Research NotesConsumption of Low Larkspur (Delphinium nuttallianum) by Grazing Sheep
Section snippets
INTRODUCTION
Low larkspur (Delphinium nuttallianum Pritz.) poisoning causes serious economic loss to livestock producers grazing cattle in the western United States and Canada (Pfister et al. 1999; Pfister et al. 2003). Cattle death losses to larkspur are estimated to be 3% to 15% annually in areas where larkspurs are abundant (Nielsen et al. 1994). Low larkspurs contain a number of toxic diterpenoid alkaloids, including the primary toxic alkaloid, methyllycaconitine (MLA). The risk of poisoning is related
Animals and Management
The sheep used in these studies were one-year-old crossbred white-faced ewes raised at the US Sheep Experiment Station near Dubois, Idaho. These animals likely encountered low larkspur (D. nuttallianum) as lambs grazing on mountain rangelands near Dubois, Idaho. In all studies, sheep were introduced into experimental pastures when low larkspur was in full flower. Bite counts (% of bites) were used in all studies to document diet selection. Beginning at 0700 every day, individual animals were
Trial 1: Collbran, Colorado (2001)
Sheep ate very small amounts of low larkspur (0.4% of bites as low larkspur); other forbs and grasses comprised 64% and 35% of sheep bites, respectively. There was no effect (P > 0.8) of low larkspur density on sheep bites of low larkspur (data not shown). The toxic alkaloid concentration in low larkspur was 1.5 mg · g−1 (dry weight). Forage availability for all trials and locations is given in Table 1.
Trials 2 and 3: Soda Springs, Idaho (2004 and 2005)
There was no effect (P > 0.6) of plant phenology on low larkspur consumption by sheep (data
DISCUSSION
There are no documented losses of sheep to tall or low larkspur; thus there has been continual interest for many years by livestock producers with persistent cattle losses in using sheep to reduce risk for subsequent cattle grazing in larkspur-dominated areas. Marsh et al. (1934) reported anecdotally that sheep eat low larkspur in quantities sufficient to reduce risk to cattle, but did no research on the subject. Ralphs et al. (1991) found that sheep consumption of three different tall larkspur
IMPLICATIONS
Under free-grazing conditions, sheep ate very little low larkspur during four grazing trials. The use of sheep to graze low larkspurs to reduce subsequent consumption by grazing cattle does not appear to be a viable option. Our observations suggest that sheep can be used to trample dense low larkspur populations.
Acknowledgments
We express our thanks to Kermit Price and Ed Knoppel for their excellent assistance with the study, and to the Animal Caretakers at the Poisonous Plant Research Laboratory, Al Maciulis, Rex Probst, and Danny Hansen, for their help with animal management and transport.
LITERATURE CITED (21)
- et al.
Toxic alkaloid concentrations in low and plains larkspurs (Delphinium spp.)
Rangeland Ecology and Management
(2007) - et al.
Ethylene production and enhanced transcription of an ethylene receptor gene, ERS1, in Delphinium during abscission of florets
Plant Physiology and Biochemistry
(2003) Conditioning sheep to graze duncecap larkspur (Delphinium occidentale)
Rangeland Ecology and Management
(2005)Eradicating tall larkspur on cattle ranges in the national forests
USDA Farmers Bulletin 826
(1917)Observational study of behavior: sampling methods
Behaviour
(1974)- et al.
Role of toxins in intake of varied diets by sheep
Journal of Chemical Ecology
(2000) - et al.
Effects of Delphinium alkaloids on neuromuscular transmission
Pharmacology and Experimental Therapeutics
(1999) - et al.
Analysis of toxic norditerpenoid alkaloids in Delphinium species by electrospray, atmospheric pressure chemical ionization, and sequential tandem mass spectrometry
Journal of Agriculture and Food Chemistry
(1999) Alkaloid levels in a species of low larkspur and their stability in rumen fluid
Journal of Range Management
(1993)- et al.
Larkspur poisoning of livestock
USDA Bureau of Plant Industry Bulletin 365
(1916)
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2020, Rangeland Ecology and ManagementCitation Excerpt :Clearly, patchy larkspur kills and nonpatchy larkspur does not. Despite occasional observations in the literature of the patchy growth of most dangerous larkspur species (Kotliar 1996; Pfister et al. 2010), this is a novel conclusion. Results for larkspur-forage overlap ran counter to our hypothesis.
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