A female buffalo (Bubalus bubalis) of the Bulgarian Murrah breed aged 1,090 days was observed to give birth to a second newborn (normally developed male) after she had calved (normal female) 49 days earlier. This phenomenon is highly associated with her melatonin treatment within a trial for induction of puberty, the last ear implants being placed approximately 50 days before the assumed date of first mating, to which point the level of progesterone had increased dramatically. Despite none of the matings of the dam was visually witnessed to prove ovulation over an existing gestation, we take the liberty to qualify this phenomenon as superfetation, ruling out the other possible phenomena, namely embryonic diapause as it is highly unlikely to occur in any livestock species, and differentiated development of twin foetuses as it is associated with foetal malformation, which was not observed in this case.

中文翻译：

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与超胎相关的水牛小母牛 (Bubalus bubalis) 中的 7 周异步双胞胎——病例报告

一头母水牛 ( Bubalus bubalis)) 1,090 天龄的保加利亚 Murrah 品种在 49 天前产犊（正常雌性）后生下了第二个新生儿（正常发育的雄性）。这种现象与她在青春期诱导试验中的褪黑激素治疗高度相关，最后一次耳植入是在假定第一次交配日期前大约 50 天放置的，此时黄体酮水平已急剧增加。尽管大坝的交配都没有目击证明在现有妊娠期间排卵，但我们冒昧地将这种现象定性为超胎，排除了其他可能的现象，即胚胎滞育，因为它极不可能发生在任何家畜身上物种，双胎的分化发育，因为它与胎儿畸形有关，