Timing of intrauterine artificial insemination (IUAI) in relation to ovulation in the tammar wallaby, Macropus eugenii
Paris, Damien B.B.P., Taggart, David A., Temple-Smith, Peter D., Shaw, Geoffrey, and Renfree, Marilyn B. (2003) Timing of intrauterine artificial insemination (IUAI) in relation to ovulation in the tammar wallaby, Macropus eugenii. In: Abstracts from the Australian Mammal Society Annual General Meeting. p. 25. From: 49th Australian Mammal Society Annual General Meeting, 7-9 July 2003, Sydney, NSW, Australia.
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Abstract
The window for fertilization is narrow in marsupials because the oocyte is transported rapidly through the oviduct (<24h) and acquires a mucoid coat that entraps and inhibits sperm penetration. Knowledge of the precise time of ovulation is required in the tammar wallaby, Macropus eugenii, to maximise artificial insemination (AI) success. In this study, the timing of ovulation in female tammars was monitored in relation to different times for intrauterine artificial insemination (IUAI). The reproductive tracts of 10 females were dissected at 36 to 41h post coitum (p.c.) and assessed for ovulation. After ovulation, tracts were flushed for embryos. A further 13 females were isolated from males for AI and checked for births every 12h. Semen (3 x 10power6 sperm) was deposited into the uterus via laparotomy at different times between 21.7-42.6h after birth was first detected. Ovaries were examined and tracts flushed for embryos in 4 females at 6h post AI, while 9 were left to give birth. Mating occurred 12.4 ± 2.7h (n=lO; 4.l-28.4h) after birth was first detected. Graafian follicles were observed at 36.0 ± 0.0h p.c. (n=3; all 36.0h) and embryos at 39.4 ± 1.4h p.c. (n=7; 36.0-41.0h). Thus ovulation occurs 36.0 to 39.4h p.c. (~48.4 to 51.8h post partum). A fertilized embryo was recovered 6.4h post AI (~49.0h p.p.) and one AI offspring was born after insemination 34.0h p.p. This confirms that anaesthesia and laparotomy do not suppress ovulation, and that spermatozoa reach the oocyte in time for successful fertilzation after IUAI between 34.0 and 42.6h after birth.