Tactics to preserve nutritional value of home-grown feeds
13 July 2001
Tactics to preserve nutritional value of home-grown feeds
By Hannah Velten
THE type of whole-crop and crimped grain required will determine the optimum dry matter of cereal crops at harvest to ensure feed is well preserved and retains its nutritional value.
Pete Kelly, of Avon-based Green and Kelly Farm Business Consulting, says: "Due to relatively low silage cuts and the predicted expense of buying in bulk feed this winter, many producers are planning to use their arable crops for forage or buy in crops for the first time."
The type of feed required will determine crop harvesting date, says Mr Kelly. "Fermented whole-crop will produce a large amount of bulk feed, but urea-treated whole-crop can only be fed at a maximum of 3kg DM in cattle rations, otherwise it can cause digestive upsets.
"Crimped grains will provide a cost-effective concentrate feed without the need for drying, while harvested straw provides a high quality forage."
Volac product manager Liz Beechener says alkalage provides a whole-crop option which contains high starch and protein levels.
The optimum crop dry matter at harvest will depend on the feed option chosen (see table), but reduced feed value and poor preservation results when harvest windows are missed, adds Mr Kelly.
Inspect crops regularly to correctly assess crop DM because fermented and urea-treated whole-crops can be harvested from 5-6 weeks before the normal cereal harvesting date and crimped or urea-treated grains three weeks before, says Mr Kelly.
On-farm dry matter testing is inexpensive and quick. The standing crop should be cut, using scissors or garden shears, at harvesting height and 1kg of the sample spread out on a baking tray and put into a oven at 100C for 5-6 hours, says Mr Kelly.
The weight of the sample after baking, compared with the original 1kg sample will show the crops DM content – a 35% DM crop will produce 350g of baked sample.
Looking at the crop and monitoring changes will also provide a guide to DM content, he adds. "Cereal grains for fermented whole-crop should be at the doughy stage and urea-treated whole-crop is ready to be taken when the top half of the stem is yellow and the bottom half still green. Grains for crimping will be soft to bite and easily pierced with a fingernail."
Alkalage crops should be taken when grains are very hard, impossible to penetrate with a thumbnail and when some heads are bending over, says Mrs Beechener. *
Optimum DM%content
System DM% Harvesting machinery
Fermented 35-45 Forage whole-crop harvester
Urea-treated 60+ Forage whole-crop harvester
Crimped grain 65-70 Combine
Urea-treated grain 65-70 Combine
Alkalage 65-80 F harvester with grain cracker