Comparative Costs

Press, Volume CIII, Issue 30610, 28 November 1964, Page 10

Comparative Costs

silage compared more than favourably with other feeds on a cost basis, according to an address given to the field day at Tai Tapu by Mr G. R. Cleland, a farm advisory officer (economics) of the Department of Agriculture in Christchurch. Mr Cleland said that to make such a comparison of the costs of the different feeds they must all be reduced to their starch equivalent, which was a measure of their feeding value.

On this basis barley at 10s per bushel cost £32 per ton of starch equivalent, hay at 4s per bale £l7 per ton of starch equivalent, conventional silage £l3 and vacuum silage £l2 per ton of starch equivalent. In vacuum silage the extra costs involved in extra plastic, seal strip, vacuum hose and pumping equipment were offset, in the larger stacks, by the decrease in wastage and the increase in quality as shown by extensive tests in the North Island. It had been shown that the usual wastage of 20 to 30 per cent in conventional silage stacks, due to the breakdown of sugars by oxygen, could be reduced to under 5 per cent in a vacuum stack. Moreover the final product from a conventional stack was 9 per cent starch equivalent compared with 11 to 12 per cent for the final product from a vacuum stack. This meant that the cost per ton of starch equivalent was 20s less in a vacuum than in a conventional stack when 100 tons or more of green grass materials were ensiled.

By way of example, to feed 100 ’ Jersey cows producing three gallons and a half of milk per day for three weeks iwould cost on conventional

silage £204 and 20 acres of grass at 10 tons per acre and on vacuum silage £lB5, and 15 acres of grass at TO tons of grass to the acre. This meant that there was a saving of £l9 and five acres of grass available for grazing by vacuum packing of silage.