by Chris Shelley
Beef operations strive to have every cow give birth each year. We think of this as a one-year system, but in reality, the cow must be ready to breed before this time. Average gestation length for cattle is around 282 days, leaving less than 83 days for cows to recuperate and be ready for breeding time. This short period from calving to breeding is called the postpartum interval.
A two-year-old heifer that has just had a calf for the first time will take longer to reach estrous again and be ready for breeding than older cows. These young mothers are going through their first lactation and still trying to grow themselves. Estrous cycles will be more likely to resume sooner if cattle have proper nutritional management.
Lactating cows require 35-50% more nutrients to produce the important milk for their calf. Restricting or limiting feed intake can reduce high feed costs but may not prove beneficial at this production stage. Researchers have found that if cattle do not get enough feed during lactation, they will have lower conception rates. Likewise, inadequate nutrient intake during lactation can decrease weaning weights.
Many cattle producers will save some of their best feeds for this time to ensure desired conception rates. Low quality forage alone will typically not be adequate to meet the requirements of cattle in this situation. However, feeds that are low in quality can be used in rations balanced to meet nutritional requirements. The following table will help give an idea of the differences in a lactation diet and a diet following weaning. These data are estimates and it is always best to balance a ration to meet the production goals that you have for your animals. Over feeding can raise your feed costs while under feeding may hurt the productivity of your herd. By balancing a ration you can meet your production needs without wasting feed.
For help with balancing a ration for your herd, contact your local extension office.