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Goiter in Domestic Pigeons
Goiter in Domestic Pigeons W. F. HOLLANDER AND OSCAR RIDDLE Carnegie Institution of Washington, Department of Genetics, Cold Spring Harbor, N. Y. (Received for publication, July 5, 1945) INTRODUCTION
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a full grown hen would suddenly drop dead, or a rooster lose his voice. . . . " Welch (1928), speaking of conditions in Montana, stated, "Goiter in poultry is very common. Flocks with a very high percentage of it have been noted in goitrous areas. The enlarged thyroid, frequently as large as the thumb, is entirely concealed by the feathers, and so far we have not observed any bad effect on the health of these fowls. The owners of goitered flocks have always reported that egg production and general health were normal. We have attempted to determine whether congenital goiter existed among newly hatched chicks but have been unable to get the material to study. No losses have been reported, at any rate, from this cause." Welch devoted much attention to losses from congenital goiter in other livestock. Scharrer and Schropp (1932) and Zajtay (1934) conducted studies on goiter districts in Europe and reported improved hatchability following the use of iodine supplement. Johnson, Pilkey and Edson (1935) made similar tests in Minnesota and reported no benefit from iodine supplement; it seems not to be certain, however, that goiter existed in the fowls treated by these investigators. Wilgus and Gassner (1941) noted poor reproduction in fowls fed a goitrogenic diet. In addition, they stated " . . . chicks hatched from eggs of hens on the experimental ration which did not contain any meat scrap were very poor. Few survived the first week, even when fed a practical ration. Chick condition and viability were pro-
HE occurrence of "simple" goiter in pigeons, and its relation to weakness of offspring at the hatching stage, have been noted by the authors (1943) in a preliminary report. The present paper provides an adequate account of the observations and tests made on this topic. Goiter in domestic birds, particularly in the fowl, has been noted by a number of investigators, but its effect on reproduction has received very little attention. Kalkus (1920) states: "It has been repeatedly observed by individuals who dress poultry that adult chickens in goitrous districts [State of Washington] are commonly affected with goitre. . . . However, newly hatched chicks are apparently not affected or at least no trouble is experienced from this source by poultry raisers." On the other hand, Kalkus described in detail the difficulties of reproduction in goitrous livestock such as pigs, sheep and goats. Apparently the chief symptoms were debility and frequent hairlessness of the newborn goitrous young. Keith (1924) described very similar conditions in farm animals, including cows and horses, of Pemberton Valley, north of Vancouver, B. C. Regarding poultry he stated as follows: " . . . all brought into the valley appeared to thrive; but their eggs, though producing embryos, failed to hatch out, the apparent cause being the thickening of the white envelope inside the shell, which was so thick and rubbery that apparently the young chick could not break its way through. Occasionally, too,
G O I T E R IN DOMESTIC P I G E O N S
portional to hatchability." Wilgus et al. (1941) showed t h a t the goitrogenic substance was in soybeans; additional iodine prevented the development of goiter, b u t did not improve the reproduction. In view of the inadequacy of present information concerning the relation of the thyroid gland to vigor of the late embryo the following observations on pigeons are of interest.
21
rather uniformly, to h a v e normal thyroids; in birds of the latter type, aged 6 to 10 weeks, the thyroids averaged about 40 to 50 mg. per bird, or about 100 mg. per kg. of body weight. These birds were raised in an area where the soil is supposedly rich in iodine, a t the Palmetto Pigeon Plant, Sumter, S. C. However, a marked increase in the thyroid weights of these young Car-
Thyroids weighing more than one gram were first obtained in the pigeon colony of this D e p a r t m e n t in 1929. The further incidence of such cases was as follows: Year 1929 1930 1932 1936 1937 1938 1939 1940 1941 1942
Total adult pigeons autopsied 215 400 480 285 230 150 135 125 235 160+
Cases o "gram goiters' 1 1 1 4 2 2 3 9 13
6+
Both the frequency and the actual weights of these large thyroids increased during these years. The median age of the "adult pigeons autopsied" was slightly less than two years while that of the goitrous specimens was more than five years. Goiter could occur, however, in younger birds; one of the 1942 group was aged 9.5 mo., and another autopsied in 1930 was aged 12.1 mo. In 1942 a pair of thyroids from a small eight-year-old male weighed 11.2 gm. In their relation to body weight (312 gm.) these are probably the largest thyroids yet recorded in a bird. During 1936, 1937, and up to October, 1938 (when goiter was present in pigeons of our own colony) young White Carneau pigeons purchased in South Carolina for immediate experimental use were found,
FIG. 1. Exposed thoracic region of White Carneau male E760, age 2 years. Right thyroid 2.17 gm., left 1.72 gm. Body massive, weight 900 gm. These thyroids caused no interference with breathing.
neaux occurred during the winter of 1938-39, and during each of the following two winters still further increases occurred, reaching a peak (in February, 1941) of about 180 mg. (average of 24 birds); the latter value is about four times the earlier or " n o r m a l " weight. These obsertions were reported in detail by Bates,
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W. F. HOLLANDER AND OSCAR R I D D L E
Riddle and Lahr (1941). Meanwhile cases of extreme goiter were discovered among adult Carneau pigeons in South Carolina, and we are indebted to the Palmetto Pigeon Plant for a number of specimens donated for study (cf. Figure 1). Except for a tendency to lethargy, adult
pigeons with advanced goiter have rarely appeared sick. T h e glands may be palpated but they seldom show as swellings in the living specimen. Pressure of the enlarged thyroids on the trachea caused more or less persistent asthmatic wheezing in some cases, and at least one bird seems to have died of asphyxiation resulting from such pressure. T h e birds are usually plump and fat, and the skin around the eyes is often puffy (Figure 2). The plumage also is generally affected: the large feathers are elongated and narrow, while the small feathers are almost hairy in appearance. The birds therefore have a rather u n k e m p t appearance. Feather regrowth after plucking is defective; it is slow, and sometimes even fails to occur. The whole picture presented by these birds is suggestive of myxedema.
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FIG. 2. Head of the same pigeon shown in fig. 1, before autopsy. Unusually puffy skin around the eyes and rather ragged feathers are common features of goitrous specimens.
During the years 1924, 1925, and 1926 not a single bird in this colony had thyroids weighing more than 200 mg., though about 500 adult pigeons were autopsied. T h e most populous race of pigeons (designated "SA-E") during this period had the appearance of "common mongrels," and the body weight of these birds was around a third of a kilogram. A frequency distribution curve for thyroid weights of this race from 1922 to 1929, inclusive, is given in Figure 3. The modal class is from 20 to 30 mg., or about 75 mg. per kilogram of body weight. Because of the skewness we use percentile analysis rather than mean and standard deviation; it seems probable t h a t individuals in the upper quartile had incipient goiter. T h a t this race was not " i m m u n e " to goiter is indicated by the fact t h a t the first "gram-goiter" found, in 1929, occurred in a pigeon of this race. Racial difference in the incidence of goiter, however, was clearly demonstrated. A mixed stock ( R u n t X Homer) and Carneaux were much more susceptible than were Tipplers and several other types. TREATMENT AND HISTOLOGICAL NOTES
Douglas (1914) appears to have been the first to make an extensive histological study of pigeon thyroids. In 150 pigeons he described four histological types, two of which seem essentially normal. He did not discuss the possibility of goiter, and could not account for the differences observed. McCarrison (1923) first studied goitrous changes in pigeon thyroids; he noted the occurrence of hyperemia, loss of colloid, and a thickening, hyperplasia, and budding of the follicular epithelium. Histological preparations of many cases of goiter coming to our attention have been made b y Mr. E. L. Lahr. We have not made an extensive study of these preparations b u t our observations are in agreement with those of McCarrison.
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23
GOITER IN DOMESTIC PIGEONS
Some of the advanced goiters, however, conform to the descriptions of "colloid goiter"-—enormous follicles with watery, pale-staining colloid, and with flattened epithelium; large amounts of connective tissue were also present. In a number of cases the effect of treatment on the histology was studied. The
compared histologically. Without exception a great increase of densely staining colloid followed treatment, and a flattening of the follicular epithelium also usually resulted. Treatment of the goiter with iodine has apparently always resulted in a decrease of thyroid size, but advanced cases never returned to normal
200 — MALES
354
(COMBINED MEDIAN
MALE
FOR
FEMALES CURVE)
THYROID
MEDIAN
FEMALE
MEDIAN
MALE
MEDIAN
FEMALE
WEIGHT » 3 7 MG.
THYROID
WEIGHT = 3 9 M G .
AGE AT AUTOPSY = J4 MO. AGE AT AUTOPSY = 14 MO.
KEY 4-MEDIAN t - F I R S T OR THIRD QUARTILE
75 THYROID
100
125
WEIGHT
150
175
200 +
-MILLIGRAMS
FIG. 3. A smoothed curve showing frequency distribution of thyroid weights (10 mg. class intervals) in a race of common pigeons. Birds aged less than 3 months or more than 48 months are not included. The period during which most of these weights were obtained was 1922 to 1929, inclusive. Median body weight for males was about 343 gm., for females 327 gm. Thyroid-body weight correlation was low. Incipient goiter in the upper quartile is indicated by the skewed distribution.
procedure was to make a biopsy (performed by Mrs. Guinevere C. Smith) and to remove one thyroid or a part of one thyroid. After this operation the feeding of small amounts of potassium iodide, or (in a few cases) of desiccated thyroid powder, was begun; then after a lapse of a few weeks another biopsy, or an autopsy, was performed. The thyroid tissues obtained before and after treatment were
size. These observations on pigeons are therefore in accord with those made on other animals and man. Goitrous pigeons "cured" by iodine dosage (with or without actual histological examination) show a return to or toward the normal state in still other features. Feather regrowth becomes rapid, the new feathers become broader and shorter than the old ones, and the "hair-
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W. F . HOLLANDER AND OSCAR R I D D L E
like" condition is lost. Eventually the pufhness of the skin around the eyes is considerably diminished. A marked loss of body weight was observed shortly after the treatment was started, and sometimes a partial moult occurred; both of these processes suggest a resurgence of thyrox-
ine secretion. Since severe emaciation followed treatment in one extreme case it is probably advisable to use very small doses of iodine to prevent such a reaction. REPRODUCTION During the periods of greatest prevalence of goiter, particularly in the winter, an unusually high mortality of the late embryos and squabs at hatching was observed, both at the South Carolina pigeon farm and in this laboratory. Egg production and fertility were not notably affected. Examination of the young at hatching revealed the following characteristic fea-
In some of the young which died at hatching it was evident t h a t the thyroids were hyperemic and enlarged (up to 30 mg.; normal was about 2 to 5 mg.). This was not true in every case, however. A fairly extensive test was made of the effect of iodine treatment on the occurrence of this type of "weakness." One of the pigeon houses (whose cages contained only individual pairs of breeding birds) was temporarily marked off, checkerboard fashion, to contain two similar groups. One group was continued on the standard regimen; the other group received, over a period of six months, the standard regimen plus K I (solution) in the mineral mixture. Vigor of the offspring from all eggs laid during this period was carefully noted. For various reasons a few mated pairs were removed during the period and replaced by new ones. Table 1 shows the results of the test. T h e amount of K I used in the test was 10 mg. per kg. of mineral mixture, and this was eaten at a rate estimated to give each bird about .1 to .2 mg. K I per week. This is a low dosage, b u t the data show t h a t its effects were definitely beneficial.
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FIG. 4. A sibling pair of squabs, soon after hatching, with umbilical hernia; the smaller squab was also anemic. Thyroid weight of the smaller squab, 4.2 mg.; of the larger, 7.7 mg.
tures: (a) a tendency for hatching to be delayed by a day or more (see Riddle, 1930); (b) a tendency to hemorrhage from the embryonic membranes during pipping; (c) frequent deaths from an unknown cause (exhaustion?) while pipping; (d) variable degrees of failure to draw in the umbilicus (see Figure 4); (e) anemia; and (f) debility or exhaustion. These condi r tions were expressed quite variously in different individuals. If the squab has strength enough to lift its head to be fed by the parents its growth usually continues in a normal manner. No malformations were noted in these " w e a k " young. Individuals of the hereditary "short-down" types (e.g., "dilute") were in general more seriously affected than others.
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GOITER IN DOMESTIC PIGEONS TABLE 1.—Effects
No. of pairs
Group
of adding potassium iodide to the mineral mixture fed to pigeons on the vigor of their offspring at hatching • Total eggs
31 24
Iodized Control
200 161
Young at hatching Hatched Vigorous 138 (69%) 103 (64%)
TABLE 2.—Offspring
6(4%) 50(49%)
females were then fed KI; one received the iodized mineral mixture described above, while the others received 10 mg. of KI at monthly intervals. These birds subsequently produced quite uniformly vigorous offspring at hatching as shown in Table 2. When these five breeding females were killed their thyroids were found to have been reduced in size during the term of treatment and to contain abundant colloid. The several lines of evidence cited above seem to warrant the conclusion that "mild" goiter in these breeding female pigeons was associated with "mild" goiter and weakness of the offspring at hatching. Iodine treatment of mothers showing the goitrous condition prevented the appearance of both of the above-named symptoms in their subsequent offspring. EFFECTS OF THYROIDECTOMY
An attempt was next made to learn whether thyroidectomy of the mother would have an effect on the vigor of the young. The data obtained from five females whose thyroids were removed by the method of Marvin and Smith (1943) are given in Table 3. It seems of interest to note that the loss of almost all of the maternal thyroid tissue
of five females before and after treatment with potassium iodide
Test period
Total eggs
Died pipping
Hatched weak
Hatched strong
Hatched, died within 3 days
Before treatment After treatment
53 51
13 2
22 1
0 30
14 2
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From the iodized group no cases of thyroid enlargement or hyperemia were found among several young killed for autopsy and thyroid histology; on the other hand, congenital goiter persisted among the controls. Histological examination of thyroids of normal young from untreated parents showed small round follicles with medium-high epithelia, and with small amounts of stainable colloid in some follicles. Young from iodine-treated parents had thyroids similar to the above but showing greater amounts of a more dense colloid. Weak young from untreated parents showed thyroids with high epithelium, hyperemia and no colloid. Five pairs, of which two were included in the above test, are of special interest. Their breeding records had shown almost complete failure due to mortality at hatching. Several races were represented in these matings. The thyroids of the five females were examined (by operation) and according to estimates made from measurements, were found to be three to six times normal weight. In one case, one thyroid, weighing 125 mg., was removed; in another case a part of one thyroid was removed. Histological examination showed hyperplasia and almost complete absence of colloid in both instances. All the above
132(96%) 53(51%)
Weak
26
W. F. HOLLANDER AND OSCAR RIDDLE
did not result in weakness of offspring (provided the eggs had adequate shells) although such weakness was associated with goiter. DISCUSSION
TABLE 3.—Notes on production of eggs and young following thyroidectomy First pair of eggs Female number
X99 X105 X30 X343 X469 3 1 2 3
Weight of thyroids mgs. (40) 121 (35) 170
Later eggs
Interval until laid
Offspring
Number
Offspring
days 21 14 73 68 (6 mo.)
2 normal 2 normal 1 normal 2
Several Several1 Several1 Several1 Numerous
Normal None None None Normal
I
None
Notes on operation at autopsy
5 mg. remnant Complete 8 mg. remnant Complete 10 mg. remnant 3 yrs. later
Shells too thin to permit complete development of embryo. The second egg of the clutch was broken. Operated when young.
Most of the pigeons were able to remain normal, and the addition of a very small supplement of potassium iodide seems to have been sufficient to prevent goiter and to restore goitrous birds to normal. McCarrison (1923, 1928) demonstrated that certain fatty foodstuffs markedly increased the iodine requirements of pigeons, and also obtained evidence that changes in the intestinal flora (through eating excreta, etc.) produced enlargement of the thyroids of these birds. It is notable that the present studies were conducted on pigeons maintained on a mixed-grain diet, which included yellow corn, wheat and Kafir (or milo). This was further supplemented with hemp or with peas. The mineral supply (oyster shell,
similar conclusion for canaries, and most manufacturers of poultry feed routinely add iodide to mashes. SUMMARY The occurrence of many cases of goiter in pigeons reared on Long Island, N. Y., and in Sumter, South Carolina, is described. Certain races have been more resistant to the development of goiter than other races reared in the same environment. Debility of the young at hatching is the most serious condition associated with goiter. The various symptoms which are here collectively called "debility" are described. Small supplements of potassium iodide
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In a consideration of the causes of the appearance of goiter in non-goitrous areas it should be remembered that the greater part of the food supply of these pigeons was grown elsewhere. Clearly the supply of iodine was at or near the border line.
grit, calcite, coarse sand, salt, iron oxide) had not been iodized. This diet is essentially similar to that used in most pigeon colonies during recent years. The effects of widespread goiter in a flock of pigeons bred for squab production may be disastrous. Goiter is probably not responsible for the majority of reproductive failures in pigeons, but the desirability of an iodine supplement in the diet of these birds seems to be demonstrated by the present study. Stroud (1941) drew a
GOITER IN DOMESTIC PIGEONS
' to the diet cured and prevented goiter in adults, and also prevented goiter and most cases of weakness at or near hatching. REFERENCES
to iodine requirements and to the thyroid gland. Indian Jour. Med. Research 11:20—51. McCarrison, R., 1928. The simple goitres. Bailliere, Tindall and Cox, London. Marvin, H. N., and G. C. Smith, 1943. Technique for thyroidectomy in the pigeon and the early effect of thyroid removal on heat production. Endocrinology 32:87-91. Riddle, 0., 1930. Does thyroxin enter the egg during oogenesis? Carnegie Institution of Washington Year Book 29:55. Scharrer, K., and W. Schropp, 1932. Fiitterungsversuche mit Jod an Hiihnern. Die Tierernahrung 4: 249-264. Stroud, R., 1941. Stop your canary losses. All-Pets Mag. 12(10) :7-8. Welch, H., 1928. Goiter in farm animals. Univ. of Montana Agric. Exp. Sta. Bull. 214. Wilgus, H. S., Jr.,, and F. X . Gassner, 1941. Effect of soybean oil meal on avian reproduction. Proc. Soc. Exp. Biol, and Med. 46:290-293. Wilgus, H. S., Jr., F. X. Gassner, A. R. Patton and R. G. Gustavson, 1941. The goitrogenicity of soybeans. J. Nutrition 22:43-52. Zajtay, A., 1934. Ueber die Wirkung der Beifutterung kleiner Jodmengen auf den Eierertrag von Hiihnern und auf das Schliipfergebnis. Die Tier ernahrung 6:102-111.
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Bates, R. W., 0 . Riddle and E. L. Lahr, 1941. A strain difference in responsiveness of chick thyroids to thyrotropin and a stepwise increase during three years in thyroid weights of Carneau pigeons. Endocrinology 29:492-497. Douglas, M., 1914. The histology of the thyroid in animals fed on various diets. J. Path, and Bact. (Cambridge) 19:341-348. Hollander, W. F., and 0 . Riddle, 1943. Relation of goiter in pigeons to embryonic vigor. Carnegie Institution of Washington Year Book 42:137139. Johnson, E. A., A. M. Pilkey, and A. W. Edson, 1935. Effect of supplementary iodine on reproduction in the fowl. Poultry Sci. 14:16-23. Kalkus, J. W., 1920. A study of goitre and associated conditions in domestic animals. Wash. Agric. Exp. Sta. Bull. 156. Keith, W. D., 1924. Endemic goitre. Canadian Med. Assoc. J. 14:284-289. McCarrison, R., 1923. Pathogenesis of deficiency disease. X I . Observations on fat-excess in relation
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a full grown hen would suddenly drop dead, or a rooster lose his voice. . . . " Welch (1928), speaking of conditions in Montana, stated, "Goiter in poultry is very common. Flocks with a very high percentage of it have been noted in goitrous areas. The enlarged thyroid, frequently as large as the thumb, is entirely concealed by the feathers, and so far we have not observed any bad effect on the health of these fowls. The owners of goitered flocks have always reported that egg production and general health were normal. We have attempted to determine whether congenital goiter existed among newly hatched chicks but have been unable to get the material to study. No losses have been reported, at any rate, from this cause." Welch devoted much attention to losses from congenital goiter in other livestock. Scharrer and Schropp (1932) and Zajtay (1934) conducted studies on goiter districts in Europe and reported improved hatchability following the use of iodine supplement. Johnson, Pilkey and Edson (1935) made similar tests in Minnesota and reported no benefit from iodine supplement; it seems not to be certain, however, that goiter existed in the fowls treated by these investigators. Wilgus and Gassner (1941) noted poor reproduction in fowls fed a goitrogenic diet. In addition, they stated " . . . chicks hatched from eggs of hens on the experimental ration which did not contain any meat scrap were very poor. Few survived the first week, even when fed a practical ration. Chick condition and viability were pro-
HE occurrence of "simple" goiter in pigeons, and its relation to weakness of offspring at the hatching stage, have been noted by the authors (1943) in a preliminary report. The present paper provides an adequate account of the observations and tests made on this topic. Goiter in domestic birds, particularly in the fowl, has been noted by a number of investigators, but its effect on reproduction has received very little attention. Kalkus (1920) states: "It has been repeatedly observed by individuals who dress poultry that adult chickens in goitrous districts [State of Washington] are commonly affected with goitre. . . . However, newly hatched chicks are apparently not affected or at least no trouble is experienced from this source by poultry raisers." On the other hand, Kalkus described in detail the difficulties of reproduction in goitrous livestock such as pigs, sheep and goats. Apparently the chief symptoms were debility and frequent hairlessness of the newborn goitrous young. Keith (1924) described very similar conditions in farm animals, including cows and horses, of Pemberton Valley, north of Vancouver, B. C. Regarding poultry he stated as follows: " . . . all brought into the valley appeared to thrive; but their eggs, though producing embryos, failed to hatch out, the apparent cause being the thickening of the white envelope inside the shell, which was so thick and rubbery that apparently the young chick could not break its way through. Occasionally, too,
G O I T E R IN DOMESTIC P I G E O N S
portional to hatchability." Wilgus et al. (1941) showed t h a t the goitrogenic substance was in soybeans; additional iodine prevented the development of goiter, b u t did not improve the reproduction. In view of the inadequacy of present information concerning the relation of the thyroid gland to vigor of the late embryo the following observations on pigeons are of interest.
21
rather uniformly, to h a v e normal thyroids; in birds of the latter type, aged 6 to 10 weeks, the thyroids averaged about 40 to 50 mg. per bird, or about 100 mg. per kg. of body weight. These birds were raised in an area where the soil is supposedly rich in iodine, a t the Palmetto Pigeon Plant, Sumter, S. C. However, a marked increase in the thyroid weights of these young Car-
Thyroids weighing more than one gram were first obtained in the pigeon colony of this D e p a r t m e n t in 1929. The further incidence of such cases was as follows: Year 1929 1930 1932 1936 1937 1938 1939 1940 1941 1942
Total adult pigeons autopsied 215 400 480 285 230 150 135 125 235 160+
Cases o "gram goiters' 1 1 1 4 2 2 3 9 13
6+
Both the frequency and the actual weights of these large thyroids increased during these years. The median age of the "adult pigeons autopsied" was slightly less than two years while that of the goitrous specimens was more than five years. Goiter could occur, however, in younger birds; one of the 1942 group was aged 9.5 mo., and another autopsied in 1930 was aged 12.1 mo. In 1942 a pair of thyroids from a small eight-year-old male weighed 11.2 gm. In their relation to body weight (312 gm.) these are probably the largest thyroids yet recorded in a bird. During 1936, 1937, and up to October, 1938 (when goiter was present in pigeons of our own colony) young White Carneau pigeons purchased in South Carolina for immediate experimental use were found,
FIG. 1. Exposed thoracic region of White Carneau male E760, age 2 years. Right thyroid 2.17 gm., left 1.72 gm. Body massive, weight 900 gm. These thyroids caused no interference with breathing.
neaux occurred during the winter of 1938-39, and during each of the following two winters still further increases occurred, reaching a peak (in February, 1941) of about 180 mg. (average of 24 birds); the latter value is about four times the earlier or " n o r m a l " weight. These obsertions were reported in detail by Bates,
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 9, 2015
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22
W. F. HOLLANDER AND OSCAR R I D D L E
Riddle and Lahr (1941). Meanwhile cases of extreme goiter were discovered among adult Carneau pigeons in South Carolina, and we are indebted to the Palmetto Pigeon Plant for a number of specimens donated for study (cf. Figure 1). Except for a tendency to lethargy, adult
pigeons with advanced goiter have rarely appeared sick. T h e glands may be palpated but they seldom show as swellings in the living specimen. Pressure of the enlarged thyroids on the trachea caused more or less persistent asthmatic wheezing in some cases, and at least one bird seems to have died of asphyxiation resulting from such pressure. T h e birds are usually plump and fat, and the skin around the eyes is often puffy (Figure 2). The plumage also is generally affected: the large feathers are elongated and narrow, while the small feathers are almost hairy in appearance. The birds therefore have a rather u n k e m p t appearance. Feather regrowth after plucking is defective; it is slow, and sometimes even fails to occur. The whole picture presented by these birds is suggestive of myxedema.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 9, 2015
FIG. 2. Head of the same pigeon shown in fig. 1, before autopsy. Unusually puffy skin around the eyes and rather ragged feathers are common features of goitrous specimens.
During the years 1924, 1925, and 1926 not a single bird in this colony had thyroids weighing more than 200 mg., though about 500 adult pigeons were autopsied. T h e most populous race of pigeons (designated "SA-E") during this period had the appearance of "common mongrels," and the body weight of these birds was around a third of a kilogram. A frequency distribution curve for thyroid weights of this race from 1922 to 1929, inclusive, is given in Figure 3. The modal class is from 20 to 30 mg., or about 75 mg. per kilogram of body weight. Because of the skewness we use percentile analysis rather than mean and standard deviation; it seems probable t h a t individuals in the upper quartile had incipient goiter. T h a t this race was not " i m m u n e " to goiter is indicated by the fact t h a t the first "gram-goiter" found, in 1929, occurred in a pigeon of this race. Racial difference in the incidence of goiter, however, was clearly demonstrated. A mixed stock ( R u n t X Homer) and Carneaux were much more susceptible than were Tipplers and several other types. TREATMENT AND HISTOLOGICAL NOTES
Douglas (1914) appears to have been the first to make an extensive histological study of pigeon thyroids. In 150 pigeons he described four histological types, two of which seem essentially normal. He did not discuss the possibility of goiter, and could not account for the differences observed. McCarrison (1923) first studied goitrous changes in pigeon thyroids; he noted the occurrence of hyperemia, loss of colloid, and a thickening, hyperplasia, and budding of the follicular epithelium. Histological preparations of many cases of goiter coming to our attention have been made b y Mr. E. L. Lahr. We have not made an extensive study of these preparations b u t our observations are in agreement with those of McCarrison.
-
23
GOITER IN DOMESTIC PIGEONS
Some of the advanced goiters, however, conform to the descriptions of "colloid goiter"-—enormous follicles with watery, pale-staining colloid, and with flattened epithelium; large amounts of connective tissue were also present. In a number of cases the effect of treatment on the histology was studied. The
compared histologically. Without exception a great increase of densely staining colloid followed treatment, and a flattening of the follicular epithelium also usually resulted. Treatment of the goiter with iodine has apparently always resulted in a decrease of thyroid size, but advanced cases never returned to normal
200 — MALES
354
(COMBINED MEDIAN
MALE
FOR
FEMALES CURVE)
THYROID
MEDIAN
FEMALE
MEDIAN
MALE
MEDIAN
FEMALE
WEIGHT » 3 7 MG.
THYROID
WEIGHT = 3 9 M G .
AGE AT AUTOPSY = J4 MO. AGE AT AUTOPSY = 14 MO.
KEY 4-MEDIAN t - F I R S T OR THIRD QUARTILE
75 THYROID
100
125
WEIGHT
150
175
200 +
-MILLIGRAMS
FIG. 3. A smoothed curve showing frequency distribution of thyroid weights (10 mg. class intervals) in a race of common pigeons. Birds aged less than 3 months or more than 48 months are not included. The period during which most of these weights were obtained was 1922 to 1929, inclusive. Median body weight for males was about 343 gm., for females 327 gm. Thyroid-body weight correlation was low. Incipient goiter in the upper quartile is indicated by the skewed distribution.
procedure was to make a biopsy (performed by Mrs. Guinevere C. Smith) and to remove one thyroid or a part of one thyroid. After this operation the feeding of small amounts of potassium iodide, or (in a few cases) of desiccated thyroid powder, was begun; then after a lapse of a few weeks another biopsy, or an autopsy, was performed. The thyroid tissues obtained before and after treatment were
size. These observations on pigeons are therefore in accord with those made on other animals and man. Goitrous pigeons "cured" by iodine dosage (with or without actual histological examination) show a return to or toward the normal state in still other features. Feather regrowth becomes rapid, the new feathers become broader and shorter than the old ones, and the "hair-
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384
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W. F . HOLLANDER AND OSCAR R I D D L E
like" condition is lost. Eventually the pufhness of the skin around the eyes is considerably diminished. A marked loss of body weight was observed shortly after the treatment was started, and sometimes a partial moult occurred; both of these processes suggest a resurgence of thyrox-
ine secretion. Since severe emaciation followed treatment in one extreme case it is probably advisable to use very small doses of iodine to prevent such a reaction. REPRODUCTION During the periods of greatest prevalence of goiter, particularly in the winter, an unusually high mortality of the late embryos and squabs at hatching was observed, both at the South Carolina pigeon farm and in this laboratory. Egg production and fertility were not notably affected. Examination of the young at hatching revealed the following characteristic fea-
In some of the young which died at hatching it was evident t h a t the thyroids were hyperemic and enlarged (up to 30 mg.; normal was about 2 to 5 mg.). This was not true in every case, however. A fairly extensive test was made of the effect of iodine treatment on the occurrence of this type of "weakness." One of the pigeon houses (whose cages contained only individual pairs of breeding birds) was temporarily marked off, checkerboard fashion, to contain two similar groups. One group was continued on the standard regimen; the other group received, over a period of six months, the standard regimen plus K I (solution) in the mineral mixture. Vigor of the offspring from all eggs laid during this period was carefully noted. For various reasons a few mated pairs were removed during the period and replaced by new ones. Table 1 shows the results of the test. T h e amount of K I used in the test was 10 mg. per kg. of mineral mixture, and this was eaten at a rate estimated to give each bird about .1 to .2 mg. K I per week. This is a low dosage, b u t the data show t h a t its effects were definitely beneficial.
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FIG. 4. A sibling pair of squabs, soon after hatching, with umbilical hernia; the smaller squab was also anemic. Thyroid weight of the smaller squab, 4.2 mg.; of the larger, 7.7 mg.
tures: (a) a tendency for hatching to be delayed by a day or more (see Riddle, 1930); (b) a tendency to hemorrhage from the embryonic membranes during pipping; (c) frequent deaths from an unknown cause (exhaustion?) while pipping; (d) variable degrees of failure to draw in the umbilicus (see Figure 4); (e) anemia; and (f) debility or exhaustion. These condi r tions were expressed quite variously in different individuals. If the squab has strength enough to lift its head to be fed by the parents its growth usually continues in a normal manner. No malformations were noted in these " w e a k " young. Individuals of the hereditary "short-down" types (e.g., "dilute") were in general more seriously affected than others.
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GOITER IN DOMESTIC PIGEONS TABLE 1.—Effects
No. of pairs
Group
of adding potassium iodide to the mineral mixture fed to pigeons on the vigor of their offspring at hatching • Total eggs
31 24
Iodized Control
200 161
Young at hatching Hatched Vigorous 138 (69%) 103 (64%)
TABLE 2.—Offspring
6(4%) 50(49%)
females were then fed KI; one received the iodized mineral mixture described above, while the others received 10 mg. of KI at monthly intervals. These birds subsequently produced quite uniformly vigorous offspring at hatching as shown in Table 2. When these five breeding females were killed their thyroids were found to have been reduced in size during the term of treatment and to contain abundant colloid. The several lines of evidence cited above seem to warrant the conclusion that "mild" goiter in these breeding female pigeons was associated with "mild" goiter and weakness of the offspring at hatching. Iodine treatment of mothers showing the goitrous condition prevented the appearance of both of the above-named symptoms in their subsequent offspring. EFFECTS OF THYROIDECTOMY
An attempt was next made to learn whether thyroidectomy of the mother would have an effect on the vigor of the young. The data obtained from five females whose thyroids were removed by the method of Marvin and Smith (1943) are given in Table 3. It seems of interest to note that the loss of almost all of the maternal thyroid tissue
of five females before and after treatment with potassium iodide
Test period
Total eggs
Died pipping
Hatched weak
Hatched strong
Hatched, died within 3 days
Before treatment After treatment
53 51
13 2
22 1
0 30
14 2
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From the iodized group no cases of thyroid enlargement or hyperemia were found among several young killed for autopsy and thyroid histology; on the other hand, congenital goiter persisted among the controls. Histological examination of thyroids of normal young from untreated parents showed small round follicles with medium-high epithelia, and with small amounts of stainable colloid in some follicles. Young from iodine-treated parents had thyroids similar to the above but showing greater amounts of a more dense colloid. Weak young from untreated parents showed thyroids with high epithelium, hyperemia and no colloid. Five pairs, of which two were included in the above test, are of special interest. Their breeding records had shown almost complete failure due to mortality at hatching. Several races were represented in these matings. The thyroids of the five females were examined (by operation) and according to estimates made from measurements, were found to be three to six times normal weight. In one case, one thyroid, weighing 125 mg., was removed; in another case a part of one thyroid was removed. Histological examination showed hyperplasia and almost complete absence of colloid in both instances. All the above
132(96%) 53(51%)
Weak
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W. F. HOLLANDER AND OSCAR RIDDLE
did not result in weakness of offspring (provided the eggs had adequate shells) although such weakness was associated with goiter. DISCUSSION
TABLE 3.—Notes on production of eggs and young following thyroidectomy First pair of eggs Female number
X99 X105 X30 X343 X469 3 1 2 3
Weight of thyroids mgs. (40) 121 (35) 170
Later eggs
Interval until laid
Offspring
Number
Offspring
days 21 14 73 68 (6 mo.)
2 normal 2 normal 1 normal 2
Several Several1 Several1 Several1 Numerous
Normal None None None Normal
I
None
Notes on operation at autopsy
5 mg. remnant Complete 8 mg. remnant Complete 10 mg. remnant 3 yrs. later
Shells too thin to permit complete development of embryo. The second egg of the clutch was broken. Operated when young.
Most of the pigeons were able to remain normal, and the addition of a very small supplement of potassium iodide seems to have been sufficient to prevent goiter and to restore goitrous birds to normal. McCarrison (1923, 1928) demonstrated that certain fatty foodstuffs markedly increased the iodine requirements of pigeons, and also obtained evidence that changes in the intestinal flora (through eating excreta, etc.) produced enlargement of the thyroids of these birds. It is notable that the present studies were conducted on pigeons maintained on a mixed-grain diet, which included yellow corn, wheat and Kafir (or milo). This was further supplemented with hemp or with peas. The mineral supply (oyster shell,
similar conclusion for canaries, and most manufacturers of poultry feed routinely add iodide to mashes. SUMMARY The occurrence of many cases of goiter in pigeons reared on Long Island, N. Y., and in Sumter, South Carolina, is described. Certain races have been more resistant to the development of goiter than other races reared in the same environment. Debility of the young at hatching is the most serious condition associated with goiter. The various symptoms which are here collectively called "debility" are described. Small supplements of potassium iodide
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In a consideration of the causes of the appearance of goiter in non-goitrous areas it should be remembered that the greater part of the food supply of these pigeons was grown elsewhere. Clearly the supply of iodine was at or near the border line.
grit, calcite, coarse sand, salt, iron oxide) had not been iodized. This diet is essentially similar to that used in most pigeon colonies during recent years. The effects of widespread goiter in a flock of pigeons bred for squab production may be disastrous. Goiter is probably not responsible for the majority of reproductive failures in pigeons, but the desirability of an iodine supplement in the diet of these birds seems to be demonstrated by the present study. Stroud (1941) drew a
GOITER IN DOMESTIC PIGEONS
' to the diet cured and prevented goiter in adults, and also prevented goiter and most cases of weakness at or near hatching. REFERENCES
to iodine requirements and to the thyroid gland. Indian Jour. Med. Research 11:20—51. McCarrison, R., 1928. The simple goitres. Bailliere, Tindall and Cox, London. Marvin, H. N., and G. C. Smith, 1943. Technique for thyroidectomy in the pigeon and the early effect of thyroid removal on heat production. Endocrinology 32:87-91. Riddle, 0., 1930. Does thyroxin enter the egg during oogenesis? Carnegie Institution of Washington Year Book 29:55. Scharrer, K., and W. Schropp, 1932. Fiitterungsversuche mit Jod an Hiihnern. Die Tierernahrung 4: 249-264. Stroud, R., 1941. Stop your canary losses. All-Pets Mag. 12(10) :7-8. Welch, H., 1928. Goiter in farm animals. Univ. of Montana Agric. Exp. Sta. Bull. 214. Wilgus, H. S., Jr.,, and F. X . Gassner, 1941. Effect of soybean oil meal on avian reproduction. Proc. Soc. Exp. Biol, and Med. 46:290-293. Wilgus, H. S., Jr., F. X. Gassner, A. R. Patton and R. G. Gustavson, 1941. The goitrogenicity of soybeans. J. Nutrition 22:43-52. Zajtay, A., 1934. Ueber die Wirkung der Beifutterung kleiner Jodmengen auf den Eierertrag von Hiihnern und auf das Schliipfergebnis. Die Tier ernahrung 6:102-111.
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Bates, R. W., 0 . Riddle and E. L. Lahr, 1941. A strain difference in responsiveness of chick thyroids to thyrotropin and a stepwise increase during three years in thyroid weights of Carneau pigeons. Endocrinology 29:492-497. Douglas, M., 1914. The histology of the thyroid in animals fed on various diets. J. Path, and Bact. (Cambridge) 19:341-348. Hollander, W. F., and 0 . Riddle, 1943. Relation of goiter in pigeons to embryonic vigor. Carnegie Institution of Washington Year Book 42:137139. Johnson, E. A., A. M. Pilkey, and A. W. Edson, 1935. Effect of supplementary iodine on reproduction in the fowl. Poultry Sci. 14:16-23. Kalkus, J. W., 1920. A study of goitre and associated conditions in domestic animals. Wash. Agric. Exp. Sta. Bull. 156. Keith, W. D., 1924. Endemic goitre. Canadian Med. Assoc. J. 14:284-289. McCarrison, R., 1923. Pathogenesis of deficiency disease. X I . Observations on fat-excess in relation
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