Rate Of Embryonic Loss Research Articles

Embryonic loss in mares: Incidence and ultrasonic morphology

Pregnancy was determined by ultrasound on Days 11, 15, 20, 25, 30, 35, 40, 45, and 50 in 154 ponies and 27 horses. In ponies, the embryonic loss rate for Days 11 to 15 ( 28 154 , 18.2%) was greater (P<0.01) than for any of the subsequent five-day intervals (0% to 3.3%). There were no losses during Days 11 to 15 in horses ( 0 27 ), and the difference between ponies and horses was significant. The loss rates for the seven periods encompassing Days 15 to 50 were not significantly different among periods. Pseudopregnancy occurred more frequently (P<0.01) following embryonic loss after Day 20 (Days 11 to 15, 26%; Days 15 to 20, 33%; after Day 20, 100%). Embryonic vesicles that were lost during Days 11 to 15 were smaller on the average than control vesicles. However, most of the vesicles grew at an apparently normal rate. Two of five vesicles that were lost between Days 15 and 20 and three of four that were lost between Days 20 and 25 were undersized during preceding examinations. Undersized vesicles were found during 13 415 (3%) examinations during Days 11 to 20 in mares that maintained the embryo and in 21 106 (20%) in mares that lost the embryo. Embryonic vesicles that were lost during Days 11 to 15 usually disappeared without previous indications, except in three mares in which the vesicle was floating in a small collection of fluid. Ultrasonic indications of impending loss at later stages included failure of fixation, an echogenic ring (vesicle) or mass floating in a collection of fluid, an echogenic area in the dead embryo, absence of heart beat, and a gradual decrease in volume of placental fluids with disorganization of the placental membranes. The solid remnants and at least some of the fluids resulting from late embryonic and early fetal death were retained sometimes for weeks or months until the debris was apparently expelled through an open cervix.

A comparison of ovulatory gonadotropic surge in two rabbit strains : no evidence for a relationship between LH or FSH surge and factors of prolificacy

Plasma levels of LH and FSH before and after ovulation were measured in two rabbit strains (New Zealand A 1077 and Californian A 1066) having a different number of ovulations and rate of embryonic loss. Maximal concentrations and total secreted amounts before ovulation were slightly higher in New Zealand, but the difference was not significant. No relationship between the number of ovulations and the increase in plasma LH or FSH level was found in either strain. In most cases, there was no relationship between gonadotropic surge and early embryonic loss.

Untersuchung der mutagenen wirkung von triethylenemelamine (TEM) in frühembryonalem gewebe und knochenmark bei der ratte mit hilfe der chromosomenanalyse

Female rats were treated with triethylenemelamine (Tretamine; TEM) with a dose of 0.4 mg/kg body weight and 0.6 mg/kg body weight respectively on days 1, 2, 3; 3, 4, 5 or 6, 7, 8 post coitum. The animals were slaughtered on day 9 of pregnancy. Corpora lutea and living and dead embryos were counted to estimate embryonic loss. Thereafter chromosome-analysis of bone marrow cells and embryonic tissue took place. Higher TEM dosage increased the rate of embryonic loss. It increased from 28.1% with a dose of 3 × 0.4 mg TEM to 75.7% with 3 × 0.6 mg TEM. The level of embryonic loss depends on the time of treatment during different stages of early gestation. It was highest on the first 3 days and lowest on days 6–8 of gestation (0.4 mg TEM on days 1, 2, 3 p.c., 71.8%; 0.4 mg TEM on days 6, 7, 8 p.c., 2.9%). By the chromosome analysis, early embryonic tissue seemed to be more sensitive to TEM than bone marrow cells. The highest rates of numerical (35.7%) and structural (5.7%) aberrations were found by treatment with the lower TEM-dose (3 × 0.4 mg TEM). A higher TEM dose induced a negative dose-effect, the frequency of aberrations decreased (3 × 0.6 mg TEM, 29% numerical and 1.2% structural aberrations). With increased embryonic loss (from 28.1% to 75.0%) structural aberrations decreased (from 5.7% to 1.2%). The time of treatment p.c. was highly correlated with the frequency of aberrations. It was highest with TEM application on days 6, 7, 8 of pregnancy; at the same time the mortality rate was lowest. The same tendencies were noted in the investigation of the chromosomes from bone marrow cells.

Untersuchung der mutagenen wirkung von triethylenemelamine (TEM) in frühembryonalem gewebe und knochenmark bei der ratte mit hilfe der chromosomenanalyse

Female rats were treated with triethylenemelamine (Tretamine; TEM) with a dose of 0.4 mg/kg body weight and 0.6 mg/kg body weight respectively on days 1, 2, 3; 3, 4, 5 or 6, 7, 8 post coitum. The animals were slaughtered on day 9 or pregnancy. Corpora lutea and living and dead embryos were counted to estimate embryonic loss. Thereafter chromosome-analysis of bone marrow cells and embryonic tissue took place. Highter TEM dosage increased the rate of embryonic loss. It increased from 28.1% with a dose of 3 X 0.4 mg TEM to 75.7% with 3 X 0.6 mg TEM. The level of embryonic loss depends on the time of treatment during different stages of early gestation. It was highest on the first 3 days and lowest on days 6-8 of gestation (0.4 mg TEM on -ays 1, 2, 3 p.c., 71.8%; 0.4 mg TEM on days 6, 7, 8 p.c., 2.9%). By the chromosome analysis, early embryonic tissue seemed to be more sensitive to TEM than bone marrow cells. The highest rates of numerical (35.7%) and (3 X 0.4 mg TEM). A higher dose induced a negative dose-effect, the frequency of aberrations decreased (3 X 0.6 mg TEM, 29% NUMERICAL AND 1.2% STRUCTURal aberrations). With increased embryonic loss (from 28.1% to 75%) structural aberrations decreased (from 5.7% to 1.2%). The time of treatment p.c. was highly correlated with the frequency of aberrations. It was highest with TEM application on days 6, 7, 8 of pregnancy; at the same time the mortality rate was lowest. The same tendencies were noted in the investigation of the chromosomes from bone marrow cells.

高エネルギー飼料給与ラットにおける胚損耗の軽減について

In our previous experiment1), the authors found that high embryonic loss rate in rats fed the high energy diet could be reduced by decreasing of calorie-protein ratio (CPR).On the other hand, DEAN et al.2), GOSSETT and SORENSEN3) reported that negative correlation was observed between backfat thickness and embryonic survival rate in gilts.This experiment was designed to determine a favorable CPR for minimizing the embryonic loss rate in female rats fed the high energy diet and to investigate the relationship between energy or nitrogen retention and reproductive performance in rats.