Bronze variety. One male of each set was assigned to each of 
the following treatments: semen collected once weekly, twice 
weekly, three times weekly, and on various series of consecu- 
tive days. They found that volume per sample was not. affected 
except when semen was collected daily. In this case, volume 
collected per day decreased steadily and then became stable by 
the fifth consecutive day of collection. Apparently, sperm 
concentration was not affected by frequency of ejaculation. In 
the second study, semen was collected at longer intervals <«- 
once each week, once every two weeks, and once every four weeks. 
They found no difference between treatments in sperm concentra- 
tion, but found that semen volume was reduced in males 
ejaculated every two and every four weeks. 
These studies were carried a step further by McCart- 
ney, Chamberlin, Carter and Wyne (1958), who studied the ef- 
fects of frequency of semen collection on fertility. They used 
Small=type White turkeys, the males being ejaculated daily, 
five days per week. Pooled semen samples were inseminated to 
a different group of females each day so that the qualities of 
each day's sample could be evaluated. They found no effect of 
frequency of semen collection on sperm concentration, but found 
that semen volume decreased gradually to the fifth consecutive 
day of collection. Fertility was not affected. 
c) Effect of external environment on semen production. 
Recently there have been several papers dealing with 
the effects of season on avian semen. In general, these re= 
ports indicate a rather marked influence of time of year on 
quantity and quality of semen, and might conceivably have some 
bearing on studies of the inhibition of fertility. 
Schindler, Volcani and Weinstein (1957) observed the 
motility of semen from White Leghorn chickens obtained over a 
twelve-month period. Semen was collected on three consecutive 
days of each month and pooled for study. They found that mo- 
tility of sperm was highest in May; it decreased to October, 
and then increased to a high level by January. Concurrently, 
4t was observed that molting started in July, was intense in 
September and ended by November. They also noticed that sperm 
motility was high in increasing daylight and was reduced in 
periods of decreasing daylight. They concluded that their data 
indicated a possible relationship between stage of molt and 
motility of sperm, as well as a possible relationship to changes 
in temperature and length of day. 
Seasonal variations in semen characteristics of adult 
Fayoumi chickens were studied by Kamar and Badreldin (1959). 
They used 18 males, collecting semen twice each month over the 
course of a year. Measurements were taken of semen volume, 
motility, concentration, per cent live sperm and per cent abe 
normal sperm. They found monthly and seasonal variations in 
each characteristic studied. The best semen quality, as measured 
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