MANY farmers will be looking to purchase additional feed to make up for the shortfall in home grown feed.
The purchased feed needs to be cost-effective, so deciding which feeds to purchase needs to be well thought through.
In many cases this season, concentrates will be a cheaper feed option than high quality fodder.
However, with concentrate feeding there is always the concern of rumen upsets when high amounts are fed.
So the question many will be asking is; “How much can I safely feed and do I need a modified mix?”
Researchers from DEDJTR Ellinbank; Dr Martin Auldist, Dr Bill Wales and Ms Marlie Wright, have been involved in Dairy Australia and DEDJTR-funded research.
The research looked at high levels of concentrates fed to cows in situations where pasture made up 50 per cent or less of the diet.
This research found it is possible to feed up to 8kg of concentrate daily (split between two feeds) without impacting on milk composition.
However, to allow the rumen to adapt, the level of grain should be increased gradually.
Above this level of feeding, a decrease in milk fat concentration could occur despite the inclusion of feed additives to stabilise the rumen.
While there are situations where additives alone are not able to maintain the desired rumen environment, it is wise to include feed additives (buffers or rumen modifiers) that help reduce the risk of a rumen upset when feeding high levels of concentrates.
A significant decline in milk fat is a good indication that the level of concentrates being fed is causing a significant drop in rumen pH.
In this situation, it is wise to review the diet, especially the amount and composition of the concentrate component of the diet.
At feeding levels where a decrease in milk fat concentration occurs, research found that replacing up to 25 per cent of the cereal grain with crushed maize grain allowed the cows to eat more concentrates and produce higher milk yields without decreasing milk fat production.
Maize is digested more slowly, so is gentler on the rumen environment. Pasture is high in protein, as is high quality pasture silage and good quality legume hay.
On many farms this summer, there might not be enough of these feeds in the diet, so high protein supplements are likely to be needed.
High protein concentrates such as canola meal are often used to increase the protein in the diet to the minimum amount required.
Usually however, only the minimum amount of protein is included in the supplements due to the relatively high cost of these feeds.
DEDJTR researchers also looked at exceeding dietary requirements by including additional protein in the form of canola meal in the concentrate mix.
Inclusion of canola in the ration generally resulted in increased milk production and increased feed intake.
The economics of feeding extra protein depends on the milk price, the cost of canola meal and availability of the extra feed that the cows ate.
In summary, cereal grain supplements are likely to provide the cheapest source of extra energy in the diet this summer (but do your own sums).
Cereal grains can be fed at reasonably high levels without depressing milk fat production.
Above about 8kg DM of grain per cow per day, replacing some of the cereal grain with more expensive maize grain, allows higher levels of concentrate supplements to be fed.
Adding canola meal to the concentrate mix will increase the protein concentration in the diet and is likely to increase feed intake and milk production.
For more information please contact Greg O’Brien, Dairy Extension at DEDJTR Ellinbank on 5624 2288.