Sunflower (Helianthus annuus L.) is the 5th most important oilseed crop in the world and accounts for 8% of oilseed world production (FAO, 2011), with 32.3 million tons for the 2010/2011 harvest (Oil World, 2011).
Sunflower is an erect, hirsute herb, 1 to 3.5 m high. It is an annual or perennial plant, but mainly grown as an annual. It has a strong taproot reaching down to 3 m, which gives it drought-tolerant properties (Ecocrop, 2011). The wide yellow flower head is 10 to 30 cm in diameter. It is composed of lots of tiny tubular flowers forming a disk. After pollination, the plant will bear as many seeds as it has flowers. Sunflower heads follow the sun’s cycle during the pollination period and remain eastward-oriented after that (Grompone, 2005).
There are two types of sunflowers: oil types containing 40% oil, and non-oil types with 30% oil (Grompone, 2005). Oil types represent 80% to 95% of sunflower seed production. The oil is mainly used for cooking including frying. Industrial uses include lighting, cosmetics, resins, lubricants and biofuel (OECD, 2007). Non-oil types are mostly used in confectionery products such as roasted and/or dehulled seeds (ERS-USDA, 2010).
Sunflower provides different products used to feed animals:
- Sunflower meal (or cake) is the by-product of oil extraction. It is a major source of protein for livestock, and particularly for ruminants (OECD, 2007).
- Sunflower hulls, obtained from the production of sunflower-based confectionery or from some oil extraction processes, are a highly fibrous product of low nutritive value. They can be a cheap source of fibre for ruminants, or used for bedding (OECD, 2007).
- Sunflower seeds are common ingredients in pet bird feeds. Their oil content and fatty acid composition also makes them valuable for livestock, notably beef and dairy cattle (OECD, 2007).
- Sunflower foliage and crop residues, such as the flower heads, are used for forage. Ensiled sunflower foliage can be valuable in areas with a season too short to produce mature maize for silage (OECD, 2007; Putnam et al., 1990).
- Sunflower oil is seldom used in livestock feed due to its higher economic value as a human food, but small amounts of sunflower oil help to reduce dust in animal meals (OECD, 2007).