cated as a major cause of low fertility. The first of these is 
a study by Parker (1961) of the low fertility problem in Cornish 
cockerels. He compared the fertility in flock matings of New 
Hampshire, Delaware and Cornish cockerels and found that the 
fertility from Cornish males was 10 to 12 per cent lower than 
that from males of the other breeds. Similar results were ob- 
tained in another year. When the fertility of Cornish males 
was compared with that of New Hampshire males and with New 
Hampshire x Delaware males in flock matings, again Cornish fer- 
tility was low. However, when matings were conducted using 
artificial insemination, the fertility of the Cornish was equal 
to that of other males indicating that the fertilizing capacity 
of the semen was not at fault. In single male mating pens, it 
was found that Cornish males failed to mate with about 8 per 
cent of their flock mates; and in flock-mated pens, the same was 
found to hold true. It was further found that certain females 
tended to remain unmated during much of the breeding season when 
mated to Cornish males but not when mated to New Hampshire males. 
Parker concluded that part of the low fertility of Cornish males 
was due to their failure to inseminate naturally a substantial 
percentage of their flock-mates, 
In studying factors which affect fertility in Jersey 
Buff turkeys, Smyth and Leighton (1953) found that the percent- 
age of total successful matings of males was of major importance 
in determining fertility. They found a correlation coefficient 
of 0.50 between the percentage of completed matings and fer- 
tility. In their study of seven turkey toms, mating efficiency 
was found to vary from 44.3 to 87.5 per cent. Efficiency was 
considered to be a trait of the male, the female having little 
influence or responsibility in this regard. The males with the 
highest per cent of completed matings had good balance, were 
patient and completed matings with a minimum of difficulty. 
Males with low percentages of completed matings had poor coe 
ordination by comparison, and were characterized by peculiar 
mating habits -- for instance, treading the floor and treading 
the female when oriented in a head=-to-rear position. 
Hale (1955) conducted a somewhat similar study using 
White Holland turkeys. He agreed that efficiency of males in 
completing matings was very important in the expression of 
fertility since if the mating were interrupted at the stage 
where the male treads and the female everts, the female will no 
longer be sexually receptive and hence will likely be infertile. 
He found a correlation coefficient of 0.79 between fertility and 
efficiency of males in inseminating females during attempted 
matings. The males studied showed marked individual variations 
in their efficiency. Low social rank contributed to reduced 
efficiency. Some of the best males were of the Broad Breasted 
Bronze variety and some of the worst were Beltsville Small 
Whites indicating that size and conformation are perhaps not of 
such great importance as originally thought. Males character- 
ized by low sex drive frequently tramped the neck of the female 
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