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Case Study: Lagrae Fixed Time AI

Article by Dr Enoch Bergman, Swans Veterinary Services

Dr Enoch Bergan speaking to producers at the ASHEEP Cattle Field Day about the results of the Fixed Time AI project.
Dr Enoch Bergan speaking to producers at the ASHEEP Cattle Field Day about the results of the Fixed Time AI project.

West of Salmon Gums, Lagrae was allocated to Laraine and Graeme Doney in 1967. They immediately commenced clearing their new land block, growing crops and raising sheep before buying their first two cows in 1995.

Over the next 25 years they have steadily built their herd up to 250 cows. In 2017 Graeme and Laraine, since joined by their son Ross and his wife Janine, volunteered to participate in the ASHEEP/Swans Veterinary Services, Meat & Livestock Australia (MLA) Producer Demonstration Site (PDS) focused on demonstrating the value of integrating FTAI utilizing “curve bender” sires into commercial heifer mating programs. “Curve Benders” are sires with Expected Breeding Value’s (EBV’s) for both superior calving ease and growth. The program was run on ten Esperance properties with variable annual participation over three years for a total of 15 sites.

“The farm was my 21st birthday present from my husband, who wanted nothing more than to clear a bush block and turn it into a farm. It has been a long hard slog, we’ve built a good cow herd and a better family.” Laraine said.

In the first year of the PDS, the Doneys had already hand selected 49 of what they considered their best potential replacement heifers in preparation for natural mating. For the trial, 25 of them were randomly selected and redirected into a synchronization program culminating in them being artificially inseminated. On the same date they were AI’d, their siblings were introduced to the bulls which the Doneys had already selected. Ten days later the two groups of heifers were commingled and remained with the bulls for the duration of the mating program.

At pregnancy testing, Lagrae’s FTAI integrated heifers demonstrated a modest 0.5% better conception rate than their naturally mated siblings. However, once calving commenced, the heifers enrolled in the FTAI integrated group on average calved well in advance of those enrolled in the strictly naturally serviced group as expected and as the intervention was intended.

“Enoch talked us into giving AI a go, thanks to the MLA-funded PDS. We weren’t sure how it would go, but once we started calving, it became obvious to us it was worth continuing with.” Laraine added.

The advantages afforded by a higher proportion of the pregnancies being sired by AI from proven AI sires with exceptional calving ease EBV’s was also abundantly evident to the Doneys once the dystocia (or calving trouble) statistics were compiled on their farm, demonstrating a massive relative reduction of 85.5% in dystocia, 66.7% in calf mortalities, and 100% in heifer mortalities amongst the heifers enrolled in their FTAI program.

Rebreeding statistics were collected from each farm enrolled in the PDS after the heifers were remated after calving.100% of the Lagrae heifers which had been enrolled in the FTAI program as heifers were pregnancy tested in calf after their second joining, similarly, 21 of the 22 naturally mated heifers also fell pregnant at their subsequent joining.

The value of synchronizing the heifers to be AI’d on the mating start date extended beyond improving rebreeding rates, as the weaners from the FTAI Integrated heifers were consistently heavier than those from the naturally mated group at Legrae. The calves born from the FTAI Integrated group were a whopping 19.3 kilograms heavier as a result of their improved calving pattern and the superior growth EBV’s amongst the AI sires used. “They were the best calves we had ever raised and the buyer rang us up especially wanting more!” Laraine exclaimed. “That really sealed the deal for us, confirming our own opinion of the calves, so we decided to continue AI’ing our heifers in the future.”

In consultation with Esperance producers both participating and observing the PDS, some economics were applied to the findings of the PDS.Having accounted for all of the AI mating costs to each cooperating producer for semen, pharmaceuticals, technician time, and travel, the average cost to each producer would have been $22.66 more to AI and back up at 2% bulls than to naturally join all of their heifers to bulls at 3%. The Doney’s calculated FTAI integration costs, due to their potential to halve their bull requirements, were only $4.76 extra per pregnancy to integrate AI over their entire budgeted replacement heifer population of 49 animals. Additional expense in the form of producer labour was estimated at 40 hours at $30 per hour per 100 heifers AI’d over the course of the average AI program in the trial.

The return on investment per pregnancy for the Doney’s was modelled using 2018 values.For modelling purposes, pregnant heifers were valued at an additional $100 per animal compared to empty heifers diagnosed at pregnancy testing.Dystocia events were estimated to average $200 in labour and/or veterinary costs per case.Deceased calves were valued at $500 and deceased heifers at the point of calving in 2018 at $1500.Kilograms of calf weaned were valued at $3.00 per kilogram live weight in 2018. Lastly, empty 2nd calvers were devalued by $750 per animal should they be empty at their second pregnancy test.An estimate of the return on investment for the Doney’s from their data from the first year of the PDS is summated below.

Recognizing the potential to reap a reasonable financial return on the process of integrating FTAI and the use of bulls with appropriate EBV’s into their heifer mating program, coupled with a far less stressful calving, the Doneys decided to pull out of the PDS after the first year in order to implement the integration of FTAI into their entire heifer mating programs for their foreseeable future. It isn’t hard to argue the logic when they appear to have benefitted in the first year of the trial by over $300 per pregnancy!

“We couldn’t see any reason to stay in the trial after the first year, we had already figured out what we needed to do!” Laraine concluded.

Disclaimer: The Association of Sheep Husbandry, Excellence, Evaluation and Production (ASHEEP) does not accept any liability whatsoever by reason of negligence or otherwise arising from use or release of the information in this article, or any part of it. Producers are encouraged to conduct their own research to ensure before adjusting their production system.


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