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INTRODUCTION IT IS well established that the external environment influences sexual maturity in birds. Light is the most important environmental factor as shown by the work of Rowan (1925) with juncos (Junco hyemalis), Bissonnette (1930) with starlings (Sturnus vulgaris), Scott and Payne (1937) with turkeys. Experiments at the Nebraska station reported in 1930 had demonstrated that lighted turkeys could be induced to start laying earlier than those not subjected to artificial light, and this was confirmed by Albright and Thompson (1933) and the later work of Scott and Payne (1937). The hypophysis has been shown by Hill and Parkes (1937) to control gonad activity in birds. Benoit (1935) has obtained evidence that light acts on receptive organs which transmit stimuli to the hypophysis which in turn produces hormones that act on the gonads. Presumably there are inherited differences in the response of different individuals to a given length of day . . .

In affected muscles of dystrophic chickens, electromyography with needle electrodes revealed hyperexcitability to mechanical stimuli such as electrode movement (prolonged "insertion activity"), spontaneous potentials, and polyphasic motor unit potentials. In agreement with pathological findings in this and previous studies, the light breast muscles exhibited more extensive electromyographic abnormalities than the more distally placed light muscles of the wings, whereas the dark muscles of the legs showed little or no electromyographic abnormality. Electrode movement in the muscles of 5-day-old chickens evoked a discharge of high-frequency, low-amplitude potentials which continued for several seconds. In normal chickens the duration of this discharge diminished with age and reached the adult level, 1 sec, at 30 days of age. Breast muscles of dystrophic chickens first exhibited distinct electromyographic abnormalities at I6 days of age. It is possible that onset occurred earlier but was obscured by the high-frequency discharges normally observed during this period of life.

SummaryA simple autosomal recessive lethal mutation that causes crowding together of the vertebrae with consequent shortening of the neck and body is described. The percentage of ash in the wing and leg bones was approximately the same as in the normal embryos, but the percentage of ash was less in the scapula, ilium, and ischium than in the corresponding bones of the normal embryos.

The pectoral muscles of chickens with n~uscular dystrophy (Asmundson and Julian, 1956) were found to have a higher fat content than those of normal birds at and after 15 weelts of age (Jordan et dl., 1959) with the pectoral muscles of the females having a higher fat content tha11 those of the males. Elevated fat content has been found in certain n~uscles of mice with nluscular dystrophy by Shull and Alfin-Slater (1958) and in some syndromes of nluscular dystrophy in man (Adams et al., 1954). This investigation was undertaken to determine if there are, in addition to the effects of the gene causing n~uscular dystrophy, inherited differences in the fat content of the pectoral muscle of chickens with nluscular dystrophy.

THE problem of undesirable or off flavor in turkeys has received considerable attention, but citation of two recent reports will suffice to indicate some of the differences in the results obtained. Cosby and Knowlton (1937) report that fish meal (20 percent of the mash, about 8 percent of the ration) had no undesirable effect on the flavor while about 1 percent of fish oil in the ration (2 percent of the mash) produced an off flavor in two out of four birds. On the other hand, Marble, Hunter, Knandel, and Dutcher (1937) reported that both fish meal (10 percent of a vacuum dried white fish meal) with or without cod liver oil (not U.S.P.) produced an off flavor. Preliminary experiments at the California Agricultural Experiment Station, Davis indicated that a high grade vacuum dried sardine meal fed at a level of 20 percent of the total ration did not produce . . .

LERNER (1950) drew attention to the need for detailed information in poultry research about non-linear interactions between genotypes and environments and the extent to which they may affect breeding programs. No interaction between strain and ration was found for weights of turkeys by Asmundson and Lerner (1940). Since then, additional results have been accumulating which indicate that, under average conditions, this phenomenon may occur for some traits but not for others, thus leaving in some doubt the practical importance of these interactions in many economic traits in poultry. For example, Gowe and Wakely (1954) found no strain-environment interaction in the egg production of several strains of White Leghorns at 6 different Dominion Experimental Stations across Canada. Johnson and Gowe (1956) reported that, in a similar test for egg quality, involving 8 White Leghorn strains, there was no interaction in the the case of albumen quality and shell strength, although a . . .

SELECTION indexes have been advocated on statistical and genetical grounds as a means of combining information on several measured traits into a single selection criterion. Theoretically, it is expected that selection decisions based on such indexes would, under mass selection, give maximum genetic gains in terms of assumed economic values. Following initial derivations of selection indexes by Smith (1936) and by Hazel (1943), a large number of studies has been carried out with the aim of providing the genetic information necessary for constructing selection indexes. Sometimes indexes have been constructed based on simplified assumptions of economic variables. However, only a few applications of indexes have been reported (Manning, 1955; Dickerson, 1955; and Christian, 1957). Apparently, no experimental verification of the results anticipated under index selection is on record. This lack of experimental validation may reflect the convincing genetic and statistical arguments that have been made in favor of selection indexes, …

SummaryNew Hampshire chickens with onset of inherited muscular dystrophy exhibited elevated plasma aldolase and glutamic oxaloacetic-transaminase (GO-T) activities. Age and sex of birds influenced plasma aldolase activity in both normal and dystrophic groups. GO-T activities varied in different tissues and were greater in a majority of tissues examined from dystrophic birds when compared to normal birds.

THIS paper presents a brief report on the effect of age on the egg production and hatching results of Bronze turkey females during the period 1927 and 1933 inclusive. Some data are also presented on the comparative mortality and rate of growth of the progeny. In compiling the data the age of the males to which the females were mated was disregarded. Egg Production All reports so far published, regarding the effect of age on egg production deal with the domestic fowl. Brody, Henderson, and Kempster (1923) reported that the egg production of the flock studied declined 12 percent each successive year. Jull (1928) and Hall and Marble (1931) have shown that the decline in egg production with age is greater in the case of the Barred Plymouth Rock, Rhode Island Red, and Wyandotte breeds than in the case of the White Leghorn. They as well as Atwood (1928) and . . .

(1963). Influence of selection for body weight at different ages on growth of Turkeys. British Poultry Science: Vol. 4, No. 1, pp. 71-82.

EXTENSIVE studies of growth rate, body size and conformation of turkeys have established that these traits are subject to considerable genetic variation (Jaap, 1938; Asmundson and Lerner, 1940; Asmundson, 1944, 1945, 1948; Asmundson and Pun, 1954a, b). Most of the heritability estimates of body weight of turkeys range from a low of .16 to a high of .62, the majority being from .35 to .50 (Abplanalp and Kosin, 1952; Goodman, Brunson and Godfrey, 1954; Bumgardner and Shaffner, 1954; McCartney, 1955; Kondra and Shoffner, 1956). The variation in these estimates may be due to differences in age or strain of turkey, or, in part, to differences in experimental technique. Heritability of body measurements (shank length, keel length, breast width and breast depth), as reported by Abplanalp and Kosin (1952) for turkeys at 26 weeks of age, ranged from about .13 to .51, while similar estimates presented by Kondra and Shoffner (1956) …

THE establishment of definite standards for measuring desirable traits of fryers, as well as reasonable assurance that predictable amounts of improvement can be made are needed before the adoption of an elaborate breeding program involving meat production may be regarded as a sound commercial venture. Recently a nation-wide attempt to stimulate interest in the improvement of poultry from the standpoint of meat quality has been initiated under the auspices of a commercial concern (the U. S. Egg and Poultry Magazine for 1946 may be consulted for a series of publicity releases on the “Chicken of Tomorrow” contest). The tacit assumption underlying such an effort is that breeders in the field can in a relatively short time produce by selection a bird markedly superior to the current product. The question, whether or not this assumption is fully justified requires examination. It is generally conceded that the characteristics of birds desirable from . . .

IT HAS been clearly demonstrated (Asmundson and Jervis 1933, Asmundson and Burmester 1936) that resection of a part of the uterus results in reduced secretion by the uterus. The shells of eggs laid after the operation weighed less than the shells of eggs laid before the operation. It may also be considered well established that resection of a part of the oviduct has no direct influence on secretion in another part of the oviduct. Thus when a part of the albumen tube was resected there was a reduction in the amount of the albumen secreted while the amount of shell secreted was not reduced except when there was an appreciable reduction in the combined weight of the yolk and albumen. This it has been pointed out, is a secondary effect since the amount of shell secreted depends not only on the area of secreting surface, but also on the total . . .

IT IS well known that when different breeds or strains of plants or animals are crossed the hybrids frequently exhibit increased vigor as measured by viability and growth. This has been well established for the domestic fowl by Warren (1930) and others. The results for different species or even subdivisions within a species differ. Thus, the results obtained by Borisenko, Altschuler, and Poliakov (1935) are of interest in that they were able to demonstrate heterosis in Drosophila melanogaster only for survival. They suggest that characters which do not influence survival are less likely to exhibit heterosis than those that do. Furthermore, their results, like those with corn (Shull, 1911, and others), show that the more homozygous the parent strains the greater the heterosis observed in the progeny obtained by crossing the various parent strains. There is some indication that crossbred chickens exhibiting heterosis make more efficient gains than the parent . . .

Statistical analysis of the trapnest records of turkeys extending over seven years shows that date of first egg is a better measure of sexual maturity in turkeys than age at first egg. Date of first egg is little influenced by variation in the time of hatch within the normal hatching season of almost two months, whereas age at first egg is influenced, the later-hatched birds starting to lay when younger than the earlier-hatched birds. Moreover, genetic differences in sexual maturity can more readily be demonstrated with date of first egg than with age at first egg. Selection for early and late sexual maturity was effective in establishing lines that differed significantly in date of first egg. When these lines were crossed the results differed according to which way the cross was made. The progeny of late male x early female laid earlier than the birds in the late-maturing line but later than the progeny of the reciprocal cross. In at least one case, the progeny of the latter (early male x late female) la...

USE of artificial light is known to bring turkey hens into egg production earlier than if the birds are exposed only to normal daylight (Albright and Thompson, 1933). Moreover, blue light was found to be ineffective by Scott and Payne, 1937, presumably because the light intensity was reduced below the required level. Turkey hens require a light intensity of about 2 foot candles (Asmundson, Lorenz, and Moses, 1946). Data on the optimum length of day are not available for turkeys, hence further tests were started. MATERIALS AND METHODS Bronze hens were used. They were selected in such a way that, for example, the first bird banded in one pen was of similar ancestry (usually a full or half sister) to the first bird banded in any of the other pens; they weighed about the same at the time the tests were started. Thus the ten birds in one pen could . . .

IT HAS been shown that much of the difference in percentage rate of growth of large and small strains and varieties of chickens occurs during the earlier months of the birds’ post hatching life. Thus Asmundson and Lerner (1934) found that Barred Plymouth Rocks grew more rapidly than Single Comb White Leghorns up to 16 weeks of age but not thereafter. Inherited differences in percentage rate of growth have been demonstrated between breeds of chickens (Lerner and Asmundson, 1932) and within breeds and varieties (Asmundson and Lerner, 1933). Inherited differences in weight have been shown for chickens based on mature weights (Waters, 1931) and about 8 weeks of age (Schnetzler, 1936). The inheritance of differences in gain and in weight at 8 weeks in turkeys has been reported by Abplanalp and Kosin (1952). They, Knox and Marsden (1944) and Asmundson (1948) have reported inherited differences in the weight of 24-week-old …

Data are presented on two groups of thirty chicks each, hatched from a susceptible and an apparently resistant flock. There was a significant difference in the incidence of fowl paralysis and lymphomatous tumors in these two groups. This is interpreted to mean that there is an inherent difference in susceptibility and resistance to fowl paralysis and lymphomatous tumors.

THE pyridoxine requirements of chicks have been reported to be from 275 to 400 micrograms per 100 grams of diet (Hogan et al., 1941; Briggs et al., 1942). No data are available on the pyridoxine requirements of turkey poults. Since the turkey’s requirements are slightly but significantly higher for pantothenic acid (Lepkovsky et al., 1945) and riboflavin (Bird et al., 1946) than those of the chick, it seemed worth while to establish their comparative requirements for pyridoxine. EXPERIMENTAL At hatching, turkey poults and baby chicks were given stock mashes for one week, after which they were given the pyridoxine-deficient diet used in our previous pyridoxine studies (Bird et al., 1943). Three series of experiments were run. In the first series, the only difference between the chick and poult diets consisted in doubling the vitamin A and D oil in the poult diet. The second and third series differed from the . . .

Observations were made on 19,446 turkey embryos and poults, of which 50.17 per cent. were males. The sex ratio of hatched poults was 49.20 per cent. males, due to heavier mortality among male embryos. The sex ratio of 8,548 chicken embryos and chicks was 49.54 per cent. males. When combined with comparable published data, the sex ratio obtained was 49.19 per cent. males or 0.98 ± 0.38 per cent. lower than for turkeys. During the last week of incubation more male than female turkeys died, whereas the reverse was true for chickens. There was a larger number of males than females in small samples of embryos of both species that died between the time when sex could be readily identified and the last week of incubation, but the significance of this finding can not be established in absence of further data. It is suggested that sex-linked genes have little or no influence on the sex ratio of the strains of turkeys studied here, whereas they perhaps exert an influence on the secondary sex ratio of at least some ...

IN A study of seasonal variation of semen production by turkey males Carson et al. (1955, a, b) obtained monthly flock-average semen volumes varying from barely measurable amounts to over 0.3 ml. During the period late February to late May the average volume was 0.24 and 0.27 ml. in two successive years. These figures are low as compared with those previously reported, e.g., by Burrows and Marsden (1938) who obtained 0.1 to 0.7 ml. with averages of 0.3 and 0.4, and by Parker (1946) who reported an average production of 0.33 ml. On the other hand, average estimates of sperm concentration obtained by Carson et al. (1955b) were higher (10.26 and 16.7 billions per ml.) than the 8.4 billions reported by Parker (1946), yielding estimates of numbers of sperm per ejaculate in the same order of magnitude: 2.3 and 4.5 billion from the data of Carson et al. and 2.8 …

ARTIFICIAL illumination has been extensively used with chickens for decades; for evidence of this fact one needs only to refer to the classical review by Whetham (1933). In the ensuing years since her review, research on artificial lighting of poultry has been sporadic until the report by King (1958) on “stimulighting.” In turkeys the research by Asmundson et al. (1946) and Asmundson and Moses (1950) indicated the necessary optimums of light intensity and total day for normal reproduction of mature spring hatched turkeys. Currently there has been increased interest in year around turkey productions so that another factor in illumination, namely light-conditioning or light-restriction is being investigated in order to bring hens into egg production during the summer and early fall months (Harper and Parker, 1957). This paper reports the conditioning effects of short days, 6 and 10 hours, respectively, for a period of 3 weeks beginning at age 20 …

The avian egg may be divided into four parts: the yolk, the albumen or white, the shell membrane, and the shell. The absolute and relative weight of the yolk, the albumen, and the shell varies for different species and also within narrower limits for eggs of the same species as shown by the summary of Grossfeld (1938, pp. 70–78). Asmundson (1939) has also shown that the absolute and relative weight of the shell membrane varies for different species, the turkey (Meleagris gallopavo) egg having a heavier shell membrane than the chicken (Gallus demesticus) egg. There was also some indication that the shell on the larger turkey eggs may weigh relatively less than the shell on the smaller chicken eggs, although the shell on turkey eggs is thicker, on the average, than the shell on the chicken eggs. This finding prompted us to inquire into the influence of egg volume, . . .

PAYNE et al. (1957) have reported a correlation of +0.39 between body weight of turkey hens and the weight of their egg. Funk (1950), however, did not observe a consistent difference in numbers of eggs laid by hens differing in body weight. Fertility and hatchability were found to be correlated negatively with body weight by Kondra and Shoffner (1950). Fertility was related to posture in males according to Robblee et al. (1957). Rooney (1957), by using artificial insemination at relatively long intervals, was able to estimate the incidence of natural mating occurring in Broad Breasted Bronze hens. Selection at different ages for increased body weight at maturity (Abplanalp et al., 1963) provided several lines of turkeys on which the effect of selection for body weight on reproduction was tested. MATERIALS AND METHODS Parental stock was selected from Broad Breasted Bronze turkeys using weight as the main criterion. The selection of…

Data on the incidence of paralysis and lymphomatous tumors in a flock of 542 pullets of six different breeds indicate the presence of both in 14 out of 52 paralyzed pullets, while an additional 22 had tumors but were not paralyzed. The association of paralysis and tumors may have been due to chance. The evidence presented, while not conclusive, points to the inheritance of resistance to paralysis. This is indicated particularly by (1) differences in the proportion of paralyzed pullets in different breeds, and (2) absence of paralysis among the progeny of certain males and in certain large families. The data obtained point to a simple mode of inheritance.

AN INCREASE in the weight of the ovary and oviduct of immature female fowl after injection of pregnant mare’s serum was reported by Asmundson and Wolfe (1935). Breneman (1936) also found that there was a marked increase in the weight of the gonads (ovaries and testes) of newly hatched chicks; mare’s serum and follicle stimulating hormone giving maximum response while there was some increase when luteinizing hormone and pregnancy urine were injected. Domm and Van Dyke (1932) had previously reported that there was an increase in the weight of the ovary after injection of extracts of the anterior pituitary into immature female fowl while Evans and Simpson (1934) have reported that the ovary of the pigeon increases in weight after injection of pregnant mare’s serum. The present paper deals with certain experiments which show in some detail what responses are obtained with varying amounts of mare gonadotropic hormone when injected . . .

WITH the multiplicity of strains of turkeys now available, it has become desirable to find out (1) what measurements show the established strain differences best, (2) to what extent the apparent differences are due merely to differences in size and to what extent they are independent of such size differences, and (3) what the mode of inheritance of these differences is. This paper deals with the first two problems. The measurements to be used should preferably be (1) simply and easily made and should (2) differentiate between desirable and undesirable conformation as judged by preferences of buyers and consumers. The measurements that have been used fall into two groups—linear measurements of bones (for example, length of the tarsometatarsus or shank) and body dimensional measurements (for instance, depth of body). Obviously the latter may be determined by the size and conformation of many organs. Most of the measurements reported have . . .

A mosaic occurred in theF 2 generation of a cross of a Bronze male on a Bourbon Red female. This bird was bronze on the head, neck, shoulders, tail and part of the rump with some patches of bronze feathers surrounded by red on the wings. The rest of the bird was covered with feathers typical of the Bourbon Red variety which thus formed a continuous band around the middle of the body. The difference in the plumage colour of the two varieties was found to depend upon a single pair of autosomal genes, the ratio in theF 2 generation being approximately 1 Bronze to 2F 1 pattern to 1 Bourbon Red. The hybrids resembled the Bronze variety more than the Bourbon Red, particularly in down pattern and adult plumage, but were readily distinguished from both parental varieties. The possible mechanisms that may account for this case are discussed.

IN THE first paper (Asmundson and Biely, 1932) of this series, results were presented on the growth to eight weeks of chicks on different fish meals. In that series of experiments, it was found that chicks fed rations supplemented with salmon and pilchard meal weighed just as much at eight weeks as did chicks receiving an equal amount of protein from milk. There was some indication, however, that pilchard meals varied in quality. This was indicated by differences in the average weight at eight weeks of two groups of chicks fed different pilchard meals. The present series was started to determine whether there was any consistent difference in the rate of growth of chicks to eight weeks when fed samples of pilchard meals from different reduction plants. The pilchard meals were obtained during the 1931 fishing season from reduction plants † situated at Ecoole, Matilda Creek, and Nootka on the west . . .

It is generally conceded that infection with salmonella pullora, the causative organism of Bacillary White Diarrhea, affects reproduction in the domestic fowl. The average fertility and hatchability of eggs and livability of chicks have been shown to be decreased by Bacillary White Diarrhea infection and it has been assumed that egg production was likewise affected, but no conclusive data have been published to support this assumption. A difference in the total annual egg production of reactors and non-reactors is, in fact, not specifically referred to in the literature on the subject. Hooker’s1 complete review of Bacillary White Diarrhea infection of fowls, Beaudette’s2 briefer review of the same subject and the more recent publication of Bushnell, Hinshaw and Payne3 fail to throw any light on the effect of the disease on the egg production of fowls. Rettger and Stoneburn4 note that infected hens seem to be poor layers especially in the . . .

THE consequences of one or more of a large number of isolating mechanisms are that birds of different species or genera either do not mate or mate only rarely (Dobzhansky, 1951; Riley, 1952; and others). Ecological isolation kept apart the three genera with which we are here concerned for a long time before they were brought together by man. Even then, sexual or psychological isolation has reduced or prevented mating between them. Only between the chicken (Gallus) and ring-necked pheasant (Phasianus colchicus) have many natural hybrids been recorded (Suchetet, 1896; Wheeler, 1910; Poll, 1912; Cutler, 1918; Serebrovsky, 1929; Yamashina, 1942). Turkeys (Meleagris gallopavo) are placed in a different family from pheasants and chickens (Friedmann, 1946) and are much larger birds. Despite the additional barrier of size, one natural hybrid of the turkey and pheasant has been reported (Edwards, 1761) but none between the turkey and chicken. The isolating mechanisms may . . .

THE riboflavin requirements of the chick and the consequences of riboflavin deficiency have been fairly well established by Lepkovsky and Jukes (1936). Jukes (1938) found that the riboflavin requirements of chicks and turkey poults for maximum growth were about the same. Later work has substantially confirmed this observation, the requirements of chicks being about 250 micrograms of riboflavin per 100 grams of feed (Bethke and Record, 1942) and that of the turkey poult 270 (Patrick et al. 1944). The consequences of riboflavin deficiency in the turkey poult are not as well established as in the chicken. Lepkovsky and Jukes (1936) found that a dermatitis developed in riboflavin-deficient turkey poults, and Jukes (1938) later confirmed this observation. No paralysis was observed by these investigators. Patrick, Darrow, and Morgan (1944) did not find dermatitis in their riboflavin-deficient poults, but did find it in biotin-deficient poults. This raised the question of whether or . . .

THE mature White Leghorn pullet responds to low light intensities (such as 0.5 or 1.0 foot candle) just as well as to more than 30 foot candles (Roberts and Carver, 1941; Nicholas, Callenbach, and Murphy, 1944). Turkey hens, like chickens, will start egg production earlier if artificial light is used to lengthen the day (Albright and Thompson, 1933; Scott and Payne, 1937; Charles Wilcox, Flagg and Tepper, 1938; Wilcke, 1939). Until now, apparently, no one has determined the effect of different light intensities upon the onset of ovulation in turkeys. The present paper reports data on this problem and on the response of genetically early- and late-maturing birds to artificial lengthening of the day. The need for such information became apparent in 1942 and subsequent years, when the enforced use of dim lights resulted in a less positive response (delay in starting to lay and a consequently lower initial rate . . .

The experiments here presented were part of an investigation into the formation of the hen’s egg (in press). Several substances were tried but only the results of trials with follicular hormone and dessicated thyroid are given in this report. Different gland preparations have been tried on domestic fowls by many investigators but only a few have used hens for this purpose and they have usually not been directly interested in the effect of these substances on the eggs laid. Consequently, there is very little information with regard to the effect of hormones on the formation of the hen’s egg. In the following paragraphs, some of the literature dealing with the effects of hormones on reproduction in birds is briefly reviewed. A. REVIEW OF THE LITERATURE Pearl and Surface (1914) reported that intra-abdominal injections of an extract of corpus luteum stopped ovulation when large doses were used. Smaller doses had little . . .