farmers provide fresh pasture in a cut-and-carry system.
“Fresh-cut pasture in a dairy goat system is what makes New Zealand unique in the world,” he said
“Typically one-third to one-half of total forage supply for dairy goats is fresh-cut pasture.”
However, fresh-cut grass was not available all year.
Most dairy goat farmers relied on grass silage as a significant component of their total forage supply system, much more so than dairy cow farmers.
“In fact, some dairy goat farmers rely entirely on grass silage.”
Grass silage offered consistency throughout the season and was used alongside supplements such as maize silage and brewer’s grain.
While some farmers made their own grass silage others got contractors to make silage for them and some bought silage in when they needed it.
“Silage is a way of dealing with the massive flush of spring pasture growth in September and October and to make sure there are good feed resources on hand year-round, especially in February and March when grass dries off.
“There is an extra cost to producing silage but it’s cheaper to make your own than buy it in later on,” King said.
However, silage quality could be variable.
“Over the past two to three years we have studied silage – including silage that dairy goat farmers have made themselves, silage they have had contractors make, and silage bought in – and there is a wide range in terms of moisture and energy content,” King said.
Researchers visited farms frequently to take samples of grass silage for lab testing.
Over the past 12 months scientists had focused closely on four case study farms to help build a picture of the role of silage in the total forage supply system.
Benchmarks for good quality silage included 30% drymatter, a metabolisable energy (ME) greater than 10 and a protein level greater than 16%.
Testing by AgResearch revealed silage on Waikato dairy goat farms ranged greatly in quality. Drymatter content ranged from 17% to 46%.
“Getting it to the right moisture content is vital,” King said.
“If silage is too wet then all of this nasty soup drains out the bottom of the silage stack.
“That means a lot of the goodness drains away.”
Farmers could expect losses if drymatter was less than 25%.
Research also found some silage had less than ideal metabolisable energy levels, with one below eight and a handful below 10 units of ME.
Some protein levels also measured low with numbers as low as 10%.
“More protein in silage is good. Like all lactating animals, goats require a high-quality diet to perform at their best.”
Silage bale and stack handling was also important.
There were some risks with feeding mouldy silage, which could result in goats contracting the disease listeriosis, which could be fatal.
This plant- and soil-based bacteria thrived in spoiled silage, generally occurring when stacks or bales were poorly covered or stored.
To attend AgResearch and the Dairy Goat Co-operative’s silage workshop on Tuesday September 9 at Hamilton’s Ruakura Research Centre, contact King to register. warren.king@agresearch.co.nz or 07 838 5159.
