Effective Strategies for Successful Pet Mating Management

The canine practitioner is usually asked by the pet owner to suggest the optimum time to breed a bitch. Canine ova are viable for several days after ovulation, which is induced in females only after coitus. These ova may be fertilized by sperms which have the ability to survive in the female reproductive tract for 4 to 11 days after a single mating. The oestrous cycle in bitches includes four phases: Proestrus, Oestrus, Dioestrus and Anoestrus.

Phases of Oestrus/Heat Cycle in Female Dogs:

Proestrus

Proestrus marks the beginning of the ‘active’ phase of the oestrous cycle and is characterized by a bloody discharge from the vagina and turgid vulva. The average duration of this phase is 9 days but can range from 2 to 16 days. The female attracts males but will not accept copulation. The concentration of the hormone, oestradiol secreted by the ovaries increases in blood during proestrus phase.

Oestrous

The bitch will accept the male during the phase of the oestrous cycle. This period normally lasts for one week but can range from 4-5 days. The discharge from vagina becomes more watery and the turgid vulva observed during proestrus softens during oestrous. The concentration of oestradiol decreases in the blood with increase in another hormone, progesterone, secreted by the ovaries.

This is the time of behavioural oestrous when female allows the male to mate by lifting her tail. This is the time when luteinizing hormone (LH) secreted by the pituitary increases in blood causing ovulation. These ova are not fully mature (primary oocytes) and are viable for several days.

After maturation (secondary oocytes) that are viable only for about 24 hours. Most canine ova become mature approximately 6-7 days after the onset of oestrous.

Dioestrus

The phase occasionally referred as ‘Metestrus’ represents the ‘luteal’ or ‘regressive’ phase of the cycle. At this time, the female will not accept the male for mating or copulation. The duration of this phase is about 60 to 80 days for both pregnant and non-pregnant bitches. There is enlargement of mammary glands both in pregnant and non-pregnant females.

Thus, the pregnancy diagnosis based on mammary gland change becomes rather impossible. Near the end of dioestrus, concentration of the progesterone declined with increase in secretion of another hormone prolactin by the anterior pituitary. This hormone is responsible for lactation in both pregnant as well as non-pregnant bitches.

Anoestrus

This is ‘quiet’ phase which is represented by the period extending from the end of dioestrus to the beginning of next proestrus. The duration of this phase is usually from 2 to 3 months but may extended up to 10 months in individual females.

Symptoms of Heat in Cats

A female cat shows symptoms of heat twice or thrice in a year. These symptoms include less interest in food, running around restlessly, rubbing the head up against objects and known inmates of the house, licking her paws, crouching down in front, raising of her hind portion and stepping from paw to paw her hind legs. The peak of her heat period (usually the 3rd day) is marked by loud yowling and the cat writhes over the floor. This heat period lasts for 3-6 days. In case there is no mating, the period of heat may continue for 10 days and sometimes for 2-3 weeks.

Management of Breeding

Normally, 9th to 12th day following initiation of vaginal swelling and bleeding is supposed to be most suitable time for breeding the bitch. However, individual females may ovulate prior to or following this period. Some bitches have a very short proestrus and will allow a male to mate soon after the owner’s observation of a swollen vulva or bloody discharge from vagina. An acceptance to a male dog provides a reliable indication of oestrus.

Once the oestrus is identified, natural mating or artificial insemination should be carried out. Normally, canine sperms are capable of inducing optimal conception rates for 4 to 11 days after mating. Therefore, breeding a bitch every fourth day beginning at the onset of receptivity is a better breeding plan than mating on days 9th and 11th after the onset of visual signs of proestrus. Some experts recommend mating that the bitch should be bred at least twice, 2 days apart. Some bitches during first mating may refuse to accept the male. In such a case manual help of the pet owner or dog trainer may be required for tie up.

Causes of Reproductive Failure

Male and female both may be responsible for reproductive failure. The best evidence of fertility in males can be established by seeing the normal litters sired with other bitches during the same time. Evaluation of the quality of semen is also useful in assessing the male’s fertility.

Strictures in the vagina or vestibule, bands of vaginal tissue. persistent hymen, congenital or acquired defects in reproductive tract, split heats, thyroid, adrenal or pituitary dysfunction, ovarian tumours and follicular cysts, canine brucellosis, herpes virus infection, endometritis etc. are the probable causes of reproductive failure in females. Advise of a veterinarian is needed in such cases.

Most of the problems stated above may be solved by minor operations, mechanical assistance, medicinal treatment and use of Vitamin A and E in foods and feeding of dogs and cats.

Pregnancy Diagnosis in Females

The pregnancy in females after mating can be diagnosed by abdominal palpation, radiography and ultrasonography. The external visible signs of pregnancy are:

• Increase in water intake by the female during mid pregnancy.
• Scratching of ventral body surface over the area of mammary gland.
• White mucoid discharge from vagina of pregnant female around day 32 of pregnancy.
• Increase in body weight gain from fifth week after mating.
• Enlargement of mammary glands with pink teats around 32 days and onwards.
• Hypertrophy of mammary tissue at the day 50th of gestation.

Laboratory Tests for Diagnosis of Pregnancy

The following laboratory tests can also be conducted for confirmation of pregnancy:

• Estimation of Relaxin hormone, which is high during pregnancy. (Normal range – 0.18 g/ml)
• Progesterone concentration is also high in pregnant females. (Normal range – 20 to 30 ng/ml)
• Total plasma protein start declining from day 21st and recovery is seen after day 42nd of the gestation. (Normal range – 6 to 7.5 mg/dl)
• Plasma albumin is gradually reduced in early pregnancy.
• Haematological changes includes increase in leucocytes count is seen around 30 days of pregnancy. (Normal range – 6000 to 8000 cells/cmm)