By Mark Callow - Norco Milk Supply Field Officer - Northern Region
Chris and Andrew Mullins milk 265 cows at Allora on the southern Darling Downs of southeast Queensland. The two brothers operate the dairy enterprise as a total mixed ration, the farm supplies 2.4ML of milk with cows averaging 9,000L of milk per annum.
The Mullins understand the link between growing, conserving and maximising dry matter intake of high quality forage with milk income. Analysis of the Queensland Dairy Accounting Scheme (QDAS) has showed that milk produced from home-grown forage contributes significantly to operating profit margin.
Chris and Andrew are always thinking of ways to further increase milk production from home-grown forage. Here are three strategies they have put into practice on their farm.
They have limited irrigation water which they apply through two centre pivots, one of which is towable. Low pressure systems, especially centre pivots, have become very popular because they require minimal labour, have relatively low electricity consumption compared to high pressure systems (i.e. travelling gun), and they provide flexibility in scheduling irrigation. The towable unit enables two areas to be irrigated instead of one, this means a second crop can be established whilst the first crop is maturing in preparation for chopping.
Chris and Andrew recently constructed a covered feedpad with concrete troughs to minimise wastage during feeding. Prior to the new feedpad cows were fed a total mixed ration from tractor tyres. Chris said that since changing over to the new feedpad with head stalls they are using 15-20% less silage. Andrew now saves 20 minutes a day in the tractor when feeding out, this works out to 5 whole days a year. During the recent heat wave cows used the shade from the feedpad for shelter which helped minimize a drop in milk yield.
In the last 18 months the Mullins harvested and stored 6500 t of silage. A mixture of starch (corn) and protein-based crops (soybean, lucerne, shaftal clover, vetch) were grown to supply both energy and protein. They worked out that the reserve of forage will supply the milking herd with enough forage for two years.
This winter they decided to experiment with making wheat earlage and then corn earlage during summer.
Chris and Andrew got the idea from attending the Walking the Season field day run by Queensland Department of Agriculture C4Milk project team at the University of Queensland Gatton campus.
The C4Milk project wanted to increase the forage to concentrate ratio from the industry standard of 60:40 to 80:20 by reducing the amount of concentrates (grain and protein meal) added to the ration by replacing them with energy and protein dense forages. They evaluated chopping the top leaf plus seedhead of a grain sorghum crop (headlage), high cut corn and soybean silage, and fed them in a ration to high producing cows. They showed that milk production and components were maintained whilst feed related costs were reduced (refer to High Milk from Forage Trial – Dairyinfo.biz).
Chris and Andrew would like to achieve a similar result to the Department using wheat headlage, corn earlage and legume crops. The agronomic management of the wheat and corn crops were grown exactly the same as previous crops. The difference being harvest time, crops for headlage and earlage are chopped at a higher dry matter content (refer to table), and more plant residue remains after chopping compared to conventional chopping.
With headlage, only the top leaf and seedhead are removed, whereas with earlage only the cobs are harvested and processed. It was estimated that harvested yield was 30 to 40% lower compared to crops chopped at the usual height of 10-15 cm above ground level.