Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias

16 t h International Congress on Animal Reproduction
Poster Abstracts 87
P178
Echo-Doppler evaluation of umbilical blood flow during
pregnancy in sheep
Suarez, G 1 *; Panarace, M 1 *; Cané, L 1 ; Garnil, C 1 ; Medina, M 1
1GOYAIKE S.A.A.C.I. y F., Biotechnology Area. Carmen de Areco CC37. CP
6725. Buenos Aires. Argentina.
Introduction Placental blood flow and vascular development are
essential components of normal placental function and are critical to
fetal growth and development. Umbilical Artery Doppler is an
ultrasound technique that allows one to gauge how much resistance
fetal blood encounters during its passage through the placenta. Ideally,
fetal blood should encounter very little resistance; with certain
placental abnormalities, increased resistance to flow may limit
oxygenation transfer to fetal blood. Therefore, blood flow in umbilical
arteries can be used to monitor placental development and fetal
hemodynamics and use these findings for assessing the condition of
the fetus.
Objective Based on the above mentioned considerations, and
considering that most of the studies of umbilical arteries in sheep has
been done in instrumented and/or anesthetized fetuses, we aimed to
characterize, noninvasively, the Doppler flow velocity waveform in
umbilical arteries of ewes with apparently normal pregnancies.
Materials and methods Fifteen multiparous, nonlactating Merino
breed ewes with singleton pregnancies achieved after natural mating
were examined weekly from 4 to 20 weeks of gestation.
Ultrasonography (Toshiba Nemio 20, Tokyo, Japan) was performed
using two different convex transducers, a 5-10 MHz (transrectal) from
4 to 8 weeks of gestation and thereafter using a 3-6 MHz
(transabdominal). Three resistance indices were calculated: S/D ratio,
Resistance index (RI) = (S-D)/S, and Pulsatility Index (PI) = (S-D)/M.
[S = systole, D = diastole, and M = mean maximum Doppler-Shift
frequency over the cardiac cycle]. A repeated measure ANOVA was
used to detect differences between mean values of each Doppler index
for every week of gestation using the Fisher test (InfoStat V1.5, FCA,
Universidad de Córdoba, Córdoba, Argentina). Correlation between
Doppler indices was also calculated. All data are shown as mean ±
S.D.
Results The duration of pregnancy was 148 ± 1.5 days, all lambs
were born naturally without any type of assistance. All three Doppler
indices were highly correlated: S/D versus RI versus PI, r > 0.84.
From weeks 4 to 9 of pregnancy, blood flow was characterized by a
systolic pattern (i.e. high resistance with absence of diastolic flow). At
10 and 12 weeks of gestation, 50% and 100% of the fetuses showed a
diastolic flow consistent with low resistance, respectively. All three
resistance indices decreased (by > 45%, P < 0.05) from week 10 (SD
= 7.62 ± 1.82; RI = 0.86 ± 0.03; PI = 1.70 ± 0.23) to week 16 (SD =
2.72 ± 0.52; RI = 0.62 ± 0.07; PI = 0.95 ± 0.18) of pregnancy, with no
substantial changes thereafter (P > 0.05).
Conclusion Umbilical artery blood flow pattern in ewes was initially
systolic (high resistance) but became diastolic (low resistance) from
week 11 of pregnancy onwards. Noninvasive Doppler sonography
was useful for assessment of umbilical blood flow from 4 to 20 weeks
of pregnancy, these reference values may be useful for assessing
placental function in high-risk pregnancies e.g. cloned derived
pregnancies.
P179
Estrogen and Progesterone Receptors in the vagina of
progesterone primed and GnRH treated anoestrous ewes
Tasende, C*, Acuña, S; López, C; Garófalo, E
Cellular and Mollecular Biology, Faculty of Veterinary Medicine, Uruguay
The Estrogen and Progesterone Receptors (ER, PR) concentrations
were investigated in vagina of anestrous Corriedale ewes treated with
GnRH or with Progesterone (P) plus GnRH. Twenty two ewes were
assigned to two groups: GnRH (n = 11) and P+GnRH (n = 11). The
P+GnRH ewes were treated with 0.33 g of P (CIDR) for 10 Days and
immediately after CIDR removal they were treated every 2 h with 6.7
ng of GnRH (i.v.) for 16 h, followed by bolus injection of GnRH (4
μg, Day 0) at 18 h. The GnRH ewes were treated according to the
same protocol without P pre-treatment. Ewes were killed on Day 1 (n
= 6, for each treatment) and Day 5 (n = 5, for each treatment) after
bolus injection. Samples of vagina and blood were taken for receptors
and P determinations when the ewes were killed. The ER and PR
determinations were performed by ligand binding assay. The ligands
used were 3H-E2 for ER or 3H-ORG-2058 for PR, while nonlabelled
ligands were diethylstilbestrol and ORG-2058 respectively. The ER,
PR and P concentration were analyzed by ANOVA. On Day 5 the P
concentration (mean ± pooled s.e.) were higher in the P+GnRH ewes
than in the GnRH ewes (6.5±0.54 vs. 3.1±0.61 nmol/L, respectively,
P