4 EFFECT OF THE TIMING OF ARTIFICIAL INSEMINATION ON THE NUMBER OF SPERMATOZOA DISCOVERED IN THE UTERINE CRYPTS OF THE BITCH
Bibliographic record
Abstract
Canine spermatozoa may be stored for several days within the genital tract of the bitch since natural matings 8 to 9 days before ovulation may result in litters. Several studies have suggested that the sperm reservoir in the dog is located in the uterine crypts and the uterotubal junction (UTJ). In the present study, we investigated the effect of the timing of artificial insemination (AI) in relation to ovulation on the sperm distribution in the genital tract of the bitch. Ten beagle dogs were inseminated intravaginally with 500 × 106 spermatozoa. Based on progesterone concentration, three dogs were inseminated 1–2 days before ovulation, four dogs during ovulation, and three dogs 2–3 days after ovulation. Ovariohysterectomy was performed 24 h after AI. The genital tract was divided into eight segments (i.e. corpus uteri; caudal, middle, and cranial parts of the uterine horn; UTJ; isthmus; ampulla; and infundibulum) which were processed for histology. From each segment, 30 histological sections were evaluated. For the UTJ and the different segments of the oviduct, the total number of spermatozoa was determined. For the different parts of the uterus, on each of these 30 sections, 100 uterine crypts of comparable size were evaluated for the presence of spermatozoa. The crypts were divided into crypts without spermatozoa, crypts with 1 sperm cell, crypts with 2 to 5 spermatozoa, and crypts with either more than 5 spermatozoa or in which the spermatozoa were clustered. The data were analyzed using univariate analysis of variance. Histology revealed that the spermatozoa were located mainly in the uterine crypts and at the UTJ, while very few spermatozoa were detected in the different parts of the oviduct. Insemination during ovulation resulted in higher percentages of crypts with spermatozoa in the different parts of the uterus (P < 0.05). Moreover, for the ovulatory group, 54.7% of the uterine crypts with spermatozoa contained more than 5 spermatozoa (or clusters) compared to 19.9% and 28.2% for the pre- and post-ovulatory groups, respectively (P < 0.05). In the pre-ovulatory group, 59.6% of the uterine crypts with spermatozoa contained only 1 sperm cell whereas in the post-ovulatory group, frequently 1 (34.0%) or 2 to 5 spermatozoa (37.9%) were found per crypt. In conclusion, sperm transport in the genital tract of the bitch is affected by the time of AI in relation to ovulation. Insemination during the ovulation period resulted in higher percentages of uterine crypts with spermatozoa, and most of these crypts contained 5 or more spermatozoa. Further research should determine whether the number of sperm binding sites expressed on the epithelium of the canine uterine crypts is influenced by the ovulation event. This research was supported by the UGent Special Research Fund, Grant numbers 011 B8698 and 011 B8301.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".