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Biomedical subjects

A C Okkens

Publications and source records attributed to A C Okkens.

9 recordsLinked to original sources
PubMed1992

[Fertility problems in the bitch].

A short review of the oestrous cycle is given, followed by a more detailed look at fertility problems caused by husbandry aspects, anatomical abnormalities, hormonal disturbances and infectious aetiologies. One of the principal causes of fertility problems appears to be mating at an inappropriate time. The ovulation period and therefore the correct time of mating can however, be defined by measuring progesterone levels in peripheral blood three times a week. Vaginoscopy can also be used for this purpose, but is a subjective and less reliable method. Sterility is normally the single symptom of cystic endometrial hyperplasia(-mucometra). This probable major cause of sterility can sometimes be diagnosed with echoscopy but sometimes only during laparotomy. Additionally, hormonal disturbances can precipitate problems such as a persistent (pro-)oestrus, a split heat, or an abnormally long interoestrous interval. Bromocriptine, 15-20 micrograms/kg body-weight, twice daily orally, can be used to induce oestrus if no obvious abnormalities are diagnosed. Attention is paid to fertility problems with an infectious aetiology, such as herpes virus or Brucella canis. A vaginitis or abnormal bacterial growth in the vagina can also influence fertility. Unfortunately, little is known about bacterial growth in the vagina in relation to fertility problems. More research is needed in this field.

Animals↗
PubMed1990

Evidence for prolactin as the main luteotrophic factor in the cyclic dog.

The role of prolactin and LH in the control of the function of the corpus luteum in the dog was studied. Experiments were performed to interfere with the secretion of a) prolactin by administering a dopamine agonist and b) LH by desensitisation with a long-acting LHRH and by stimulation. Treatments with prolactin-lowering dosages of bromocriptine, (20 micrograms/kg body weight twice a day, orally; n = 8) which started between day 1-5 (n = 4) and day 20-24 (n = 4) of the luteal period resulted in a similar pattern of progesterone, concentration in peripheral blood in both groups. The progesterone release in the second half of the luteal period (13.1 +/- 1.8% (sem) of the progesterone release of the total luteal period) was significantly lower than in control dogs (24.7 +/- 2.2%). Treatment at about day 30 of the luteal period with LHRH CR (1.34 mg, intramuscularly; n = 3), which significantly suppressed the LH level, did not reduce the progesterone release in the second half of the luteal period, 21.3 +/- 4.7% compared to 24.7 +/- 2.2% in the control dogs. The endogenous LH peak resulting from treatment with LHRH had no effect on the progesterone concentration in the blood. It is concluded that prolactin is the main luteotrophic factor in the cyclic dog during the second half of the luteal period.

Animals↗
PubMed1989

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.

Animals↗
PubMed1989

Hysterectomy during the luteal period in dogs chronically treated with bromocriptine.

To determine whether prolactin has luteolytic properties during the first part of the luteal period, hysterectomy was performed in four dogs, in which prolactin had been chronically suppressed by bromocriptine administration. The concentration of progesterone in the peripheral blood decreased upon hysterectomy during the first part of the luteal phase and regained normal values after about seven days. The progesterone patterns during the perisurgical period in these dogs were similar to those patterns observed in dogs hysterectomised without bromocriptine treatment. It is concluded therefore that, in the dog, luteolytic properties can not be attributed to prolactin.

Animals↗
PubMed1977

[Vaginitis in the bitch (author's transl)].

During a period of two and a half years (2 1/2), sixty-two patients wre submitted to the Department of Veterinary Obstetrics and Gynaecology, where a diagnosis of vaginitis was established. These patients often were young large dogs. Most of the females showed a vaginal discharge, although some bitches were only very attrative to males. There were no complaints concerning the general physical condition of the patients. On clinical examination, the vulva was found to be swollen. Exudation was also frequently observed, externally (vaginoscopy). Ninety per cent of the patients showed normal haemograms. On bacteriological examination, streptococci, E. coli and pasteurellae were often isolated. As a rule the bitches were treated locally (deeply intravaginal), the choice of the drug depending on the results of bacteriological examination. Another bacteriological examination was made after treatment. An inquiry was made into the results of treatment in these sixty-two dogs, wherever possible. On the other hand, the prognosis in those bitches in which bacteriological examination is negative at the time of discharge from the department is likely to be better than it is in those in which bacteriological examination is still positive at that time. The extent to which vaginitis may influence fertility is not known at the time of writing. The differential diagnosis of vaginitis and endometritis may present difficulties.

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