The correlation between the cytology of the vaginal smear and the time of ovulation in the bitch

The correlation between the vaginal smear and the calculated time of ovulation was studied in 22 bitches, during a total of 24 heat periods. Blood plasma was analysed for levels of oestradiol and progesterone from 6 days before to 6 days after the day of maximum keratinization of the vaginal smear. In all 24 heat periods (100 per cent) maximum keratinization of the vaginal epithelial cells was observed at least 3 days after peak oestradiol levels and in 17 of the heat periods (70.8 per cent) maximum keratinization was seen when the peripheral plasma level of progesterone had increased to >5.44 ± 0.93 ng/ml, which has been calculated as the ovulatory level.     

Timing the mating of dogs on the basis of blood progesterone concentration

The optimal time for mating bitches was determined by measuring the progesterone concentration in peripheral blood three times a week after the start of vulval bleeding. Of 104 bitches with reduced fertility 81 (78 per cent) became pregnant and of 112 bitches with normal fertility 105 (94 per cent) became pregnant. Of 121 bitches mated once, 102 (84 per cent) became pregnant, and of 95 bitches mated more than once, 84 (88 per cent) became pregnant. The mean (+/- sd) interval between the start of vulval bleeding and the optimal time for mating in 88 bitches was 11.8 +/- 3.1 days. The blood progesterone concentration appears to be an excellent indicator of the best time for mating, particularly in bitches with reduced fertility.     

Effect of Time for Mating and Gestation Length on Reproductive Efficiency in Dogs

The purpose of this study was to examine the effect of time for mating and gestation length on reproductive efficiency in dogs. Groups of eight, six and six beagle bitches were mated with a total of three sires on days 3, 5 and 7, respectively, after the luteinizing hormone (LH) surge. All the bitches whelped successfully. The gestation lengths (the intervals from the LH surge to the whelping) were 65.1 +/- 1.9, 65.5 +/- 1.9 and 68.0 +/- 1.8 days, respectively. This length of mating 7 days after the LH surge was significantly longer than that of mating 3 and 5 days after the LH surge (p < 0.05). The litter sizes were 5.5 +/- 2.2, 6.2 +/- 1.9 and 4.8 +/- 2.1, respectively and there was no significant difference between any of the groups. In conclusion, mating 3-7 days after a bitch's LH surge results in a good reproductive efficiency and the intervals from the LH surge to the whelping of mating 7 days after the LH surge shows a longer day significantly in comparison with mating 3 and 5 days after the LH surge.     

Changes in LH Pulsatility Profiles in Dairy Heifers During Exposure to Oestrous Urine and Vaginal Mucus

Difficulty in observing oestrus is a problem for many dairy farmers performing AI. Finding ways to synchronize oestrous cycles or strengthen display of oestrus without hormonal treatments would be of great interest because many consumers object to the use of exogenous hormones on healthy animals. Modification of reproductive cycles through chemical communication has been reported in several species including cattle. LH is an important regulator of the follicular phase and could possibly be subject to pheromonal influence. This study focuses on the effect of volatile compounds from oestrous substances on LH pulsatility preceding the preovulatory LH surge in cattle. Four heifers of the Swedish Red breed were kept individually in isolation. Exposure to water during the control cycle (CC), and bovine oestrous urine and vaginal mucus during the treated cycle (TC), started simultaneously with induction of oestrus. Blood sampling at 15‐min intervals started 37 h after administration of PGF_2α and continued for 8 h. Monitoring of reproductive hormones, visual oestrus detection and ultrasonographic examination of the ovaries continued until ovulation had occurred. The mean concentration of LH at pulse nadir was significantly higher during TC (2.04 ± 0.18 ng/ml) than during CC (1.79 ± 0.16 ng/ml), and peak amplitude was significantly higher during CC (Δ1.03 ± 0.09) than during TC (Δ0.87 ± 0.09). No other parameters differed significantly between the two cycles. We conclude that the difference in LH pulsatility pattern may be an effect of exposing heifers to oestrous vaginal mucus and/or urine and that the mechanism behind this needs further investigation.     

Twenty-four-hour Profiles of Serum Prolactin and Luteinizing Hormone in Anoestrous Crossbred Bitches

The dynamics of prolactin (PRL) and luteinizing hormone (LH) secretion in the anoestrous bitch is poorly known. Therefore, the objective of this study was to characterize the 24 h profiles of serum PRL and LH in crossbred anoestrous bitches and to assess whether a relationship exists between the secretory patterns of these two hormones. Serum PRL and LH concentrations were measured in 10 healthy anoestrous crossbred bitches at 145 min intervals for 24 h. During the experiment the animals received continuous artificial illumination and remained undisturbed except at the time of blood sampling. Serum PRL was measured by a homologous enzyme‐linked immunosorbent assay, whereas LH and progesterone (P₄) were determined by radioimmunoassay. The anoestrous state of the bitches was assessed by vaginal cytology, vaginoscopy and physical examination. Two groups of animals were identified according to their PRL levels: a high PRL group (n=3, mean ± SEM 12.3 ± 2.7 ng/ml) and a low PRL group (n=7, mean ± SEM: 2.5 ± 0.9 ng/ml). In the low PRL group, the PRL profiles were flat and did not show any significant circadian pattern. Nevertheless, occasional single‐point peaks were detected in some of the bitches. In the high PRL group the individual PRL profiles were variable. To detect the presence of a circadian change of PRL concentrations, two different sets of time windows (TW) of sampling were studied. The first set was: day [TW1A, samples 1–5 (0900–1840 h)] and night [TW1B, samples 6–10 (2105–0645 h)]. The second set was chosen after visual inspection of the average PRL profiles for both (high and low) groups: [TW2A, samples 3–7 (1350–2330 h) and TW2B, samples 1–2 and 8–10 (0155–1125 h)]. PRL concentrations were not significantly different between day and night. In the high PRL group, but not in the low PRL group, average serum PRL was significantly (p < 0.01) higher in TW2A than TW2B. In both groups serum LH levels were more homogeneous than PRL levels. Neither TW showed circadian changes in LH patterns of secretion (TW1A versus TW1B, p < 0.69; TW2A versus TW2B, p < 0.88). On the other hand, bitches in the high PRL group showed significantly (p < 0.01) lower serum LH levels than those in the low PRL group of animals. Serum PRL concentrations presented a significant inverse correlation with LH concentrations (r=?0.21, p < 0.03) and a significant positive correlation with P₄ concentrations across the study (0.92, p < 0.01). It is concluded that in anoestrous crossbred bitches serum PRL is highly variable and inversely related to LH. No circadian rhythm of PRL secretion appears to exist in most anoestrous bitches.     

Practical use of a combination of a dopamine agonist and a synthetic prostaglandin analogue to terminate unwanted pregnancy in dogs

The combination of a dopamine agonist, caber-goline, and a synthetic analogue of prostaglandin F_2a, cloprostenol, was used to induce termination of pregnancy from day 25 after the estimated luteinising hormone surge (day 27 ± 4 after the first mating) in five mature beagle bitches. Caber-goline was administered orally at 5 μg/kg daily and cloprostenol was injected subcutaneously at 1 μg/kg every other day. Treatment efficacy, in terms of pregnancy termination, was 100 per cent. Termination always took place by resorption of the fetuses. No side effects were observed. A mean of three injections of cloprostenol and nine days of cabergoline treatment was necessary to eliminate all signs of gestation. Termination was in each case accompanied by a decline in plasma progesterone (to less than 1 ng/ml) within 72 hours of initiation of treatment. In a control group of five, untreated bitches, plasma progesterone remained elevated throughout a corre-     

Use of exfoliative cytology for diagnosis of transmissible venereal tumour and controlling the recovery period in the bitch

Transmissible venereal tumour (TVT) is a rare vaginal tumour that can be treated surgically or cryosurgically as well as by radiotherapy or chemotherapy. Vincristine has been found to be very effective for treating TVT. Since vaginal secretion or discharge may contain neoplastic cells, the cytological identification of TVT cells is possible. The present study was carried out in 12 bitches. Vaginal smears were obtained with cotton swab from the anterior vagina and TVT suspected structures. The smears were stained according to Papanicolaou and assessed by light microscopy. Additionally the general condition of the patients was evaluated by haematological and radiographic examinations. In bitches with TVT vincristine sulphate was administered intravenously at weekly intervals. The total treatment period was three to six weeks until no atypical cells were found in the smear. This was the case after an average of 3.2 +/- 1.3 applications. Tumour masses became smaller and by this non-visible from the rima vulva after 4.2 +/- 0.7 applications. During the treatment, two of the 12 bitches (16.7%) suffered from vomiting and diarrhoea while three (25%) showed neutropenia. Twelve months after completion of treatment, the bitches were examined again and vaginal smears were taken in order to control the recovery process or a possible recurrence of TVT. No atypical cells were found in any vaginal smear. By this exfoliative cytology has proved to be a safe and easy method for TVT diagnosis and for observing the recovery process.     

Practical aspects of the estimation of the time of ovulation and of insemination in the bitch

The aims of this study were to assess the precision of the estimates of the time of ovulation derived by various methods, and to define the most appropriate methods for the determination of the optimal time for insemination of bitches with fresh semen (artificial insemination or natural mating), or with frozen-thawed semen. In 11 Labrador bitches, ovulation was estimated (plasma LH surge + 48 h) to occur 9 to 20 d after the start of the cycle, 0 to +4 d after the onset of positive postural reflexes (2 bitches showed no positive postural reflexes), -4 to +7 d after reaching a vaginal cytological eosinophilic index (EI) of 100%, over a range of 2.5 to 5.5 d based on plasma progesterone concentrations of 4 to 10 ng/ml, over a range of 2 to 3 or 4 d based on 2 indirect methods of estimating the time of the plasma LH surge from plasma progesterone concentrations. Assuming fertilisation occurs 2 to 3 d after ovulation, these findings indicate that for fresh semen (with an estimated lifespan of greater than 4 days) an appropriate procedure would be to inseminate/mate on the day after the onset of positive postural reflexes; then 3 days later. For bitches not showing positive postural reflexes, insemination should occur when the vaginal EI = 90% and then each 3 d until day 1 of dioestrus (D1). For frozen-thawed semen (with a lifespan of less than 24 h) insemination should occur 4 to 5 d after the plasma LH surge.(ABSTRACT TRUNCATED AT 250 WORDS)     

Temporal sequence of events in the estrous cycle of the bitch.

Serum concentrations of luteinizing hormone (LH), estradiol-17 beta, and progesteron were compared with the onset of diestrus in Beagle bitches. The LH peak occurred 8.0 (standard error (SE), 0.3) days before the onset of diestrus. Vaginal cytologic characteristics during proestrus were studied, and vaginal cornification was complete 12.1 (SE,0.2) days before the onset of diestrus. A time sequence of hormonal, vaginal cytologic, and developmental events was outlined during proestrus, estrus, and early diestrus.     

Effect of aglepristone (RU534) administration during follicular phase on progesterone,estradiol-17β and LH serum concentrations in bitches

Aglepristone was administered in bitches during the follicular phase to evaluate its effects on progesterone, estradiol-17β and LH serum concentrations. Ten German Shepherds were divided into two groups (treated n = 5; control n = 5). Treated bitches received 10 mg/kg BW of aglepristone subcutaneously during the early follicular phase, 24 hr after and then 7 days later. The control group was injected, at the same time periods, with saline solution (0.3 ml/kg BW). For the steroid evaluations, blood was collected daily from the onset of proestrus until the first day of cytological dioestrus. For LH base-line serum determination, blood was also collected every 20 min for 2 hr at the onset of proestrus. For LH surge identification, blood was collected daily (every 6 hr) starting from the day of the first administration of aglepristone or saline solution until the first day of dioestrus. All animals ovulated but the treated group presented longer ovulation-dioestrus intervals than the control group (5.2 ± 2.2 days p < .05). Serum concentrations of the evaluated hormones were similar between experimental animals except for serum LH. Indeed, no LH peaks were detected in the treated group while LH surges were clearly observed in the control group (9 ± 1 days after the beginning of proestrus. In particular, the area under the curve for LH was significantly lower in treated than control animals (12 ± 4 ng/ml x Day; p = .01). In conclusion, administrations of aglepristone during the follicular phase of the bitch does not affect the steroid hormone patterns but does prevent the occurrence of a LH surge. This work raises significant questions and opens perspectives concerning the mechanisms of ovulation in bitches.     

Induction of oestrus by administering Inhibin antiserum along with equine chorionic gonadotropin in anoestrous bitches

As dogs experience oestrus only once or twice a year, it is necessary to establish an effective method of oestrous induction for efficient breeding. In the present study, we evaluated inhibin antiserum (IAS) on oestrous induction in anoestrous females. Bitches were administered 0.5 ml/kg IAS or a mixture of 50 IU/kg equine chorionic gonadotropin (eCG) and 0.5 ml/kg IAS and 500 IU human chorionic gonadotropin (hCG) administered 7 days after the mixture injection. As a control, bitches received 50 IU/kg eCG, with 500 IU hCG administered 7 days after eCG injection. Blood-tinged vaginal discharge, vulvar swelling, plasma progesterone concentrations and ovarian follicular development were assessed from day 0 to day 14. IAS alone injection did not induce oestrus in bitches at the anoestrous stage. Conversely, vulvar swelling, blood-tinged vaginal discharge and an estimated luteinizing hormone (LH) surge appeared on days 3–7, days 3–6 and days 7–9 after the IAS+eCG mixture injection, respectively, in all five bitches at the anoestrous stage. The average number of developing and ovulated follicles in bitches administered IAS+eCG was 8.8 and 9.6 respectively. A single eCG injection followed by hCG induced oestrous signs, with an average of 8.3 developing follicles and 4.5 ovulated follicles. This study revealed that IAS alone did not induce oestrus, but when IAS was used in combination with eCG, it induced oestrus and promoted a considerable number of ovulations in anoestrous dogs.     

Thermoregulatory effects and electrical conductivity in vagina of cow during oestrous cycle

Measurement of vaginal temperature and electrical conductivity of cervicovaginal mucus were conducted in 20 dairy cows and were related to the phase of the oestrus cycle. Temperature and electrical conductivity in the anterior part of the vagina changed in synchronicity with phases of the oestrous cycle. About 12 hours before ovulation, the vaginal temperature increased from 37.94 +/- 0.33 degrees C to 39.00 +/- 0.64 degrees C, as compared to the pre-oestrus value. The occurrence of oestrus was accompanied by an increase in electrical conductivity of mucus in the anterior part of the vagina from 7.60 +/- 0.33 mS to 12.00 +/- 0.54 mS. Vaginal temperature dropped to 38.50 +/- 0.29 degrees C, and electrical conductivity dropped to 10.00 +/- 0.55 mS at ovulation time. Rises in vaginal temperature and electrical conductivity in the anterior part of the vagina were additional symptoms of oestrus and were followed by decrease in these values, indicating ovulation in cows.     

Effects of whelping and season of the year on the interoestrous intervals in dogs

An analysis of 319 interoestrous intervals of 36 beagles, 36 German shepherd dogs and 20 labrador retrievers was made to study the influence of whelping on the length of this interval and the within-year variation in length of interoestrous intervals and timing of the oestrous periods. The mean interoestrous interval was significantly longer for beagles (247±5 days) than for German shepherd dogs and labrador retrievers (both 198±5 days)(P<0–001). For bitches that had not whelped there were no significant differences between breeds (beagles 172+10; German shepherd dogs 166±6; and labrador retrievers 172±7 days). The mean interoestrous interval after whelping was significantly lengthened in all breeds (P<0–001). This increase was more pronounced for beagles (84 days)(P<0–001) than for German shepherd dogs (58 days) and labrador retrievers (52 days). Heat periods were evenly distributed over the year for the labrador retrievers and German shepherd dogs that were kept as family pets. For the beagles kept as a colony and housed outdoors without heating or supplementary light, there were significant differences between months (P<0001), with a peak in May. The longest interoestrous intervals were found in beagle bitches that had been in oestrous and whelped during autumn.     

Some observations on the aerobic bacterial flora of the genital tract of the dog and bitch

The aerobic bacterial flora from the genital tracts of 143 bitches and 51 dogs was investigated. Beta haemolytic streptococci (group G), Staphylococcus aureus and Escherichia coli were among the organisms isolated from normal bitches in heat, abnormal bitches and normal dogs. Repeated sampling of two bitches during oestrus, and the dog to which they were mated, showed that bacteria were transmitted from bitch to dog, but did not become established. Guarded swab samples taken from the vagina collected less bacteria than samples from the vestibule. Numerous bacteria were seen in vaginal smears taken from bitches during oestrus, but numbers fell rapidly with the appearance of leucocytes in the smear at the onset of metoestrus.     

Vaginal isolation of beta‐haemolytic Streptococcus from bitches with and without neonatal deaths in the litters

The aim of the study was to identify beta‐haemolytic streptococci in the vagina of bitches who had delivered healthy litters and bitches who had delivered litters in which neonatal deaths occurred. Fifty‐one bitches divided into two groups were used. Group 1 (G1) included 28 bitches that had delivered healthy litters and group 2 (G2) included 23 bitches that had delivered puppies who died in the neonatal period. Two vaginal samples were taken, one in proestrus and the other at the end of gestation (EG). Beta‐haemolytic Streptococcus (BS) was isolated from 16 bitches (57%) in G1 and from 21 bitches (91%) in G2. The bacteriological cultures, serological tests (Streptex^®) and PCR assay allowed identification of Streptococcus canis and Streptococcus dysgalactiae in G1 and G2. Ultramicroscopic studies allowed the observation of M Protein and capsules in strains of S. dysgalactiae and S. canis in G1 and G2. The S. canis strains isolated from G2 showed thicker capsules than S. canis strains isolated from G1 (234 ± 24.2 vs 151.23 ± 28.93 nm; p < .001.). No differences were observed in capsule thickness between strains of S. dysgalactiae isolated from G1 and G2 (210 ± 13.54 vs 211.66 ± 19.67 nm; p > .70). All strains of beta‐haemolytic Streptococcus isolated were penicillin sensitive. Penicillin was administered from EG to 5 days post‐partum in 10 G2 females with isolation of BS (G2A). Saline solution was administered in eleven G2 females with isolation of BS (G2B). Ninety per cent of the puppies survived in G2A and 25% survived in G2B. Our results suggest BS is involved in canine neonatal deaths.     

Exfoliate vaginal cytology and plasma concentrations of progesterone, luteinising hormone and oestradiol-17sZ during oestrus in the bitch

Oestrus was characterised in nine German shepherd bitches by measuring plasma levels of luteinising hormone (LH), progesterone (P) and oestradiol-17ß (O). Hormone concentration data were compared with the eosinophilic index (EI) obtained from exfoliate vaginal cytology. Maximal values of O and LH occurred before the maximal EI value. The EI peak followed the O peak, with a two day delay. LH increased during the first 24 hours after the maximum 0 value, and P levels were then slightly higher than basal.     

Vaginal cytology studies on the determination of the onset of estrus cycle post partum in sheep]

State of vaginal cells and arborisation grade of cervical mucus were studied in 364 Merino ewes of meat type from the 7. day ante partum. The Pundel modified Shorr-straining method and the Papanicolaou-straining method were used for differentiation of the cells (casal-, parabasal-, intermediate-and superficialcells). Near the 44., 54. and 70. day post partum a maximum of superficialcells and simultaneously a high grade of cervical mucus arborisation in elongating cyclic intervals can be observed in lactating ewes. In conclusion an early weaning of lambs between the 40. and 50. day post partum is considered to be in aggreement with cyclus.     

Clinical Evaluation of the Use of Aglepristone Associated with Oxytocin to Induce Parturition in Bitch

To evaluate the efficacy and safety of aglepristone 15 mg kg⁻¹ for induction of parturition in bitches, 22 pregnant beagle bitches were injected subcutaneously on day 60 post-estimated LH surge, and again 24 h later with aglepristone and subsequently were given 0.15 IU kg⁻¹ oxytocin at hourly intervals until delivery of the last puppy. Six pregnant beagle bitches were used as a non-treated control group. In the control group, parturition occurred at 63.2 ± 0.5 days, 29 pups were born and the average expulsion time per puppy was 1.0 ± 0.6 h. In the treated group, parturition was obtained on average 29.7 ± 5.6 h after aglepristone administration, 121 pups were born and average expulsion time per pup was 1.1 ± 0.4 h. The percentage of live puppies, 7 weeks after birth, was 86.1% (25/29) and 86.8% (105/121) for the control and treated groups, respectively. No significant difference was observed between the control and treated groups for the average expulsion time per live puppy and for the percentage of live puppies at birth, 48 h, 7 days or 7 weeks after birth (p > 0.05). This study confirms previous results and demonstrates that the combination of aglépristone and oxytocin can be safely and reliably used to induce parturition in beagle bitches, at 60 days post-estimated LH surge.     

Studies on canine pregnancy using B-mode ultrasound: Diagnosis of early pregnancy and the number of conceptuses

The ultrasonic (B-mode) detection of canine pregnancies was first achieved 21 to 23 days after the calculated luteinising hormone peak when daily examinations were made in six bitches. In 51 pregnant bitches examined for the first time between 20 and 35 days, one bitch was incorrectly diagnosed as non-pregnant 24 days after the calculated luteinising hormone peak. In only 31-8 per cent of pregnancies was conceptal number accurately determined. The greatest tendency was to underestimate the number of conceptuses.     

Prediction of Parturition in Bitches Utilizing Continuous Vaginal Temperature Measurement

The objective of this study was to determine sensitivity and specificity of a body temperature decline in bitches to predict parturition. Temperature loggers were placed into the vaginal cavity of 16 pregnant bitches on day 56–61 after estimated ovulation or first mating. This measurement technique has been validated previously and enabled continuous sampling of body temperature. The temperature loggers were expelled from the vagina before delivery of the first pup. The computed values for specificity (77–92%) were higher than sensitivity (53–69%), indicating a more precise prognosis of parturition not occurring. In conclusion, our findings may assist interpreting vaginal temperature measurements in order to predict parturition in bitches.