The origin of amniotic polymorphonuclear leucocytes in the mare.

The objective of this study was to investigate the presence and origin of polymorphonuclear leucocytes (PMNLs) in the amniotic fluid of mares giving birth to healthy foals. Material from 25 mares was included. Amniotic fluid was collected during parturition before breakage of the amniotic vesicle. Manual microscopic cytologic evaluation was made on cytospin preparations after staining. PMNLs were found in all amniotic samples examined. The genomic DNA was extracted from 12 of the amniotic fluid samples and was genotyped. The results indicate that the PMNLs originate from the foetus.

Relationships between early foal health, future performance and their dams reproductive health.

The objectives of this study were to investigate: (i) relationships between early foal health and their dams' reproductive health at mating/conception as well as after parturition and (ii) health status during early foal life and its association with performance as an adult. The study included 35 foals showing clinical symptoms indicating septicaemia, sometimes in combination with other disturbances, within their first 18 h postpartum (Group I). Eighty-eight foals that were healthy during their first few days of life were used as control (Group II). All foals were born in the same region of Sweden and during the same period, and were expected to become performance athletes based upon the pedigree of their parents. Cytological and bacteriological examination of uterus at the time of mating/insemination at which the foal was conceived, revealed no difference between dams of Group I and Group II foals. Within 2-3 days after parturition, 29% and 4% of dams (p < 0.001) of Group I and Group II foals had metritis, respectively. At 30 days post-parturition, 64% of the dams of Group I foals and 32% of the dams of Group II foals (p = 0.002) had cytological indication of endometritis, and 57% of the dams of Group I foals and 21% of the dams of Group II foals (p < 0.001) showed bacterial growth upon culture. Altogether 29% of the Group I foals and 7% of the Group II foals were killed or died before 2 years of age (p = 0.001). The majority of the remaining Group I foals were poor performers and some were used just for pleasure riding. It is hypothesized that (i) mares--delivering foals that compromised within their first 18 h postpartum--might have suffered from an ascending infection during late gestation and (ii) health status during early foal life might be associated with their performance as adult.

Occurrence of bacteria and polymorphonuclear leukocytes in fetal compartments at parturition; relationships with foal and mare health in the peripartum period.

This study investigated the relationship of the health of the newborn foal and (1) number of polymorphonuclear leukocytes (PMNLs) in the amniotic fluid, (2) bacteria present in the amniotic fluid and the venous umbilical blood, and (3) bacteria present in the uterus of the newly foaled mare. A further aim was to investigate relationships between the bacteriologic findings in the amniotic fluid, umbilical blood, and uterus postpartum. Samples were taken from 50 Standardbred trotter foaling mares from a well-managed stud in Sweden. Parturition was spontaneous in all cases. Length of pregnancy, parturition and postpartum complications, health status of the foal, the time between foaling and the expulsion of the placenta, and the number of postfoaling mares becoming pregnant after insemination were recorded. Amniotic fluid was collected when the amniotic vesicle was clearly visible; it was analyzed for bacteriology and occurrence of PMNLs. Umbilical blood was analyzed for the presence of bacteria and the concentration of serum amyloid A. The uterus of the mare was swabbed for bacteriology 6 to 17 hours postpartum. A blood sample was taken from the foal before administering plasma. The foals were divided into two groups: group 1 required up to 2 hours to rise after birth (≤2 hours; 31 foals) and group 2 required more than two hours (>2 hours; 19 foals). The length of gestation varied between 332 and 356 days; there was no significant difference in gestation length between the two foal groups. Partus and postpartum complications occurred in a significantly higher proportion of mares giving birth to group 2 foals than group 1 foals (P = 0.02), although uterine culture postpartum and the subsequent pregnancy rate per season were not different between the groups. Compromised health status was significantly higher among foals belonging to group 2 than group 1 (P = 0.001). Most of the amniotic samples contained 5% or less PMNLs. Only three samples contained more than 30% PMNLs; group 2 foals had the highest percentage of PMNLs. Bacterial growth was found in both amniotic fluid (57%) and umbilical blood (35%) in mares irrespective of whether their foals were healthy or compromised. Coagulase-negative staphylococci were the most frequent bacteria. There were no differences in bacterial occurrence in amniotic fluid or in umbilical blood between the two foal groups.

Successful timing of ovulation using deslorelin (Ovuplant) is labour-saving in mares aimed for single ai with frozen semen.

To minimize the number of matings/inseminations, controlled ovulation has been practised since a long time ago. A potent short-term implant, releasing the GnRH analogue deslorelin (Ovuplant((R))) has been used in Australia and North America for several years for hastening the ovulation time in mares, but the product is not registered on the European market. This study was aimed to investigate: (1) ovulation time in mares implanted with Ovuplant when the largest follicle was 42 mm or more in size, (2) repeatability of ovulation time in successive oestruses when treated with Ovuplant, (3) pregnancy rate after single insemination with frozen-thawed semen near ovulation. This study included 11 mares, and altogether 17 timed ovulations. Follicular growth and ovulation were determined by palpation per rectum and by ultrasonography in the morning (at 7:00 hours) every second day until observation of a follicle of at least 42 mm in diameter. Then the mares were re-examined in the afternoon (at 19:00 hours), and an Ovuplant was inserted in the mucosa of the vulva. For detection of ovulation, the mares were palpated and ultrasounded repeatedly from 36-42 h after the insert. The mares were inseminated with frozen-thawed semen once at ovulation. All mares ovulated at 36-48 h after treatment and 94% at 38-42 h after treatment. The six mares that were treated at two oestruses ovulated at 39.9 and 39.7 h, respectively. Five of 11 mares (45.4%), inseminated with frozen-thawed semen at the first oestrous cycle were pregnant day 14-16 after ovulation. Using this protocol, there is no need of palpation/ultrasonography during night hours, and examination at 36 and 41 h after implantation might be enough for estimation of ovulation time.

Retrospective study on vulvar conformation in relation to endometrial cytology and fertility in thoroughbred mares.

Changes in the conformation of the vulva predispose the mare to uterine infection. Vulvoplasty for closure of the upper vulvar lips improves fertility. Not all mares are resutured after parturition, but are resutured after mating. No clinical data have hitherto been published on the reproductive outcome in mares that are resutured or not after parturition. The objectives of the present study were to investigate relationships between vulvar status (not Caslick-operated, group A; previously Caslick-operated and/or not resutured after the last parturition, groups B and C respectively) and endometrial cytology, conception rate and live foal rate for different age groups and categories of Thoroughbred mares. A careful examination of the vulvar area, and endometrial sampling for bacteriology and cytology was performed. The mares were naturally mated once during oestrus (never foal heat) by one of two stallions. Mares belonging to vulvar status group A had the highest conception rate and live foal rate, whereas the lowest conception rate and live foal rate occurred in mares with vulvar status group C. A multifactorial analysis revealed that the vulvar status at arrival had a significant effect on pregnancy rate and live foal rate, but not on fetal loss. Stallion, year and age group had no significant effect on any of the three variables analysed. In conclusion, optimizing managerial factors such as resuturing Caslick-operated mares immediately after parturition to minimize growth of micro-organisms with a subsequent endometritis will contribute to their conception and that they carry a pregnancy to term.

Reproductive performance of thoroughbred mares in sweden.

During 1997-2001, a total of 430 Thoroughbred mares were mated by one of the two Thoroughbred stallions on a well-managed stud farm in the central part of Sweden. On arrival, a thorough gynaecological examination of all mares was performed. An early pregnancy examination was performed on days 14 and 15 after ovulation. The overall conception rates for the two stallions were 92.2 and 88.8%, and the corresponding live foal rates were 82.6 and 75.2%, respectively. The mean number of served oestrous cycles was 1.60 per mare per conception and 1.86 per live foal. The first and second cycle conception rates are reported for different age groups, mare categories and month of mating. The age of the mares had a significant influence on the live foal rate, being lower for mares >13 years of age. Resorption and abortion occurred in higher percentages among mares >8 years of age. The highest embryonic death occurred among mares with a history of being barren, or with having resorbed or aborted foetuses during the previous season. The month of mating had no significant influence on the first cycle conception rate or the second cycle conception rate. The frequency of twinning was 10.5% and the results of manual crushing of one of the conceptuses was successful in 88.9% of all cases, according to the ultrasound scanning 2 days later.