maciation and
weakness, or a prolonged semistarvation in winter may be sufficient cause.
It is, however, much more common as the result of degeneration or extensive
and destructive disease of the secreting organs (testicles, ovaries) which
elaborate the male and female sexual products, respectively. Such diseases
are, therefore, a common cause of sterility in both sexes. The old bull,
fat and lazy, becomes sluggish and unreliable in serving, and finally gets
to be useless for breeding purposes. This is not attributable to his weight
and clumsiness alone, but largely to the fatty degeneration of his
testicles and their excretory ducts, which prevents the due formation and
maturation of the semen. If he has been kept in extra high condition for
exhibition in the show ring, this disqualification comes upon him sooner
and becomes more irremediable.

Similarly the overfed, inactive cow, and above all the show cow, fails to
come in heat at the usual times, shows little disposition to take the bull,
and fails to conceive when served. Her trouble is the same in kind, namely,
fatty degeneration of the ovaries and of their excretory ducts (Fallopian
tubes), which prevents the formation or maturation of the ovum or, when it
has formed, hinders its passage into the womb. Another common defect in
such old, fat cows is a rigid closure of the mouth of the womb, which
prevents conception, even if the ovum reaches the interior of that organ
and even if the semen is discharged into the vagina.

_Preventive._--The true preventive of such conditions is to be found in a
sound hygiene. The breeding animal should be of adult age, neither overfed
nor underfed, but well fed and moderately exercised; in other words, the
most vigorous health should be sought, not only that a strong race may be
propagated, but that the whole herd, or nearly so, may breed with
certainty. Fleming gives 79 per cent as the general average of cows that
are found to breed in one year. Here more than a fifth of the progeny is
sacrificed and a fifth of the product of the dairy. With careful management
the proportion of breeders should approach 100 per cent. The various local
and general obstacles to conception should be carefully investigated and
removed. The vigorous health which comes from a sufficiently liberal diet
and abundant exercise should be solicited, and the comparative
bloodlessness and weakness which advance with undue fattening should be
sedulously avoided.