Pseudopregnancy in bitches: cabergoline vs placebo — POSSIBLE

In bitches with clinical pseudopregnancy, does cabergoline vs placebo shorten lactation and behavioural signs?

Shelf #356 · gate-verified and approved by the developer

POSSIBLE: Cabergoline shortens the lactation and mammary signs of clinical pseudopregnancy versus placebo, and a genuinely placebo-controlled comparison does exist. In Gobello 2001, 30 overtly pseudopregnant bitches were randomly allocated to placebo, bromocriptine 7.5 µg/kg or cabergoline 5 µg/kg (10 per group): complete remission was 40% vs 0% at day 7 (P < 0.05) and 90% vs 0% at day 14 (P < 0.01) for the dopaminergic-agonist treated groups pooled against placebo, and cabergoline did not differ from bromocriptine in prolactin suppression. In da Silva 2021 (40 pseudopregnant bitches, four groups of 10), cabergoline 5 µg/kg/day for 20 days on its own suppressed lactation, reported as differing from the placebo group. The stamp is POSSIBLE, not higher, because Gobello's remission figures pool the two agonists rather than isolating cabergoline, da Silva's abstract prints internally inconsistent P-values, neither record establishes blinding, and behavioural signs were never reported as a separate outcome in either record — the carded benefit is on lactation and mammary signs. Drafted Nov 10, 2026 (VetMed build, topic #356); all figures from abstracts fetched and verified at drafting.

Gobello 2001: dopaminergic-agonist treatment (cabergoline or bromocriptine, pooled) gave complete remission in 90% by day 14 vs 0% on placebo

Randomized Controlled Trial (record's publication type); randomly allocated, placebo-controlled

Who: Dogs: 30 overtly pseudopregnant bitches randomly allocated to three groups of 10 — placebo, bromocriptine 7.5 µg/kg, or cabergoline 5 µg/kg — treated from day 0, with clinical signs (serum/milk secretion and mammary gland enlargement) graded on days 1, 7 and 14.

Result: Serum prolactin and progesterone on day 1 were 17.70 ± 2.05 ng/ml and 1.13 ± 0.13 ng/ml (least squares means ± SEM). During the experiment, serum prolactin was lower in the dopaminergic-agonist treated groups (bromocriptine and cabergoline pooled) than in the placebo group (P < 0.05); after one week the percentage change in prolactin was −62.52 in the treated groups vs +102.16 ± 46.20 on placebo (P < 0.01), with no significant difference in prolactin change between bromocriptine and cabergoline. Complete remission of pseudopregnancy signs differed significantly between treated and placebo groups on day 7 (40% vs 0%, P < 0.05) and day 14 (90% vs 0%, P < 0.01). No significant differences were found in progesterone percentage change among groups.

Watch out: Key limit, on the face of the card: the remission figures pool bromocriptine and cabergoline — this record does not report a cabergoline-only remission rate, so it establishes the drug-class effect against placebo, with cabergoline shown equivalent to bromocriptine on prolactin change. The record does not state that allocation or assessment was blinded — blinding is not established. Signs were graded as overall intensity (milk secretion and mammary enlargement); behavioural signs were not reported as a separate outcome.

Gobello C, de la Sota RL, Goya RG. Study of the change of prolactin and progesterone during dopaminergic agonist treatments in pseudopregnant bitches. Anim Reprod Sci. 2001;66(3-4):257-67. PMID: 11348786. Registry ID: none in the record. MeSH: Animals · Bromocriptine · Cabergoline · Dog Diseases · Dogs · Dopamine Agonists · Ergolines · Female · Placebos · Progesterone · Prolactin · Pseudopregnancy

da Silva 2021: cabergoline 5 µg/kg/day suppressed lactation in pseudopregnant bitches, matching high-dose vitamin B6 and differing from the placebo group

Controlled clinical trial with a placebo group (record indexed as Journal Article; no randomisation or blinding stated in the record)

Who: Dogs: 40 female dogs of no defined breed, in non-gestational diestrus with a clinical complaint of milk production (pseudopregnancy), divided into four groups of 10 treated orally for 20 days — pyridoxine hydrochloride 10 mg/kg/day, pyridoxine 50 mg/kg/day, cabergoline 5 µg/kg/day, or placebo (control group).

Result: The 50 mg/kg pyridoxine group and the cabergoline group were equally efficient in lactation suppression and were reported as differing from the other groups (including placebo). There were no systemic side effects or uterine changes associated with the treatments studied. The authors concluded vitamin B6 at 50 mg/kg was a safe alternative for lactation interruption in pseudopregnant bitches, on a par with cabergoline in this study.

Watch out: The abstract prints '(P>0.05)' for both the equivalence and the difference-from-other-groups comparisons, which is internally inconsistent as a significance statement — the group pattern is reported here as the record states it, but its P-values cannot be relied on as printed. Only 10 bitches per group, the record does not state randomisation or blinding, and the outcome is lactation suppression, not behavioural signs.

da Silva MC, Guedes PEB, Silva FL, Snoeck PPDN. Use of pyridoxine hydrochloride in the interruption of lactation in female dogs with pseudopregnancy. Anim Reprod. 2021;18(1):e20200062. PMID: 33936292. Registry ID: none in the record. MeSH: none in the record.

Synthesis: a genuinely placebo-controlled comparison exists — cabergoline's class beats placebo decisively, but cabergoline-only numbers are thin

Synthesis

Who: Synthesis of the cards above: Gobello 2001 (30 overtly pseudopregnant bitches randomly allocated to placebo, bromocriptine or cabergoline) and da Silva 2021 (40 pseudopregnant bitches in four groups including cabergoline and placebo).

Result: Yes, a placebo-controlled comparison exists: in Gobello 2001, no placebo bitch achieved complete remission by day 14 while 90% of dopaminergic-agonist treated bitches did (pooled bromocriptine + cabergoline; cabergoline and bromocriptine did not differ on prolactin suppression). In da Silva 2021, the cabergoline group on its own suppressed lactation, matching high-dose pyridoxine and differing from the placebo group as the record reports it. Together these support cabergoline shortening the lactation/mammary signs of clinical pseudopregnancy versus doing nothing. What neither record separately quantifies is the effect on behavioural signs, and neither establishes blinding — hence POSSIBLE rather than a higher stamp.

Watch out: Pseudopregnancy is self-limiting, and the placebo arms here are short (14–20 days); the trials show faster remission/suppression against placebo over that window, not a change in the eventual outcome for every bitch. Gobello's headline percentages must never be quoted as cabergoline-only figures.

Synthesis of Gobello C et al. (PMID: 11348786) and da Silva MC et al. (PMID: 33936292). Registry ID as on the individual cards.

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