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Research on qualitative genes of poultry is underway at several locations in the United States. Some of the research is done cooperatively by poultry scientists under Regional Research projects NE-...

Research on geese is underway at several locations in the United States. Much of the research is related to disease producing organisms such as Escherichia coli, Heterakis gallinarum, Histomonas me...

INTRODUCTION TURKEYS are noted for extreme sex dimorphism in body weight, the females of most varieties weighing about 65 percent as much as males at 24 weeks of age. Asmundson (1948) noted that 60 percent of the variation of body weight in turkeys is due to sex. Therefore, it would seem that, with such wide differences existing between sexes, the magnitude of such differences might be influenced by heredity. The recent interest in turkey broilers emphasizes the need for uniformity in body weight at market age. Producers are finding that when males reach broiler weight the females are too small and conversely when females are the proper weight the males are too heavy. In attempts to overcome the difficulty some growers are using sexed poults and raising the sexes separately while others are marketing the males two or three weeks earlier than females. Producers could market a more uniform product . . .

THE fact that the activity of the thyroid glands of all adult vertebrates serves as a powerful metabolic regulator is well established, yet the extent to which altered thyroidal activity in animals can be utilized by man for more efficient animal production remains very limited. Reviews of the literature applicable to poultry have been provided by Blaxter et al. (1949), Sykes et al. (1953), and Sturkie (1954). A further review of the general subject at this time seems unnecessary. Shaklee and Shaffner (1952) demonstrated that the degree of response of the thyroid gland to thiouracil feeding was amenable to selection. By use of the sib test it was possible to develop lines of New Hampshires differing markedly in this respect. These selection experiments were initiated on the assumption that the weight of the thyroid gland after a period of thiouracil feeding might provide some indication of the activity of the …