94 ABSTRACTS
collect the semen samples from the bulls; in each case
1-2 c.c. of semen was used to inseminate the cows and
laboratory examinatien was made with the remaining
portion of the semen to evaluate its quality. The labora-
tory examination of semen included (i) total amount of
ejaculate (ii) microscopic estimation of motility (iii)
spermatozoa counts (iv) tabulation of the number and
different kinds of abnormal spermatozoa (v) pH determi-
nation. Semen samples were evaluated as excellent, good,
fair or poor, and the sperm counts were made with haema-
cytometers with normal saline as the diluting fluid. In
making semen smears, ordinary blood smear method was
used, which were, stained with eosinhaematoxylin method
after being fixed in Schaudinns solution. Hydrogen-ion
determinations were made with a potentiometer with
glass and colomel electrodes.
The authors could not find any correlation between
the quality of the semen samples as evaluated by the
laboratory methods employed by them and the actual
breeding performances. In one bull, however, a slight
negative correlation was noted between the number of
abnormal forms of spermatozoa and the fertilizing ability.
The results obtained by the authors demonstrate a consi-
derable diurnal and daily variations in the characteris-
ties of the semem, differences being more pronounced in
samples obtained from bulls in excessive sexual use. A
correlation was noted between the motility and viability
of spermatozoa and changes in the pH values of semen in
the first few hours after the sample has been taken. Sperm
motility has been found to be a factor in causing the
hydrogen-ion changes of semen. Very motile samples
showed a gradual rapid decline in pH. Semen samples of
two bulls known to be of poor fertility were usually
alkaline and on standing, the pH values increased. When
the spermatozoa were inactivated by refrigeration or
treatment with 0.2 c. c. of a 1:1,000 solution of bichlo-
ride of mercury, the rapid decline in pH was prevented.
Hydrogen-ion determinations were also made on seminal
vesicle secretions and ampuli contents of 17 abattoir
spocimens; pH of the former varied from 5. 59 to 6. 48
and that of the latter from 5. 66 to 6. 33. It has been
suggested that pH deteminations of semen samples should
be made immediately after collection.
A few preliminary experiments have also been made
to find out whether or not there is any correlation bet-
ween the ascorbic acid content of semen and breeding
performances of the bull. Seventeen semen samples obtai-
ned from five bulls were analysed and the ascorbic acid
content of semen varied from 0. 97 mg. to 8.08 mg. per
100 c. c. of semen. Although the ascorbic acid content of
semen from one bull with poor breeding performance was
rather high, the results obtained indicated a positive
correlation between ascorbic acid content of the semen
samples and the breeding efficiency of the bulls.
The authors remark that no single test can be used to
judge the fertilizing quality of semen and that even
when all the common tests are made the evaluations are
of doubtful value except in extreme cases. [P. B.]
A method of determining the reproductive effi-
ciency of cattle. H.E. KINGMAN and H. E.
KINGMAN, (1942). J. Amer. Vet. Res. 3
IN this article the authors have shown how to keep and
arrange records relating to reproduction in cattle so that
the breeding histories of individuals or groups can be
studied separately or collectively. They have discussed
the importance of statistical analysis of data for deter-
mining the reproductive efficiency of the herd. Various
methods of calculation of reproductive efficiency
been discussed and their merits shown. The following
been found to be the most suitable one.
Cq (Calf equivalent)/Cr (Cow years) ×100=R (%Reproduc
ciency), when
Cq=M (Months of Normal Pregnancy)/ 9 (Gestation period in cat
and Cr =
ber of cows in each year ; the basis of calculation
cow year is 12 months, but when a cow is in the herd
9 months or more, she is included in the 12 month gr
The general formula for estimating the breeding effici
ency of the bull consists of dividing the number of succes
ful services by the total number of services and mult
ying by hundred, the result is expressed in percent.
methods of calculation for comparing the reproduc
efficiency of a bull by various system of breeding
when comparing the reproductive efficiency of diffe
bulls by the same method of breeding have also 1
given. The forms used at the Wyoming Hereford Ra
Trust for keeping the daily reports, records of indivi
cow compiled from the daily reports and veterinary
reports have been reproduced and their advantages di
ssed. The methods of analysis have been illustrated
charts, tables and graphs. [P. B.]
The bacterial content of goat milk. C S. BRY
(1942). Amer. J. vet. Res. 3. 92-95
THIS study was undertaken to determine the incide
of infectious and non-infectious mastitis in dairy g
and the effect of udder infection on the quality
quantity of the milk produced. The tests employed
(1) standard plate count, (2) methylene blue reduct
test and (3) resazurin reduction test. The chemical
cellular quality was noted by finding the percentage
chloride, the pH and leucocyte content of the milk.
In all the milk samples from 380 goats in 15 herds
per cent had streptococcal mastitis, 1.3 per cent
staphylococcal mastitis and 0.5 per cent had non-in
tious mastitis; and 95.9 per cent had neither infect
nor non-infectious mastitis. The distribution of same
among the various classes of the tests employed b
close relationship to the results obtained upon tes
similar samples from cows; but the chloride determ
tion, pH test and leucocyte count of milk cannot be
to determine the udder infection, although they acc
tely determine the chemical and cellular content of
milk.
The bacteriologic quality of the milk produced
goats, with and without udder infection, was determine
by the methylene blue and resazurin reduction tests
the standard plate count; the results varied from
sample to the other.
Ninety-seven and one-half per cent of the non-infec
animals gave milk of class I methylene blue test qual
94.0 per cent of class I resazurin test quality, and
per cent had a bacteria count of over 1,000. Consider
the goats with staphylococcal mastitis, 56.0 per
gave milk of class I methylene test quality, 40.0 per
class I resazurin test quality, and 12. 0 per cent h
bacteria count of more than 1,000. The quality of
produced by the goats affected with streptococcal
tis was greatly reduced; only 40. 0 per cent gave mill
class I methylene blue test quality, 37. 0 per cent
I resazurin test quality, and 50. 0 per cent yielded
with a bacteria count of more than 1,000. [R. H.]