Select Sires

Calving Ease (Part Two)
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio Which Aired Sept. 11, 2003
With Chuck Sattler, vice president, progeny testing,
Select Sires Inc.

In this week’s Reproductive Moment we continue our discussion of calving ease with Chuck Sattler, vice-president of progeny testing at Select Sires. Chuck, to recap last week you focused on how difficult calvings cost money because they reduce the survival chances of the calf and cause poor reproduction in the cow, and lead to reduced production. You mentioned that heifers need to be bred so they are not too old when they calve, and monitoring the calving process is as important as well, so small problems don’t turn into big ones. You also touched on genetics, which are a factor, the USDA calculates updated genetic estimates twice a year and they provide two values. One is called service-sire calving ease, indicating how easily the calves of this bull are born, The other is called daughter-calving ease which indicates how easily the daughters of this bull will deliver calves. These values are expressed as percent-difficult births. The average value for A.I. sires is eight percent, with the range between four and 14 percent.

As we continue our discussion, what calving ease selection criteria would provide the best return for producers?

Since calving difficulty is primarily a problem in first calf heifers, the most important place to use the calving ease evaluation is in choosing A.I. sires to use in a heifer-breeding program. I recommend choosing sires with service-sire calving ease values of eight percent or less when breeding heifers. It may be tempting to get a little more strict with this, in an aggressive effort to really reduce calving ease, but making more strict standards for calving ease will reduce your opportunities to select for other important traits; like increased production or improved udder conformation. So, it is important to find a balance in what you are selecting for, and eight percent, I think, is a good value to use for service-sire calving ease that would provide the right balance.

Daughter-calving ease values are also useful as well, especially when you are looking at including them in a selection index like net-merit-dollars, or cheese-merit-dollars. They have recently been added to these USDA merit indexes and may eventually be added to additional nationally published indexes as well.

We will be talking more about those selection indexes on next week’s program. But, to wrap up this week in summary, what do you suggest producers do with genetic selection to help reduce calving difficulty?

Selection of service sires that are known calving-ease bulls can help reduce the number of difficult calvings. Again, use bulls that have service-sire calving ease of eight percent or less when breeding heifers and consider including daughter-calving ease in an overall selection index like cheese-merit-dollars. Difficult births are a costly problem and reducing them will lead to fewer reproductive problems in your cows.

Thank you, Chuck. That is Chuck Sattler, vice president of progeny testing at Select Sires.

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