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ALTHOUGH the literature is replete with studies of the concentrations and in terrelations of the hormones during the physiological state of pregnancy in A. JV the mare, investigationsinvolving similar studies during the various phases of the estrous cycle of the non′pregnant mare are rare. Zondek (I) reported comparative data upon the estrogenic hormones in the urine of the pregnant and non-pregnant mare, and more recently Cole and Goss (2) cited the presence of gonad tropic hormone in the blood of the latter. However, nowhere in the literature are studies available upon the estrogens of the urine or follicular fluid in relation to the various phenomena of the estrual cycle. For periods beginning in February or April and ending about the middle of July of the years 1937,1938, and 1939 detailed studies were made in the physiology of the non-pregnant mare at the United States Range Live-Stock Experiment Station, Miles City, Montana.

ALTHOUGH the physiology of reproduction of the female domestic fowl has been very, carefully studied by a large number of investigators, relatively mew studies have been made with the male. Important contributions have been made in this field by Hutt (1929), Penquite, Craft, and Thompson (1930), Burrows and Quinn (1937), Burrows and Titus (1939), Munro (1935, 1938, and 1938a), and most recently by Sampson and Warren (1939). The purpose of these investigations was to obtain information concerning the sexual activity and sperm production in the male domestic fowl. EXPERIMENTAL The data presented herein are based upon observations with New Hampshire males which were hatched early in the spring of 1938. Unless otherwise indicated, the semen was collected by means of a semen collector especially devised for use in the studies (Parker, 1939). The males were all given 36 hours of sexual rest before they were released into a small enclosure . . .

Conclusions1. At sperm concentrations from 1 to 6 billion cells per cc an increase in concentration was accompanied by a decrease in sperm respiration rate. At concentrations of 0.2 to 1 billion sperm per cc this effect of concentration was not invariably observed. 2. In contrast with the behavior of sperm cells, respiration rates of yeast cells remained constant at concentrations from 1 to 8 billion cells per cc. 3. The effect of sperm concentration on sperm respiration rate does not appear to be due to changes in pH, diminished supply of O2 to individual cells, an enzyme, or products of metabolism. 4. When comparisons are to be made of relative respiration rates of semen samples, the samples must be adjusted to the same level of sperm concentration.

Conclusions1. Extra-cellular respiration was exhibited by seminal plasma of the boar. Oxygen consumption of seminal plasma ranged from 5 to 22% of that of the whole semen. The R.Q. was unity. After the plasma had been held for 5 minutes at 100°C respiration at reduced intensity was observed. Respiration was not exhibited by that fraction of the seminal plasma which passed through a porcelain filter. 2. The metabolic rate of the ejaculate of a cryptorchid boar was of the same order as that of seminal plasma. 3. No errors in measurement of oxygen consumption were detected which could be attributed to the presence of bacteria.

THE development of the sex organs in the male domestic fowl is of concern to poultry breeders as well as scientific workers. During the late summer and fall months relatively large percentages of infertile eggs are often produced by matings in which yearling and older cocks are used. With an increasing tendency toward fall hatching in some sections this infertility results in considerable economic loss. The possibility of using early hatched cockerels as breeders makes it desirable to have information on the sexual development of young males. Additional data on the normal development of the sex organs of chicks should prove of some interest to the endocrinologist. The studies described herein constitute one phase of a project investigating some factors affecting the fertility of the domestic cock. The work was done at the Missouri Agricultural Experiment Station. REVIEW OF LITERATURE Studies of the development of testes and combs of male . . .

Conclusions(1) Hydrogen ion concentrations of the media in which sperm of the boar and ram are suspended definitely influence respiration rates of the sperm. (2) Optimum pH for respiration of boar semen is 7.2 to 7.3, and for ram semen 7.0 to 7.2. (3) As the pH is raised or lowered from the optimum the respiration rate progressively declines. (4) Unit change in pH has significantly less influence on respiration rate of ram sperm than on that of boar sperm. (5) Differences of 0.4 pH unit or more are accompanied by significant differences in respiration rates of boar and ram semen. Conditions for valid comparisons of different samples are presented.

Published October 1951. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog