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Deflating fixed-time AI myths

Conception rates in these three herds averaged 62, 65 and 76 per cent for an overall average of 67 per cent compared to an industry average of 50 per cent with a range of 40 to 60 per cent

inserting an AI device into a heifer

If the advantages of using fixed-time artificial insemination in your breeding program aren’t enough to convince you to give it a try, turn it around and ask yourself, “why not?”

Three Saskatchewan producers who had never used fixed-time AI put that question to the test last spring as part of a fixed-time AI project sponsored by the Rudy Feeder Co-operative and funded by the provincial ADOPT (agriculture demonstration of practices and technology) program.

Saskatchewan regional livestock specialist Travis Peardon who co-ordinated the trial says the results basically deflated many of the myths that seem to keep Canadian beef producers from trying this technology. The results weren’t a surprise to Peardon, however, as he is going into his fourth season using fixed-time AI on his family’s own cattle herd.

The first myth is that all the calves would be born on the same day. Peardon says project heifers calved over the course of 10 days even though all were bred within a couple hours of each other.

Another is that conception rates from AI are marginal at best. In fact, Peardon says conception rates in these three herds averaged 62, 65 and 76 per cent for an overall average of 67 per cent compared to an industry average of 50 per cent with a range of 40 to 60 per cent.

The use of a CIDR (controlled internal drug release) device required by the synchronization protocol didn’t cause the test heifers that failed to catch with AI to miss any natural heat cycles. In fact, heifers that didn’t catch with fixed-time AI were turned out with cleanup bulls 10 days later and the calving records show 14 to 25 per cent of them conceived on their first natural heat, approximately 21 days after they were bred AI. In one herd, all of those not pregnant after AI conceived on the first natural heat.

Running animals through the chute got easier, not harder during the three passes over nine days required for synchronized AI — another myth squashed. According to these producers having heifers accustomed to routine handling actually became a plus at calving time.

Peardon admits this tight schedule requires a considerable commitment, but seeing the start time is of your choosing he says everything can be arranged months in advance.

The producers never put a dollar value on their own time but the general consensus was that any extra time spent during breeding season would be saved at the start of calving season. In fact, the time involved was generally less than they anticipated. Each farm randomly designated half its heifers to the AI group, which worked out to 21 at two locations and 29 at the other. With those numbers it took about an hour for each step in the protocol recommended by Dr. Colin Palmer, a theriogenologist at the Western College of Veterinary Medicine:

  • Day 0 – inject estradiol benzonate and insert a CIDR progesterone-releasing vaginal implant.
  • Day 7 – remove the CIDR and inject cloprostenol.
  • Day 9 (54 to 56 hours after CIDR removal) — AI and inject gonadotropin-releasing hormone.

The producers did most of the work and bought the semen but AI technician Craig Thoms of Saskatoon inseminated the heifers. Richard Carlson, Genex Co-operative’s Western Canadian beef sales manager, also helped out.

Compared to turning the bulls out this is a complicated process but the three co-operators on this project didn’t have any problems following the schedule. Peardon recommends writing the protocol on a calendar along with the drugs to be used on critical days just to avoid any mix-ups.

The drugs are available from veterinarians but Peardon suggests arranging for them ahead of time to be sure everything will be available when it is needed.

Another caution is to ensure heifers or cows are in good body condition, on a rising plane of nutrition and cycling before you start. Nutrition is the most important factor in the success of any breeding program, including fixed-time AI. No protocol will override a lack of condition or low fertility.

data chart for breeding heifers

At times the amount of performance and genomic information available on AI sires today can be overwhelming but Peardon says this is really one of the benefits to breeding AI because added data improves the accuracy of the EPDs on a sire and improves the chances that you will make the right selection for your herd — all for quite a bit less than you would pay for a bull of the same calibre.

Peardon initially started using fixed-time AI to improve weaning weights in his own family’s commercial herd. His dad became convinced on the technique when their first-calf heifers started weaning heavier calves than their mature cows.

In this project, the cost of natural service worked out to $71 per calf based on an average cost for a bull of $4,000, a salvage value after four years of $1,500, depreciation at $2,500, $1,000/year to cover yardage/feed/pasture, a 10 per cent death and vet costs of $100/year for a total of $8,500 to get 120 calves sired.

That was $24 less than the $94 it cost per calf from the AI program that included $25 for semen and $26 per calf for the drugs and related costs. The cleanup bulls, which were billed at 40 per cent of the cost of natural service.

Profit was calculated on the difference in weaning weight between AI and natural-service calves. In the three herds AI-sired calves averaged 14, 27 and 174 pounds more than the natural-service calves for an overall average difference of 72 pounds per calf.

Based on calves selling for $1.55 per pound the profit from this weaning weight advantage worked out to $246, $18.01, and -$1.34, or an average profit of $87.56 per calf on all three herds.

This total doesn’t account for any future benefit from the reproductive momentum that comes from having a higher percentage of your heifers calve during the first 10 days of the calving season. More on this concept of reproductive momentum can be found in our article Front Load the Heifers with Dr. John Campbell on page 20 in the March 2014 issue of Canadian Cattlemen.

Two of the co-operators were intrigued enough to sign up for a followup project, breeding some or all of the heifers from both groups last spring to AI sires around 45 days postpartum. Keeping first-calf heifers on track with the second calf is a common problem and if fixed-time AI works well on second calvers, Peardon says it might be a way to get the second calf on time and set the heifers up to become productive cows for years to come.

One immediate finding from this second project was that fixed-time AI on cows with calves at foot didn’t prove to be the hassle some make it out to be. They didn’t have any trouble sorting off the calves before running the moms through the chute for each treatment.

Another project involving six commercial producers is set to start this spring using the same protocol with AI at the normal time and again 24 hours later. The thinking here is that the timing of the first AI may be just missing the heat. If this improves conception rates over the first trial, it may be financially feasible for farmers to AI more heifers than they need for replacements, preg check 30 days after breeding, and sell the open heifers when the price for grasser cattle is relatively high.

The results from these ADOPT projects will be posted on the Government of Saskatchewan Agriculture Development Fund website as they become available. Travis Peardon can be reached at 306-867-5504 or [email protected].

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