Artificial insemination in the emu (Dromaius novaehollandiae): effects of numbers of spermatozoa and time of insemination on the duration of the fertile period

In emus, the duration of the fertile period was measured following a single artificial insemination (AI) and investigated the effect of time of AI in the egg cycle on the duration of the fertile period. Semen was collected by artificial cloaca, pooled and used undiluted for AI within 30 minutes. For insemination, a female was followed until she assumed the voluntary crouch. A speculum was then inserted into the cloaca and an insemination straw introduced into the vagina to a depth of 1-2 cm, and semen deposited. Following a single insemination with 100, 200 or 400 million spermatozoa, female emus laid fertilized eggs for 10.0œ0.4, 12.0œ0.9, and 15.0œ0.6 days. When 400 million spermatozoa were used for insemination on Day 1, 2 or 3 of the oviposition cycle, the duration of the fertile period appeared to change in a day-dependent manner. After AI on Day 1, female emus laid fertilized eggs for 15.8œ1.1 days, after AI on Day 2 for 12.5œ2.2 days, and after AI on Day 3 for 10.0œ1.5 days. The results suggest that female emus need to be inseminated the day after oviposition to maximize the duration of their fertile period.