The key to the best silage is starting with good quality grass, cutting and baling it at the optimum time and then feeding it out in the right increments.
This is how Parkham, Tasmania, dairyfarmer Ji Streets manages the silage he grows on his 210-hectare property for 535 milking cows, only bringing in extra fodder for calving.
Mr Streets hosted a Tasmanian Institute of Agriculture TopFodder silage field day earlier this year, with more than 30 farmers attending to find out how to make the most of their grass.
The field day focused on measuring silage quality and minimising wastage through correct storage and feedout.
Managing the timing of growing, fertilising, cutting, baling and feeding was a "juggling act".
"It comes back to knowing your farm," Mr Streets said. "Decisions on farms are very important and doing it as quick as possible is the key."
Mr Streets has been managing the farm for four years and said he learned what to do from his father and invested in personal development, similar to the field day, when he was younger.
"We don't tend to change too much unless we have to," he said. "A lot of guys are mucking around with their feed and other things but we try to stick to one thing and do a good job."
Mr Streets participated in a study of homegrown silage that was conducted on dairy farms around northern Tasmania, and the results from his feed tests formed the basis of discussion. Mr Streets brought along samples from three batches of silage made on the farm, which were analysed alongside other samples from northern dairy farms collected by the TIA dairy extension team.
The results from these silage samples highlighted the relationship between metabolisable energy (ME) and neutral detergent fibre (NDF).
When pasture starts to develop seed heads, NDF increases and ME decreases, which results in a lower quality silage.
Two of the silage samples provided by Mr Streets showed a significant difference due to stage of cutting. One was from a second-cut of silage, harvested when the pasture was still in the green, leafy, vegetative phase. The other was silage made from pasture that was cut when the seed head was already developing.
The one megajoule (MJ) difference between these two samples might not seem like much but equates to 250MJ per bale, which has the potential to produce 45 litres of milk. Multiply this by the number of bales made on the farm and it can make a big difference.
Field day speaker Jason Lynch, from Macquarie Franklin, spoke to farmers about understanding their silage costs and limiting energy losses.
"It's about trying to make the best possible silage that you can," Mr Lynch said.
"You've got a bucket of energy that's full when you've got it in the grass and then you start cutting it and baling it and putting it somewhere, you get all these little energy losses that add up. By the time you want to give it back to the cow you want that bucket to be as full again as you can possibly have it.
"Some of the factors affecting energy loss and wastage in silage are grass quality, maturity, wilting, respiration, but also when and how it is fed it out.
"It's all about trying to preserve that energy to get it back to the cow. From the moment it is cut all these steps add up."
Another factor mentioned was using nitrogen fertiliser to boost surplus grass. "Silage should be made from the surplus the cows can't get to in spring," Mr Lynch said.
"If you put nitrogen fertiliser on to manufacture that surplus, the costs go through the roof. There are probably other ways to feed cows cheaper."
Mr Lynch said a slight change to the amount of wastage could make a big difference to the overall cost of silage. "It costs as much to produce a poor bale of silage as it does a good bale of silage," he said.
Mr Lynch said the cost of making silage was generally considered in relation to the purchase price, however, there were 'hidden costs' in feedout and wastage that should be included to calculate the true cost of making silage. The true cost could be compared with other supplementary feeds, and the value of boosting silage yields (using nitrogen, for example) could also be measured. Table 1 shows how to calculate the true cost of making silage.
Mr Lynch said perhaps the scariest number associated with silage (except maybe the bill for making it) was the amount that could be lost through wastage at feedout. This can be up to 40 per cent. When considering the time, effort and cost of making silage, the thought of losing this much was concerning.
Mr Lynch said silage quality was more important than quantity. Cutting higher quality pasture early in the season helped to preserve the most energy and crude protein, which would support the best milk response from cows and encourage the maximum amount of pasture regrowth.D