Kris Ringwall, NDSU Extension Service, Published August 30 2010
Beef Talk: Late-calving cows simply are that: late-calvingIf one stands by the fence and discusses calving, most producers are sympathetic to the late- calving cow. At least she has a live calf is the general response. That is true, but the challenge is to move beyond acceptance and perhaps refocus and rethink this subtle, but real acceptance of late-calving cows.
Calving interval is not a term that seems to frequent cow producer
conversations. In reality, it probably is the No.1 trait in the cow-calf
operation. Calving interval is the time between the birth of one calf and the next. Ideally, a cow should have a calf every 365 days.
As a cow ages and has more calves, calving dates can be averaged to come up with the calving interval. Through time, the ideal cow will maintain an average calving interval that is close to 365 days.
Why is this so important and why now? Well, some cattle producers are
ultrasounding cattle as bulls are being pulled and brought home. Many more
producers will be pregnancy-checking this fall and culling cows as they ask
themselves who is pregnant. Some will go a step further and ask if the cow will be early or late.
Producers seldom actually cull the late cows. Why? I'm not sure, but there seems to be comfort in maintaining the status quo. The most important point is that most cows do calf on an annual basis and generally close to when they calved the previous years.
Thus, a cow that is late this year will be late next year and years after that, so, for all practical purposes, the cow will be late for her entire reproductive lifetime. There are managerial changes that can be made, such as better nutrition, appropriate intervention with newer reproductive hormonal programs or even calf withdrawal at breeding. However, these imply that there will be additional inputs and labor, which come at an expense.
This year, the Dickinson Research Extension Center came to the realization that the center also was accepting the status quo. Bulls were allowed to run with the cows throughout the summer, so the cows were calving later. This means a longer calving season and more shuffling of the cows, even after the main herd was worked and sent to pasture.
A concerted effort was made to re-establish a short and concise calving season. The bulls were pulled in July. Let me repeat that the bulls were pulled in July. The first group of cows was ultrasounded the other day. The results were promising. These cows were time synchronized and artificially bred on June 14. Cleanup bulls were placed with the cows on June 15 and then pulled on July 20.
All 48 head of cows were pregnant. Thirty-two cows conceived through artificial breeding and 16 cows bred naturally to the cleanup bulls. That is great and means no late calves in that group next year. The artificially bred cows have an expected calving date of March 31. The average calving date for the remaining cows is estimated to be April 20. The actual spread in the later cows is from April 7 to May 1.
A couple of points can be made. First, these cows bred exceptionally well, but not beyond expectations. Also, these cows are good cows because they have an average calving interval of 366 days. The range in calving interval for the 48 cows was 344 days to 382 days.
The cow that has the longest calving interval is raising her 12th calf. She bred through artificial insemination and will give birth at the beginning of the calving season next year. Good job for an old cow. However, she may be culled next year because of her age, but she deserves a pat on her back.
Typically, the shorter calving intervals are with the younger cows. As the cows get older, they slowly drop back in calving date. The average age on this set of cows is 6.4 years. They have given birth to an average of 5.4 calves, weaned 4.3 calves and now are raising their next calf. They will have raised 5.3 calves if all the calves make it home this fall. That is a good set of cattle that, for all practical purposes, are right on schedule by producing calves every 366 days.
If some cows have a longer calving interval, then the herd as a whole is going backwards and managerial intervention is a must. However, to start with, don't keep late-calving cows because they simply will keep calving late.
May you find all your ear tags.
Your comments are always welcome at http://www.BeefTalk.com.
For more information, contact the NDBCIA Office, 1041 State Ave., Dickinson, ND
58601, or go to http://www.CHAPS2000.com on the Internet.
Ringwall is a beef specialist with the NDSU Extension Service.