Lupine-induced Crooked Calf Disease and a Management Method to Reduce Incidence

RICHARD F. KEELER, LYNN F. JAMES, JAMES L. SHUPE, AND KENT R. VAN KAMPEN

Highlight: Crooked calf disease is produced when pregnant cnws between the 40th and 70th days of gestation graze certain members of the genus Lupinus that contain the qninolizidine alkaloid anagyrine. Calves born to these cows may have twisted or bowed limbs (arthrogryposis), twisted or bowed spine (scoliosis or kyphosis), twisted neck (tortieollis), cleft palate, or a combination of any of these. The concentration of the teratogen anagyrine in these lupines is very high early in growth, decreases to a low level during flowering, rises abruptly in mature seeds, and decreases tn a very low level after seeds have dropped. Data collected from 6 ranches for 8- to 25year periods showed no consistent correlation between incidence of the disease and the free-choice feeding of a variety of mineral supplements. Marked variation in incidence did occur, however, during these peridds. The variation was related to the period of gestation at which the cows grazed the lupine and to the stage of growth of the lupine-in other words, the amount 01 anagyrine ingested. Management programs that prevent pregnant cows from eating highly teratogenic early growth or seed-stage lupine plants between gestation days 40 and 70 will reduce crooked calf disease incidence.

Maternal ingestion of certain lupines has long been suspected (Wagnon 1960) and more recently experimentally shown (Shupe et al. 1967~1; 1968) to cause congenital crooked calf disease. The disease is characterized by twisted or bowed limbs (arthrogryposis), twisted or bowed spine (scoliosis or kyphosis), twisted neck (torticollis), cleft palate, oracombinationofanyof them. Generally the disease affects less than 10% of a herd, hut incidence varies with the year, area, and herd (Shupe et al. 1967a; 1967b).

Because of the serious economic problems the disease causes, ranchers have long sought ways to reduce the incidence or eliminate the disease. Many believed it to be an hereditary condition and changed bulls and sacrificed affected animals and yet could not reduce the incidence. Others have advocated that mineral supplementation would reduce the incidence. Burkett (1959), for example, suggested that proper mineral nutrition prevented the disease in Montana. But much of the strong advocacy has been passed by word of mouth, and only a few ranchers who have had problems with this disease have not tried some form of supplementation. Advocates generally have believed that a “healthy” cow will be less susceptible and less likely to eat the plants. With the exception of the suggestion and experimental work by Dyqet al. (1964), who showed that a

manganese deficiency could produce symptoms similar to at least some of the crooked calf symptoms, no experimental data have pointed to a specific mineral deficiency.

An alternative approach to reduction of incidence of the disease can now be taken. The strategy is based on identification of the active principle (teratogen) in the plant, understanding of it? concentration in plant parts as a function of plant growth stage, knowledge of the insult period (or the gestational age at which the developing fetus is adversely affected by the terato- gen) in pregnant cows, and ability to recognize the clinical signs of the disease.

In this report we review publisheddataonclinical signsof the disease, insult period susceptibility, information on the active principle, and the concentration of the teratogen in plants as a function of plant growth stage. We also report information we have collected from various field trial mineral supplementation programs advocated by others to reduce disease incidence from anumberof ranch sources over an 8- to 25-year period. Finally, on the basis of the data, we suggest range utilization practices unrelated to supplementation which will reduce the incidence of crooked calf disease.

The Disease

Clinical Signs Crooked calf disease is characterized grossly by congenital

malformations of the skeletal system (Shupe et al. 1967b). Arthrogryposis is the most commonly observed malformation (Fig. 1). Elbow joints are often immobile because of mal- positioning and malalignment of the ulna with the xticular surfaces of the distal extremity of the humerus. The part of the limbs distal to the elbow joint is often rotated laterally. Such deformed joints are flexed and cannot be extended, even after the flexure tendons are cut. Therefore, arthmgtyposis of cmoked calf disease is unlike the condition referred to as contracted tendons, in which joints are all in proper alignment without lateral or medial rotation. With contracted tendons, the affected limbs can be extended with pressure or can usually be corrected surgically. Most calves born with contracted tendons

recover spontaneously. In crooked calf disease, the osseous changes observed are permanent and generally become progres- sively worse as the calf grows and its limbs are subjected to greater load-bearing stress. Torticollis (Fig. 2), cleft palate, and scoliosis (Fig. 3) arc occasionally observed also in crooked calf disease. The spinal curvature in the torticollis and scoliosis forms of the disease results from vertebral wedging or rotation of the vertebral column, and recovery is not spontaneous.

Etiology and Insult Period Wagnon (1960) reported that production of congenital de-

formities in calves was thought by California ranchers to be due to maternal ingestion of Lupinus laxflorus. He continued as follows:

Deformed calves are most likely to be produced by cows bred in July then poisoned in late August. The incidence of congenital de- formities has been highest with heifers at first calving, but has occurred with females of all ages. It has been reported that setting the breeding season ahead two months from July to May and moving cattle out of lupine areas are effective prevention pm- cedures. Cattle apparently show no interest in this lupine until the seed pods are well formed, usually during later August. The seed pods and plant tops are extensively fed upon.

However, his feeding trials of lupine to pregnant cows failed to produce the disease.

Our own feeding trials of various plants, including lupine and certain other preparations, finally culminated in establishing that lupine could indeed produce crooked calf disease. Trials in 1964 and 1965 in which pregnant cows were fed Lupinus sericeus or L. caudatus produced a number of crooked calves. We were able to establish that the most susceptible gestational period (insult period) of the fetus was from the 40th to the 70th day of gestation (Shupe et al. 1967~1; 1968). Deformities at periods that did not include at least some of the 40th to the 70th days were only questionable or very modest.

Active Principle (or Teratogen)

Information from Epidemiological Correlations We instituted a program some years ago to identify the active

principle or teratogen from the plant. Nearly all lupines are classified as poisonous plants because of their high content of toxic alkaloids. Alkaloids were therefore attractive to US as mssible temtogens among the various compound classes from ihe plant. -

We had collected a few hundred luvine Dlant samoles over a number of years and had records co&ming their relationship to crooked calf disease. We believed that if an alkaloid were responsible, then we should be able to see a correlation between the presence or concentration of individual alkaloids and the ability to produce crooked calf disease.

We compared by gas chromatography lupine alkaloid distri- bution among members of the genus Lupinus that produced crooked calf disease experimentally with those that failed to do so. We further compared distribution in plants from areas where the disease is common with those from areas where the disease is not known. Alkaloid separation pattern similarities in all active plants were not shared by inactive plants. Four major alkaloid peaks were generally present (Fig. 4) in active samples, but peak 4 was the only one invariably present in active plants and invariably absent or of low concentration in inactive ones (Keeler 1973~1). That peak proved to be anagyrine (Fig. 5) by chemical analysis (Keeler 1973b).

Identification of the Teratogen by Feeding Trials Each year for a number of years, we have been preparing

lupine plant extracts and fractionated material for feeding trials in pregnant cows in an effort to isolate and then identify the teratogen. During some of,those years, the experimental design was such that the preparemom contained alkaloids. During the fmal 3 years, when it has become probable from the epi- demiologic information mentioned that alkaloids were respon- sible, experiments were specifically designed to obtain alka- loids.

These experiments finally established (Keeler 1976) that alkaloid extracts from teratogenic lupines did indeed produce crooked calf disease when the extracts were administered to cows during the susceptible gestational period (Fig. 6). The data allowed the conclusion that the alkaloid anagyrine was in all probability the teratogen because preparations rich in that alkaloid were active whereas the other alkaloids fed to other cows had not been active. The preparations were essentially devoid of nonalkaloidal contaminants. Thus, both feeding trials and epidemiologic evidence ascribed the teratogenic propensity to anagyrine. In the various preparations administered, the severity of the malformation was directly related to the level of anagyrine present.

Variability of Teratogen Concentration in the Plant Very few of the lupines growing in western United States that

were tested contained significant amounts of the teratogen anagyrine (Keeler 1973a). Our chemical analysis has shown, however, that L. sericeus, L. caudatus, and two or three others do (Keeler 1973b). We believed that if concentration of the teratogen in the plant varied as a function of plant maturity, that fact might be exploIted in range utilization inasmuch as cows were principally susceptible at only a specific gestational period (40th to 70th days). Thus, cows could be prevented from grazing lupine during the susceptible period if teratogen content in the plant were high. The possibility that content might vary seemed good because Wagnon (1960) had reported on seasonal vanation in incidence of the disease and our own unpublished observations suggested the same.

We collected teratogenic lupines from four areas where the disease is common. The collections were made of various plant parts and of various stages of plant maturity during two separate

yearly growing seasons. We measured the concentration of total and individual major alkaloids in these collections, especially the teratogen anagyrine. Concentrations of all alkaloids, in- cluding anagyrine, were high in above-ground parts early in gmwth and decreased markedly as plants matured, except for an

increase in mature, intact seeds. Concentrations in roots were lowest; those in mature leaves and stems were only slightly higher. Therefore, a pregnant cow in the susceptible gestational period runs the greatest risk when grazing teratogenic lupine early in growth or during seeding. Early flowering and post- seeding stages are of low hazard (Keeler et al. 1976).

Mineral Supplementation

We have followed with considerable interest the experience of six ranches with a history of crooked calf disease. We have compiled a record of disease incidence, free-choice supple- menta,tion practices, and other management programs related to the etiology of the disease from personal interviews with the ranchers and with public land managers in the affected areas. In the discussion that follows, the ranches are identified as ranches one through six because of a desire for anonymity on the part of most of the SIX ranchers. The ranches are located in three states-Oregon, Montana, and Idaho.

Table 1. Crooked calf incidence and management-Ranch 1.

Grazing year

No. of Deformed cows calves Supplementation program** Other management parameters

1955 38 0 Trace mineralized salt, 20,OOOIU vit. A/lb, cake M

1956 59 9 1957 59 6 1958 59 0 1959 90 8 l%O 90 0 l%l 155 2 1%2 155 3 1%3 155 8 1964 177 10 1%5 243 27 1%6 259 8 1%7 282 19 1%8 285 10 1%9 278 10

1970

1971 287 3 1972 59* 1 1973 102 0 1974 120 0

251 0

t, I, I,

I,

” (+0.015% I, 10% yeast), 5&X)0 IU vit. A/lb I,

‘r I, I, I, I, l&O0

I, ,,

I, I, ,I I, ,, r, v I,

I,

Same as 196; + special mineral mix # 1 ,, +20,000 IU vit. E

Same as 1963 + special mineral mix #2 No mineral therapy program - salt + cake M

,I I, ,, ,, ” + cake T !I I, #I

I, I, t,

I, !I

I, n

t, ,,

I, !I

*Owner had heart attack and had to reduce herd in 1972.

**Trace mineralized salt approximate composition = 98% NaCI, 0.3% Zn, 0.3% Mn, 0.2% Fe, 0.04% Cu, 0.01% I, 0.01% Co. Cake M = a pellet of wheat, barley, hay protein, binder, vitamins A and D added, I% P; 100% of daily requirements of Zn, Mg, Mn, Co, Fe, Cu, I per I.5 lb of pellets. Cake T = a pellet of grain, corn, hay, urea, protein, and NaCI.

Special mineral mix #I = IO% Mn, IO% Zn, IO% Fe, 1% Cu. 0. I% I, 0. I% Co, balance as NaCI. Special mineral mix #2 = 13.2% Fe, 26.4% Zn, 3.3% Cu. 0.066% 1, 0.066% Co, 13.2% Mn, balance as NaCI. All supplements available year round.

40-70 gestation day; cows had ready access to young lupine

I,

u

40-70 gestation day cows allowed less access to lupine + spraying lupine

Data from each of these ranches and various aspects of management as they related to incidence are reported. The common conclusions that we draw from the experience of these six ranches are: (1) incidence was highly variable from year to year; (2) variation in incidence was unrelated to mineral supple- mentation programs; and (3) incidence was related to abundance of lupine (amount grazed), level of teratogen in the plant, and gestational stage of cows when they ingested it. Ranches 1 and 2 are considered separately but ranches 3 through 6 are considered together because all use a common public land allotment.

Ranch 1

gestation at about the time the lupine is at its most teratogenic

stage (young plant) and, until recent years, had unrestricted access to the plant at that time.

Ranch 2

Data from Ranch 1 are reported in Table 1. The records cover a 20-year period during which time the rancher built his herd from 38 to 287 cows in 197 1. He had to reduce his operation to 59 cows in 1972 because of a heart attack. In his initial encounter with crooked calf disease in 1956, he assumed a genetic cause and replaced his bulls, to no avail. Subsequently, in 1958 and for a few years thereafter (through 1963), he added iodine and yeast and increased the vitamin A content of his trace mineralized salt mixture; and he added vitamin E in 1963. Incidence was variable, regardless of supplementation. In 1964 and 1965, he fed two separate special high manganese mineral mixes on the supposition that the disease was a manganese deficiency. The mineral mixes did not help. From 1966 to date, he has had no specific mineral therapy program. During the first 4 years of no mineral therapy, incidence averaged about the same as that in previous years. But during the last 5 years, his incidence has been very low. He ascribes this low incidence to the fact that he allows cows less access to lupine when they are in the 40th to 70th days of gestation. He has accomplished this by a more restrictive use of pastures with abundant lupine and by a program of herbicide treatment (2,4-D and 2,4,5-T) to kill lupine in the abundant areas. His cows average 40 to 70 days of

Data from Ranch 2 are reported in Table 2. The records cover a 25-year period during which the rancher grazed from 39 to 70 COWS on the lupine-abundant range (except in 1971 when only 10 animals were allowed access to that range area). At this ranch, the grazing period on lupine areas has centered around the seeding period of the plant rather than the early growth period as with Ranch 1.

During the 25-year period, incidence varied rather spectacu- larly and was sometimes very high, regardless of the supple- mentation (including phosphorus supplementation for an alleged phosphorus deficiency), except that for the years 1971-74 no crooked calves were born during the time mineral mix B was fed. One might conclude that mineral mix B was effective, but another conclusion emerges from the data. Although variable, the disease occurred only during years when cows were turned to the grazing areas when they averaged the 40th to 50th gestations days (meaning that many were grazing the plant when in the hazardous 40- to 70-day period). No crooked calves were born in years when cows were turned to the range when they averaged the 78th day of gestation and most were consequently beyond the susceptible gestational period. Furthermore, when cows were turned out on the 78th day (about September 28), the plant was usually past the hazardous seeding stage. Seed pods had shattered, seeds had dropped, and the plant was no longer a hazard. Thus the apparent efficacy of mineral mix B in the years 1971-74 might rather be related to susceptible gestation period and plant hazard. Data reported below show directly that the same mineral mix B was not efficacious.

100 X)URNAL OF RANGE MANAGEMENT 30(2), March 1977

Table 2. Crooked calf incidence and management-Ranch 2.

Grazing No. of Deformed Turnout year cows calves date* Supplementation program** Observations on status of lupine

1950 70 1951 70 1952 70 1953 70 1954 45 1955 45 1956 60 1957 50 1958 50 1959 50 1960 45 1961 39 1962 45 1963 55 1964 55 1965 55

1966 55 0 1967 55 0 1968 55 0 1969 56 25 1970 50 12 1971 10 0 1972 55 0 1973 55 0 1974 55 0

2 3 8

14 18 3 6 3

0

402 15 I, I, U ,, l, U ,I I, I, I, I, I, l, U I,

I,

78 ? 15 I,

50* 15 r,

78 + 15 l, I, I,

salt rr I, r,

Trace mineralized block salt I, ,I

Trace mineralized loose salt % trace mineralized salt, r/z dicalcium phosphate ‘/z trace mineralized salt, ‘/2 plain salt +$ trace mineralized salt, ‘/3 dicalcium phosphate

,I l, r, ,I

Trace mineralized block + sodium triphosphate, organic I (0.5%)

I, V ,I I,

Mineral mix A Mineral mix B

l, I, ,I

Drouth year; sparse lupine Lupine beyond seed stage

I,

Lupine in seed l,

Lupine beyond seed stage U !I V

* Approximate beginning gestation day when turned onto hazardous range area; 40th gestation day corresponds to 20th Aug., 50 to 30th Aug., 78 to 28th Sept. turnout dates. Gestation day figures represent the range in which 90% of the COWS fall.

**Trace-mineralized salt and block approximate composition = 98% NaCI, 0.3% Zn, 0.3% Mn, 0.2% Fe, 0.04% Cu. 0.01% I, 0.01% Co. Mineral mix A = P (as Na,P ,O,,,) 4.8%. 10.01%. Co 0.05%, Cu 0.25%. flavor (anise) 0.5%. corn oil 0.5%. molasses 18, rolled barley 5.09, NaCl about 75%. vitamin A 20,000

IU/lb. Mineral mix B = same as A, but I increased to 0.4%, corn oil increased to 1.0%. (1950-64-supplemented on range only; l965-74-supplemented year-round.)

Ranches 3-6 date of cows was about May 15. Hence, cows were in the W area Data from ranches 3 through 6 for an 8-year period are

reported in Table 3. These four ranches shared a public land allotment for 490 cows. Over 95% of the allotment was divided into two separate areas designated W and TC. Data from these two areas are reported here.

The long-standing custom had been to graze these two areas as follows: The W area was grazed from June 1 to August 1, and the TC area thereafter. This program had been considered best for water availability and range utilization. Average breeding

from an average of the 15th to 75th days of gestation and in the TC area thereafter. The W area has a very abundant stand of lupine and it is in early growth stage (highly teratogenic) during June and early July, whereas the TC area has much less lupine. Thus, cows in the susceptible gestation period were in an area of highly abundant, highly teratogenic lupine. The years 1967 and 1968 indicate the usual consequences. Crooked calf disease incidence was variable, but was as high as 23%.

In 1969, two changes were instituted: (1) a mineral mix was

Table 3. Crooked calf disease incidence and management-Ranches 3, 4, 5, and 6. -_

Ranch 3 (76 cows) Ranch 4 ( 100 cows) Ranch 5 (119 cows) Ranch 6 ( 195 cows)

Management*** Management Management Management

Supple- Disease Area Disease Area Disease Area Disease Area Year ment* incidence** grazed Lupine incidence grazed Lupine incidence grazed Lupine incidence grazed Lupine

1%7 salt 12% W abundant 23% W abundant 15 % W abundant 15% W abundant I%8 salt 7 W abundant 22 W abundant 4 W abundant 3 W abundant 1%9 mixA 3 TC sparse 0 TC sparse 0 TC sparse 15 W abundant 1970 mixB 14 W abundant 9 W abundant 13 W abundant 0 TC sparse 1971 nlixc 30 W abundant 30 W abundant 4 W abundant 18 W abundant 1972 n 0 TC sparse 2 TC sparse 2 TC sparse 2 TC sparse 1973 rJ 0 TC sparse 2 TC sparse 0 TC sparse 0 TC sparse 1974 ” 0 TC sparse 4 W/TC abundant/ 0 TC sparse 0 TC sparse

(% on ea.) sparse

*Mix A = P (as Na,P,Oro) 4.8%, J O.Ol%, Co 0.05%, Cu 0.25%, flavor (anise) 0.5%, corn oil 0.5%, molasses I%, rolled barley 5.0%, NaCl about 75%, vitamin A 20,000 IU/lb.

Mix B = Same as A, but I increased to 0.4%, corn oil increased to 1 .O%. Mix C = Same as A, but ‘/2 lb organic iodine added/ton, and 30,000 IU vitamin A/lb rather than 20,ooO units.

(1969 and 1970 supplements fed for 30 days before the grazing period: 1971-1974 supplement fed year-round.)

**Disease incidence calculated as follows: crooked calves

x 100 = % incidence. # cows

***Breeding usually began about May 1 and cows were turned onto range about June I. Beginning gestation day when cows were turned to the range was therefore about 15 T 15 days. TWO principal grazing areas were available in the allotment; area W, a high hazard area with an abundance of lupine of early growth late in June and early July; and area TC, with much less lupine.

JOURNAL OF RANGE MANAGEMENT 30(2), March 1977 101

fed before cows went on he range; and (2) only Rancher 6 had cows grazing the W area during the 15th through 75th gestation day period, while the other three ranchers had cows grazing the TC area. In 1970, the mineral mix was changed slightly, and the grazing arrangement was reversed. Ranchers 3, 4, and 5 had cows grazing the W area and Rancher 6 had cows on the TC area. The incidence of the disease in animals grazing the W area was high in both years and incidence in animals grazing the TC area was very low. Use of neither mineral mix A nor B was related to incidence.

During 1971-74 while mineral mix C was fed, the incidence of the disease was high any time the cows grazed the W area during susceptible gestational periods (all ranches in 1971 and one-half of animals from Ranch 4 in 1974) and very low when animals grazed the TC area during the susceptible gestational period. Mineral mix C was not efficacious.

Supplement Feeding Conclusions

Though the data do not prove that no mineral mix that can be conceived will ever reduce crooked calf disease incidence, they nonetheless suggest that the mixtures used by the six ranchers were not responsible for variation in incidence from year to year. The more plausible explanation, it seems to us, is that variation in incidence was related to susceptible gestation period and relative plant hazard (teratogen level) considerations.

Because the hope is so widespread that mineral supplementa- tion will reduce incidence of crooked calf disease, it seems appropriate to consider the basic premises on which this belief tests. In fact, the common hope is that a wide variety of problems that plague livestock can be corrected “if just the right supplement can be found.” These hopes are based on various premises-some sound, and some unsound. Among the prem- ises that underlie hopes that supplements will reduce crooked calf disease incidence are the following: (1) Animals are deficient in some mineral element and the lupine is high in that element. Animals correct the mineral deficiency by seeking a source of that mineral because they have an alleged “depraved appetite.” The plant supplies the mineral; but if animals are supplemented, they will not eat the plant. (2) Supplementation somehow induces animals to change their grazing habits and eat less lupine, not by supplying a deficient mineral, but simply by changing their taste preferences. (3) If the rumen microflora were sufficiently active, they would degrade the lupine toxin (teratogen). Supplying a mineral supplement enhances this rumen activity. (4) Lupine contains a metabolic analog. Supple- mentation supplies an element that reverses this antagonism, or competitive inhibition.

No sound scientific evidence is available that any of these premises apply in the lupine-induced crooked calf disease. Each rests upon a hope that “losses” can be prevented. When it is shown experimentally that a specific mineral element does satisfy the alleged “depraved appetite,” does change grazing habits, does enhance rumen degradation of the teratogen, or does reverse an as yet unidentified antagonism, then supple- mentation will be warranted. Hope must not lie with supple- ments simply because they can be fed.

Successes claimed or failures from various mineral supple- mentation programs to reduce incidence of crooked calf disease can be traced, we believe, to the level of teratogen ingested by

the dam during the susceptible period and not to the supplements themselves.

Management to Reduce Incidence

On the basis of data reviewed herein, now that the teratogen is known and assuming one’s ability to recognize the clinical signs, the best available strategy for reduction of the incidence of crooked calf disease lies in capitalizing on the knowledge of susceptible gestation period and variation of concentration of the teratogen in lupine as it matures.

Table 4. Crooked calf disease hazard from grazing teratogenic lupines.

Hazard Average gestation period Stage of growth of lupine

Maximum 4Oth-70th day Before flowering and mature seed

Minimum Before 40th or after 70th day Early flower and post-seed

The significant data are summarized in Table 4. The hazard is maximum when either young lupine or else lupine in mature seed stage is grazed by cows whose average stage of gestation is between the 40th and the 70th day. The hazard is minimum when lupine of either early flower or post-seed stage is grazed by COWS whose average stage of gestation is either earlier than the 40th or later than the 70th day. As management programs are devised in areas with a history of crooked calf disease, a reduction in incidence can be expected by striving for the minimum hazard conditions (1) by suitable arrangement of time periods for grazing, (2) by advancing or delaying breeding periods, (3) by a range program (such as spraying) to reduce the abundance of lupine, or (4) by a combination of the above. The remaining viable alternative requires that the range be foraged by nonpregnant stock only-an alternative that may not be open in some management situations.

Literature Cited

Burkett, W. H. 1959. Improve your roughage with phosphorus nutrition. Northwest Livestock Directory, Western Livestock Reporter, Billings, Mont.

Dyer, I. A., W. A. Cossett, Jr., and R. R. Roa. 1964. Manganese deficiency in the etiology of deformed calves. Bioscience 14:31-32.

Keeler, R. F. 1973a. Lupin alkaloids from teratogenic and nonteratogenic lupins. I. Correlation of crooked calf disease incidence with alkaloid distri- bution determined by gas chromatography. Teratology 7:23-30.

Keeler, R. F. 197313. Lupin alkaloids from teratogenic and nonteratogenic lupins. II. Identification of the major alkaloids by tandem gas chromato- graphy-mass spectrometry in plants producing crooked calf disease. Teratol- ogy 7:31-36.

Keeler, R. F. 1976. Lupin alkaloids from teratogenic and nonteratogenic lupins. III. Identification of anagyrine as the probable teratogen by feeding trials. J. Tox. Environ. Health (in press).

Keeler, R. F., E. H. Cronin, and J. L. Shupe. 1976. Lupin alkaloids from teratogenic and nonteratogenic lupins. IV. Concentration of total alkaloids and individual major alkaloids particularly anagyrine, the probable teratogen in crooked calf disease, as a function of plant part and stage of growth. J. Tox. Environ. Health (in press).

Shupe, J. L., W. Binns, L. F. James, and R. F. Keeler. 1967a. Lupine, a cause of crooked calf disease. J. Amer. Vet. Med. Ass. 151:198-203.

Shupe, J. L., L. F. James, and W. Binns. 1967b. Observations on crooked calf disease. J. Amer. Vet. Med. Ass. 151:191-197.

Shupe, J. L., W. Binns, L. F. James, and R. F. Keeler. 1968. A congenital deformity in calves induced by the maternal consumption of lupin. Aust. J. Agr. Res. 19:335-340.

Wagnon, K. A. 1960. Lupine poisoning as a possible factor in congenital deformities in cattle. J. Range Manage. 13:89-91.

102 JOURNAL OF RANGE MANAGEMENT 30(2), March 1977