By Dean Kreager,
How do you avoid getting stuck in a rut? Take a different path. There was a real shortage of high quality or even medium quality hay made last year. Forage analysis results that I reviewed last fall were all lower quality than expected. As a result, many cowherds were much thinner at the beginning of the spring calving season this year. The problem with having thin cows at calving time is that they are likely to be even thinner at breeding time.
When a cow eats, her use of nutrients is prioritized. First is maintenance for survival, followed by lactation and growth, which includes weight gain, and finally, reproduction. While reproduction is the number one priority trait for profitability, it is not at the top of the list when the body of the cow is deciding how to use its nutrient resources.
Years of research have established that thin cows are often difficult to get bred. Results often show around a 30% decrease in the number of cows displaying estrus by 60 days post-calving on a cow with a body condition score at calving of 4 vs 6. Similar results are seen when comparing pregnancy rates within a 90 day window of calving. These thinner cows also produce calves with lower weaning weights.
Early weaning has often been suggested during drought years but can also have a place when managing thin cows. The energy that is required for lactation is high enough to keep many cows in a negative energy balance while nursing a calf. Removing the calf from the cow will stop lactation and allow the cow to begin to use energy toward reproduction. Weaning times of 45-60 days allow cows to begin a positive energy balance and start cycling earlier.
If you are past the time where a 45 to 60 weaning is possible, consider weaning calves at 3-5 months of age instead of 7 months. While you will not get the immediate reproductive benefits, this still provides the cows with an extra opportunity to gain a body condition score or two so they will be better prepared for next winter. A 5 to 7 body condition score at the beginning of the calving season will increase the likelihood of cycling early and getting pregnant early in her next season. Having a calf early in the breeding season is one of the most important determinates of profitability.
Extra management, resources and facilities are needed when early weaning calves but there are also some benefits in addition to the improved reproductive performance of the dams. Early weaned calves can be very efficient at growing. Their feed conversion can be in the neighborhood of 1 pound of gain from 5 pounds of feed. This efficiency is a big part of why young calves are worth more per pound. Early weaning calves started on a good nutrition and health program can provide increased value of the calves when sold.
The importance of pregnancy checking is even higher in herds with thin cows that may remain anestrus for extended periods. Lack of signs of estrus is no guarantee that a cow was pregnant when the bull was removed. If the bull remained with the cows for extended periods, do you know when the breeding occurred? The cost of pregnancy checking 20 cows is likely less than the cost of feeding one open cow through the winter.
There are three commonly used methods for pregnancy checking cows. They are rectal palpation, ultrasonography, and blood testing. While the first two depend on the skill of the technician, all three are highly accurate. Ultrasonography and blood testing can be performed around 28 days while rectal palpation is usually after 35 days. There are advantages and disadvantages of each method. Ultrasonography and rectal palpation typically require a farm visit from a veterinarian but are capable of staging the age of the fetus. Blood testing is inexpensive and can be completed by most producers but does not provide the age of the fetus. Finding the open cows or the ones that did not breed back within the desired calving season will allow you to remove them from your herd early to conserve feed resources for the rest of the herd.
Maybe this is the year to look at a different management approach. Don’t get stuck in a rut.
Source: osu.edu