Sorghum cultivation is increasingly becoming an alternative to corn in the situations of limited water reserved. The reasons are numerous. First of all, global warming effects and the need to preserve water resources are evident since last few years. Secondly, 80% of the Eastern Europe planting surfaces are not equipped with irrigation system. Sorghum crop needs low inputs level (pesticide and fertilization) which makes its cost of production competitive. For these reasons, more and more farmers are looking to sorghum in animals feed. In this article, you will find answers to frequently asked questions when introducing sorghum in animal nutrition.
- What is the tannin content of sorghum?
The tannins are generally concentrated in the husk of the grains. Old varieties of sorghum had very high tannin values: between 1.0 over 3%. Today, those types of sorghums can be essentially found in Southern America, China and sometimes in CIS countries. It helps to limit predator damages in the field, as a high value of tannin makes the grain less appetent. The peculiarity of this anti-nutritional factor of tannin, or polyphenols, is its correlation with protein digestibility. Polyphenols form resistance mechanisms to enzymatic attack in the gastrointestinal tract, which greatly reduce the digestibility of proteins.
That’s why since more than 20 years, sorghum breeder are focused on finding the varieties with very low tannin level. It is also interesting to know that the varieties grown in the European Union cannot be listed in the Official Catalogue if their level of tannins is high (should be 0.30% dry matter, ISO 9648). Today EURALIS varieties are guaranteed with very low tannin content for optimum use in animal feed. To sum up, by introducing modern sorghum hybrids in the feed ration, a farmer can be sure to have protein and energy values similar to the corn.
- What is the nutritional composition of sorghum in animal feed?
> Starch and Fat.
The starch and fat contents of sorghum are similar to corn. Moreover, the advantage of sorghum is its protein content. Sorghum has a low level of fiber and slightly different from corn amino acids profile: less lysine and sulphurous, but more threonine and tryptophan. It is also a source of watersoluble vitamins. Thus, it doesn’t contain vitamin A and xanthophyll (The xanthophylls are yellow molecules derived to carotenes). Vitamin A favors the yellow pigmentation of eggs and chicken meat. A consumer preferance for the pigmentation depends on the food habits of the population. In Italy for example, consumers prefer white chicken meat and therefore sorghum feed is widely used. For the yellow lover clients, the coloring of chicken can be corrected by exogenous complement, a natural xanthophylls-rich ingredients in the ration.
>Energetic value.
The sorghum digestible energy is quite high, about 86% of the dry matter (DM), as well as the digestibility of proteins and amino acids.
For growing pork,
digestible energy of sorghum is practically equal to corn: 3931 kcal / kg DM for sorghum against 3924 kcal / kg DM for corn (source: INRA); for sows: sorghum – 4002 kcal / kg DM, corn – 4081 kcal / kg DM (source: INRA). The sorghum fat content is similar to corn but with more favorable fatty acid profile. Fatty acid profile of the pigs ration influences the carcass. Fat contained in sorghum has less unsaturated fats. Sorghum has also less linoleic acid and polyunsaturated fatty acid. The advantages of sorghum compare with corn have been confirmed by the researchers. The sorghum grains have good available phosphorus content. Compare to corn, the requirement of supplemental inorganic phosphorus is less. The introduction of sorghum in pork feed has reached 50%. For example, today Spanish ham producers commonly use sorghum grain in their farms. That is the reason why 40% of the total French productions of grain sorghum are exported.In Catalonia for pork farm. Sorghum can replace corn in a pork feed without affecting growth performance.Sorghum’s flexibility in ration formulation (for example with soybean) allows nutritionist to decrease the costs and maintain similar growth performance.
For poultry,
the most commonly used cereals in poultry ration are corn, wheat, barley, rice and sorghum. Among them, sorghum is the most energetic cereal. In the United States, sorghum ranks second among the cereals used in farm of broilers, turkeys and laying hens. Since 2009, the energy value of sorghum is relatively stable, and even a little bit higher than of corn. In France, in 2014 the average sorghum energy was 3775 kcal / kg (2013: 3780 kcal / kg), against 3705 kcal / kg for corn (source: INRA). Protein digestibility and amino acid levels are almost identical for sorghum and corn (see table on the right).
Some studies have shown that whole and uncrushed sorghum grains may be incorporated in feed without causing loss of the digestibility. It is also possible to introduce up to 55% in rations for turkeys and up to 70% in rations for broilers and laying hens. The unanimous opinion of nutritionists all over the world is that sorghum is similar to corn in terms of nutritional value for poultry (under the condition that sorghum grains have low tannin level).
For beef cattle,
cereals are the most common source of energy (see table). The use of starch in the rumen is essential when increasing animal performance. Therefore the high content of sorghum starch, which is on the same level that corn, makes it useful in the feed for fattening the cattle. Sorghum ferments more slowly than other cereals, however, the calculated rate of digestion of crude protein, starch and dry matter are the same for corn and sorghum (HerreraSaldana, 1990). Sorghum contains more crude protein than corn. According to Owen et al. (1997), feed efficiency was improved by 5% with a mixture of sorghum and corn, where comes the importance of this association! If needed, a partial substitution of corn by sorghum might be done. It will decrease the need for supplemental crude protein (sorghum contain 10% more of crude protein than corn). In USA, several studies have shown similar animal performance between sorghum and corn, under the condition that sorghum is processed correctly.
For dairy cow,
Barley, wheat, corn and sorghum grains are all potential sources of energy for dairy animals (see table). The choice will depend of climatic situations and irrigation possibilities. Sorghum is a preferable crop when water resources are limited. Grain starch is the primary source in dairy cow rations when feeding for high level of milk production. Starch in the rumen is the first improvement of milk yield and efficiency of production. In this case, sorghum grain is a very significant source of starch. Sorghum fermentation is slower than others grains, but it is completed after 48 hours of ruminal exposure. The studies have proven that the replacement of corn grain by sorghum for lactating cow diets do not decrease the milk production and performance results (Mitzner and Al. 1994 and Theurer and Al. 1999). Sorghum grain does have slightly greater ash content than corn, but with minimal effects upon the mineral supplementation of dairy diets. If we replace corn by sorghum the main advantage is the opportunity to reduce the supplemental crude protein level of the diet. Steam flaking process (compare to dry rolling) can increase sorghum energy value by 13-20% and increase the utilization of sorghum grain for the rumens to produce microbial protein. Definitely this is also economic and ecologic advantage to use sorghum for dairy cows rations
- Are there any peculiarities to know on sorghum grain?
The crushing is an important point to ensure the digestibility of sorghum, for optimum result crush at 2 mm.
The crushing is an important point to ensure the digestibility of sorghum. Its grains have the same requirements as those of corn. The sorghum particle size is more important for the production of poultry nutriments. Excessive crushing of grain sorghum could cause cross chemical bonds and reduce the amount of available nutrients. Note that a 2 mm of sorghum crushing increase the level of digestibility of main amino acids, in comparison with a 4 mm of sorghum crushing.
The diversity of colors and types of sorghum grains is very important. With sorghum farmer has a wide range of variability of grains to choose for his animals.
- Why animal feed producers prefer corn and not sorghum?
A lack of grain sorghum on the market creates a risk of shortage. That is why we need to produce more to secure the industry.
Definitely nutritionists and animal feed producers agree that sorghum has its place in animal feed with its proven quality. Moreover, financial savings can be made by incorporating sorghum in the rations while keeping the high level of nutritional qualities. From another side, the main concern of the animal feed producers is the lack of sorghum grain, which creates the risk of ration imbalance. As normally, the ration need is calculated for the whole year and the quantity of available sorghum grain are not sufficient. That is why for the moment sorghum has lower application in the feed compare to corn.
Today, we need to produce more sorghum and secure the sector with the optimum balance for the use, as sorghum grain has its proven positive nutritional values.
EURALIS red grain and white grain sorghum hybrids have all the qualities required for the animal feed. Grain quality for optimal use by animal feed producers is the main breeding target of the company.
