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Wheat versus maize
Dr Ioannis Mavromichalis
Questions whether maize can replace wheat - or the other way round - are
frequently asked. Such concerns usually emerge when alternative cereals are
priced competitively (due to oversupply or lower quality).
The question whether maize can replace wheat is often
asked in major wheat-producing areas (e.g., Canada, Europe) where there is
considerable experience in feeding wheat. Similarly, producers in major
maize-producing areas (e.g., USA, Latin America) frequently ask whether wheat
can replace maize. Such concerns usually emerge when alternative cereals are
priced competitively (due to oversupply or lower quality).
There is ample evidence suggesting
that properly balanced diets using similar quality wheat or maize will yield
similar results, at least in terms of animal performance (see table). Obviously,
replacing good quality wheat (or maize) with moldy maize (or wheat rich in
arabinoxylans) will fail to produce similar results. Therefore, more emphasis
should be placed on quality than nutrient composition when comparing
cereals.
Table 1. Feeding wheat or maize to
nursery pigs.
Replacing
When
replacing wheat for maize the following should be taken into
consideration:
• Wheat has less energy (95% of that in maize), more protein
(11-12 versus 7-8%), and higher phosphorus bioavailability (50 vs 14%) than
maize. Thus, a one-to-one substitution based on weight will produce severe
nutrient imbalances.
• Wheat contains certain anti-nutritional factors
(arabinoxylans) that could be detrimental to animal performance at high
concentrations. In this case, a wheat-specific enzyme (xylanase) is recommended
for piglet diets.
• Finely, ground wheat increases pellet durability (but
pellets also become harder), decreases feed flow in bins and feeders, and may
increase incidents of ulceration in susceptible pigs.
Microflora
Finally, there is some evidence to
suggest that wheat (and barley) support a more healthy microflora than
maize-based diets, especially in the absence of feed-grade
antibiotics.
In conclusion, local availability, quality, and price should
be the main factors determining use of wheat or maize in most parts of the
world. Properly balanced diets that take into account the strong and weak
features of each ingredient support excellent performance throughout the world.
However, when replacing wheat or maize with other cereals of lower nutrient
density and higher concentrations of fibre and anti-nutritional factors, such as
barley and rye, performance may suffer without serious alterations in diet
design.
The above appeared in Applied Nutrition for Young Pigs, by
Ioannis Mavromichalis (CABI, 2007). This book can be obtained at
www.e-nutritionist.com.
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