Page 896 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

852 SECTION | XIV Poisonous Plants

VetBooks.ir Herbicidal Control
Larkspur losses can be greatly reduced if dense larkspur
populations are reduced by herbicides. Picloram, metsulfur-
on, and glyphosate have proven to be effective in killing
tall larkspurs when applied at specific growth stages
(Ralphs et al., 1991). These herbicides do not reduce toxic
alkaloid concentrations in treated larkspur plants, and met-
sulfuron may increase toxicity. Therefore, sprayed areas
should not be grazed until the following growing season.

LUPINES (LUPINUS SPP.)

The Lupinus genus contains more than 150 species of
annual, perennial, or soft woody shrub lupines. More than
95 species occur in California alone. The lupines are rich
in alkaloids, responsible for most of the toxic and terato-
genic properties. There are domestic lupines that through
plant breeding are low in alkaloid content and have been
FIGURE 61.4 Lupinus leucophyllus.
selected for ornamental purposes or for animal and human
food. Only those range lupines known to cause poisoning
neither the annual nor the woody species have been
or birth defects are discussed here.
reported in livestock poisoning.
Stockmen have long recognized the toxicity of lupines
Chemical profiles (chemo-taxonomy) can support or
when livestock, particularly sheep, were poisoned in the
contradict taxonomic identification, and this is a valuable
fall by the pods and seeds of lupine. Major losses in sheep
resource if included in a voucher specimen, especially if
were reported in the 1950s, and individual flock losses of
the identified species is implicated in toxicoses or terato-
hundreds and even thousands were reported. Lupines are
genicity and is identified by geographical location. Cook
also poisonous to other livestock, and field cases of poi-
et al. (2009b) demonstrated this variability in a single spe-
soning in cattle, horses, and goats have been reported.
cies, Lupinus sulphureus, which is yellow lupine species,
However, the most recognized condition of lupine inges-
selected from herbaria or collected from different geo-
tion is the “crooked calf syndrome,” a congenital condi-
graphical regions of Oregon, Washington, and British
tion in calves resulting in skeletal contracture-type
Columbia. A total of seven distinct alkaloid profiles were
malformations and cleft palate after their mothers have
reported, and each alkaloid profile was unique in its geo-
grazed lupines during sensitive periods of pregnancy
(Panter et al., 1999a,b). The condition was first reported graphical distribution and its potential risk to livestock.
in 1959 and experimentally confirmed after large out- A collection near Pendleton, Oregon, came from a popu-
breaks in Oregon and Montana in 1967. lation that was responsible for a significant outbreak of
crooked calf syndrome in a herd of cattle (56% loss) and
the alkaloid profile showed high levels of the teratogen
Description anagyrine (Panter et al., 1997). Therefore, taxonomic clas-
sification without chemical support is of little value in
Lupines belong to the Leguminosae family, with alternate
predicting risk of crooked calf syndrome.
palmately compound leaves with 5 17 oblong to lanceo-
late leaflets (Figure 61.4). Flowers are terminal legume-
like and can be blue, purple, white, yellow, or reddish. Distribution
The seeds are flattened in legume-like pods. Range
lupines are generally low, perennial or annual forbs, and Most species of lupines grow in states and provinces from
species and varieties are taxonomically difficult because the Rocky Mountains westward. They are classified as
extensive hybridization occurs and the literature may be increaser species; that is, they increase in abundance fol-
somewhat confusing in this regard. lowing disturbance from overgrazing or fire, to the point
The plant grows early in spring, flowering in early to that they may dominate the plant community at times.
mid-summer, and forms pods in late summer or early fall. Their populations also cycle, increasing in wet years and
Seedlings may germinate in fall if temperature and mois- dying back during drought. Table 61.4 lists species
ture are conducive for seed germination. Some lupines are involved in toxicity and their common names, habitats,
annuals and others are woody and shrub-like; however, and geographical distribution.