Coat colour changes associated with cabergoline administration in bitches

Cabergoline or bromocriptine were administered orally to 60 bitches at doses of 5 microg/kg and 15 microg/kg daily, respectively, for two to 45 days for the treatment of pseudopregnancy or for oestrus induction. Seven of the dogs which received cabergoline for more than 14 days developed coat colour changes from the second week of administration to the next coat shedding. Of these, fawn-coloured bitches developed a yellowish coat colour while Argentine boar hounds became black spotted, mainly on their extremities. In previous untreated oestrous periods, these bitches had shown no coat colour changes. It is concluded that a colour shift in certain haircoats of particular breeds could be mediated through the inhibition of the secretion of melanocyte-stimulating hormone by the administration of the dopaminergic agonist cabergoline for more than two weeks. Transient coat colour changes should be considered a possible side effect when planning long-term treatment with dopaminergic agonists in dogs.     

Seasonal incidence of estrus and interestrous interval for bitches of seven breeds

For 7 breeds of bitches (Toy Poodle, Cocker Spaniel, Basset Hound, Boston Terrier, German Shepherd Dog, Pekingese, and Beagle), estrous activity occurred in all seasons. Differences in seasonal incidence of estrus were not statistically significant when compared within the total group or within and between breeds. The German Shepherd Dog breed had the shortest interestrous interval (149 +/- 28.5 days), which was significantly different from that of the other breeds. Means interestrous interval in parous Beagle bitches was not significantly different from that in nonparous Beagle bitches. In Beagle bitches, the mean interval between fertile estrous periods was not significantly different from the mean interval between nonfertile estrous periods.     

Treatment of spontaneous pyometra in 22 bitches with a combination of cabergoline and cloprostenol

Twenty-two bitches with ultrasonographically diagnosed spontaneous pyometra were treated with a combination of 5 microg/kg cabergoline per day and 5 mug/kg cloprostenol every third day, and potentiated sulphonamide twice a day. Bitches with either open-cervix or closed-cervix pyometra showed a rapid clinical improvement, associated with a reduction in plasma progesterone concentration, increased vulval discharge and a reduction in the diameter of the uterus. The haematological profiles of 21 of the bitches returned to normal within six days of treatment, and their biochemical profiles returned to normal within nine days; 19 of the bitches were managed successfully by a 10-day period of treatment. Two bitches required a further three days of treatment, and in one bitch with a partial uterine torsion the treatment was not successful. Adverse effects of the treatment were limited to the 60 minutes immediately after the administration of prostaglandin, and included retching, vomiting, mild abdominal straining, diarrhoea and panting. The incidence of adverse effects was reduced after each successive dose of prostaglandin. Eleven of the 21 successfully treated bitches were mated at the next oestrus, and seven became pregnant; their litters were smaller than the published breed averages. In four of the bitches the pyometra recurred after the next oestrus.     

Comparative efficacy of bromocriptine,cabergoline and thyroxine in inducing oestrus in bitches

Forty bitches in anoestrus for more than six months from the last heat, with a serum progesterone level less than 1 ng/ml were subjected to oestrus induction trials using anti-prolactin drugs and levothyroxine, once daily orally for 20 consecutive days. The mean serum progesterone level among them was found to be 0.57 ± 0.03 ng/ml. Out of 10 animals treated in each group, five (50%) in Group I (bromocriptine @ 50 μg/kg body weight), nine (90%) in Group II (cabergoline @ 5 μg/kg body weight), eight (80%) in Group III (thyroxine @10 μg/kg body weight) and seven (70%) in Group IV (thyroxine @ 5 μg/kg body weight) responded by evincing proestrual bleeding. The mean (±SEM) time taken from initiation of treatment to onset of proestrual bleeding in Groups I, II, III and IV was 28 ± 3.39, 13.44 ± 3.12 (P < 0.05), 24.50 ± 3.18 and 33 ± 2.21 days respectively. The mean (±SEM) duration of proestrus and oestrus in the treatment groups was 9.80 ± 0.86, 10.11 ± 0.68, 11.25 ± 0.88 and 10.71 ± 0.68 days and 7.60 ± 0.24, 8 ± 0.29, 8.5 ± 0.63 and 7.85 ± 0.46 days respectively. The conception rate in relation to the number of animals responding to oestrus induction in the treatment groups was 80%, 78%, 63% and 57%, respectively. The mean (±SEM) gestation length calculated from the last breeding date and litter size in the treatment groups varied from 60.50 ± 1.55 to 64.00 ± 0.82 days and 5.14 ± 0.34 to 6.40 ± 0.40 respectively.     

Comparison of the use of cabergoline and gonadotrophin to treat primary and secondary anoestrus in bitches

Objective To determine the efficacy and reliability of cabergoline and pregnant mare's serum gonadotrophin (PMSG) for induction of oestrus in bitches with primary or secondary anoestrus. Procedures We studied 39 healthy bitches of various breeds aged 2–6 years and in primary or secondary anoestrus: 20 bitches were administered 5 µg/kg/day cabergoline orally until day 2 after the onset of pro‐oestrus or for a maximum of 42 days, and 19 bitches were administered 20 IU/kg/day PMSG intramuscularly for 5 consecutive days, followed by an additional single injection of 25 IU/kg of human chorionic gonadotrophin on the fifth day. Results The rates of oestrus induction in the primary and secondary anoestrous bitches treated with cabergoline and PMSG were found to be similar. Pregnancy and whelping rates in the cabergoline group were statistically different from the rates in the PMSG group (P < 0.001). Conclusion Cabergoline is more effective and reliable for the induction of a fertile oestrus in bitches with primary or secondary anoestrous.     

Epidural administration of combinations of ropivacaine,morphine and xylazine in bitches undergoing total unilateral mastectomy: a randomized clinical trial

ObjectiveTo investigate the epidural administration of combinations of ropivacaine, morphine and xylazine in bitches undergoing unilateral mastectomy.Study designProspective, randomized, blinded, clinical study.AnimalsA total of 22 bitches scheduled to undergo unilateral mastectomy for mammary tumor excision.MethodsDogs were anesthetized with acepromazine (0.02 mg kg^–1) and morphine (0.3 mg kg^–1) intramuscularly, propofol intravenously (IV) and isoflurane. Prior to the beginning of surgery, dogs were randomly administered one of three epidural treatments: ropivacaine (0.75 mg kg^–1) with morphine (0.1 mg kg^–1) (group RM, n = 7); ropivacaine with xylazine (0.1 mg kg^–1) (group RX, n = 8); or ropivacaine with morphine and xylazine (group RMX, n = 7). Cardiopulmonary variables and the expired concentration of isoflurane (Fe′Iso) were recorded intraoperatively. Meloxicam (0.1 mg kg^–1) was administered IV during skin closure. Postoperative pain scores were evaluated with the Glasgow composite measure pain scale short form for 24 hours, and rescue analgesia with morphine (0.5 mg kg^–1) was administered intramuscularly when pain scores were ≥ 6/24.ResultsFe′Iso was significantly higher in group RM than in groups RX and RMX. Heart rate decreased significantly in groups RX and RMX, but blood pressure remained within acceptable values. The number of dogs administered rescue analgesia within 24 hours was significantly higher in group RX (seven dogs, 87.5%) than in groups RM (one dog, 14.3%; p = 0.01) and RMX (two dogs, 28.6%; p = 0.04). Time to standing was significantly longer in group RX than in group RM.Conclusions and clinical relevanceAll epidural treatments provided adequate antinociception with minimal cardiovascular adverse effects during mastectomy. The inclusion of morphine (groups RM and RMX) provided the best postoperative analgesia. Owing to the undesirable effect of xylazine on ambulation, the combination ropivacaine–morphine appeared to provide greater benefits in bitches undergoing unilateral mastectomy.     

Radiographic pelvimetry for assessment of dystocia in bitches: a clinical study in two terrier breeds

Radiographic pelvimetry was used to assess the role of pelvic anatomy in obstructive dystocia in bitches. Based on the history of previous whelpings, 20 Boston terrier and 14 Scottish terrier bitches were divided into two equal groups: normally whelping bitches and bitches with obstructive dystocia. Additional whelpings during the period of study were closely observed and the pups were immediately weighed and measured. The bitches were clinically examined and the pelvis was radiographed in ventrodorsal and lateral projections. Measurements from the radiographs showed a significantly smaller pelvic size in the bitches with obstructive dystocia compared to the normally whelping bitches. Fetal-pelvic disproportion in the Scottish terrier was mainly due to a dorsoventrally flattened pelvic canal, whereas in the Boston terrier it arose from the combination of a dorsoventrally flattened pelvic canal and big fetuses with large heads. These results suggest that radiographic pelvimetry could be used to predict a disposition for dystocia in individual bitches, and as a basis for selection of breeding animals.     

Immunosuppression in bitches with pyometra

The function of the immune system was studied in 34 bitches affected by pyometra. The mean age of the animals was 8.1 +/- 2.8 years. Samples of peripheral blood were examined using a battery of immunological tests. Data obtained from four sets of animals, grouped according to the severity of their disease, were compared. Leucocytosis (neutrophilia and partial monocytosis) and lymphopenia were detected in 62 per cent and 35 per cent of the bitches, respectively. The increase in the number of leucocytes was higher in the severely affected bitches. Inhibition of mitogen-driven lymphocyte proliferation was the characteristic feature of the immunological profile in bitches affected by pyometra, and this corresponded with the impairment of the general state of health. Sera from bitches showing functional inhibition of lymphocytes suppressed the activity of lymphocytes isolated from normal dogs. Sera from bitches affected by pyometra also had higher levels of immunoglobulins, lysozyme and circulating immune complexes. It can be concluded that pyometra is associated with an inflammatory response, but also with a marked suppression of immune system activity.     

Oestrus control and the incidence of mammary nodules in bitches,a clinical study with two progestogens

Summary

The incidence, size and location of mammary nodules were established in 10 practices in The Netherlands by the clinical examination of bitches in which oestrus was controlled with proligestone (P), 331 animals, or medroxyprogesterone acetate (MAP), 341 animals and in 339 animals never medicated with such compounds.

In comparison with the unmedicated controls and the P‐medicated animals of comparable age the incidence of mammary nodules of all sizes was significantly increased in the MAP‐medicated animals.

There was no significant difference in nodule incidence between the P‐medicated animals and the control animals.

Based on the assumption that nodules above a certain size are most likely tumours, these results indicate that oestrus control with MAP stimulates tumour development even in animals medicated for less than four years.

The practical value of the reported differences, especially in relation to the subsequent requirement for surgical removal of tumours in bitches, medicated for oestrus control, is discussed.     

Evaluation of a new non-hormonal substance for terminating pregnancy in bitches in clinical trials

A new non-hormonal contragestational agent (DL 717-IT), the 2-(4 chlorophenyl)-s-triazole |5,1-a|-isoquinoline, was tested in clinical trials to determine its efficacy for interrupting the pregnancy in the bitch. Five hundred and sixty-five bitches were given a single intramuscular injection of the drug between the first and 15th day after the mating. Of the 475 bitches that received 2–5 mg/kg, 430 (90-5 per cent) did not whelp at all, 15 (3-2 per cent) delivered a few stillborn or weak puppies that died some hours after birth, and 30 (6-3 per cent) delivered at least one normal live pup. Of 90 bitches treated with 3–5 mg/kg, 87 (96-7 per cent) did not whelp at all, two (2-2 per cent) delivered a few stillborn or weak puppies that died some hours after birth, and one (1 1 per cent) delivered normal live puppies. DL 717-IT, owing to the high effectiveness and minimal side effects, must be considered a very reliable drug for the interruption of pregnancies in the bitch.     

Oestrus control and the incidence of mammary nodules in bitches, a clinical study with two progestogens

The incidence, size and location of mammary nodules were established in 10 practices in The Netherlands by the clinical examination of bitches in which oestrus was controlled with proligestone (P), 331 animals, or medroxyprogesterone acetate (MAP), 341 animals and in 339 animals never medicated with such compounds. In comparison with the unmedicated control and the P-medicated animals of comparable age the incidence of mammary nodules of all sizes was significantly increased in the MAP-medicated animals. There was no significant difference in nodule incidence between the P-medicated animals and the control animals. Based on the assumption that nodules above a certain size are most likely tumours, these results indicate that oestrus control with MAP stimulates tumour development even in animals medicated for less than four years. The practical value of the reported differences, especially in relation to the subsequent requirement for surgical removal of tumours in bitches, medicated for oestrus control, is discussed.     

Oestrus control in bitches with chlormadinone acetate

A clinical study of oestrus control in bitches with chlormadinone acetate (CMA) is reported. The commercial 1-0 per cent crystalline suspension of CMA was injected subcutaneously at a dose of 3 mg/kg, or somewhat lower for the largest animals. Treatment was initiated always in anoestrus and was repeated twice annually for as long as requested. The longest, 9-year, period of anoestrus was achieved by twenty repeated treatments. A total of 2,471 treatments were given to 568 bitches (an average of 4-4 treatments per bitch) during a period of over 10 years, with an efficacy of 98 per cent. The incidence of false pregnancy, uterine inflammatory disorders and mammary nodules in the treated group were compared to those of an age-related control group of 487 bitches that did not receive hormonal treatment. A lower incidence of false pregnancy and the two clinical entities was observed in the group of treated animals. It is concluded that CMA can be used safely and reliably for oestrus control in bitches and is therefore, an appropriate alternative for ovariohysterectomy.     

Oestrus control in bitches with proligestone, a new progestational steroid

A study of oestrus control in bitches with a new type of progestagen, proligestone, in six Dutch and three UK practices is reported. The product was given subcutaneously, regardless of the stage of the sexual cycle and of the usual contraindications for progestagens. A 97% efficacy was obtained with dosages varying from 20–33 mg/kg for the smallest animals to 10–13 mg/kg for the largest animals, when the first treatment was given in anoestrus with repeated treatments after 3 months, 4 months and thereafter every 5 months.
Following treatment in pro–oestrus, heat symptoms disappeared in 96% of the animals within 5 days. By retreatment after 3 months, oestrus prevention could be maintained in 97% of these cases.
Where the animals had been treated only with proligestone (1608 treatments in 776 bitches) there were five cases of the cystic hyperplasia pyometra complex; none of these occurred after treatment in pro–oestrus. Of the animals previously treated with other progestagens for oestrus control (814 treatments in 307 bitches) there were 11 cases.
Forty–one out of 46 bitches which had a history of reproductive disorders did not show signs again.
Other side–effects were also negligible (<0–5%). Fertility at the first oestrus after treatment appeared normal.     

Cushing's disease in dogs: cabergoline treatment

The treatment of pituitary-dependent hyperadrenocorticism (PDH) in dogs has for a long time been focused on inhibiting the adrenal gland using drugs such as o-p'-DDD, Ketoconazole and Trilostane, without attacking the primary cause: the corticotrophinoma. Corticotroph cells can express the D2 dopaminergic receptor; therefore cabergoline (Cbg) could be effective as a treatment. Follow-up over 4 years was carried out in 40 dogs with PDH that were treated with Cbg (0.07 mg/kg/week. Out of the 40 dogs, 17 responded to Cbg (42.5%). A year after the treatment, there was a significant decrease in ACTH (p<0.0001), alpha-MSH (p<0.01), urinary cortisol/creatinine ratio (p<0.001), and of the tumor size (p<0.0001) evaluated by nuclear magnetic resonance. Dogs responding to Cbg lived significantly longer (p<0.001) than those in the control group. To conclude, Cbg is useful in 42.5% of dogs with PDH, justifying its use as a treatment.