Heat detect VS FTAI for 7&7 Protocol

[CJohnson]

I am planning on using the 7&7 Protocol this year on 150 cows. As I have read the published trial, they put heat detect patches on when PG shot given on day 14, but bred all cows 66 hours after the PG shot, and gave GNRH to only those not in heat. Would it be better to breed any that are in heat earlier than 66 hours using the AM/PM rule, or just do FTAI at 66 hours? In other words, would you expect any to come in heat at 30 or 42 hours and be AIed at 42 and 54 hours, or just breed all at 66 hours and not worry with pulling early ones? Pulling early ones would be possible but not easy as all have calves. Thanks for any advice, Chris

 

[Dsth]

I synced my cows 2 weeks ago using 7 day CIDR and PG when removing CIDR. first cows were standing at 48 hours and latest cows were standing at 96 hours. My opinion is breed at visible signs of standing heat. my opinion is that breeding on TAI is less affective (about 66%) vs. visual heat breeding (maybe 80 - 85%) is due to different ovulation time. I had one cow out of 19 that did not show heat so repeated CIDR and PG and bred on standing heat this weekend. some breeders have very good luck using TAI but I breed on observed heat. I have tried TAI on a few cows without much luck if no visible signs of heat, but did breed one last year on mucus discharge only and she had a calf 2 weeks ago. Other factors may determine your decision like if you use a bull for cleanup on next cycle or watch for heat and AI second time if she didn't settle.

 

[Katpau]

I've wondered the same thing. The 7 plus 7 is a new protocol, and there aren't many who have enough experience with it to answer your question. The University of Missouri did field studies on this plan and you can find a paper on it at their website. https://extension.missouri.edu/publications/g2023
I have sent an email to one of the papers authors. Jordan Thomas, assistant professor, animal sciences. I'll let you know what he says, if he responds.

 

[Katpau]

I received a quick response from Mr Thomas. I will quote you from that response.

"In general, my suggestion is not to go to the effort of pulling early heats unless there is a concerningly high proportion in heat prior to, say, 36 hours. Ovulation occurs approximately 30 hours after onset of estrus, so when heat activity is occurring that early, there certainly is potential for reduced fertility in those cows that expressed estrus so early. It would be fine to pull those specific cows early for AI 12-18 hours after onset of estrus."

He goes on to caution that inseminating too early can also be problem. Since ovulation does not occur until 30 hours after estrus onset, breeding too early might mean the life of the semen is too short. He also said that with this protocol, most cows will show heat in 42-48 hours.

 

[wbvs58]

I think the whole idea of this protocol is to narrow down the time span that most will be in oestrus to get more reliable timing for the majority with fixed time AI which it seems to do well. If you are going to heat detect then I think you are better off using one of the shorter protocols.

Ken

 

[CJohnson]

Thanks guys, I appreciate the responses. I will post my experience after we breed. Chris