The oldest cow I have is 8. After that it goes to 4. I started 3 years ago and my program is built entirely on buying bred heifers each fall and having calves in the spring. I do have about 4 heifers that came as fall calvers. So I have been involved in getting heifers bred back. I have not done anything and in fact didn't know I was suppose to do anything other than have a bull on them. My heifers have been breeding back with a calf at their side in about 40 days. Not been a single heifer not breed back in the last 3 years. That's my experience. I think folks that have seen my pictures know my cattle are simangus. Every fall I buy from Rocking P. My cattle have good pasture, are wormed at least twice a year and are vaccinated for anything that poses a remote risk. They are over-conditioned in many folks opinion. My heifers breed back and so do the cows. I have had onlt one exception. I had an 8 year old cow that did not get bred and a friend palpatated her and thought there was too much fat in her reproductive tract to get the egg into the uterus. I provide that as hearsay because he is not a vet. I sold her and she weighed 1, 890 pounds. I used the money to buy another bred heifer. If the heifers are not suppose to be breeding back so flawlessly, don't tell them. :D