Masatoshi Takeishi

Determination of optimal time for mating by artificial insemination with chilled semen using luteinizing hormone surge as an indicator in beagles

Artificial insemination (AI) was conducted using the second fraction of semen, which was collected from 15 male dogs, diluted to a total sperm count of 100x10(6) for each insemination with egg-yolk Tris (eyT) citrate acid buffer and incubated at 4 degrees C for 48 hours. Luteinizing hormone (LH) surge was detected to determine the optimal time for mating using canine LH assay kits. Artificial insemination using 100x10(6) sperm was performed on the fourth and sixth days or the fifth and seventh days after the LH surge. The conception rates were 33% (4/12) and 89% (8/9), respectively; the whelping rates also showed similar results. Serum LH and follicle stimulating hormone (FSH) concentrations were measured in nine dogs, and the mean LH concentration (+/- standard deviation) at LH surge was 15.77+/-7.66 ng/ml. The time of the LH surge detected by the canine LH assay kit was very similar to that measured by radioimmunoassay (RIA).

Shrinkage in the horizontal dimensions of the vulva (vulvar shrinkage) as an indicator of standing heat in the beagle.

During the proestrous and estrous periods in 12 beagles, the following parameters were measured daily: the horizontal dimensions of the vulva, vaginal cytology, and serum luteinizing hormone (LH) and progesterone concentrations. Measurements of serum LH concentrations allowed for the identification of the LH surge and the optimal time for artificial insemination (AI). Nine out of the 12 beagles became pregnant through AI and completed a gestation. Shrinkage in the horizontal dimensions of the vulva (i.e., vulvar shrinkage) was primarily observed prior and subsequent to the LH surge. In six of the nine (66.7%) beagles that became pregnant, vulvar shrinkage was observed on the days in which the LH surge was confirmed, and the rate of vulvar shrinkage tended to be greater at higher serum LH concentrations. Further vulvar shrinkage was identified in all nine beagles within two days of the LH surge. An increase in the serum progesterone concentration was observed after the LH surge in each of the beagles that became pregnant, together with clinical signs of estrous behavior (i.e., standing heat) as well as a change in vulva condition from swollen to soft. This demonstrates that vulvar shrinkage is induced in response to the onset of the LH surge and that the LH surge can be predicted through the measurement of the horizontal dimensions of the vulva, vaginal cytology, and the assessment of serum progesterone concentrations in beagles.

Urinary estrogens in pregnant cows

1.ホルスタイン種の妊娠牛における排尿量の季節変動については夏季に最高量を認めた。また,妊娠月令による排尿量の変動は殆どみられなかった。排尿回数は妊娠初期に多い傾向がみられ,1日の排尿回数は15時から20時の間に最も多く,0時から5時の間が最も少なかった。2.ホルスタイン種の妊娠牛における尿中エストロジェン分画値の妊娠月令に伴う変動については,とくにE8値が妊娠月令の進むに伴い増量し,E1,17β-E2からE8への転換の増加が認められた。また,流産牛尿中のE8値は流産の2ヵ月前から陰性値を示したことから,エストロジェンがウシの妊娠維持に重要な役割を有していることがうかがえた。さらにエストロジェン測定における早朝尿利用の臨床的意義も明らかにされた。

Estrogen content in the allantoic or amnionic fluids of cows.

ウシの羊水中のEは尿膜水に比較して非常に微量であった。尿膜水中のEは胎齢の進むに伴い増量し,また性別では,E1,E2が雄胎児在胎の場合に多かった。とくに,胎齢8,9ヵ月の雌胎児在胎時にはE3の著明な増量がみられた。

Charactristics of vaginal mucus of the bovine fetus

1) 牛胎児の腟粘液は胎令に併行した増量を示し,pHは胎令の進むに伴い中性から弱酸性に傾いた。結晶形成並びに精子受容性はほとんどのものにみられ,この両者はNaCl濃度に併行した反応を示した。2) 腟粘液中のE量は微量認められ,胎令に併行した増量を示したが,E分画ではestradiol-17βが多く認められた。

The effect of sow's pituitary gonadotropins on hypovaria of dairy cows

The biological assay of A. P. G. was conducted on the extract of 4, 000 sow hypohysis collected at the slaughter house.The results obtained by the Imamichis method, using the hypohysectomized immature male rat, indicated that the activity of 952 μg of sow A. P. G. extract was equivalent of 1 prostate Unit. And testicular weight of hypophysectomized male rat injected with 27 μg of sow A. P. G. extract was 2 times as compared with that of the control animal.The activity of 25 μg of sow A. P. G. extract was equivalent to 1 R. ov. U. by adult female rat ovulation inducing reaction and 67 μg of the extract was determined to be 1 Rab. U. by Friedmann reaction.Moreover, on the mouse uterine weight reaction, 20 mg increase was obtained by injecting 1, 000 μg of the extract.For the treatment to ovarian dysfunction in the cow, effect was obtained with 5 mg of the extract by intravenous injection.