Among the many causes of empty pregnancy, the inability to determine the ovulation time and optimal breeding time of the female dog may be an important cause of empty pregnancy. The author analyzes the methods of judging the ovulation time of bitches from the aspects of investigation of reproductive history, clinical examination, laboratory examination, and laparoscopic observation of changes in uterus and ovary, and strives to find the most suitable dog breeding time. method for use.

Teacup dog

I. Survey Reproductive history mainly understands age, health status, epidemic prevention system, feeding management, last estrus time and cycle, pregnancy and childbirth, litter size, weaning time and number of weaning, family reproductive capacity, whether to use contraceptives or pregnancy interruption drugs, etc. .

2. Clinical examination

(1) Vaginal examination. In the pre-estrus period, the vulva edema, enlargement, and bleeding secretions, and the hair around the vulva and the tail is moist and sticky; the swelling is obvious in the estrus period, the tail swings to one side when the vulva and the vulva are touched, and the posterior drive increases, and the edema is somewhat later in this period. Decreased; recovered 1-2 weeks after the end of estrus, manifested as small vulva, wrinkled, and good tension.

(2) Examination of vaginal secretions. Uterine and vaginal secretions flow during estrus, labor, and certain stages of the postpartum period, as well as under certain pathological conditions. The secretions in the preestrus stage are bloody, and the color of the secretions gradually changes to yellow or straw-yellow. Little or no secretions are excreted in the late estrus and aestrus periods.

(3) Vaginal examination. After cleaning the vagina, use an opener and a suitable light source to observe the mucous membranes and secretions and feel the tension of the vagina. In the early stage of estrus, the edema is obvious, the mucosal surface is smooth, and the opener is easy to insert; in the later stage of this stage, there is resistance, the mucosa is rose-red, there is edema, there is a lot of blood-stained secretions in the folds, and the cervix is slightly opened. In estrus, there is resistance to the insertion of the opener, and the mucosa is thickened, pale, and wrinkled. Since changes in the vulva, vagina and secretions are secondary to changes in hormone levels in the body, estimating the time of ovulation is not accurate enough and requires experience. When using this method to determine the breeding time, it should be bred twice at an interval of 48 hours.

3. Laboratory examination

(1) Cytological examination. Changes in vaginal epithelial cytology are closely related to changes in estrogen levels, and examinations should be carried out at intervals of 24 hours, combined with other clinical examinations and fertility history investigations. When sampling, fix the dog on the table, keep the vagina horizontal, separate the vagina with two fingers, and sample with isotonic saline-soaked cotton balls and thin tubes. When using a cotton ball for sampling, insert the cotton ball into the vagina and turn it to remove it; when using a thin tube for sampling, insert the thin tube into the cervix and withdraw it slightly, squeeze out a few drops of isotonic saline, and then suck it into the thin tube and take it out. . Place the collected sample on a slide, push the slide with another slide, and fix it. After staining, use an ordinary microscope to check, and those who do not stain can use a phase contrast microscope to check. Epithelial cells have nuclei in the proestrus stage, and a large number of basal cells and intermediate cells appear in the early stage, and there are white blood cells and red blood cells; in the later stage, the number of basic cells, small and medium cells, and red and white blood cells decreases, and eosinophilic epidermal cells appear. In the initial stage of estrus, a large number of eosinophilic and basophilic epidermal cells, some large intermediate cells, and a small amount of anucleated cells and red blood cells appear; in the later stage of this stage, mainly eosinophilic epidermal cells, anucleated cells and cell debris, leukocytes and nucleated epithelium appear cells reappear. In the late estrus, epidermal cells still existed, and the basal cells and intermediate cells increased; the white blood cells increased in the first 10 days, then decreased, and disappeared after 20 days, and the foam cells and the late estrus cells appeared in large numbers. A small number of basal-like cells, intermediate cells, and leukocytes, and sometimes foam cells, can be seen in anestrus. It should be noted that vaginal cytology does not determine the time of LH peak and ovulation, but can infer cycle stage from this.

(2) Determination of progesterone in blood. The progesterone concentration in peripheral blood was measured by the rapid progesterone determination method three times a week. It can be seen that when the LH (luteinizing hormone) peak appears, the progesterone concentration begins to increase, and when ovulation begins, the progesterone concentration increases rapidly. With this method, the time of ovulation can be determined more accurately, thereby improving the fertility rate of breeding. Since there is no rapid method for measuring LH at present, the mating time cannot be determined by directly measuring LH.

4. Observing the changes of uterus and ovary with laparoscopy

Some data show that the ovulation time can be determined by observing the changes of blood vessels in the uterus of the bitch.

In fact, using laparoscopy to observe the development of follicles on the ovary can accurately determine the time of ovulation, that is: a part of the follicle protrudes about 1.5 mm from the surface of the ovary, and its top is transparent, which indicates that the mother The dog is about to ovulate, and this is the best time for breeding. If the follicle seen on the ovary is a collapsed middle and a fleshy red color, this indicates that ovulation has occurred and the follicle at that time has developed into the corpus luteum. Through several practices, the author found that this method is unrealistic, because the ovaries of dogs are different from other domestic animals that can be seen, and the ovaries of most bitches are surrounded by thick fat, making it difficult to see the development of follicles.

Whether this method is feasible remains to be proved by practice.

5. Determine the time of the most suitable species

Since it takes 2-5 days to complete meiosis after ovulation, and it takes about 7 days for sperm to be capacitated in the reproductive tract of the female dog. hours, so the optimal seed time can be determined according to the following parameters.

Determination of the best time for the breed

Parameters....the best time for the breed

The bitch became interested in male dogs....3— After 5 days

The female dog is willing to accept the male dog to straddle.... 2-3 days

Blood secretions appear in the vagina....10-14 days

Vaginal discharge turns straw yellow.... 2-3 days

Progesterone concentration increases rapidly.....2-3 days

Anucleate and epidermal cells....abundant When it appears

WBCs.... when estrus reappears