ABSTRACTS
Age as a factor influencing breeding efficiency in a dairy herd. G. A.
BOWLING, D. N. PUTHAM AND R. H. ROSS (1940). J. Dairy Sci. 23, 1171.
O NE objection to the exclusive use of proved bulls in a dairy herd is the larger numbe
of services required for heifers when old bulls are used.
The Breeding efficiency is of considerable economic importance in the case of dairy cattle.
The authors studied data found in the herd books of the West Virginia Agricultural
Experiment Station to determine the effect of the age of the bull on the number of
services required per conception for females grouped by number of conceptions. The
records of only animals which had calved or those known to be breeders were consider-
ed. Bulls ranged in age from one to fifteen years. Forty-three bulls and seven
hundred and six cows were included in the study.
The average number of services per conception for cows, using bulls of different ages,
was 2.79, 1.86, 1.79, 1.82 and 1.80 for the first, second, third, fourth, and the fifth
and sixth conception respectively. When age of both the bull and the cow was con-
sidered the breeding efficiency of bulls under four years was found to be better than older
bulls for heifers. This was also true for the second conception, but to a smaller extent.
This greater breeding efficiency of young bulls did not hold for cows bred for the third
or higher conception. The services per conception for bulls under four years varied
from 1.49 to 1.62 for the first conception, 1.45 to 1.58 for the second, 1 . 38 to 1.76 for
the third, 1. 57 to 2 .00 for the fourth, and 1.33 to 1.77 for the fifth and sixth. For bulls
over four years of age the ranges of services per conception were 1. 79 to 5 .50, 1 * 58 to
2.52, 1.42 to 2.52, 1.25 to 3.00, and 1.20 to 3.14 for the first, second, third, fourth,
and fifth and sixth respectively. A gradual decrease in breeding efficiency occurred as
the age of the bull increased. With cows of all ages this lower efficiency of the bull be-
came significant after six years of age : after thirteen years of age the breeding efficiency
of bulls dropped off markedly. Prompt conception in heifers, it is shown, is more certain
if young bulls are used.
[J. N. W.]
Notes on the artificial insemination of horses in the Philippines. FLORENCIO
A. SOLIVEN (1940). Phil. J. Ani. Husb. 7, 459.
T HE proper introduction of sperm cells obtained from the male into the sexual appara-
tus of the female for the purpose of effecting conception without sexual intercourse is
called artificial insemination. ' This practice was first used by the Arabs but present
methods are largely due to Prof. Ivanov of the Soviet Russian Government. The instru-
ment, cleanliness of the operation and -the quality of the semen determine the success of
artificial insemination. Collection of horse semen may be carried out by the artificial
vagina or by recovering that portion of the ejaeulum which remains in the penis after
natural intercourse.
The artificial vagina consists of a large outer metal tube, long enough to receive the
full length of the penis of the stallion, with a thin rubber lining. The space between the
tube and lining is filled with warm water and the inside lubricated with vaseline or liquid
petrolatum. At the outer end a small rubber sack or breeder's bag is attached to the
lining to receive the ejaculum. For insemination a speculum is required for insertion
into the vagina of the mare ; it should reach the cervix and extend outside the vulva a
few inches. A syringe, preferably glass, fitted with a long rubber tube is used for inject-
ing the semen sample through the cervix into the uterus. Inserting capsules containing
semen into the uterus is suggested for mares with abnormal cervical passages.
The sanitation of the operation must be carefully controlled. If semen is to be re-
covered from the penis of the stallion after natural intercourse, the tail, buttocks, anus
and vulva of the mare and the entire penis of the stallion must be thoroughly washed
with warm water and soap. If semen is to be obtained by the other method the glass
parts of the artificial vagina must be carefully washed with hot soda water, dried and
rinsed with 65 per cent alcohol. For the rubber parts soap may be used with the hot water,
followed by the alcohol rinse.
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