SHORTENING OF INTEROESTROUS INTERVAL IN DOGS USING CABERGOLINE AT DIFFERENT STAGES OF ANOESTRUS
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Date
2018
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES-MANNUTHY,THRISSUR
Abstract
The exceptionality of canine oestrous cycle is that an obligatory
anoestrus follows dioestrus in dogs making the interoestrus interval (IEI)
unpredictable. The efficacy and safety of prolactin antagonist, cabergoline at two
dose rates and at two different stages of anoestrus in reducing the interoestrous
interval (IEI) was studied. Group I (n = 14) and group II (n =6) dogs were treated
with cabergoline @ 5 and 0.6 µg /kg.b.wt/orally/ day starting from 90 ± 3 days of
preceding proestrous, while group III (n =11) and group IV (n = 8) dogs were
treated with high and low doses of cabergoline starting from 120 ± 3 days of
preceding proestrus until induced proestrus or for 40 days. Group V (n = 11)
consisted of anoestrous dogs that completed 90 ± 3 days of preceding proestrus
and was persued through their natural oestrus during the study period. The response
to treatment was complete, except for two dogs in group I ( 85.71% ) and one dog in
group IV (87.55%) .The duration of treatment was significantly (p<0.05) shorter in
dogs treated with 5 µg /kg.b.wt/ day (high dose cabergoline) when treatment was
initiated on day 120 ± 3 days of preceding proestrus, in comparison to other
treatment groups. In response to treatment, the interoestrous interval (IEI) also
reduced in all the treatment groups. On the contrary, an increasing trend in IEI
(228.90 ±15.47 days) was noticed in control group. A satisfactory conception rate
was noticed in all treated groups in comparison to the control group. The results
signify the merits of cabergoline in terminating the obligatory anoestrus and thereby
reducing the IEI, irrespective of the dose and the outcome happens moderately
quicker with treatment initiated at 120 days than 90 days. Induced oestrous cycles
were normal with proestrus and oestrus parameters and in which the ovulation and
hormone profiles identical to physiological cycles. Fewer side effects were noticed
with cabergoline decreased with adaptation. Duration of treatment was inversely
proportional to depth of anoestrus. No hyperprolactinaemia was noticed in dogs
during anoestrus as the serum prolactin level was less than 0.5 ng/ml and thus
concluded that the action of cabergoline was not associated with the reduction of
prolactin level, but a direct stimulatory effect on gonadal axis and other
dopaminergic effects. Though all treatment protocols were successful in inducing a
fertile oestrus and decrease the IEI, the most recommendable treatment from this
study is use of low dose cabergoline at 90 ± 3 days, as the duration of treatment was
shorter with a maximum shortening of IEI and a good conception rate.