Details of inséminant traits are presented in Table 20.2.

was obtained and diluted in TEST egg-yolk diluent with no glycerol (one part semen to two parts diluent), then stored at 4°C for 24 and 48 hours until used for AI. During the same period (1998 to 2000), the combined practice of natural mating and AI was conducted in 18 breeding trials involving ten females (5.5 to 19.5 years of age) at the Wolong Breeding Centre (Table 20.4).

Excellent semen quality with high ratings of sperm motility, morphology and intact acrosomes was observed for all males used in these trials. Mean (± SEM) ejaculate traits in the four male sperm donors and six ejaculates used for the 'AI only' females were: ejaculate volume 3.3 ± 0.5 ml; sperm concentration 1429.8 ± 235.4 x 106 cells per ml; sperm motility 81.7 ± 2.1%; sperm forward progression (0-5; 5 is best) 3.1 ± 0.1; structurally normal sperm 79.3 ± 9.2%; and normal acrosomes 98.0 ± 1.0%.

For transcervical AI (n = 15) in these seven females, mean inseminate traits were: spermic volume inseminated 2.3 ± 0.4 ml; sperm motility 73.5 ± 2.9%; sperm forward progression 2.5 ± 0.1; and total motile sperm inseminated per AI 684.2 ± 118.2 x 106 cells.

Results revealed that transcervical AI using semen from non-breeding giant panda males was effective for producing pregnancies and live offspring (Fig. 20.4 Plate XXXIX). Cold storage of semen at 4°C maintained high sperm percentage motility, percentage live and forward progression for at least 48 hours in vitro. Four of seven (57.1%) giant pandas inseminated with fresh, cold-stored and/or frozen semen became pregnant and produced a total of five cubs after AI without natural mating (see Table 20.2). Mean gestation and litter size were 132.5 ± 9.7 days and 1.3 ± 0.3 cubs per litter, respectively. Three of the four pregnancies produced (in females SB 444, 446 and 382) resulted from the use of fresh semen on the first day of AI and cold-stored semen (4°C for 24 hours) from the same male on the second day of AI. And, in female SB 382, frozen-thawed semen was used on the third day. One cub produced from this strategy was female SB 473 (Mei Xiang), which was born in 1998 and currently resides at the Smithsonian's National Zoological Park in Washington, DC (see Fig. 20.4; Plate XXXIX). In turn, this female now has produced an offspring by AI (Table 20.1).

AI using only cold-stored semen from the nonbreeding male SB 305 with skin cancer was effective for producing a pregnancy in SB 432 (see Table 20.2 and 20.3). Because this male was wild born and had never reproduced, this was an especially important milestone in that AI allowed perpetuating valuable genes for the ex situ population. This

Table 20.4. Results of the combined use of natural breeding and artificial insemination (AI) in giant pandas at the Wolong Breeding Centre from 1998 to 2000 (18 AI trials; ten females

Female Age Date of No. of cubs Sire (SB) of

SB no. (years) Type of breeding Date Male SB no. Pregnant (gestation) birth (sex SB no.) cub(sf

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