Combined thickness of the uterus and placenta and ultrasonographic examinations of uteroplacental tissues in normal pregnancy, placentitis, and abnormal parturitions in heavy draft horses

Use of Transabdominal Ultrasound and Maternal Hormone Testing for the Prenatal Monitoring of Equine Fetal Enlarged Bladder

Ultrasound examination during late gestation is one of the best methods for monitoring potential pregnancy risks. Enlarged bladder is a urological disorder rarely observed in equine fetuses. This clinical case report aimed to present a case illustrating the development of equine fetal enlarged bladder using transabdominal ultrasound examinations and maternal hormone evaluation during gestation. An 8-year-old Hokkaido native pony was impregnated by embryo transfer, and at 215 days of gestation, abnormalities of the fetal bladder were detected. The bladder volume increased with gestational age, and a second bladder was observed at 257 days of gestation. No abnormalities were observed in the fetal kidneys. Moreover, the maternal plasma progesterone concentration was measured throughout the gestation period. The progesterone concentration was elevated from 36 weeks of gestation until parturition. At 363 days of gestation, parturition induction was conducted, and a foal successfully delivered. This case report is the first to describe the development of equine fetal enlarged bladder and record the corresponding ultrasound and hormone profiles.

Pregnancy monitoring in mares: Ultrasonographic and endocrine approaches

Methods to diagnose and monitor equine pregnancy continue to advance with improved instrumentation enabling the development of novel, non-invasive approaches to assess fetal well-being and viability using ultrasound and endocrine testing. From early embryonic loss to placentitis, that is typically encountered later in gestation, fetal viability and development as well as placental function can be evaluated using two fundamentally different, structural and functional, approaches. Ultrasound provides structural information on embryonic and fetal growth using such parameters as combined thickness of the uterus and placenta (CTUP), visual assessment of fetal fluids, activity, heart rate and multiple biometrics involving the fetal head and eyes, limbs and joints among many others, depending on the stage of gestation. Endocrine profiles that include progesterone and 5α-dihydroprogesterone, other metabolites, androgens and estrogens can be evaluated simultaneously using liquid chromatography-tandem mass spectrometry (LC-MS/MS) providing more functional information on fetal and placental competence and development. Endocrine information can be used in making clinical decisions including the need for progestin supplementation or when it can cease, and even estimating gestational stage in mares that cannot be easily palpated or scanned, as with mini-breeds or rancorous animals most notably. When used together, monitoring gestation by ultrasound and hormonal analysis provides unusual insight into feto-placental well-being and the progress of pregnancy, helping to identify problems needing therapeutic intervention.

The effects of aging and gestational month on uteroplacental vascular perfusion, and umbilical artery hemodynamics in pregnant jennies

This study aimed to correlate the pulsed wave spectral indices of the middle uterine artery at both sides with placental development in jenny within mid-late pregnancies, and establish umbilical Doppler values for different ages and different gestational months. Twenty Equus Asinus pregnant jennies 260-450 kg (average, 320 ± 10 kg) were examined from 5 to 9 months of pregnancy with different ages (4-14 years). Monthly B-mode ultrasound examination was performed on both the combined thickness of the uterus and placenta (CTUP; mm) and umbilical artery cross-sectional diameter, and Doppler mode examination was performed on both the middle uterine (MUA at right [R] and left [L] sides) and umbilical arteries to measure both Doppler indices that expressed by resistance (RI) and pulsatility indices (PI), and blood flow rate. CTUP was elevated within pregnancy time at different ages (P < 0.05). L. PI was significantly declined throughout different ages (P < 0.05), but this declining trend was not observed in L. RI. The L. blood flow rate (R; bpm) was elevated among different ages and different months (P < 0.05). Both RI and PI were significantly decreased from 5 to 9 month of gestation period in jennies (P < 0.05).. The umbilical arteries cross-sectional diameter (Umb A; mm), was elevated among different ages and different months, while both Doppler indices were declined. A positive correlation was found (between both Doppler indices of both umbilical and uterine arteries P < 0.001). There was elevated vascular perfusion in uterine and umbilical arteries associated with reduced both Doppler indices along the course of pregnancy at different ages.

Effect of prostaglandin F2α administration on uterine polymorphonuclear neutrophil counts in Japanese heavy draft horses

The objective of this study was to examine the effect of prostaglandin F2_α (dinoprost) and oxytocin administration on uterine polymorphonuclear neutrophil counts in the Japanese heavy draft mare. To compare polymorphonuclear neutrophil (PMN) counts in the endometrium, a total of 162 samples were collected from 54 estruses of 47 mares (before ovulation, day 0, and day 2) using a double-guarded cytology brush. Dinoprost (PG; 5 mg) was administered intramuscularly (i.m.) only once, on day 0, whereas oxytocin (OT; 20 U i.m.) was administered three times at 12-hr intervals starting on day 0. The plasma progesterone concentrations from days 0 to 14 were not different between the non-treatment (CON), PG treatment, and OT treatment groups. The PMN counts increased in all the groups from before administration to day 0 (CON, 0.90 to 3.55; PG, 1.20 to 8.45; and OT, 0.70 to 1.70; P=0.0014, 0.0046, and 0.0073, respectively). There was a significant decrease in PMNs from day 0 to day 2 only in the PG group (P=0.0073). The pregnancy rate was not different among the CON (12/18), PG (14/18), and OT (10/18) groups. The results of this study indicate that dinoprost can reduce uterine polymorphonuclear neutrophil counts.

Ultrasonographic examination of equine fetal growth parameters throughout gestation in pony for Equine-Assisted Therapy

Equine-Assisted Therapy (EAT) is gaining popularity. Ultrasound examination is used to decrease the abortion rate in horses. In this study, to monitor fetal well-being throughout the gestation for EAT, we measured fetal heart rate (FHR), fetal eye orbit (FEO), fetal gonad length (FGL), fetal kidney length (FKL), and the combined thickness of the uterus and placenta (CTUP) by ultrasonography in pony mares. Additionally, we measured the plasma progesterone (P₄) and estradiol (E₂) concentrations in pregnant horses using enzyme immunoassay. The FGL peaked at week 32 and then decreased to term, and a strong correlation (r=0.72, P<0.001) between the FGL and E₂ concentration was observed. A strong correlation with gestational age was detected among the FEO (r=0.96, P<0.001), FKL (r=0.85, P<0.001), and CTUP (r=0.96, P<0.001). The P₄ concentration peaked at week 10, decreased to low levels (below 5 ng/ml), and peaked before parturition. In conclusion, this study provides information on fetal growth throughout gestation in pony mares for EAT. In addition, it revealed the relationship between ultrasonographic profile and plasma hormone concentrations during gestation.

The feto-maternal immune response to equine placentitis

PROBLEM

Ascending placentitis is one of the leading causes of abortion in the horse. Minimal work has focused on its effect on fetal fluids or the antenatal immune response of the fetus.

METHODOLOGY

Placentitis was induced via transcervical inoculation of Streptococcus equi ssp Zooepidemicus, and fluids/serum/tissues were collected 4-6 days later following euthanasia. Cytokine concentrations were detected using a multiplex immunoassay within fetal fluids (amniotic and allantoic) and serum (maternal and fetal) in inoculated and control mares. In addition, tissues from fetal (spleen, liver, lung, umbilicus, amnioallantois) and maternal (spleen, liver, lung, chorioallantois, endometrium) origin were analyzed in inoculated and control mares utilizing qPCR for expression of cytokines.

RESULTS

No difference in cytokine concentrations in maternal or fetal serum was noted between inoculated and control mares. Concentrations of IL-1β, IL-6, IL-10, and GRO were upregulated in the amniotic fluid following inoculation, with a trend toward higher IL-6 concentration in allantoic fluid. The amnioallantoic tissue separating the two fluids had higher expression of IL-1β and IL-6 following inoculation, while chorioallantois and endometrium upregulated IL-1β and IL-8 expression. IL-1β was upregulated in the maternal spleen following inoculation. Fetal spleens were upregulated in expression of IL-1β, GRO, and IL-6, while IL-6 was higher in fetal liver after inoculation than in controls.

CONCLUSION

The maternal response to placentitis is primarily pro-inflammatory while the fetus appears to play a regulatory role in this inflammation. Additionally, amniotic fluid sampling may be more diagnostic of ascending placentitis than circulating cytokines.

Transrectal ultrasound of the combined thickness of the uterus and interplacentome region in healthy pregnant Holstein cows

Combined thickness of the uterus and placenta (CTUP) has been used for many years to assess fetal well-being and placental health in the mare and most recently the combined thickness of the uterus and interplacentome region (CTUIR) in water buffalo. The aim of this study was to develop normal reference ranges in regards to the CTUIR in 25 Holstein cows throughout pregnancy. The CTUIR was measured every 30 days from 60 days of gestation until 270 days of gestation. Measurements were obtained by transrectal ultrasonography with the position of the ultrasound probe being placed cranial and lateral to the cervix. CTUIR measurements increased every month beginning with an average of 4.6mm at 60 days and culminating with an average thickness of 11.7mm at 270 days of gestation. The greatest increases in CTUIR thickness occurred during the first and second trimesters.