ABSTRACTS
341
over an extended period and still deliver a satisfactory ejaculate, especially if the semen
is to be used artificially. If more ejaculates are obtained., the bull's fertility is lowered.
Stored semen when used 24 or more hours after collection compared favourably in ferti-
lity with average fresh semen samples. Cows bred early in heat and late in heat are less
likely to conceive than those bred 18 to 24 hours after the onset of external symptoms of
heat. Virgin heifers conceived more readily than mature cows due to low incidence of
disease in virgins. Cows with normal genital tracts conceived much more readily than
cows affected with disease of genital tracts.
Certain problems in technique and variation in semen samples are discussed such as
preparation of a new semen collector for use, methods of cleaning it, the temperature of
the collector when used, care to be taken to protect the semen against sudden temperature
changes, methods of transporting semen, dilutors and the quality, colour and consistence
of semen. [P. R. K.]
Inheritance of broodiness in Rhode Island Reds. F. A. HAYS (1940).
Massachusets Agri. Exp. Bull. 377, 1-11
B REEDING tests on the inheritance of broodiness in Rhode Island Reds were carried
out over a period of 10 years with 1767 females bred from 72 males and
210 females. The results show that the inheritance of broodiness in a stock can be
measured fairly accurately by measuring the number of broody periods in the first
laying year. Of the daughters of dams which had only one broody period in their first
laying year 72 per cent were non-broody, 10 per cent were broody once, 7 per cent were
roody twice and 11 per cent were broody three or more times. In another group of dams
which went broody twice only 28.3 per cent of the daughters were non-broody and more
than 39 per cent had three or more broody periods.
In the case of dams which showed no broodiness during their first year 89.3 per cent
of the daughters were non-broody, 7.1 per cent went broody on one occasion and 2 .2
per cent went broody twice and 1.3 per cent were broody three or more times. In dams
which showed no broodiness over a period of two years 92.8 per cent of the daughters were
non-broody and the majority of the others went broody only on one occasion.
The record of broodiness from daughters of dams that were free from broodiness
over a period of three years was very similar to that of daughters bred from dams which
were non-broody for a period of two years.
From an analysis of the results obtained it is concluded that broodiness depends
upon the inheritance of two complementary dominant genes, A and C, neither of which is
sex-linked. [A. J. M.]
The effect of ration deficient in phosphorus and protein on ovulation, oestrus
and reproduction of dairy heifers. L. S. PALMER, T. W. GULLICKSON,
W. L. BOYD, C. P. FITCH and J. W. NELSON (1941). J. Dairy
Sci. 24,199
I N order to study the effect of rations low in phosphorus and protein on ovulation,
oestrus cycles and sexual activity, the authors undertook an experimental study
in 1933. Observations were made on eleven grade Holstein animals over a period of 24
to 59 months. These animals were fed on rations consisting of prairie hay obtained from
a phosphorus-deficient farm. In addition, a small amount of grain mixture was also
given. The average amount of phosphorus in hay was 0 .066 per cent and of crude
protein 5.31 per cent.
Except for brief periods, or during lactation in the latter phases of the study, the
animals consumed 5 to 8 gm. phosphorus and 0.4 to 0.75 pound digestible crude protein
daily, depending on their age and their appetite for the hay. The digestible crude protein
comprised between 5 and 10 per cent of the total digestible nutrients.
Frequent observations were made for evidences of pica, physical condition and general
behaviour and it was found not only that most of the animals grew at a subnormal rate,
but they developed the course, unthrifty appearance, disproportionately large heads,
F