Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias

16 t h International Congress on Animal Reproduction
112 Poster Abstracts
P254
Effect of impaired uterine drainage via cervix in normal
mares after insemination
Reine, E 1 *; Reilas, T 2 ; Rivera Del Alamo, M 3 ; Katila, T 4
1Faculty of Veterinary Medicine, Latvian University of Agriculture, Latvia;
2Equine Research, MTT Agrifood Research Finland, Finland; 3 Faculty of
Veterinary Medicine, Autonomous University of Barcelona, Spain; 4 Faculty of
Veterinary Medicine, University of Helsinki, Finland
Introduction In normal mares, the acute endometrial inflammation
caused by artificial insemination (AI) peaks around 8 h and subsides
appreciably within 24 h after AI. In mares susceptible to endometritis,
inflammation and infection may persist because of reduced
myometrial contractions. The necessity of a patent cervix has been
recognized, and manual dilatation of the cervix has been used to aid
evacuation of fluid collections. The roles of lymhatic drainage and
drainage through an open cervix warrant further investigations.
Objective To examine the role of the cervix in uterine drainage, a
balloon-tipped catheter was used to impaire uterine drainage via
cervix. Numbers of polymorphonuclear neutrophils (PMNs) were
evaluated after AI in 3 treatments: A) AI, catheter closed for 25 h, B)
AI, catheter closed for 6 + 19 h, and C) AI, no intracervical catheter.
Methods Twenty-nine clinically normal mares were assigned to 4
groups and followed through 5 oestrus cycles. During the first, third
and fifth oestrus, the uterus was swabbed. In the second and fourth
oestrus, the mares were treated in the following order: group1) CA,
group 2) AC, group 3) CB, and group 4) BC. AI dose was 500 x 10 6
progressively motile sperm extended with skim milk (20 ml, pooled
semen from 2 stallions). In treatments A and B, clamped catheters
were inserted immediately after AI. Uterine fluids were collected
either using a tampon 25 h after AI in C (tampon fluid TF) or by
draining fluid from the catheter at 25 h in A, and at 6 and 25 h in B
(catheter fluid CF). Oxytocin was injected i.v. to aid fluid drainage. At
25 h, the uterus was lavaged using 500 ml of Ringer’s solution (lavage
fluid LF). PMNs were counted using a Bürker chamber.
Results In the second oestrus, at 25 h after AI, PMN concentrations
(10 6 /ml) were similar in treatments A and B (CF-A: 73.2 ± 8.4, CF-B:
66.3 ± 19.9, LF-A: 2.4 ± 0.4, LF-B: 2.4 ± 0.8), and lower in treatment
C (TF-group 1: 3.8 ± 0.5, TF-group 3: 2.9 ± 0.4). In the fourth oestrus,
PMN numbers in treatment C were 10 times higher than during the
second oestrus (TF-group 2: 27.7 ± 4.2, TF-group 4: 31.1 ± 12.5). In
treatments A and B, PMNs were only slightly elevated compared to
values in the second oestrus (CF-A: 143.3 ± 17.3, CF-B: 97.9 ± 16.7).
PMNs in LF between treatments did not differ. Draining the uterus at
6 h had no effect on PMN numbers in CF 19 h later. Swabs were
negative for bacterial endometritis.
Conclusion Impaired cervical drainage seemed to have a profound
effect on uterine inflammation showing the important role of the
cervix.
P255
Serum aldosterone concentrations in Spanish Purebred
mares during pregnancy
Satué, K*; Domingo, R
Faculty of Veterinary Medicine, Cardenal Herrera-CEU University, Valencia,
Spain
Introduction The need to supply oxygen and nutrients to the
fetoplacental unit and to counterbalance the effects induced by the
release of new gonadotropic hormones during pregnancy requires
important adjustments of all hormones involved in the regulation of
blood volume, hydration and electrolytic state, and therefore of blood
pressure.
Objectives The main purposes of this research were: 1) to establish
reference ranges for serum aldosterone (ALD) concentrations in
Spanish Purebred mares; 2) to analyze pregnancy-related changes
related to pregnancy in serum ALD concentrations and 3) to assess the
effect of the age of the mare in serum ALD.
Material and Methods Thirty-three Spanish Purebred broodmares,
aged between 4 and 17 years were selected for this study. Jugular
venous blood samples were taken every month during pregnancy in
the morning. After withdrawal, blood was centrifuged and serum was
harvested. Serum ALD concentrations were measured by competitive
immunoassay.
Results Mean serum ALD concentrations were 562.21 pg/ml, with
maximum and minimum values of 1936.77 and 101.50 pg/ml
respectively. Mean values in the 1 st month of pregnancy were 628.79
pg/dl, they diminished in the 2 nd month, when the minimum mean
values were achieved (346.09 pg/ml). In the 3 rd and 4 th months, serum
ALD progressively increased to reach maximum mean values in the
5 th month (795.19 pg/ml). From this moment on, the mean values
fluctuated without significant differences up to the partum, with
means comprised between 458.59 and 658.17 pg/ml. No significant
differences were detected in relation to the age of the mares.
Discussion The Spanish Purebred broodmares showed serum ALD
concentrations higher than those described for foals and adult horses
of different breeds. Most of the studies have been carried out in sport
horses and it is well known that the loss of Na in sweat leads to a
compensatory release of ALD. Serum ALD concentrations increased
two to three-fold in pregnant women, bitches and laboratory animals.
The main mechanisms involved in the increased serum ALD
concentrations during pregnancy could be: release of renin and
angiotensin II, and changes in ACTH concentrations.
Conclusions In conclusion, pregnancy in Spanish Purebred
broodmares induces a progressive increase in serum ALD
concentrations. This finding might imply a better conservation of Na
and water in the kidneys in order to favor the expansion of the
fetoplacental barrier. In this way, a suitable supply of nutrients and
oxygen to the fetus as well as a correct blood pressure would be
guaranteed, contributing to the internal homeostasis of the fetus and
the mare. In addition, this result could be a consequence of the
interaction of several neuroendocrine factors during pregnancy.
P256
The duration of the effects of active immunization against
GnRH to suppress ovarian activity in mares in South
Africa
Schulman, ML*; Botha, AE; Bertschinger, HJ; Guthrie, AJ
Faculty of Veterinary Science, University of Pretoria, South Africa
Introduction A GnRH-vaccine to suppress reproductive function was
administered to a large group of horse mares. The effects of
vaccination on ovarian activity were monitored over a period of one
year using serum progesterone concentration (SPC).
Methods Sixty five cyclic mares (age range: 3 to 24 years) were
assigned randomly in the middle of the summer season to either a
control (Group C, n = 10) or an experimental (Group E, n = 55)
group, respectively. Both groups were subdivided into three age
categories: Category 1 (3 to 5 years), Category 2 (6 to 14 years), and
Category 3 (> 15 years). On Day 0, all mares were examined by transrectal
palpation and ultrasound to establish their reproductive status.
Group E mares were injected intramuscularly with 2 mL of GnRHvaccine
(Improvac ® , Pfizer Laboratories, Sandton, SA). Group C
mares similarly received an equal volume of sterile normal saline
solution. The injections were repeated on Day 35, and the clinical
examinations on Days 35, 70 and 260. The last examination
corresponded approximately with the onset of the following summer
season. Blood samples were collected at weekly intervals from Day 0
until Day 360 from all mares for SPC using a radioimmunoassay kit
125
(Progesterone Coat-a-Count, Diagnostic Products Corp, Los
Angeles, CA, USA). As the SPC results correlated significantly with
the clinical findings, SPC alone was used to monitor ovarian activity
from Day 260 until 360. All data was analyzed using NCSS software
(Number Cruncher Statistical Systems, Kaysville, UT, USA) and a
multivariate analysis of variance (ANOVA) assessed the effects of
treatment and age on clinical parameters and SPC. Values were
considered to be statistically significant at P < 0.05.
Results On Day 0, all Group C and E mares showed clinical evidence
of ovarian activity. On Day 35, all Group C and 8 (14.5 %) Group E
mares showed ovarian activity. The SPC results showed all Group E
mares were non-cyclic by Day 56. On Day 70, examination and SPC
indicated all Group C, and none of Group E mares showed ovarian