Details

Common Name
Leucaena, Whitelead tree, Guaje, Huaxin, Koa haole
Botanic Name
Leucaena leucocephala
Plant Family
Fabaceae (Mimosaceae)
Habitat
Frost-free, sub tropuical and tropical areas of the world
Distribution
Hawaii, and Gulf States
Animals Affected
Cattle, sheep, goats, horses, pigs
Leucaena leucocephala
Toxic Principle
Although Leucaena is nutritionally equivalent to alfalfa, and ruminants find the leaves palatable and nutritious, Leucaena is poisonous to ruminants that have not been adapted to the plant. The toxin in Leucaena is the mimosine. The leaves, new growth especially, and pods of leucaena contain the toxic amino acid mimosine which is broken down by microbes in the rumen to 3 hydroxy-4-(1H)-pyridone (DHP) a goitrogen, which is normally broken down further by rumen microorganisms to non-toxic compounds. In Hawaii and other tropical countries where livestock regularly graze leucaena, these adapted microrganisms are present in the rumen in sufficient quantity to quickly detoxicfy the mimosine and DHP. Where ruminants are not adapted to Leucaena, this detoxification does not occur and toxicity results. THe DHP depresses the uptake of iodine causing the evelopment of hyperplastic goitre in ruminants and consequently in the developing fetus. Sheep fed leucaena do not detoxify the mimosine to DHP rapidly enough to prevent absorbtion of mimosine itself, which results in fleece shedding. Sheep can be adapted to leucaena by initially feeding small amounst of the plant over several weeks to allow their rumen microflora to adapt and detoxify the mimosine and DHP.
Description
A branching, thornless, shrub or tree that can reach heights of 7-18 m. Leaves are bipinnate with 6-8 pairs of pinnae bearing 11-23 pairs of leaflets 8-16 mm long. The inflorescence is a cream coloured globular shape which produces a cluster of flat brown pods 13-18 mm long containing 15-30 seeds. At least 14 species exist in the genus that readily hybridize among themselves.
Gastrointestinal
Decreased feed consumption, excessive salivation
Musculoskeletal
Poor weight gain
Congenital Defects
Enlarged thyroid glands (Goitre) in the fetus and dam
Treatment
Reduce or stop the consumption of leucaena, and feed a nutritious ration such as alfalfa.
Integumentary System
Hair loss, fleece loss
Special Notes
References 1.Jones RJ, Megarrity RG. Comparative toxicity responses of goats fed on Leucaena leucocephala in Australia and Hawaii. Australian J Agricultural Research 1983, 34: 781 – 790. 2.Holmes JHG. Toxicity of Leucaena leucocephala. II. Reduced fertility of heifers grazing Leucaena leucocephala. Papua New Guinea Agric J 1980,31:47-50. 3.Meulen U ter, Struck S, Schulke E, El Harith EA. A review on the nutritive value and toxic aspects of Leucaena leucocephala. Trop Anim Prod 1979 4:2 113. 4.Hammond AC et al. Prevention of Leucaena toxicosis of cattle in Florida by ruminjal inoculation wth 3-hydroxy-4-(1H)-pyridone degrading bacteria. Am J Vet Res 1989, 50: 2176-2180. 5.Jones RJ, Blunt CG, Nurnberg I. Toxicity of Leucaena leucocephala. Austr Vet J. 2008, 54: 387-392. Transfering fresh rumen contents from cattle/sheep/goats that are adapted to grazing leucaena in quantity will provide the specific detoxifying microrganisms to the unadapted animal thereby
Leucaena leucocephala
Leucaena leucocephala leaves and flower
Leucaena leucocephala seed pods