Written by: Dr. Jacquie Jacob, University of Kentucky
Rye (Secale cereale) is a highly versatile crop. It can be grown as forage for cattle and other ruminant livestock, and it can be used as a green manure in crop rotations as part of organic farming. It can also be grown for grain that can be used as a feed ingredient, for alcohol distillation, and for human consumption.
The number of rye cultivars is relatively low, especially when compared with wheat and barley. There has been considerably less effort put into the development and improvement of rye, in part because rye is a cross-pollinator, whereas wheat and barley are self-pollinators. (It is difficult to maintain pure lines of breeding stock for cross-pollinators.)
Rye cultivars are typically differentiated on the basis of growth habit as either winter rye or spring rye. Rye has amazing tolerance for cold weather and is able to germinate at air temperatures in the 30s (°F), as long as the soil is warmed by the sun to a temperature slightly warmer than the air. Once established, rye will continue to grow in the fall until the temperature drops below 40°F. Growth resumes when the temperature rises above 40°F in the spring. Spring rye is grown in areas where the winters are too severe for even the hardy winter rye. Typically the yields of spring rye are lower than those of winter rye.
Rye is able to produce economical yields on poor, sandy soils not suitable for other crops. Rye has a deep root system that makes it good at competing with weeds, which is another reason rye is often used in crop rotation in organic farming. Rye can be planted as pasture in both the fall and spring or can be grown as pasture in the fall and raised as a grain crop in the spring.
The nutrient content of rye is very similar to that of wheat and corn, but its nutritive value for poultry is very poor. When rye is included in poultry diets, the poultry experience depressed growth performance and/or reduced egg production. The use of rye in turkey and broiler diets results in sticky droppings that add moisture to the litter and can cause problems with ammonia. The fecal material can also gather around the vent, giving birds "pasty butts."
Rye grain is not recommended for growing chickens (such as broilers and pullets) and turkeys. Including high levels of rye grain in poultry diets typically causes problems for growing chicks. Rye is composed in small part (about 3.5%) of water-soluble, highly viscous nonstarch polysaccharides referred to as pentosans or arabinoxylans. These polysaccharides interfere with poultry's digestion of all the nutrients in a diet—especially the fats, fat-soluble vitamins, starch, and protein. Chicks fed diets that include rye grain produce wet and sticky fecal material. There is also a higher moisture level in litter, increasing the problem of ammonia production.
Rye may be fed to laying hens, but it should be introduced only after the hens have reached peak egg production (about 40 weeks of age). Rye should not compose more than 40% of the diet. Birds that consume rye may have sticky droppings, which can increase the incidence of stained eggs.
Although there are commercial enzymes available that can counteract the negative effects of rye, reluctance to using rye grain as a feed ingredient persists. The primary concern is the presence of ergot alkaloids. Ergot, a fungus, is the most common disease of rye. The fungus can be very toxic if present in sufficient concentrations. Ergot is less of a problem as newer cultivars of rye are developed that are resistant to ergot. Controlling wild grasses around field borders also reduces the chances of an ergot problem.