Select Sires

Tips for Decreasing Average Age at First Calving - Part 1
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio, Which Aired June 19, 2003
with Dr. Joe Dalton, extension dairy specialist,
University of Idaho

Today’s Reproductive Moment is with Joseph Dalton, extension dairy specialist at the University of Idaho.

Today, Joe, you are talking about ways to decrease the average age at first calving. Why is this so important?

Well, various economic analyses report that it costs about $1,300 to raise a heifer from birth to calving at 24 months-of-age. Unfortunately, the cost of one month over a goal of 24 months-of-age may be conservatively estimated at about $60 per heifer, with an average age at first calving of 25.3 months. With a 35 percent replacement rate, which is common on many farms, this translates into an extra expense of over $2,700 per 100 cows in the herd.

What types of goals should dairy producers set?

Dairy producers should set realistic goals for their heifers. If we are talking about Holstein heifers, the weight at first breeding should be about 800 pounds. The age at first calving should be between 22-24 months, and weight at first calving between 1,350 to 1,400 pounds. The height at first calving should be 54 inches or greater, and the body condition score should be about 3.5 on a one to five scale.

Should heifers be bred based on size or age?

Heifers should be bred based on size, and by that I mean weight, rather than age. We have to remember that if a Holstein heifer gains 1.8 pounds per day, 800 pounds will be reached by 13 months-of-age. Now, if Holstein heifers gain weight faster than expected and attain the proper size or weight for breeding at 10-11 months-of-age, we should go ahead and breed them.

Let's talk about the importance of heat detection in conception rates on age at first calving.

If your heat detection efficiency is 50 percent, and your conception rate is 50 percent, then at least four estrus cycles will be required to get the average heifer pregnant. If you start breeding at 800 pounds and 13 months-of-age, the average heifer in your herd will not conceive until almost 16 months-of-age and not calve until 25 months-of-age. This is already outside our goals. So, we can see that heat detection and conception rate are very important, and we want to maximize both.

Joe, what kind of tips can you provide for the foundation of a good heifer management program?

We really have to remember that colostrum is the foundation of a good heifer management program. Therefore, all calves should receive two gallons of colostrum within the first 24-hours of birth.

In conclusion, Joe, give us your final thoughts.

The expense associated with raising a heifer from birth to calving is an investment in the future profitability of the dairy business. We need to focus on growth monitoring, heat detection, and conception rates. And we need to unlock the full potential of our heifers by decreasing the average age at first calving to between 22-24 months-of-age.

Joe Dalton, extension dairy specialist at the University of Idaho.

Copyright 1996-2003 Select Sires Inc. Last updated 17-Jul-2003.

Select Sires Inc., 11740 U.S. 42 North, Plain City, Ohio 43064 / Phone: (614) 873-4683 Fax: (614) 873-5751