344
ABSTRACTS
Thirty yearling ewes with an average body weight of 85 pounds were used. Alfalfa
hay only was fed ad libitum throughout the study ; during this time they were kept inside
a barn, except for brief exercise periods in a dry lot. Daily vaginal smears were taken,
by use of a glass speculum and a glass rod, within 1 to 2 inches from the cervix. The
mucus was noted and recorded as ' thin, thick, or cheesy '; no mucus was recorded as
' clear '. Examination of the mucus was made microscopically with eosin under the
low power objective. Large, round, nucleated epithelial cells, cornified epithelial
cells and leucocytes were estimated and evaluated as none, very few, few, several, many
or very many.
A few ewes, usually four, were injected at a time during May, June and July. All
ewes were tested daily for oestrus by an aproned male. Untreated ewes served as control
animals in each case. Finally the ewes were spayed in order to check the ovarian res-
ponse to the treatment.
Progynon-B, the benzoic acid ester of dihydrofollicular hormone, was injected
subcutaneously in the shoulder region. Pregnant mare serum, prepared by acetone
precipitation and desiccation and assayed with rats, was injected subcutaneously as an
aqueous solution into the shoulder and flank regions. Sheep anterior pituitary extract
prepared from acetone-desiccated powder by a triple water extraction followed by pre-
cipitation and then drying with acetone after centrifugation, and assayed with rats,
was injected either subcutaneously or intravenously.
Pregnant mare serum, in single 100 rat unit subcutaneous injections, produced
ovulation in seven out of eight anoestral ewes, but without apparent signs of oestrus.
Of four ewes receiving pregnant mare serum and Progynon-B simultaneously, two
ovulated with no signs of heat; one of the two not ovulating showed signs of oestrus.
Three of the four ewes receiving pregnant mare serum followed by Progynon-B ovulated ;
the fourth neither ovulated nor showed signs of oestrus. Eight ewes received Progynon-B
alone ;five of them came into heat. Four ewes receiving sheep anterior pituitary extract
all ovulated with no apparent signs of oestrus ; this was also true of one ewe receiving
pregnant mare serum and sheep anterior pituitary extract and one ewe receiving pregnant
mare serum, sheep anterior pituitary extract and Progynon-B.
Doses were 2.5 grams of pregnant mare serum in single subcutaneous injections
and 2 .5 gram-equivalents of the sheep anterior pituitary extract in four daily sub-
cutaneous injections of 0.5 gram-equivalent each followed by an intravenous injection
of the same amount. Progynon-B doses were 1000 or 2000 rat units. Assays showed
that the dose of pregnant mare serum contained approximately twice as many rat units
as that of anterior pituitary extract. In spite of this, however, the ovulation rate was
greater in ewes which received the pituitary extract. The authors suggest that the
method of injection and/or a greater response per rat unit of pituitary extract may
explain this difference. Oestrus was not regularly produced with either small or large
doses of Progynon-B, neither did the study show which dose was more successful.
No significant difference occurred in the vaginal smears during ovulation with
induced oestrus from those in ewes with induced oestrus without ovulation. [J. N. W.]
A genetic history of Hampshire sheep. R. C. CARTER (1940). J. Hered. 31,
2, 89
T HE Hampshire breed of sheep originated in the counties of Wilts, Hants, and Berks
in southern England, where the Wiltshire Horned and Berkshire Knot breeds were
found in 1830. Mr. Wm. Humphries, it is reported, used two Southdown rams to
linebreed within his flock which was closed to outside blood. He fixed a type which
proved to be the foundation of the Hampshire breed. The Hampshire Down Sheep
Breeding Association, in England, was organized in 1889, issuing its first flock book
in the following year. Rams were registered individually, the ewes by the flock. Since
1908 eligibility for registration has been limited to animals whose sire and dam are both
registered.
Importation into the United States, starting in 1855, brought about the establish-
ment of the American Hampshire Down Sheep Breeding Association in the same year
as the English organization. Rams and ewes were registered individually; only those