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Dr. Jamie Courter is your Mizzou Beef Genetics Extension Specialist

By Jared E. Decker Many of you have probably noticed that things have been a lot less active on the A Steak in Genomics™   blog, but you probably haven't known why. In January 2021, I was named the Wurdack Chair in Animal Genomics at Mizzou, and I now focus on research, with a little bit of teaching. I no longer have an extension appointment. But, with exciting news, the blog is about to become a lot more active! Jamie Courter began as the new MU Extension state beef genetics specialist in the Division of Animal Sciences on September 1, 2023. I have known Jamie for several years, meeting her at BIF when she was a Masters student. I have been impressed by Jamie in my interactions with her since that time.  Dr. Courter and I have been working closely together the last 6 weeks, and I am excited to work together to serve the beef industry for years to come! Jamie holds a bachelor’s degree in animal science from North Carolina State University and earned a master's degree in animal

ARSBC 2018: General considerations for implementing an artificial insemination program or other reproductive technologies

George Perry
South Dakota State University

Criteria that heifers should meet:
What has the pregnancy rate in your heifers been over the past few years?
Have your heifer received growth promoting implants?
Have your heifers reached the target weight? Typically 65%.
What are the Reproductive Tract Scores of the heifers?

Heifers have to reach 55% of their mature weight to start reaching puberty. However, how well can we know what the mature weight will be? When targeting 55% at breeding, we are really walking on the knife's edge. By targeting 65%, we are hedging for uncertainty.

Heifers with Reproductive Tract Scores that are 1 or 2 not only have lower conception rates as heifers, they also have lower conception rates at 2-year olds.

Criteria that Cows Should Meet

What was the body condition score of your cows at calving? Should be greater than 5.
What is the current body condition score of your cows?
How many days postpartum will your bows be when estrus synchronization is started?

Animals that are not cycling (anestrous) cannot be breed.

Replacement heiferes should be vaccinated before and at weaning.
Both heifers and cows should be vaccinated at least 45 days before breeding.

40% of naive animals that were given a modified live vaccine had an abnormal cycle, which greatly reduces fertility. Even on second cycle, conception rate was only 30%.

Naive animals is dictated by vaccination program. If you didn't give the injection at weaning (purchased later), you can't guarentee it was given.

Cows that are vaccinated less than 45 days before the beginning of the breeding season had reduce conception rates.

There are several estrus detection aids out there. It is important that you use one you are familiar and comfortable with.

When comparing intense vs casual estrus detection systems, the intense estrus detection had a 71% pregnancy rate vs a 35% pregnancy rate with casual detection.

The timing of insemination is a balancing act of the lifespan of the semen and the aging of the ovum (egg). The balance point is typically 12 hours after the expression of estrus.

29% of females display heat from midnight to 6 am. Highlights the need for a detection aid!

Looking at over 10,000 head, there is a 27% improvement in fertility when animals express estrus. When selecting for higher fertility, we see increased expression of estrus.

When semen is deposited in the correct location at the correct time, fertilization occurs 95% of the time. There is a 10% decrease in fertility when semen is deposited in the cervix. No advantage to depositing semen deeper into the uterine, and there is a risk of scratching the uterus and causing bleeding when depositing too deep.

Maternal recognizition of pregnancy doesn't occur until day 15 to 17 of pregnancy. "What is the easiest thing to loose? Something you don't even know you have," Perry said. This can happen to cows that haven't yet recognize pregnancy.

Heifers put on a truck 1 to 4 days after insemination have pregnancy rates around 72%. There is a 12% loss in pregnancy for heifers shipped 8 to 12 days after insemination, a 9% loss for heifers shipped 29 to 33 days after insemination, and a 6% loss for heifers shipped 45 to 60 days after insemination.

Prior grazing exprience creates higher average daily gains compared to heifers that don't have grazing experience (have been in a dry lot). Pregnancy rates are also higher in those heifers that have prior grazing experience. Heifers that have been in dry lots travel around the pasture much more than heifers with previous grazing experience. Heifers from dry lots take 5 days to calm down and not walk too much.

Heifers on restricted diets have less mature embryos and lower quality embryos. A simple 6 day restriction of nutrition caused these differences.

Equation of Reproduction
1. Animals detected in heat and inseminated
2. Inseminator efficiency
3. Fertility level of the herd
4. Semen fertility level

What are the primary problems?

  • Cattle are not good candidates for an estrus synch/AI program (heifers too young, not reach puberty, too many anestrus cows)
  • Protocol compliance
  • Facilities
  • Shipping (trucking) stress
  • Cattle lose weight during breeding season 
  • Others...

See ARSBC Newsroom for more information. http://www.appliedreprostrategies.com/2018/newsroom.html

Note: this post was live blogged and may contain errors.


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