Fertility after fetotomy: a clinical study focusing on heavy draft mares.

Although fetotomy is recommended for all mares when the fetus is dead and difficult to extract, little has been written about fetotomy and heavy draft mares. This lack includes indications for fetotomy in heavy draft mares, differences in treatment and prognosis of heavy mares kept by farmers of low socioeconomic status, and how this procedure affects the mare's further fertility. The literature on mares, in general, also differs on the survival rate of mares that undergo fetotomy, the prevalence of postpartum complications, and further fertility. To answer these questions, we reviewed the medical records of 102 mares that underwent fetotomy, mostly heavy draft mares (n=93). Head malposture (62.7 per cent) was the most common fetal maldisposition, which required fetotomy in all cases. The survival rate was 84.3 per cent (n=86). The most common postpartum complications were endometritis puerperalis (32.5 per cent) and retained placenta (27.9 per cent). 61 mares (70.9 per cent) both showed foal heat and cycled regularly in the first season after fetotomy. Out of 45 mares that were bred in the first season, 14 became pregnant (31.1 per cent). Survival rate and further fertility were reduced by delayed requests for veterinary assistance due to the difficult economic situation of the owners. Fetotomy is the method of choice for serious maldispositions, especially head malpostures, because in contrast with cesarean sections, it has a higher survival rate and allows the mare to return to breeding in the same season.

Puerperal development of ewes following dystocia: a retrospective analysis of two approaches to caesarean section.

The objective of this study was to retrospectively analyse the puerperal development of ewes referred to a veterinary teaching hospital following caesarean section in comparison with assisted parturition. Laparotomy was performed either via left flank incision (group 1, n=86) or ventral mid-line approach (group 2, n=33). Both groups were compared with ewes following non-surgical intervention (group 3, n=73). The overall fetal death rate was 41 per cent. There was no significant difference in fetal deaths between groups 1 and 2, but assisted delivery led to a higher number of liveborn lambs compared with caesarean section (P<0.05). Seven ewes (3.6 per cent) died or were euthanased on welfare grounds during caesarean surgery, and the overall maternal mortality rate following dystocia in the postpartum period was 10.9 per cent. While there was no significant difference between groups 1 and 2 in the percentage of ewes developing healing disorders, the complications that occurred were more severe after the left flank approach (P=0.04), and the mean hospitalisation period was significantly longer in group 1 than in group 2 (P<0.05), leading to the conclusion that ventral mid-line laparotomy has some advantages over a left flank approach.

Pathogenesis of Korean type 1 (European genotype) porcine reproductive and respiratory syndrome virus in experimentally infected pregnant gilts.

The aims of this study were to determine (1) the pathogenesis of experimental infection with a Korean type 1 porcine reproductive and respiratory syndrome virus (PRRSV) by defining the viral distribution and the sites of viral replication and (2) the relationship between viral replication and apoptosis in stillborn fetuses and live born piglets from infected pregnant gilts. At 3 weeks ante partum, four pregnant gilts were inoculated intranasally with Korean type 1 PRRSV. Stillborn fetuses from the infected gilts were of crown-to-rump length 25.8-27.1 cm consistent with fetal death between 106 and 110 days of gestation. Type 1 PRRSV was isolated from the fetal tissues and these isolates were shown to be identical to the challenge virus by sequence analysis. Type 1 PRRSV RNA was detected in the lung, lymph node, heart, tonsil, thymus, liver, adrenal gland and spleen of live born piglets and stillborn fetuses from the infected gilts. The mean number of apoptotic cells per unit area of lung (P = 0.003), heart (P = 0.011), thymus (P = 0.003), liver (P = 0.011) and spleen (P = 0.002) was significantly higher in stillborn fetuses than in live born piglets. Dual labelling showed that the majority of cells either contained type 1 PRRSV or were apoptotic, but not both. Apoptotic cells were more numerous than PRRSV(+) cells. The results of the study demonstrated that type 1 PRRSV induces reproductive failure in pregnant gilts. Apoptosis induced by type 1 PRRSV may be associated with the incidence of stillborn fetuses in PRRSV-infected pregnant gilts.

Delayed postpartum fetotomy in an Asian elephant (Elephas maximus).

A 37-yr-old Asian elephant (Elephas maximus) started parturition after 640 days of pregnancy but no fetal parts entered the birth canal. Despite veterinary intervention, the calf was not delivered. After 13 mo calving resumed and a full-term dead calf advanced into and lodged within the vagina. With standing xylazine tranquilization, the dam received a vagino-vestibulotomy to permit total fetotomy of the calf, which presented with bilateral carpal arthrogryposis. Severe infection of the caudal vaginal vestibulum complicated wound healing, and over the following year two corrective surgeries were performed, which resolved the fistula 3 mo after the second debridement. The elephant not only survived the procedures but also resumed normal estrous cycles, as demonstrated by blood progesterone concentration monitoring.

Exposure of mares to processionary caterpillars (Ochrogaster lunifer) in early pregnancy: an additional dimension to equine amnionitis and fetal loss.

REASONS FOR PERFORMING STUDY: Equine amnionitis and fetal loss (EAFL) is an unusual form of abortion in mid- to late-gestation mares, first identified in Australia in 2004. It has been shown that both whole processionary caterpillars (Ochrogaster lunifer) and their shed exoskeletons can induce abortion in mares during midgestation. These abortions exhibited gross pathology and bacteriology results consistent with field cases of EAFL. OBJECTIVES: To determine whether exposure of mares to the shed exoskeletons of processionary caterpillars can induce abortion in the preplacentation (<35 days' gestation) and early placentation (45-60 days) stages of pregnancy. STUDY DESIGN: In vivo experimental study. METHODS: Mares less than 35 days' gestation and between 45 and 60 days' gestation were exposed to a slurry of shed processionary caterpillar exoskeletons by nasogastric intubation. Mares were monitored by clinical examination daily. Transrectal ultrasonography was performed daily (control and treated preplacentation mares, treated early placentation mares) or every second day (control early placentation mares). Uterine swabs were collected from mares that aborted. All live foals underwent a clinical examination. Placentas were examined, with sampling for bacteriology and histopathology if appropriate. RESULTS: Abortions occurred in treated mares in both experiments without signs of impending abortion. One mare aborted in the embryonic stage experiment and 2 in the early placentation experiment. Embryonic and fetal death was detected on transrectal ultrasonography prior to abortion. In the early placentation experiment, one foal was born 5 weeks preterm and was very small, with laxity of the tendons in all limbs. Enteric or environmental bacteria, consistent with EAFL, were isolated from the mares that aborted. Focal mucoid placentitis lesions were present on the placentas of 2 treated mares, one from each experiment. CONCLUSIONS AND POTENTIAL RELEVANCE: Processionary caterpillar exposure may be associated with EAFL-related embryonic and early fetal loss in mares. Processionary caterpillars may also play a role in the occurrence of focal mucoid placentitis.

Recurrent abruptio placentae in a cynomolgus monkey (Macaca fascicularis).

INTRODUCTION: Abruptio placentae, defined as premature separation of a normally implanted placenta, is a life threatening pregnancy complication with unknown pathophysiology. A history of abruptio placentae is the major risk factor for this pregnancy complication in humans. We describe the first case of recurrent abruptio placentae in a Macaca fascicularis. MATERIAL AND METHODS: A pregnant M. fascicularis at term gestation was presented with weakness and hypothermia. Cesarean section revealed retroplacental hemorrhage with partial placental separation from the uterus. RESULTS: The weight of the female fetus was within the lower birth weight range for these species. The maternal side of placenta contained necrotic tissue, occupying approximately 60% of the maternal surface. The placental implantation bed demonstrated neutrophil infiltration. Perivascular collections of lymphocytes were noticed in the uterine smooth muscle. CONCLUSION: This case report underlines the importance of neutrophil infiltration and uterine venous drainage in the cascade of events leading to abruptio placentae.

Intrauterine fetal death with subsequent quill exfoliation and dissemination in a North American porcupine (Erethizon dorsatum).

An adult female, wild North American porcupine (Erethizon dorsatum) presented with bilateral cataracts and naso-ocular discharge. A pregnancy was identified by radiography with a near-full-term fetus, which was delivered stillborn 4 wk later with hard, developed quills. At that time, a repeated examination and further imaging, including computed tomography, demonstrated a uterine mass that was identified as a choriocarcinoma following ovariohysterectomy. Additionally, numerous exfoliated quills were discovered throughout the abdomen, most of which were removed during the surgical procedure. Ultimately, development of peritonitis despite medical care led to the porcupine's death. Necropsy confirmed a wide migration of the quills with extensive serosal adhesions and granulomas affecting liver, lungs, urinary bladder, kidneys, and gastrointestinal tract.

Development of bovine embryos derived from reproductive techniques.

Assisted reproduction techniques have improved agricultural breeding in the bovine. However, important development steps may differ from the situation in vivo and there is a high mortality rate during the first trimester of gestation. To better understand these events, we investigated the development of embryos and fetal membranes following fixed-time AI (FTAI), IVF and nuclear transfer (NT). The onset of yolk-sac development was not normal in cloned embryos. Later steps differed from conditions in vivo in all three groups; the yolk-sac was yellowish and juxtaposed with the amniotic membrane. Vascularisation of the chorioallantoic membrane was relatively late and low in NT gestations, but normal in the others. The overall development of the embryos was normal, as indicated by morphology and regression analysis of growth rate. However, NT conceptuses were significantly smaller, with the livers in some embryos occupying the abdominal cavity and others exhibiting heart abnormalities. In conclusion, the yolk-sac and the cardiovascular system seem to be vulnerable to morphogenetic alterations. Future studies will focus on gene expression and early vascularisation processes to investigate whether these changes may be responsible for the high incidence of intrauterine mortality, especially in clones.

Effect of season, late embryonic mortality and progesterone production on pregnancy rates in pluriparous buffaloes (Bubalus bubalis) after artificial insemination with sexed semen.

The use of sexed semen technology in buffaloes is nowadays becoming more and more accepted by farmers, to overcome the burden of unwanted male calves with related costs and to more efficiently improve production and genetic gain. The aim of this study was to verify the coupling of some variables on the efficiency of pregnancy outcome after deposition of sexed semen through AI. Pluriparous buffaloes from two different farms (N = 152) were screened, selected, and subjected to Ovsynch protocol for AI using nonsexed and sexed semen from four tested bulls. AI was performed in two distinct periods of the year: September to October and January to February. Neither farms nor bulls had a significant effect on pregnancy rates pooled from the two periods. The process for sexing sperm cells did not affect pregnancy rates at 28 days after AI, for nonsexed and sexed semen, respectively 44/73 (60.2%) and 50/79 (63.2%), P = 0.70, and at 45 days after AI, for nonsexed and sexed semen, respectively 33/73 (45.2%) and 33/79 (49.3%), P = 0.60. Pregnancy rate at 28 days after AI during the transitional period of January to February was higher when compared with September to October, respectively 47/67 (70.1%) versus 47/85 (55.2%), P = 0.06. When the same pregnant animals were checked at Day 45 after AI, the difference disappeared between the two periods, because of a higher embryonic mortality, respectively 32/67 (47.7%) versus 40/85 (47.0%), P = 0.93. Hematic progesterone concentration at Day 10 after AI did not distinguish animals pregnant at Day 28 that would or would not maintain pregnancy until Day 45 (P = 0.21). On the contrary, when blood samples were taken at Day 20 after AI, the difference in progesterone concentration between pregnant animals that would maintain their pregnancy until Day 45 was significant for both pooled (P = 0.00) and nonsexed (P = 0.00) and sexed semen (P = 0.09). A similar trend was reported when blood samples were taken at Day 25, being highly significant for pooled, nonsexed, and sexed semen (P = 0.00). Hematic progesterone concentration between the two periods of the year was highly significant for pregnant animals at 28 days from AI when blood samples were taken at Day 20 after AI for pooled, nonsexed, and sexed semen, respectively P = 0.00, 0.00, and 0.06, and for pregnant animals at Day 45 for pooled, nonsexed, and sexed semen, respectively P = 0.00, 0.00, and 0.01. From these results, it can be stated that hematic progesterone concentration measurement since Day 20 after AI can be predictive of possible pregnancy maintenance until Day 45. Furthermore, the transitional period of January to February, although characterized by a higher pregnancy outcome when compared with September to October, suffers from a higher late embryonic mortality as evidenced by a significant different hematic progesterone concentration between the two periods at Day 20 after AI.

Short-term and long-term outcomes of ewes and their offspring after elective cesarean section.

Postoperative outcomes of animals that have undergone cesarean delivery have been reported previously; however, in most studies results were influenced by a combination of surgery per se and the preoperative condition of the animal, which was frequently impaired because of the presence of dystocia. To evaluate the effects of the cesarean section itself we conducted a matched cohort study comparing postpartum complications and future reproductive performance of 162 ewes subjected to elective cesarean section and 162 ewes that had an unassisted vaginal delivery. Survival and subsequent growth of their lambs were also compared. Effect of mode of delivery on weight gain was estimated using linear mixed models. Case ewes, which underwent surgery during the period from 1996 through 2004, and control ewes were from the flock at the Animal Production Experimental Centre, Norway. Two ewes (1.2%) that underwent cesarean section died; one developed peritonitis and the other experienced uterine prolapse and did not recover. Postoperatively, four ewes suffered from metritis, three suffered a wound infection, and four a delayed wound healing; all recovered after treatment. One of the ewes that delivered vaginally died 3 days after lambing. The incidences of fetal and postnatal deaths did not differ significantly between the cesarean and the vaginal delivery groups (fetal deaths, 3.5% and 3.1%, and postnatal deaths, 9.9% and 7.1%, respectively). Survival rates and weight gains of the lambs the subsequent months were similar for the two groups. Seventy percent of the ewes that had a cesarean section and 72% of those that had a vaginal delivery were bred the next season; conception rates were 89% and 90%, respectively. However, the ewes subjected to surgery the previous year gave birth to significantly fewer live-born lambs (mean, 1.64) than those that had had a vaginal delivery (1.93). The difference was the result of a reduced litter size and an increased number of fetal deaths in the former group. Birth weights of the live-born lambs the second year did not differ between the groups. In conclusion, severe short-term complications were rare among the ewes that underwent elective cesarean section. Survival and growth of their lambs and their conception rate the subsequent season did not differ from the corresponding outcomes of the ewes that delivered vaginally, but their fertility was reduced in the sense that they gave birth to fewer live-born lambs the following lambing season.

Reproductive parameters following a PRRS outbreak where a whole-herd PRRS MLV vaccination strategy was instituted post-outbreak.

This study assessed the effect of whole-herd porcine reproductive and respiratory syndrome (PRRS) modified-live virus (MLV) vaccination on herd-level reproductive performance, PRRS virus (PRRSV) viremia, and antibody in a subset of females in a 1,200-sow commercial herd in Thailand. Following a PRRSV outbreak, the entire herd was vaccinated with PRRS MLV twice at 3-week intervals and at 3-month intervals, thereafter. Reproductive performance data over a 3-year period were available for analysis. Serum samples were collected before and after vaccination and tested by PRRSV ELISA and reverse transcription-polymerase chain reaction. Vaccination was statistically associated with a lower abortion rate (1.4 vs. 1.6 %), farrowing rate (83.8 vs. 90.0 %), total born (10.6 vs. 11.4 piglets/litter), liveborn (10.0 vs. 10.3 piglets/litter), stillbirths (4.6 vs. 7.0 %), mummies (0.7 vs. 1.6 %), and a higher return rate (11.3 vs. 5.9 %) when compared with the period before the PRRSV outbreak. Pregnant females vaccinated during early gestation farrowed fewer liveborn and more mummies than the comparison group, whereas females vaccinated during late gestation had a lower farrowing rate. In this herd, PRRS whole-herd vaccination had neutral, positive, and negative effects on reproductive performance. Thus, the decision to implement whole-herd vaccination should be balanced between the benefits derived from reproductive performance improvements, e.g., fewer abortions, stillborn piglets, and mummified fetuses, and the effect of vaccination on pregnant females.

Meningoencephalitis due to Listeria monocytogenes in a pregnant rhesus macaque (Macaca mulatta).

We here report a spontaneous case of meningoencephalitis due to Listeria monocytogenes in an adult primiparous rhesus macaque (Macaca mulatta) during an outbreak of listeriosis in an outdoor enclosure. Clinical signs included tremors, abnormal posture, and altered mental status. Hematology and analyses of cerebrospinal fluid were consistent with bacterial infection. Pure cultures of L. monocytogenes were recovered from the placenta-abortus, cerebrospinal fluid, and brain tissue. The macaque did not respond to treatment and was euthanized. Histopathologic examination of the brain revealed acute meningoencephalitis. This case represents an unusual clinical and pathologic presentation of listeriosis in a nonhuman primate in which the dam and fetus both were affected.

Analysis of several factors of variation of gestation loss in breeding mares.

The files for ultrasound diagnosis of gestating mares belonging to the French equine herd recorded for 3 consecutive years were joined with the files for foal birth of these same mares, allowing the statistical analysis of factors of pregnancy loss. For 28 872 positive diagnoses of gestation, 2898 losses were recorded, that is, a global rate of gestation interruption of 9.12%. The etiology of these interruptions is mainly extrinsic: the year and month of insemination, as well as region for climatic reasons. The intrinsic causes that are implicated are breed of the father (heavy breeds except the hypermetric ones lose fewer pregnancies than warm-blooded breeds), age of the mother (losses are lower in mares of 7 to 10 years of age) and status (mares with foals have fewer pregnancy losses than mares not having foaled the previous year), as well as fetuses with consanguinity (when this increases, the pregnancy losses increase as well). However, the additive genetic effect is extremely low; it corresponds to heritability below 5% and few effects of the environment, common to the offspring of the same mare, were identified. This therefore gives little hope of being able to select against the 'gestation loss' trait.

Mummified fetus in the thoracic cavity of a domestic short-haired cat.

This short communication describes the diagnosis, treatment, and clinical course of a domestic short-haired cat with diaphragmatic hernia in which the herniated structure in the thoracic cavity contained a mummified fetus. The cat was pregnant when rescued from the street and, days later, gave birth without abnormalities. Some months later, during an ovariohysterectomy, an abnormal localization of the uterus was observed, and at that time the case was referred to our center. A thoracic radiograph showed an abnormal thoracic mass cranial to the heart. The main suspicion was the presence of a thoracic hernia with the uterus herniated and containing a mummified fetus. A thoracotomy was performed to confirm the nature of the mass and reduce the diaphragmatic hernia. Although this clinical case is quite rare, a mummified fetus can be observed in thoracic hernias.

An overview of molecular and cellular mechanisms associated with porcine pregnancy success or failure.

Prenatal mortality remains one of the major constraints for the commercial pig industry in North America. Twenty to thirty per cent of the conceptuses are lost early in gestation and an additional 10-15% is lost by mid-to-late gestation. Research over the last two decades has provided critical insights into how uterine capacity, placental efficiency, genetics, environment, nutrition and immune mechanisms impact successful conceptus growth; however, the exact cause and effect relationship in the context of foetal loss has yet to be determined. Similar to other mammalian species such as the human, mouse, rat, and primates, immune cell enrichment occurs at the porcine maternal-foetal interface during the window of conceptus attachment. However, unlike other species, immune cells are solely recruited by conceptus-derived signals. As pigs have epitheliochorial placentae where maternal and foetal tissue layers are separate, it provides an ideal model to study immune cell interactions with foetal trophoblasts. Our research is focused on the immune-angiogenesis axis during porcine pregnancy. It is well established that immune cells are recruited to the maternal-foetal interface, but their pregnancy specific functions and how the local milieu affects angiogenesis and inflammation at the site of foetal arrest remain unknown. Through a better understanding of how immune cells modulate crosstalk between the conceptus and the mother, it might be possible to therapeutically target immune cells and/or their products to reduce foetal loss. In this review, we provide evidence from the literature and from our own work into the immunological factors associated with porcine foetal loss.

Associations between intrapartum death and piglet, placental, and umbilical characteristics.

Intrapartum death in multiparous gestations in sows (Sus scrofa) is often caused by hypoxia. There is little information in the literature on the assessment of the placenta in relation to intrapartum death in piglets. The aim of this study was to evaluate the impact of the placental area and weight upon piglet birth characteristics and intrapartum death. Litters from 26 Landrace-Yorkshire sows were monitored during farrowing and the status of each piglet was recorded, including blood parameters of piglets and their umbilical veins. Of 413 piglets born, 6.5% were stillborn. Blood concentrations of glucose, lactate, and CO(2) partial pressure were increased in the stillborn piglets (P < 0.05) and corresponding umbilical veins (P < 0.01) vs. live-born piglets, whereas pH and base excess were decreased (P < 0.001). Time from onset of parturition until birth was increased for piglets born dead vs. live (P < 0.001). Mean birth weight for piglets born dead was not different from live-born piglets (P = 0.631), whereas mean body mass index was reduced (P < 0.001). Mean placental area and placental weight belonging to stillborn piglets were not different from live-born piglets (P = 0.662 and P = 0.253, respectively). Blood concentrations of lactate, hemoglobin, and hematocrit recorded in all piglets pooled were associated with placental area (P < 0.05), but not with placental weight (P > 0.2). Piglet BW was positively correlated with placental area and placental weight (P < 0.001). The risk of being born dead increased with increasing birth order group, and broken umbilical cords explained 71% of the stillbirths (P = 0.001). We conclude that placental area and placental weight are both positively associated with piglet birth weight, but not with the probability of being born dead. Placental area was a better predictor of piglet vitality than placental weight. Because umbilical cord rupture and prolonged birth time were associated with being born dead, umbilical cord rupture and placental detachment seem to be probable causes of intrapartum death.

Impact of BVDV infection of white-tailed deer during second and third trimesters of pregnancy.

While it has been demonstrated that persistent bovine viral diarrhea virus (BVDV) infections can be established in white-tailed deer (Odocoileus virginianus) following in utero exposure in the first trimester of gestation, there is little to no information regarding the outcome of infection in later stages of pregnancy in deer. Our goal was to observe the impact of infection of white-tailed deer in the second and third trimesters of pregnancy. Five white-tailed deer in the second trimester of pregnancy and four in the third trimester were infected with a BVDV type 2 virus previously isolated from a BVDV-infected deer harvested from the wild. Infection of deer in the second trimester of pregnancy resulted in loss of the pregnancy in three of five deer. Fawns born to the two remaining deer appeared normal and were born BVDV antigen-negative with neutralizing serum antibodies against BVDV. Infection of does in the third trimester of pregnancy did not result in fetal death or persistent infection and all does gave birth to live, healthy fawns that were BVDV antigen-negative and born with antibodies against BVDV. These results, combined with those previously reported regarding BVDV infection in the first trimester of pregnancy, suggest that the impact of BVDV infection of pregnant white-tailed deer is very similar to that observed in pregnant cattle.

Full-term development of gaur-bovine interspecies somatic cell nuclear transfer embryos: effect of trichostatin A treatment.

Trichostatin A (TSA) has previously been used in somatic cell nuclear transfer (SCNT) to improve the cloning efficiency in several species, which led our team to investigate the effects of TSA on the full-term development of bovine SCNT and gaur-bovine interspecies SCNT (gaur iSCNT; gaur somatic cells as donors and bovine oocytes as recipients) embryos. Treatment with 50 nM TSA for 10 h after fusion had no positive effects on the rates of fusion, cleavage, or the development to eight-cell or morula stages in both bovine SCNT and gaur iSCNT embryos. However, TSA treatment significantly enhanced the blastocyst formation rate in bovine SCNT embryos (44 vs. 32-34% in the TSA-treated and TSA-untreated groups, respectively), but had no effects on gaur iSCNT embryos. The fresh blastocysts derived from bovine SCNT and gaur iSCNT embryos (fresh groups), as well as vitrified bovine SCNT blastocysts (vitrified group), were transferred to bovine recipients. We found that TSA treatment increased the pregnancy rates only in recipients receiving fresh bovine SCNT embryos. In recipients receiving TSA-treated bovine SCNT embryos, three cloned calves from the fresh group and twin cloned calves from the vitrified group were delivered; however, no calf was born from the TSA-untreated bovine SCNT embryos. In contrast, one gaur iSCNT calf was born from a recipient receiving blastocysts from the TSA-untreated group. In summary, TSA improved the preimplantation development and pregnancy rates of bovine SCNT embryos, but did not have any beneficial effect on gaur iSCNT embryos. However, one gaur iSCNT calf reached full-term development.

The Neospora caninum-Spain 7 isolate induces placental damage, fetal death and abortion in cattle when inoculated in early gestation.

The Nc-Spain 7 isolate of Neospora caninum, which was newly obtained from an asymptomatic congenitally infected calf, demonstrated a similar virulence as Nc-1 strain in mouse models. The aim of this study was to characterize the pathogenesis of Nc-Spain 7 isolate in cattle after experimental infection at 65 days of gestation. For this purpose, thirteen pregnant heifers were divided into three groups as follows: group A: 7 heifers inoculated with 1 × 10(8) tachyzoites of Nc-Spain 7 isolate; group B: 4 heifers inoculated with 1 × 10(8) tachyzoites of Nc 1 strain; and group C: 2 heifers received PBS. Serum samples were collected weekly and heparinized blood samples were collected three times (0, 28 and 42 days after inoculation) by jugular venipuncture. Placenta and fetal tissue samples were collected at time of necropsy. Specific antibody response in the dams was tested by IFAT, indirect ELISA, and rNcGRA7 and rNcSAG4 based-ELISA. Specific antibody response in fetal fluids was tested by IFAT. IFN-γ production was measured after in vitro culture of PBMC and the supernatant was assessed using a commercial kit (BOVIGAM). A significant increase in N. caninum antibody responses was detected in groups A and B by IFAT and by i-ELISA from day 14 after inoculation onwards. Besides, antibody response against rNCGra7 protein was also detected in all inoculated heifers by rNcGra7-based ELISA. Four fetuses from group A and one from group B were aborted between 3 and 5 weeks after infection. In the recovered fetuses, only 3 out of 4 fetal fluids from fetuses of group A and 1 out of 3 of group B were seropositive by IFAT, but all of them were positive by PCR. Transplacental transmission could be determined in all fetuses from groups A and B by PCR and/or IHC. Heifers of group C and their fetuses remained negative by all techniques. The results of this study demonstrate that the NC-Spain 7 isolate could be transmitted transplacentally, and produced fetal death and abortion in cattle.