Page 900 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

Poisonous Plants of the United States Chapter | 61 855

VetBooks.ir simple piperidine from poison hemlock, and anabasine 0.40 Anagyrine in plants and Lupine in diets 40
(6), a simple piperidine from tree tobacco (Nicotiana
Lupine in diet
glauca), induced the same defects in cattle, sheep, and
goats. Although comparative studies support the hypothe- 0.35 Anagyrine in plant
sis that the cow may metabolize the quinolizidine anagyr- 0.30 20
ine to a complex piperidine, evidence regarding the Anagyrine % 0.25 % of bites
absorption and elimination patterns of many of the quino-
lizidine alkaloids, including anagyrine, in cattle, sheep, 0.20 0
susceptible
and goats does not support the metabolism theory
0.15 breed dates period
(Gardner and Panter, 1993). This research is currently
ongoing at the Poisonous Plant Research Laboratory. A 6/6 6/20 7/4 7/18 8/1 8/15
review of lupine-induced cases of crooked calf syndrome
reported to the Poisonous Plant Research Lab during the FIGURE 61.5 The relationship between the concentration of the terato-
gen anagyrine in the plant and the amount of lupine in the diets of cattle
past 20 years can be found in Lee et al. (2007a).
during breeding and susceptible gestational stages.
Different lupines produce varying toxic syndromes in
a given species of livestock, apparently because the alka-
loid profile varies remarkably among species. Season and and seed pods may also have contributed to its lack of
environment influence alkaloid concentration in a given palatability. Once the seeds shattered in early July, the
species of lupine. Generally, alkaloid content is highest in alkaloid concentration declined, and the cows began
young plants and in mature seeds. Alkaloids are not lost selecting lupine. Figure 61.5 shows the overlap of lupine
upon drying, so wild hay may be highly toxic if young consumption with the susceptible period of gestation, in
lupine plants or especially seed pods are present. For relation to the anagyrine concentration in the lupine
many lupines, the time and degree of seeding vary from plants. Cattle selected velvet lupine in July after cheat-
year to year. Most losses occur under conditions in which grass and other forbs matured.
animals consume large amounts of pods in a brief period, The abundance of lupine is another factor influencing
such as when they are being driven through an area of the amount of lupine consumed. Lupine population cycles
heavy lupine growth, unloaded into such an area, trailed are influenced by weather patterns. Catastrophic losses
through an area where the grass is covered by snow but from lupine-induced crooked calves occurred in the
the lupine is not, or when feeding lupine hay when lupine Channel Scabland region of eastern Washington in 1997.
is in the pod stage, which apparently is palatable. Most Annual precipitation from 1995 to 1997 was 33% above
serious poisonings may occur in the late summer or early average, initiating an outbreak of lupine throughout the
fall because lupine remains green after other forage has region. The density of velvet lupine plants has declined
dried and seed pods are present. Once the poisonings since then (Ralphs, unpublished data), and the incidence
were understood, the practice of harvesting lupine hay for of crooked calves has returned to what has become an
winter sheep feed was discontinued. acceptable tolerance of 1 5% incidence.
Clinical signs of poisoning are those of muscular
weakness (neuromuscular blockade) beginning with
Cattle Grazing nervousness, frequent urination and defecation, depres-
Lupine is not very palatable to cattle, although it has been sion, frothing at the mouth, relaxation of the nictitating
considered fair to good quality feed on some ranges that membrane, ataxia, muscular fasciculations, weakness,
are heavily utilized. Its palatability or acceptability lethargy, collapse, sternal recumbency followed by lateral
depends on availability and maturity of other forage. In a recumbency, respiratory failure, and death. Signs may
grazing study of velvet lupine (L. leucophyllus) on annual appear within 15 min to 1 h after ingestion or as late as
cheatgrass ranges in eastern Washington (Ralphs et al., 24 h depending on the amount and rate of ingestion.
2006), cows selected lupine in July and August after Death usually results from respiratory paralysis.
cheatgrass dried and other forbs were depleted or matured The incidence of crooked calves is variable geographi-
and became rank. The deep-rooted lupine remained green cally and from year to year within a given herd. Up to
and succulent longer into the summer than the other for- 100% of a given calf crop may be affected, and indivi-
age. Lupine was higher in crude protein and lower in fiber duals may be more severely affected than others. Affected
(NDF) than the other forages throughout the season (the calves are generally born alive at full term. Dystocia may
crude protein level in foliage was 15%, and in seeds it occur when calves are severely deformed and assistance
was 36%). However, the thick, velvety pubescence was is required, often by cesarean section.
believed to be partially responsible for its lack of palat- Arthrogryposis is the most common malformation
ability. The high alkaloid concentration in the floral parts observed and is often accompanied by one or more of the