Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias
Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias
Reproduction in Domestic Animals - Facultad de Ciencias Veterinarias
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16 t h International Congress on Animal <strong>Reproduction</strong><br />
26 Workshop Abstracts<br />
Workshop 18 - Pregnancy, fetal well-be<strong>in</strong>g and the periparturient<br />
dam<br />
Mo<strong>de</strong>rator: Marcel A. M. Taverne (The Netherlands)<br />
WS18-1<br />
Assessment of fetal well-be<strong>in</strong>g dur<strong>in</strong>g bov<strong>in</strong>e and equ<strong>in</strong>e<br />
gestations result<strong>in</strong>g from <strong>in</strong> vivo and <strong>in</strong> vitro produced<br />
embryos<br />
Chavatte-Palmer, P<br />
INRA, UMR 1198; ENVA; CNRS, FRE 2857, Biologie du Développement et<br />
<strong>Reproduction</strong>, Jouy en Josas, F-78350, France<br />
Pregnant dams need to be monitored <strong>in</strong> or<strong>de</strong>r to precociously diagnose<br />
any pathological process and start treatment. Pregnancies established<br />
after natural breed<strong>in</strong>g or artificial <strong>in</strong>sem<strong>in</strong>ation may not require<br />
specific monitor<strong>in</strong>g if the dam is reproductively sound and <strong>in</strong> absence<br />
of maternal pathology (i.e. colics <strong>in</strong> horses). In contrast, <strong>in</strong> vitro<br />
produced embryos, and particularly cloned embryos, have been<br />
associated with severe placental abnormalities and fetal losses,<br />
requir<strong>in</strong>g regular assessment of the health of both the recipient and the<br />
fetus.<br />
In terms of imag<strong>in</strong>g technologies, rectal and transabdom<strong>in</strong>al<br />
ultrasound scann<strong>in</strong>g have been used for a long time <strong>in</strong> the horse to<br />
assess fetal growth and activity and evaluate placental health (ma<strong>in</strong>ly<br />
through the measurement of the utero-placental thickness) throughout<br />
pregnancy. Transabdom<strong>in</strong>al ultrasound has also been used<br />
successfully <strong>in</strong> cattle to diagnose the Large Offspr<strong>in</strong>g Syndrome<br />
(<strong>in</strong>creased fetal size, placental e<strong>de</strong>ma, abnormal placentome<br />
structures) before cl<strong>in</strong>ical signs are prom<strong>in</strong>ent and maternal welfare is<br />
affected. Transrectal doppler sonography of the uter<strong>in</strong>e artery can also<br />
be performed to evaluate uter<strong>in</strong>e blood flow both <strong>in</strong> the mare and the<br />
cow and will provi<strong>de</strong> helpful <strong>in</strong>formation on placental perfusion.<br />
More recently <strong>de</strong>veloped methods, like 3D Doppler scann<strong>in</strong>g, are<br />
be<strong>in</strong>g evaluated for visualiz<strong>in</strong>g the placenta <strong>in</strong> rum<strong>in</strong>ants, but the use<br />
of Magnetic Resonance Imag<strong>in</strong>g is preclu<strong>de</strong>d both because of the<br />
price and the size of the animals. Ultrasound gui<strong>de</strong>d amniocentesis<br />
and allantoidocentesis have been performed both <strong>in</strong> cattle and horses<br />
but rema<strong>in</strong> so far too risky for rout<strong>in</strong>e use, especially if repeated. It<br />
would be worth, however, <strong>de</strong>velop<strong>in</strong>g safe procedures to be used <strong>in</strong><br />
practice as this is a simple technique provid<strong>in</strong>g potentially very useful<br />
cl<strong>in</strong>ical <strong>in</strong>formation. F<strong>in</strong>ally, placental biopsies can be performed <strong>in</strong><br />
cattle but may not provi<strong>de</strong> significant <strong>in</strong>formation on fetal well-be<strong>in</strong>g.<br />
Most useful maternal blood markers for fetal well-be<strong>in</strong>g <strong>in</strong>clu<strong>de</strong><br />
estrone sulfate and progestagens <strong>in</strong> the horse. In cattle, the maternal<br />
plasma concentration of placental Pregnancy Associated<br />
Glycoprote<strong>in</strong>s (PAG) is rout<strong>in</strong>ely used for pregnancy diagnosis but<br />
may also be helpful <strong>in</strong> <strong>de</strong>tect<strong>in</strong>g animals likely to <strong>de</strong>velop the Large<br />
Offspr<strong>in</strong>g Syndrome. F<strong>in</strong>ally, the diagnostic and prognostic <strong>in</strong>terest of<br />
other molecules, such has the acute phase prote<strong>in</strong> Serum Amyloid A<br />
(SAA) must yet be explored.<br />
WS18-2<br />
Monitor<strong>in</strong>g of the bov<strong>in</strong>e fetus dur<strong>in</strong>g and shortly after<br />
birth<br />
Bleul, U<br />
Department of Food <strong>Animals</strong>, Cl<strong>in</strong>ic of Reproductive Medic<strong>in</strong>e, Switzerland<br />
Approximately 3% of all bov<strong>in</strong>e fetuses die dur<strong>in</strong>g or shortly after<br />
birth. In the majority of cases the reason for this peripartal mortality is<br />
dystocia. This bears the risk of fetal damage caused by hypoxia,<br />
hypercapnia and acidosis. In the field methods for monitor<strong>in</strong>g the<br />
well-be<strong>in</strong>g of the fetus dur<strong>in</strong>g parturition are almost lack<strong>in</strong>g. The<br />
evaluation of vitality is based ma<strong>in</strong>ly on reflexes, meconium sta<strong>in</strong><strong>in</strong>g<br />
of the fetus and the amniotic fluid or the <strong>de</strong>tection of a heart beat <strong>in</strong><br />
the fetus, but they do not allow an accurate estimate of fetal acidosis.<br />
In the last years new methods were <strong>de</strong>scribed which may help to<br />
recognize fetal distress.<br />
In human medic<strong>in</strong>e, cardiotocography measurement is the standard<br />
procedure for fetal monitor<strong>in</strong>g <strong>in</strong>trapartum and has been evaluated <strong>in</strong><br />
experimental studies with bov<strong>in</strong>e fetuses. Cardiotocography measures<br />
the fetal heart beat and the <strong>in</strong>trauter<strong>in</strong>e pressure cont<strong>in</strong>uously and the<br />
fetal heart rate correlates well with the neonatal outcome.<br />
Further methods were recently <strong>de</strong>scribed, which measure the fetal<br />
oxygen saturation or blood gas parameters. Oxygen saturation was<br />
measured us<strong>in</strong>g pulsoximetry by plac<strong>in</strong>g an oxygen sensor <strong>in</strong> the<br />
mouth aga<strong>in</strong>st the mucosa of the hard palate of the fetus. Although<br />
postnatal acidosis can be predicted by cont<strong>in</strong>uously measur<strong>in</strong>g the<br />
oxygen saturation of the fetus <strong>in</strong>trapartum, technical modifications are<br />
required to improve its usefulness. In experimental studies, bov<strong>in</strong>e<br />
fetal blood has been collected transvag<strong>in</strong>ally from the umbilical<br />
vessels, by centesis or catheterization of the carpal or digital ve<strong>in</strong>s.<br />
Capillary blood has been collected from the dorsolateral aspect of the<br />
distal pastern when the calf’s forelimbs protru<strong>de</strong> from the vulva.<br />
Blood gas values dur<strong>in</strong>g stage II labor were suitable <strong>in</strong> or<strong>de</strong>r to<br />
diagnose fetal asphyxia and selected parameters showed high<br />
correlations with the level of postnatal acidosis.<br />
Determ<strong>in</strong>ation of blood gas values of venous blood is an established<br />
method for <strong>de</strong>tect<strong>in</strong>g the metabolic component of the mixed<br />
metabolic-respiratory acidosis <strong>in</strong> calves immediately after birth.<br />
Because the respiratory component of acidosis is difficult to<br />
<strong>de</strong>term<strong>in</strong>e with venous blood, collect<strong>in</strong>g arterial blood is a more<br />
reliable method for evaluat<strong>in</strong>g pulmonary function by <strong>de</strong>term<strong>in</strong>ation<br />
of the partial pressure of carbon dioxi<strong>de</strong> and oxygen of arterial blood.<br />
Various methods of monitor<strong>in</strong>g the calf dur<strong>in</strong>g and after birth have<br />
been established which may reduce fetal mortality by <strong>in</strong>dicat<strong>in</strong>g the<br />
right time for an obstetrical <strong>in</strong>tervention, or the necessity of a<br />
therapeutic <strong>in</strong>tervention <strong>in</strong> the newborn calf.<br />
WS18-3<br />
The sow and her piglets dur<strong>in</strong>g the farrow<strong>in</strong>g process<br />
Van Dijk, J<br />
Faculty of Veter<strong>in</strong>ary Medic<strong>in</strong>e, Utrecht University, The Netherlands<br />
Per<strong>in</strong>atal asphyxia is an important cause of per<strong>in</strong>atal mortality and<br />
reduced viability and vitality of newborn piglets. The occurrence of<br />
per<strong>in</strong>atal asphyxia is clearly associated with the farrow<strong>in</strong>g process.<br />
Consequently, several factors affect<strong>in</strong>g the duration of the expulsive<br />
stage of farrow<strong>in</strong>g (DF) have been i<strong>de</strong>ntified. Whereas the effect of<br />
parity is controversial, breed significantly affects DF and <strong>in</strong> this<br />
respect the Meishan holds a rather unique position as the number of<br />
stillbirths is not related to DF. Furthermore, a <strong>de</strong>creased gestational<br />
length and <strong>in</strong>creased number of liveborn and / or stillborn piglets<br />
result, <strong>in</strong><strong>de</strong>pen<strong>de</strong>ntly of each other, <strong>in</strong> a significant <strong>in</strong>creased DF. To<br />
lower the risk for per<strong>in</strong>atal asphyxia at birth, attempts have been ma<strong>de</strong><br />
to reduce the DF by adm<strong>in</strong>istration of oxytoc<strong>in</strong>. However, <strong>de</strong>spite a<br />
reduction of DF, <strong>in</strong>creas<strong>in</strong>g numbers of <strong>in</strong>trapartum stillbirths with<br />
ruptured umbilical cords and severe meconium sta<strong>in</strong><strong>in</strong>g at birth are<br />
observed. Regard<strong>in</strong>g factors affect<strong>in</strong>g <strong>in</strong>dividual birth <strong>in</strong>tervals<br />
between piglets (BI), it has been shown that higher birth weights,<br />
posteriorly presented piglets and stillborn piglets are associated with<br />
<strong>in</strong>creased BI. Besi<strong>de</strong>s, a curvil<strong>in</strong>ear relationship exists between rank<br />
(relative position <strong>in</strong> the birth or<strong>de</strong>r) and <strong>in</strong>dividual birth <strong>in</strong>tervals and<br />
breed significantly affects this relationship. Several of the factors<br />
affect<strong>in</strong>g BI are also shown to affect acid-base balance values <strong>in</strong><br />
umbilical artery blood samples of liveborn piglets at birth. Piglets<br />
born with ruptured umbilical cords show significantly lower pH<br />
values and a ten<strong>de</strong>ncy for higher pCO2 values at birth. Interest<strong>in</strong>gly,<br />
<strong>de</strong>creased birth weights are associated with a slightly more severe<br />
metabolic acidosis at birth. Furthermore, posterior presentation at<br />
birth, <strong>in</strong>creas<strong>in</strong>g cumulative birth <strong>in</strong>tervals and an <strong>in</strong>creas<strong>in</strong>g rank<br />
result <strong>in</strong> a more pronounced mixed respiratory-metabolic acidosis at<br />
birth. The <strong>de</strong>gree of acidosis that gradually <strong>de</strong>velops dur<strong>in</strong>g the<br />
expulsive stage of farrow<strong>in</strong>g is not as severe as observed <strong>in</strong> newborn,<br />
highly asphyxiated piglets at birth. Consequently, it has been stated<br />
that traction, occlusion or rupture of the umbilical cord is an<br />
<strong>in</strong>evitable factor <strong>in</strong> the evolvement of birth asphyxia and concomitant<br />
mortality and reduced viability at birth. However, a mo<strong>de</strong>l of<br />
umbilical cord clamp<strong>in</strong>g (average duration of cord clamp<strong>in</strong>g: 7<br />
m<strong>in</strong>utes) <strong>in</strong> late pregnant sows suggests an additional role of<br />
cumulative uter<strong>in</strong>e contractions, occurr<strong>in</strong>g dur<strong>in</strong>g the expulsive stage<br />
of farrow<strong>in</strong>g, <strong>in</strong> the evolvement of a more or less severe <strong>de</strong>gree of<br />
birth asphyxia.