Ask the Vet

Dr. Ken McMillan, Contributing Columnist

READER: We are getting ready for breeding season and wanted to AI (artificially inseminate) some of our cows. There are so many programs out there. Is there anything new and better you would recommend? Do any of the programs lead to better pregnancy rates?

DR. McMILLAN: I asked a friend, Len Holliman, who has worked for Select Sires for at least 30 years, this question, and this is a summary of his comments with my additions inserted.

There are lots of studies on pregnancy rates with various protocols, but in my experience, 60% is what I see. Cows will normally be mid- to upper 60s, upper 70s being the extreme.

Use heat-detection aids; I prefer Estrotect. For heifers, I like the split-time option and tend to get results into the mid-60s. With this protocol, an Eazi-Breed CIDR (controlled internal drug release) is inserted on Day 0 and removed on Day 14. On Day 30, the heifers receive prostaglandin (Lutalyse, Estrumate, etc.) and are bred on detected heat from Day 30 to 33. All nonresponders are given GnRH (gonadotropin-releasing hormone) such as Cystorelin or Factrel at 72 plus or minus two hours and bred.

I think the 7 & 7 Synch protocol helps shorten postpartum for a cow and may give a slight bump in response to cows that are not in optimal condition. It also seems to be better for eared cattle. With the 7 & 7 protocol, cows have a CIDR inserted and a prostaglandin injection on Day 0. On Day 7, they are given GnRH. On Day 14, the CIDR is removed, and they are given another prostaglandin injection. Then all cattle are bred at 54 plus or minus two hours and given another GnRH at the time of breeding.

Each operation needs to work with its veterinarian, semen supplier and AI technician, if needed, to decide what program is best. Cattle must be in good body condition and on a positive plane of nutrition. Protocols must be followed precisely, and a good AI technique is essential. Also, realize these numbers are based on the skills of someone who breeds thousands of cattle every year.

**

-- For full-scale version of Beef Cow Protocols chart, visit https://beefrepro.org/…

-- For more information, visit https://beefrepro.org

-- Please contact your veterinarian with questions pertaining to the health of your herd. Every operation is unique, and the information in this column does not pertain to all situations. This is not intended as medical advice but is purely for informational purposes.

-- These are only my thoughts and general guidelines. Please get with your veterinarian and together develop the best program for your herd.

-- Email Dr. Ken McMillan at vet@dtn.com

[PF_0425]

(c) Copyright 2025 DTN, LLC. All rights reserved.