Grazing amazing maize

Research shows that maize is a much more versatile crop than many believe. Roelof Bezuidenhout reports.
Issue date: 28 March 2008

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Research shows that maize is a much more versatile crop than many believe. Roelof Bezuidenhout reports.

Unharvested maize, OR so-called grazing maize, is excellent winter grazing for sheep. Weaner lambs – either from your own flock or bought in – can be grown out on grazing maize, or it can be used to feed winter-lactating ewes. That’s according to Erika van who is based at the Dundee research station of the Department of Agriculture and Environmental Affairs in KwaZulu-Natal. “Grazing maize effectively fills the winter gap in a fodder flow from autumn until the first spring rains,” says Dr Van Zyl. “It can be used to feed sheep on its own or in combination with other winter pastures or crop residues. can also be saved for bridging the difficult August-September period. Grazing maize is a low-risk, high-potential winter pasture produced with summer rain and kept until winter as foggage. Unlike dryland winter grains, it’s not dependent on unreliable autumn rains.”

There are several advantages: a relatively reliable estimate can be made of the amount of fodder available before winter and in the case of high grain yields, some rows can be harvested for grain, while the crop residues of the reaped areas can contribute to the feed available on the land. In addition, weed control costs may be lower because grassy weeds make for good grazing material. What the researchers recommend C ultivating maize for grazing he carrying capacity of maize largely depends on the grain yield. Plant a suitable, high-yield cultivar for the area. Normally, the cultivar best suited for grain and silage production in your area will also be good for use as grazing maize.

Grazing period
Maize can be grazed from the first frost right up to the first spring rains, which is approximately 100 days. As the season progresses, dry material losses will be unavoidable and in the later part of the grazing season, maize will be of a lower quality. Some farmers prefer to start the grazing earlier when it’s still a bit green, so that the sheep ingest more leafy material and less grain, and can adapt more easily.

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Adaptation of sheep to grazing
Because of maize’s high energy content, acidosis (suurpens) is a real threat, but adapting the animals properly before grazing and combining buffers in the lick can control the problem. S tart by giving sheep that are still on the veld or other pasture a steadily increasing amount of whole maize supplement (or even maize cobs) each day. Start with 100g per mature sheep per day and increase over the next two weeks to 1 000g per mature sheep per day. Grazing can then begin without interruption. Some farmers prefer to start grazing maize immediately, but with initially restricted grazing periods that are increased daily. But Dr Van Zyl cautions that good supervision is essential, especially at the start of the grazing period and when changing camps. “Ensure that internal parasites are under control and inoculate against pulpy kidney,” she warns.

Ewes with lambs
Lambs should be at least three weeks old when grazing starts, to ensure they’re strong enough and don’t get separated from their mothers. they start grazing, lambs will gradually adapt to the high energy diet and shouldn’t be susceptible to acidosis. They’ll also benefit from their mother’s good milk production on the maize. Creep feeding may be considered, depending on financial circumstances. Inoculate weaner lambs against pulpy kidney and adapt as above. However, Dr Van Zyl warns that grazing maize has one serious shortcoming – it doesn’t provide enough protein for lactating ewes or growing weaner lambs. “But this can be easily rectified by providing either a lick or a protein-rich companion crop such as Japanese radish. Protein supplementation in a lick is very effective and eliminates many practical problems. Just ensure enough lick trough space and enough intake, and supply fresh lick often.”

Dr Van Zyl also suggests that farmers should graze limited areas at a time to reduce selective grazing and tramping losses. “Otherwise sheep will select a high-quality diet first that’ll become poorer with time. Temporary or electric fences can be used to create a number of smaller camps. Move the sheep to the next camp when the area is well-used, but ensure some grain is still available. Non-producing animals, like old ewes, can be used as scavengers.”

Pre-weaning growth of lambs should be 180g to 250g a day. Lactating ewes should grow 50g to I00g a day and weaner lambs between 180g to 200g a day or more.

Grazing capacity norms
Dr Van Zyl says grazing capacity figures are linked to grain yield. The number of sheep per hectare isn’t as important as carrying capacity linked to a grazing period. That’s because the maize is a dormant (non-growing) feed source. A few animals can graze for a long period, or many for a shorter time. The number of sheep kept will be determined by the period for which the feed is needed. A general norm for the higher rainfall areas is 1t grain/ha = 1 000 sheep grazing days per hectare (sheep weight 45kg to 50kg and 1kg maize per sheep). For example, 3t grain/ha = 3 000 sheep grazing days per hectare. In the drier western maize producing areas, the norm should be adapted to 600 to 660 sheep grazing days/ha with 1t/ha grain potential. A further advantage is that good winter feed with enough protein will advance wool growth and decrease the possibility of tender wool. Ewes would also be in good condition after weaning, which will contribute to higher conception during the next breeding season. “And although breeding ewes increase in weight, they aren’t really marketable, but can contribute to wool income.” Contact Dr Erika van Zyl on 034 2122 479 or e-mail [email protected].