Use of alternative cereals to maize and wheat in animal feed

It is well known that food accounts for 70% of the costs of a livestock farm, so the knowledge of different nutritional alternatives (alternative cereals), is an indispensable tool to maintain the profitability of the system.

Cereals (from Ceres, the Latin name for the goddess of agriculture) are plants of the grass family grown for their grain.

A large part of the world’s production goes to animal feed. In developed countries, 56% of cereals produced are for livestock feed, and 23% in developing countries. Globally, 37% of cereal production goes to animal protein production.

In animal nutrition practically all cereals are used in various forms: whole grain, ground grain (incorporated into feed), whole plants harvested before maturity and silaged (corn, barley, sorgo). In addition, some cereals are used as fodder (fiber source).

Among cereals, the most prominent as energy source is maize, 70% to 80% of its production is used as a feed ingredient in the world. Wheat, traditionally reserved for human consumption, is also one of the main raw materials in compound feed. Therefore, having a strategy to replace them in whole or in part with another cereal is an excellent way to alleviate the risk inherent in commodity market volatility.

Below are described some of the main alternative cereals used to replace maize and wheat:

Sorghum

Sorghum, with an adequate raw protein level (8 to 12%) and a high level of carbohydrates (65 to 80%), is a good substitute for wheat and maize, thanks to its availability, low price and limited human consumption, in addition to the advantage that varieties rich in tannins (brown) have of being able to be grown in arid areas resistance to drought, birds, insects and fungal infection.

One of the biggest conditioners for the use of sorghum in animal feed is the presence of anti-nutritional factors, especially trypsin inhibitors and condensed tannins.

The effect of tannins is particularly severe in monogastric animals such as chickens, where anti-nutritional factors reduce the growth rate of birds through decreased availability of certain nutrients, such as proteins and carbohydrates in the gut. The severity of the impact depends on the amount of tannins present in the diet.

Diets with high tannin content can lead to a decrease in consumption and body weight in hens. Tannin levels between 1.5 and 3% cause depression in growth rate and a possible decrease in egg production.

The concentration of tannins varies depending on the color of the grain cover. Those yellow (white sorghum) shows the lowest concentrations of tannins (<0.25%), while the concentration of tannins is higher in those that have a darker color in their outer layer. On the other hand, yellow sorghums are nutritionally superior to the other varieties for their better energy value and higher digestibility of proteins.

In regards to maize, sorghum has lower fat content and linoleic acid in particular. This is an essential fatty acid, is the fatty acid with the greatest presence in cell membranes. In a more general sense, the profile of the fatty acids of a feed affects the fatty acid composition of animal tissues, therefore, the better this profile will be, we will see the effects on meat, eggs, milk and embryos of pigs. In addition, we must take into account the absence of xanthophylls (pigments) in the sorghum grain when we use this grain to replace maize, which generates a lower pigmentation of the skin of chickens and egg yolk. This can be solved by using synthetic pigments or another ingredient rich in natural xanthophylls.

Although sorghum has a protein content (11-13%) slightly higher than that of maize, its profile is comparatively deficient in lysine and threonine, limiting amino acids in birds and pigs.

Finally, we will say that it is important to take into account the grinding of the sorghum grains, since it is necessary that the grain breaks during the process in order to be digested by the animal. For this, it is worth to be aware of the size of the mesh, that is, that it does not allow whole grains to pass through it, but also that no pulverulent material is generated, since it affects the palatability of the feed.

Barley

Barley (Hordeum vulgare) is considered a grain of medium energy. It has a low starch content, high fiber content and some anti-nutritional factors.

Like maize and wheat, barley contains high levels of starch, so it is used as an energy source in feed, however, its levels are between 55-60%, which is a lower percentage than the other two cereals. In terms of protein levels, barley is similar to wheat and higher than maize, the level of this nutrient can vary between 9 and 12-13%. It is an excellent source of some vitamins of group B (thiamine, riboflavin, pyridoxine, pantothenic acid) and niacin.

Barley has a high fiber content, higher than that of maize and wheat, resulting in a lower nutritional value for species sensitive to the content of it. The fiber of this grain is represented by ß-glucans and pentosans, which cause an increase in the viscosity of the intestinal content, which implies a decrease in ingestion and makes it difficult to absorb the other nutrients. In addition, the increase in intestinal viscosity results in sticky stools that, in chickens cause damage to their legs and chest giving lower quality products. The same is true in laying hens, sticky faeces mark the egg, reducing its value

The inclusion of enzymes ß-glucans and pentosans in the diet can alleviate these problems.

Barley is one of the most commonly used grains in feed for dairy cows and fattening cattle. Due to its high ruminal digestibility, barley has high metabolizable energy values for ruminants. It is very common to chop and silage the whole plant, which is an excellent resource for calves of breeding and finishing.

Oat

Oat contain much less starch than maize, wheat and barley. This, coupled with its high content of fiber and lignin, significantly reduces its energy value.

Oat is rich in pentosans and ß-glucans. These polymers, as we explained in barley, increase intestinal viscosity, causing digestive problems in monogastrics, so it is necessary to supplement feed intended for these species with the appropriate enzymes.

Oat has higher lysine content than sorghum and maize, but its high fiber content limits its inclusion in monogastric diets. Also because of its high fiber content as with barley, these cereals are recommended for use in feed for pregnant sows, milk cows, rabbits and horses, if their price justifies. Oat must not exceed 30% inclusion in pig finishing feed.

Triticale

Triticale (x Triticum-secale) is the product obtained from wheat hybridization (mainly varieties of durum wheat) and rye. The physical characteristics and chemical composition of the triticale grain are generally intermediate between the two progenitor species, combining the high energy and protein value of wheat with the rusticity and quality of rye.

The average starch content of the grain is 58%, intermediate between wheat and rye, as well as fiber and fat levels. In terms of protein levels, these vary between 10 and 20% of dry matter in the triticale, levels higher than those of wheat. The composition of the protein is also similar to that of the protein, but somewhat superior in lysine.

Modern varieties of triticale (alternative cereals), are an excellent replacement for maize due to its high lysine content. The average concentration of this amino acid for triticale is 0.39% and 0.26% for maize. The bioavailability of phosphorus is 30% higher than that of maize, which reduces the need for phosphate supplementation in the diet.

Rye

Rye contains high values of anti-nutritional factors compared to maize and wheat. It is a rich source of soluble non-starchy polysaccharides, particularly pentosans. The result of these is a negative effect causing digestive disorders resulting from the increase in viscosity of the intestinal content, favoring bacterial proliferation.

For its use should be considered the quality of the rye grain and the use of an appropriate enzyme to counteract the effects of its high pentosan content. However, it is safest to limit its inclusion to a maximum of 25%. It should not be administered to lactating sows or piglets, as their low palatability reduces consumption. In the case of birds, it can be used by up to 20% in laying hens and no more than 10 to 15% in parrots, depending on age.

Rye may be affected by the fungus Clavicieps purpurea, which causes a disease called the rye ergot. The alcaloids (ergonovin, ergometrine, ergotamine and ergovaline) produced by the microorganism are highly toxic to animals.

Another complication of rye is the presence of resorcinol, an anti-nutritional factor that causes feed rejection.

Conclusion

The cost of raw materials has a very high impact on the profitability of a livestock farm. Knowledge of the different nutritional strategies are a tool that allow us to mitigate the constant fluctuations experienced by the grain market.

We must know the characteristics of each cereal, its benefits and its conditions. Also, respect the inclusion limits that are stipulated for each specie and productive stage.

The addition of enzymes in formulations containing alternative cereals allows to raise inclusion levels and improve digestibility, while reducing food costs by maximizing the use of other materials Premiums.

• Fedna: Fundación española para el desarrollo de la nutrición animal