Reproductive success in the ex situ breeding programme
Giant pandas have been held ex situ in China since 1953 when a panda was taken from Guanxian County to Chengdu Zoo (Hu et al., 1990). Two years later, Beijing Zoo also added giant pandas to its collection. The first ex situ giant panda birth, however, did not occur until 1963 when female studbook (SB) 25 (Li Li) gave birth to male cub SB 60 (Ming Ming) at Beijing Zoo (Kan & Shu-hua, 1964). In the late 1970s, both Beijing and Chengdu Zoos began investigating assisted reproduction, with the first successful AI and cub produced at Beijing Zoo in 1978 (Liu, 1979, 1981; Liu et al., 1979). In this case, there were three males that did not breed naturally, so semen was collected for the first time by electroejacula-tion. Following fresh sperm insemination of four females, one giant panda (SB 132, Juan Juan) became pregnant and produced twins in September 1978, 15 years after the first birth by natural mating at this same institution. This was followed two years later by the first successful AI with frozen semen, which occurred in female SB 152 (Mei Mei) at Chengdu Zoo (Hu & Wei, 1990; Ye et al., 1991; Zhang et al., 1991).
Since these milestones, Chinese zoos and breeding facilities have made continuous progress in breeding giant pandas naturally and by AI. Animals have reproduced successfully in captive facilities in Beijing,
Kunming, Shanghai, Hangzhou, Chengdu, Chongqing, Fuzhou, Xi'an and at the Wolong Breeding Centre. To increase pregnancy success, it is now common practice (especially at the Chengdu and Wolong centres) to combine natural mating and AI, with the latter focused on using semen from males that normally fail to breed. Breeding facilities outside China have also used AI. Giant panda cubs have been born after AI of oestrual females at the Zoo de la Casa de Campo (Madrid, Spain), Ueno Zoological Gardens (Ueno, Japan), the Zoological Society of San Diego (San Diego, USA) (Hodges et al., 1984; Moore et al., 1984; Masui et al., 1989; Durrant et al, 2003) and the Smithsonian's National Zoological Park (Washington, DC). A compilation of the details associated with six successful inseminations conducted at these institutions is listed in Table 20.1. At Madrid Zoo, inseminations were conducted on the day of peak urinary oestrogen excretion (AI number 1), the day of oestrogen decline (AI number 2) and one day thereafter (AI number 3). Using a combination of fresh and frozen-thawed sperm, two cubs were born after a 160-day gestation. At Ueno Zoo, a single cub was produced from the same female in 1985, 1986 and 1988 following only one insemination each year with fresh semen inseminated on the day of oestrogen decline or 2 days later (see Table 20.1). The durations of gestation in this individual ranged from 102 to 121 days. At the Zoological Society of San Diego, a cub was born following three consecutive inseminations beginning on the day of urinary oestrogen decline (134-day gestation). At the National Zoological Park, a single cub was born following only one AI with fresh sperm inseminated after oestrogen decline (121-day gestation).
Efficiency of artificial insemination at the Wolong
The Wolong Breeding Centre in the Wolong Nature Reserve was established in 1982, and currently achieves a high pregnancy success rate using the combined practice of natural mating and AI. From 1998 to 2000, seven females (4.5 to 10.5 years of age) were anaesthetised for transcervical AI without mating (Huang et al, 2001, 2002). These females were selected for only AI (usually on two or three consecutive days) due to a young age (4.5 years; SB 432 and 434) or because of weak behavioural signs of oestrus (SB 444, 418, 446, 382 and 385) (Table 20.2). One particularly interesting case was a young female, SB 432, who was inseminated with only cold-stored semen from a wild-born, nonbreeding male with skin cancer (squamous cell carcinoma; see Chapter 4) (Table 20.3). Despite the chronic progression of the cancer, excellent quality semen
Table 20.1. Successful artificial inseminations (AI) in giant pandas outside China in Spain, Japan and the USA
Female Age Male
Date of oestrogen Motile sperm" Gestation duration6; No. of cubs decline (xlO6) birth date (sex SB no.)
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