5 day versus 7 day AI protocol

[Katpau]

I have begun a 7 day protocol on my cows, which will synchronize them with my heifers for timed AI. I am regretting not doing the 5 day protocol. Could I give two shots of PGF, after pulling CIDRs on day 7 as in the 5 day protocol?
I could pull the CIDRs on day 5, but then I would end up breeding cows 2 days before the heifers. That would mean bringing in my help twice.

 

[Buck Randall]

The 7 day protocol is more effective in cows, so it's probably worth the hassle of setting up two different groups.

Just so I understand you correctly, you're talking about giving a shot of PGF on day 7 when you pull the CIDR, and giving another shot of PGF in day 8? Not only is it okay, you'll probably get a slight increase in conception rate over giving a single PGF shot. Studies in Holsteins found a 5% improvement in conception rate with that protocol.

 

[Katpau]

The 7 day protocol is more effective in cows, so it's probably worth the hassle of setting up two different groups.

Just so I understand you correctly, you're talking about giving a shot of PGF on day 7 when you pull the CIDR, and giving another shot of PGF in day 8? Not only is it okay, you'll probably get a slight increase in conception rate over giving a single PGF shot. Studies in Holsteins found a 5% improvement in conception rate with that protocol.

I was reading about studies that showed the 5 day protocol having superior results to the 7 day. I have done both in the past, but this year I decided to use the 7 day before reading about those studies. With the 5 day, two shots are given 8 hours apart. I was wondering if I could give a second shot of PG 8 hours after pulling CIDRs on the 7th day. You are suggesting giving a second shot the day after pulling the CIDR on day 7, rather than 8 hours after pulling CIDRs?

My heifers are on the 14 day protocol, but I started them so that heifers and cows will arrive at AI time together. Had I read this first, I would have put the CIDRs in the cows two days later.

https://www.extension.purdue.edu/extmedia/AS/AS_575_W.pdf

 

[Buck Randall]

The 7 day protocol is more effective in cows, so it's probably worth the hassle of setting up two different groups.

Just so I understand you correctly, you're talking about giving a shot of PGF on day 7 when you pull the CIDR, and giving another shot of PGF in day 8? Not only is it okay, you'll probably get a slight increase in conception rate over giving a single PGF shot. Studies in Holsteins found a 5% improvement in conception rate with that protocol.

I was reading about studies that showed the 5 day protocol having superior results to the 7 day. I have done both in the past, but this year I decided to use the 7 day before reading about those studies. With the 5 day, two shots are given 8 hours apart. I was wondering if I could give a second shot of PG 8 hours after pulling CIDRs on the 7th day. You are suggesting giving a second shot the day after pulling the CIDR on day 7, rather than 8 hours after pulling CIDRs?

My heifers are on the 14 day protocol, but I started them so that heifers and cows will arrive at AI time together. Had I read this first, I would have put the CIDRs in the cows two days later.

https://www.extension.purdue.edu/extmedia/AS/AS_575_W.pdf

The five day is superior in those studies because of the second PGF shot, not the shorter window. If you give a second PGF as part of the seven day program, it will perform better than the five day (only in cows).

To answer your question, yes, you can give a second PGF eight hours after the pulling the CIDR. Most people I know give it 16-24 hours later, but that's mostly about convenience. It works either way.

 

[Katpau]

Thank you!