Cactus pear makes an ideal feed, because it is highly digestible, tasty and relatively cheap and easy to establish. Furthermore, it is drought resistant and adapts to a range of climatic and soil conditions and is able to supply food at any time of the year.
History of Cactus Pear
Cactus pear has been used as a feedstock since the Aztec times, and was slashed and fed to oxen, transporting cotton to the southern tip of Texas during the United States Civil War. The oxen reportedly only had to drink water once a week in winter and three times a week in summer, thanks to the high water content of the cactus.
In South Africa spineless varieties have been imported and evaluated since the 1970s, primarily to produce feed during times of drought, but the succulents have since matured into a feed crop in its own right.
Planting Conditions
While cactus pear is highly adaptable, it does not tolerate temperatures below five degrees Celsius, with some cultivars being more tolerant to low temperatures than others. Young plantings are also vulnerable to frost damage.
The soil should be well-drained, with a pH of 6.5 to 7.5 and a minimum depth of 300 mm. The planting site should preferably be flat, although slopes of up to 3% would be tolerated. While the plants are adapted to arid to semi-arid conditions, they would require a minimum of 200 mm of water per year under rain-fed cultivations.
The Agricultural Research Centre (ARC) and University of Free State (UFS) in their production guideline, Verbouing van Doringlose Turksvey vir Voer-en Vrugproduksie in die Hoëveld, advise farmers to protect plantings against grazing, since the plants are irresistible to game, such as rabbits, tortoises and deer.
Propagation of Cactus Pear
Cactus pear is propagated from leaves to ensure they are true to type. Plant material can be ordered from nurseries or produced from existing plants on the farm.
The material is planted with roughly half to a third of the leaf sticking out of the soil, depending on the soil type. The leaves should be placed upside down, with the wound facing upwards, if the wound is not completely dry, or with the wound facing downward if it is dry.
The material should preferably be planted once the danger of frost damage is over, but no later than November. All fruit should be removed early during the first two years of production to stimulate leaf development. Growers in general, prune the plants in winter.
The succulents are sensitive to competition, so weeds should be removed before planting and regularly thereafter. This also helps to prevent pest and disease problems.
Cultivars of Cactus Pear
Different varieties of cactus pear exist, with different feeding and production potential. Varieties such as Fusicaulis and Fresno produce high fodder yields, but are poor fruit producers so should not be planted if both feed and fruit production are targeted.
Consider, however, that fruit formation results in a waste of energy. Farmers, for this reason, should rather plant small numbers of fruit bearing cactus pear around their house if the fruit would only be used for household purposes. Morado is a good double-purpose alternative, according to the University of the Free State and ARC.
Feed Value
Cactus pear has a high energy content, ranging between 8% and 12%, but a low crude protein content, ranging between 4 to 7%. The crude protein is higher for plantations that are fertilised, than ones that are not.
The ARC and UFS estimate that a well-established plantation could contain roughly 90 000 litres of water per hectare in its leaves and produce about 100 tons of dry matter per hectare. Research from Brazil has found that production can be increased to roughly 400 tons of wet material per year by planting 18 000 plants per hectare at a row spacing of 0,4 meters between plants and 1,4 meters between rows.
The ARC and UFS, however, warns that higher density plantings require intensive management, fertilisation and more water than under normal conditions.
Feeding of Cactus Pear
While the leaves can be grazed from the plants, it is best to prevent overgrazing by feeding harvested leaves to livestock.
If the succulents will be grazed directly, farmers should use ultra-high density grazing to prevent overgrazing. This means that high volumes of animals should be released into small grazing areas for short periods, with their movement being controlled through electric fencing. The areas should then be left to fully recover before animals are allowed back into that specific part of the plantation.
Only plants that are roughly two years of age or that are renewed every two years.
The whole plant can be used as feed, from the roots to the leaves, which could be necessary during dry years. Farmers should however ensure that at least 0,5 meters of the plant material is left over after grazing or harvesting, and then only do a light prune the year thereafter to allow the plants to recover.
Under normal conditions only the leaves are used as feed. The leaves are traditionally supplied fresh, either whole or chopped into strips or squares. Sometimes the leaves are also chopped or carved and then sundried for up to two weeks, depending on climatic conditions. The leaves should not be bruised during the carving process, as this will cause the material to become slimy, which in turn will make it difficult to dry.
Sheep can survive on roughly 4 kg a day, while a big cow will be able to do with 14 kg of cactus a day, but the feed needs to be supplemented with proteins to make up for its deficiency in cactus pear. The leaves should preferably be chopped up when served to dairy cows to render it more easily digestible. Farmers should beware that too much cactus pear may cause digestive problems, especially with milk goats and dairy cows.
For the best results, farmers should consult an animal dietician to help them develop a balanced ration based on the resources that are readily available to them.