The first case of genetically confirmed monozygotic twinning in the dog

Monozygotic twinning has not previously been genetically confirmed in the dog. This case report describes the finding of two viable male monozygotic foetuses within one placental site during caesarean section. Their umbilical cords attached to a single placenta. Genetic profiling using a total of 38 microsatellite markers, as well as amelogenin and SRY for sex determination, revealed identical DNA profiles, whether derived from blood or tissue (buccal swabs) samples. To the best of our knowledge, this is the first report of monozygotic twinning in the dog confirmed using DNA profiling

The first case of genetically confirmed monozygotic twinning in the dog

Monozygotic twinning has not previously been genetically confirmed in the dog. This case report describes the finding of two viable male monozygotic foetuses within one placental site during caesarean section. Their umbilical cords attached to a single placenta. Genetic profiling using a total of 38 microsatellite markers, as well as amelogenin and SRY for sex determination, revealed identical DNA profiles, whether derived from blood or tissue (buccal swabs) samples. To the best of our knowledge, this is the first report of monozygotic twinning in the dog confirmed using DNA profiling

Prediction of the optimal time for insemination using frozen-thawed semen in a multi-sire insemination trial in bitches

The aims of the study were to determine which of Days 5, 6 or 7 after the blood plasma progesterone concentration (PPC) of bitches first reached 6–9 nmol/L (Day 0) yield the highest fertility and whether day of insemination affects the gender ratio of conceptuses. Six bitches were inseminated on Days 5 and 6 and 6 on Days 6 and 7. Ten million progressively motile frozen-thawed sperm from each of 5 dogs were pooled for the first insemination. The same number of sperm from 5 other dogs were pooled for the second insemination. Only one batch of semen from each dog was used on all bitches, which largely prevented any effect of male and semen. Twenty-three autosomal microsatellites and the amelogenin gene were used to determine the paternity and gender of the conceptuses. Pregnancy rate was 100%. Out of 103 ovulations 66 conceptuses were conceived (conception rate: 64%). The proportion of available oocytes fertilised was 0.11, 0.56, and 0.27 for Days 5, 6, and 7, respectively. The odds of fertilisation was 16.7 and 4.2 times higher from insemination on Day 6 compared to Day 5 (P < 0.001) and Day 7 (P = 0.013), respectively. The numbers of male- and female conceptuses were equal (33 each) and gender was independent of insemination day (P = 0.18). This study suggests that intrauterine insemination of bitches should best be done 6 days after PPC first reaches a value between 6 and 9 nmol/L with a second insemination one day later.http://www.elsevier.com/locate/anireproscihb2014ab201

Estimated impact of multiple conceptuses per follicle on fecundity in the bitch

Multiple conceptuses from one follicle due to multi-ovular follicles or monozygotic twins inflate the ratio between the numbers of conceptuses and corpora lutea and possibly the effect ascribed to experimental treatment. The aim of this study was to estimate the impact of multiple conceptuses per follicle on fecundity in the bitch. The numbers of conceptuses and corpora lutea of 105 bitches originated from 7 published experimental studies and of 132 from ovariohysterectomies done in a private practice and a welfare organisation. Ninety five bitches, producing 597 conceptuses, had at least as many conceptuses as corpora lutea; 83 had as many, 10 had one more and 2 had 2 more. Bootstrap resampling on these 95 bitches let us to conclude that 12.6% of bitches are expected to produce more oocytes that are each capable of yielding a conceptus than the number of follicles that ovulate and that 2.35% of conceptuses are expected to be in excess of the number of follicles that ovulate. Applying the results of the current study to 2 earlier studies showed that multiple conceptuses from one follicle may, at maximum, have increased the effect ascribed to prostatic fluid by 0.022 and 0.024 conceptuses per corpus luteum, which is minor in relation to the magnitude of the ascribed effects of 0.34 and 0.22 conceptuses per corpus luteum. The number of conceptuses relative to the number of corpora lutea provides a valid and precise measurement of fertility in the bitch.http://www.theriojournal.com2018-10-15hj2017Production Animal Studie

The distribution of small preantral follicles within the ovaries of prepubertal African elephants (Loxodonta africana)

BACKGROUND: Data on the distribution of primordial (single layer of squamous granulosa cells), early primary (some granulosa cells cuboidal) and primary (all granulosa cells cuboidal) follicles, grouped together as small follicles (SF) within the ovary of the elephant is lacking, yet such information is necessary to be able to estimate accurately the total numbers of small follicles in the ovaries of elephant throughout their lifespan. AIM: To determine if the density of SF differs between ovaries, between the surfaces of an ovary, or between the interpolar and intermarginal zones of an ovary. MATERIALS/METHODS: Stereological techniques were employed on 25 μm thick histological sections of the ovaries recovered from 12 prepubertal elephant calves aged 2 months to 4.5 years. Cell densities were calculated using the optical brick method and Cavalieri's principle for volume calculation. RESULTS: The density of SF (numbers of SF per unbiased counting frame [UCF]) did not differ between the left (1.11 ± 0.39 (mean ± sd)) and right (1.10 ± 0.39) ovaries (P = 0.82, n = 12), or between the lateral (median 1.24; interquartile range 0.85–1.39) and medial (1.03; 0.76–1.36) surfaces of the ovary (P = 0.22, n = 24) or among the 5 segments of the ovary between the two poles (P = 0.20, n = 24). The third of the cortex nearest to the mesovarial margin of the ovary had fewer small follicles per UCF (0.85; 0.51–1.28) than the middle third (1.01; 0.78–1.42; P = 0.034), and the third adjacent to the free margin (1.27; 0.79–1.51; P = 0.0024), n = 24 per group. CONCLUSION: Providing a random sample is taken from the full interpolar and intermarginal dimensions of ovary of a non-pregnant elephant, the density of small follicles throughout the cortex may be accurately measured using stereological techniques applied to one of its surfaces.http://www.elsevier.com/locate/anireprosciab201

Is the biparietal diameter of fetuses in late gestation too variable to predict readiness for cesarean section in dogs?

Correct assessment of readiness for cesarean section is essential for timing elective cesarean section during late pregnancy in the bitch. In humans, biparietal diameter is sufficiently precise and accurate and used in a clinical setting daily. The objectives of this study were to determine whether fetal biparietal diameter in late gestation in the dog could be used to predict readiness for cesarean section by having reached a minimum cut-off value and to correlate the biparietal diameter to birth weight. The biparietal diameter of 208 puppies in 34 litters from 31 English bulldog bitches and 660 puppies in 78 litters from 70 Boerboel bitches were measured immediately after delivery by cesarean section, performed at full term, using digital calipers. At the same time the birth weight of the same 208 English bulldog puppies and 494 of the same Boerboel puppies in 59 litters from 54 bitches was measured by means of an electronic scale. With a cesarean section, all the puppies in a litter are delivered simultaneously and readiness for cesarean section must be determined for a litter. The minimum, median and maximum biparietal diameter varied from 21.1 to 47.8, 32.9 to 50.0 and 34.2–58.2 mm, respectively, among English bulldog litters and from 18.4 to 48.7, 35.5 to 49.7 and 39.8–54.3 mm among Boerboel litters. This large variation suggests that biparietal diameter is too variable within and among litters to be useful as a means of determining readiness for cesarean section.http://www.theriojournal.com2019-06-01hj2018Production Animal Studie