Heifers not showing heat

[jlahc]

This is our 3rd year keeping replacement heifers and breeding them AI. We have been watching for heat for at least 20 days and 5 days ago I gave them all (4 hd Charolais) a shot of Lutalyse to induce heat. As per our breeding program, we watch for heat for 5 days, give a shot of Lutalyse to anyone who hasn't shown, watch for heat, 6 days later give another shot to anyone who hasn't shown yet and continue to heat detect. Usually we might get one or 2 that need the second shot but tomorrow is the 2nd shot date and I haven't seen anyone doing anything yet. The heifers are all in good shape, are yearlings (Mar - April 2006) and we have been doing the same thing that we have always done in the past. Why aren't we seeing anything going on? Is there something else we should try?

 

[Moocow11]

i don't know about you but i would give one say tomarrow and then wait 12 days-2 weeks and then give another one and in 2-4 days they will be in heat but hay that is just what i do and we breed 600 hefiers AI each year

 

[KNERSIE]

As per our breeding program, we watch for heat for 5 days, give a shot of Lutalyse to anyone who hasn't shown, watch for heat, 6 days later give another shot to anyone who hasn't shown yet and continue to heat detect.

heat detect for 7 days, then a shot PGF2, heat detect for 7 days should do the trick IF they were cycling to begin with.

Shot PGF2, heat detect and breed for 7 days, and give the second shot PGF2 after 11-13 days, heat detect and breed will give better results, the 6 days you wait between shots don't make sense.

The crux is the heifers need to be actively cycling and have a corpus luteum for the PGF2 to have any effect at all.

 

[milkmaid]

What's their body condition?