8 April 2014

3 minute read

Feedback asked experts for their advice to producers interested in using two AI techniques: fixed time and observed heat. Here we focus on fixed time AI (FTAI), write advisers at Meat and Livestock Australia.

If you’re chasing rapid genetic gains for a large herd, FTAI is the most viable and practical solution, according to reproduction researcher Dr Sophia Edwards.

Working on an MLA-funded project to improve pregnancy rates in Brahman cattle, Sophia said that, even with FTAI’s modest success rates (40–60 per cent pregnancy on the first cycle), it was the cheapest way to access bulls of high genetic merit.

“If you wanted to buy a bull with estimated breeding values (EBVs) in the top 10 per cent of its breed, you could expect to spend about $40,000. At best, he could cover 50 cows and at a 70 per cent weaning rate that only translates to 35 calves (at $1,142 each). It makes him very expensive,” she said.

“However, if you buy equivalent semen at $40/straw or less, you can spread those genes much further.”

Sophia said the first step when considering an FTAI program was to identify the breeding objective and set a realistic budget.

“About $20/straw is a good ballpark figure to work on,” she said.

“If you’re spending more than $50/straw or the semen is rare, I wouldn’t recommend FTAI. I’d use a heat detection program, which is more labour intensive but generally more successful.”

Sophia said heifers were the most cost-eff ective group to include in an FTAI program but generally achieved lower pregnancy rates, usually only 40 per cent for Brahmans in a well-managed herd. Lactating cows, on the other hand, could achieve 50–60 per cent .

“Even if producers don’t want to AI, there are benefi ts to using the synchronising drugs,” she said.

“The progesterone device can jump-start cows in lactation anoestrus to cycle.”

FTAI is considered labour efficient because there is no need to manually heat detect, which takes time each morning and night over several weeks, the infrastructure requirements are less and you don’t need an experienced inseminator available for the same extended period. Also, there is no need for small holding paddocks or add-on feed costs.

MLA R&D Coordinator Geoff Niethe said that for many producers, particularly those in harsh environments, breeding their own bulls using artificial insemination made a lot of sense.

“AI is still the cheapest and most practical tool for producers in remote areas to rapidly disseminate highly sought after and emerging genetic traits such as polledness and improved fertility,” he said.

“It’s also an excellent way of breeding high genetic merit bulls that are well adapted to your environment and won’t need a ‘let-down’ period before they start work.”

Geoff suggested the factors which would lead a producer to choosing FTAI over observed heat were:

1. Availability and cost of skilled AI technician (one day versus 2–3 days).
2. A tight management program and the need to minimise time, fodder and staff to handle stock.
3. Inability to commit to regular heat detection.
4. Lacking confidence/skills/ infrastructure to achieve good heat detection.

Good Timing

Fixed time artificial insemination (FTAI) describes the process where the oestrous cycles of cows and/or heifers are synchronised using drugs and all females are inseminated at the same time. This differs to other synchronised AI programs where females are only inseminated on signs of being ‘on heat’. FTAI eliminates the need for manual heat detection and reduces the insemination period and time in yards.