In captive rhinoceros stillbirth and perinatal death are recorded at a rate of 6-17% in the various species. At the same time there is a substantial lack of knowledge on rhinoceros parturition. Yet, predicting parameters for birth and progress of parturition are fundamental for the recognition of dystocia and perinatal problems. Therefore, we here intended to pay close attention to the Achilles heel of the 1.5-2.5 year reproduction cycle in rhinoceros, the parturition. For the prediction of parturition we recorded timelines for pre-birth udder development, genital swelling, milk production, behavioral unrest, and decrease of serum progesterone concentration and the gestational length in 19 white rhinoceros. First, second and third labour stage, foetal presentation and events in perinatal period were recorded to describe normal parturition and establish a guideline for better birth management in rhinoceros. Udder development and genital swelling were observed 3 and 2 weeks prior birth, respectively. Milk production was observed to start up to 3 weeks prior birth and increased significantly in the last week with most significant increase one day before parturition to 50.6 ± 45.4 mL (p < 0.006). Serum progesterone concentration started to decrease 7 days prior parturition and more significantly 48 h before parturition. While behavioral unrest and first stage labour was not observed reliably in all females the break of foetal waters and thus the start of second stage labour was unmistakably observed. Second stage labour, when foetal membranes had ruptured until the foetus was born, took 1:50 ± 0:20 h:min. Eighty-four percent of fetuses were born in anterior presentation (n = 16/19) and the final expulsion took <25 min suggesting that this is the normal presentation in white rhinoceros. In the less frequent posterior presentation final expulsion took up to 47 min. Overall, 95% of calves were born alive. Calves were standing and nursing in 0:55 ± 0:12 min and 3:32 ± 0:53 h:min, respectively. In 10.5% of births (n = 2/19) in anterior presentation perinatal complications occurred. Stillbirth occurred once (5.3% n = 1/19) when the foetus was born in posterior presentation. The recorded gestational length was 506 ± 2d. Delivering live offspring is of key importance to establish a new generation and secure long-term survival of a species. Various pre-birth changes, significant decrease of serum progesterone 48 h prior birth, different labour stages, foetal presentation and perinatal events described here add substantial knowledge on the understanding of normal rhinoceros parturition and may help diagnose dystocia and perinatal complications.

中文翻译：

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白犀牛的分娩

在圈养犀牛中，不同物种的死产和围产期死亡的比率为 6-17%。同时，人们对犀牛分娩的知识也非常缺乏。然而，预测出生和分娩进程的参数是识别难产和围产期问题的基础。因此，我们在这里打算密切关注犀牛1.5-2.5年繁殖周期的阿喀琉斯之踵，即分娩。为了预测分娩，我们记录了 19 头白犀牛的出生前乳房发育、生殖器肿胀、产奶量、行为不安以及血清黄体酮浓度和妊娠长度降低的时间表。一、二、三产程，记录围产期胎儿的出现和事件，以描述正常的分娩，并为犀牛更好的分娩管理建立指导方针。分别在出生前 3 周和 2 周观察到乳房发育和生殖器肿胀。观察到产奶量从出生前 3 周开始，并在最后一周显着增加，分娩前一天增加最显着，达到 50.6 ± 45.4 mL (p < 0.006)。血清黄体酮浓度在分娩前 7 天开始下降，在分娩前 48 小时更显着。虽然并非在所有女性中都可靠地观察到行为不安和第一阶段分娩，但可以明确观察到胎儿断水和第二阶段分娩的开始。第二阶段分娩，当胎膜破裂直到胎儿出生时，花了 1:50 ± 0:20 h:min。84% 的胎儿出生前先露 (n = 16/19)，最后排出时间 < 25 分钟，这表明这是白犀牛的正常表现。在不太频繁的后部展示中，最终驱逐需要长达 47 分钟。总体而言，95% 的小牛出生时都是活的。小牛分别在 0:55 ± 0:12 min 和 3:32 ± 0:53 h:min 内站立和哺乳。在 10.5% 的出生 (n = 2/19) 中，发生了前庭分娩的围产期并发症。死产发生一次 (5.3% n = 1/19) 当胎儿在后位出生时。记录的孕期长度为 506 ± 2d。提供活后代对于建立新一代和确保物种的长期生存至关重要。各种出生前变化，出生前48小时血清孕酮显着下降，