Staff Reporter Windhoek-Some toxic plant species have been linked to the series of abortions which have lately been experienced by farmers especially in the Khomas Region, among other regions. In the face of barren grazing in some parts of Namibia, poisonous plants which affect livestock differently are in the spotlight because for some peculiar reasons, toxic plants tend to be resilient and ripen and grow faster than normal vegetation. The Dichapetulum cymosum poisonous plant (poison leave, “gifblaar”, “otjikuryoma”) is an old foe especially of farmers in the Omaheke and Otjozondjupa regions, who have lost countless animals due to the effects of this silent killer. Although farmers now co-exist and are experienced enough with the management of this poisonous plant, it still threatens their livelihood. “Gifblaar” occurs in dry, sandy areas, and prefers acidic soils. Some communal farmers have started calling “gifblaar” the equivalent of HIV. Cattle are mostly affected, but sheep, goats and game also get poisoned. Affected cattle are seen just dropping dead due to heart failure after drinking water. Sometimes, cattle also die due to stress, such as from excessive handling, or after being chased by predators. Before they die, farmers might observe signs of difficulty in breathing, salivation and nervous symptoms such as trembling, convulsions and twitching. Death usually occurs within 24 hours after consuming the plant. The identification of “gifblaar” in the field is important in the prevention of toxicity, and hence an outbreak. Upon opening the carcass, a farmer will notice the undigested leaves in the rumen (big stomach). The carcass might appear bluish due to oxygen shortage, and the heart will have an abnormal colour. There are no clear-cut remedies against these devastating plants. Acute blindness and death in small stock are caused by another poisonous plant named Helichrysum argiosporum (“sewejaartjie”, “ongara”). Sheep and goats can also succumb to the normal widespread devil’s thorn. This is a common plant with small yellow flowers and sharp little thorns and is called the Tribulus terrestris plant (“ohongwe” or “duwweltjie”), which has a tendency to grow all over, especially after the lovely first rains of last week in sandy areas. “Ohongwe” thorn poisoning causes swollen face and ears in sheep, hence the common Afrikaans name of the disease “geel dikkop” (yellow swollen head). Usually the affected animal will scratch or rub its head on objects because the skin on the head becomes itchy. Inside the mouth, the gums (mucus membranes) will be yellow and swollen. The same also happens inside the eyes. With the swollen head and itchiness, the animal will refuse to eat, and will be depressed and tend to have difficulty in breathing. “Slangkop” is a dreaded name familiar to any Namibian farmer. Some call them wild onions and the scientific name is Dipcadi glaucum, which is “malkopui” – (mal (crazy), kop (head), ui (onion)) – in Afrikaans. Other local names for this onion are “dronkui”, “slangkopui”, “groenlelie”, “gifui”, “gifdronkui”, “wildeui”, or “onjanga”. A peculiar sign of animals poisoned by the wild onion is that they will just stand with their heads down in a water trough, but without drinking. Another little devil is Trachyandra laxa (“rolbos” in Afrikaans). It is a perennial glabrous herb, erect to ± decumbent, up to 90 cm tall from a small woody rhizome, acaulescent; roots many, somewhat fleshy, usually swollen and tapering to the tip or narrowly fusiform or terete and fibrous, often with root hairs producing a felted covering. There are no definite preventive measures which are able to stop the animals from eating poisonous plants, besides fencing off the plants. Most poisonous plants also are very difficult to get rid of.
2017-11-28 09:39:57 9 months ago