When to measure success Fixed-time artificial insemination “I'm not sure that pregnancy rates for artificial insemination are all that important,” said Cliff Lamb, associate director of the North Florida Research and Education Center (NFREC). … “My goal is the percentage of cows that get pregnant in the first 30 days of the breeding season. That's probably the most important economic indicator in our operation.”
NFREC is a research and education campus of the University of Florida that operates a commercial cattle herd that has transitioned from naturally bred cattle to FTAI, giving all cows the opportunity to be impregnated through AI.
Overall, pregnancy rates at the end of the season ranged from 81% to 86% before the season began. Synchronize We introduced FTAI seven years ago. The calving rate for the past three years has been 92% to 94%. The calving season is getting shorter every year.
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“In five years, we've gone from 120 days to Breeding season “The breeding season is set at 70 days and all cows can be artificially inseminated on the first day of the breeding season,” Lamb explains.
Beyond technique, NFREC emphasizes the importance of establishing and following management and selection criteria that are realistic for each operation's goals, environment and resources. Here are the rules that Lamb established and has followed for the past seven breeding seasons:
• All cows calve by 24 months of age.
• Every cow must give birth to a calf every 365 days.
• All cows She has to give birth unassisted.
• The dam must provide adequate resources to enable the calf to reach its genetic potential.
• Calves must be genetically capable.
• Cows Body Condition Score in a ranch environment.
• Cows should not have crazy personalities.
Additionally, cows must be bred within 25 days to remain in the herd. NFREC conducts pregnancy tests 25 to 28 days after breeding. Lamb acknowledges that there have been many discussions about this issue over the years. Selection of storage quality The cow was bred on day 26. But they are not fazed.
“They might be very good animals on other farms, but on our farm we want to get them pregnant sooner,” Lamb said. “I don't think we're selecting for fertility. We're not selecting for pregnancy. We're just hoping that in our environment and our management system, these cows will get pregnant.”
Lamb used results from a larger study he was involved in in South Dakota to demonstrate another major benefit of timed insemination: increasing the number of days between birth and the next breeding season. The study included seven days of CO2 synchronization and a controlled internal drug release (CIDR) protocol (a gonadotropin-releasing hormone (GRO)-induced ovarian syndrome). [GnRH] CIDR on day 1, CIDR removal and prostaglandins on day 7, and GnRH and timed AI on day 10).
Three herds achieved first mating pregnancy rates between 56.9% and 65.8%, which many would consider acceptable, while the other five herds had rates that many would consider disappointing (44.4% to 50.4%).
Lamb stresses the need to have realistic expectations for those with little experience of FTAI.
“Each cattle farming operation needs to have different expectations depending on how the cattle are treated each year,” Lamb said.
The researchers found just one consistent difference between the herds that showed the higher rate and the other herds.
“These three herds had been artificially inseminated consistently for over eight years, regardless of pregnancy rates the year before,” Lamb explained. “They Synchronization Year after year.”
Lamb compared the calving distribution of herds that had never used artificial insemination to herds that were continually inseminated.
In bull-raising herds, 44 percent of calves were born within 30 days of the first calf's arrival, and these herds had well-managed calving seasons of less than 75 days, Lamb said.
The mean postpartum interval (PPI) at the start of the next breeding season in these herds was 64 days, with 43% of cows showing a PPI of less than 50 days at the start of the next breeding season.
In FTAI herds, 88% of cows calved within the first 30 days of the calving season. The average PPI to the start of the next breeding season was 79 days. Only 7% of cows had a PPI of less than 50 days at the start of the next breeding season.
“We are increasing the number of post-calving days by 15 days, the period during which cows can recover and start estrus before the next breeding season,” Lamb emphasizes. “Of those cows, the odds of them starting estrus and becoming pregnant in the next breeding season are higher. So anything we can do to bring the calving season forward will increase fertility in the next breeding season.”
Ultimately, Lamb explains, transitioning NFREC's herds to FTAI continues to produce significant economic benefits compared to previous natural breeding – and that's before genetic improvement is taken into account.
“I've made over $50,000 in revenue from this business. [about 300 calves annually, valued the same year to year] Just putting pregnancy pressure on the herd, making it a rule that we expect every cow in the herd to be pregnant when we want them to be.”
Check out the Android or Apple app stores for the free AI Cowculator app developed by Lamb and his colleagues. You can listen to Lam's presentation here.
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