Browsing Journal of Range Management, Volume 45, Number 1 (January 1992) by Authors
Impact of plant toxins on fetal and neonatal development: A reviewPanter, K. E.; Keeler, R. F.; James, L. F.; Bunch, T. D. (Society for Range Management, 1992-01-01)Many poisonous plants grazed by livestock on ranges and pastures in the western USA are fetotoxic causing fetrl malformations, embryonic or fetal death, abortion, or early parturition. Decreased incidence of plant-induced livestock malformations may be accomplished through grazing management strategies. To develop these strategies one must understand some basic principles of toxicology and teratology such as susceptible livestock species, type of compound and concentration in the plant and its disposition in the animal, dose response, and the susceptible gestational period. Much of this information is known for certain plants; however, additional information will enhance our ability to control livestock losses from these plants. Certain criteria may be established to maximize grazing management methods to minimize teratogenic effects of poisonous plants. When the suspect plant grows in a restricted habitat, poses a hazard only at certain growth stages or when the susceptible period of pregnancy is relatively short, minor adjustments in management methods can be considerably successful in reducing incidence of malformations and subsequent financial loss.
Impact of poisonous plant on the livestock industryJames, L. F.; Nielsen, D. B.; Panter, K. E. (Society for Range Management, 1992-01-01)Livestock poisoning by plants is one of the serious causes of economic loss to the livestock industry. Losses can be classified as either direct or indirect. Direct losses include deaths, weight loss, abortions, lengthened calving intervals, decreased efficiency and other effects on the animals. Losses from death and some reproductive losses in the 17 western states are estimated at 340,000,000. In addition to these are the indirect losses such as fencing, herding, supplemental feeding, medical costs, management alterations, and loss of forage which are associated with efforts to prevent or minimize poisoning of livestock by plants. Nearly all plant communities include poisonous plants, thus, most grazing animals are exposed to intoxication. However, the presence of these plants does not cause poisoning. Poisoning is usually associated with management errors, lack of forage due to range conditions, drought, and other events that would cause Livestock to consume vegetation normally unacceptable. Often a sequence of events, such as storm, frost, cold, and other occurrences can influence an animal to where it will eat too much of a toxic plant too fast.
Larkspur chemistry: Toxic alkaloids in tall larkspursManners, G. D.; Pfister, J. A.; Ralphs, M. H.; Panter, K. E.; Olsen, J. D. (Society for Range Management, 1992-01-01)Three species of tall larkspur (Delphinium barbeyi (Huth), Delphinium occidentale (Wats.) Wats, and Delphinium glaucescens) that are toxic to cattle were chemically analyzed to determine “total alkaloid” content. D. barbeyi and D. occidentale contained more “total alkaloids” than D. glaucescens. The “total alkaloid” content of all plant tissues in the 3 species declined as the growing season progressed. Variation in the occurrence of specific diterpenoid alkaloids was established by gas chromatographic analysis of D. barbeyi plant tissues at different phenological growth stages. Highest yields of specific alkaloids were found in early growth stage plant tissues. Deltaline was the most prominent diterpenoid alkaloid in D. barbeyi and 14-0-acetyldictyocarpine is a new diterpenoid alkaloid with high occurrence in this plant. The toxicity of specific diterpenoid alkaloids obtained from the tall larkspurs evaluated in a mouse bioassay showed methyllcaconitine to be highly toxic. Other diterpenoid alkaloids isolated from the 3 Iarkspurs showed much lower levels of toxicity compared to methyllycaconitine