The longer calves feed before getting pregnant and producing milk, the more they subtract from the farm’s bottom line.
A recent study involving 1,500 Holsteins at three upstate New York farms provides insights into how to speed up conception rates.
Julio Giordano, assistant professor of dairy cattle biology and management at Cornell, has been presenting the study’s findings to dozens of farmers across the state, including at a recent meeting in Greenwich.
The program, called Dairy Cattle Reproductive Management, was put on by Cornell’s Pro-Dairy program.
“The goal is to reduce the amount of time cows are nonproductive, nonlactating and get them to produce earlier,” Giordano said. “This is one thing reproductive management can help us change a lot.”
Calves’ lives are marked by a series of phases from the time they’re born all the way to gestation. The immediate post-birth period, when they’re fed milk, is the most expensive time, but it can’t be significantly shortened. Neither can the post-weaning, prebreeding phase.
“The breeding period is the one we can affect the most,” Giordano said. “With good reproductive management, a lot of heifers get pregnant earlier. A heifer that’s still eating in your heifer barn is not producing milk in your cow barn.”
The cost is significant for a calf that conceives one week after becoming eligible versus another that takes three months or more, he said.
There is a direct rearing cost, plus the cost of lost opportunity when the cow could be making milk and generating profits.
“The faster they get to pregnancy, the lower the costs,” he said. “We’re trying to reduce the number of days on feed and get them to lactate earlier.”
All 1,500 heifers in the study were begun at 1 year of age. Farmers, though, must decide for themselves when they believe a heifer is eligible for breeding, Giordano said.
“Some farms do it by height, some farms will estimate body weight,” he said. “Height should not be used as the condition for starting to breed heifers.”
Weight is a better benchmark, he said. A heifer that conceives at 55 percent of a mature cow’s body weight will likely calve at about 80 to 82 percent.
“You should have an idea, in theory, of the weight of your cows,” he said.
At two of the three farms that participated in the study, breeding is done when heifers are in estrus. The disadvantage is that it might be difficult for workers to detect when heifers are in heat, or it’s simply inconvenient to keep monitoring them.
The third farm has a different approach, relying on timed artificial insemination when all heifers are inseminated at the same time.
Forty percent of the cows conceived in the first few days. This method was 22 percent faster than breeding them strictly by heat detection, Giordano said.
“At the end of the day, this is what matters to you, how quickly they conceive,” he said.
But timed AI is more expensive.
“Is that all that matters?” he asked. “No. We have to see if we can compensate for that extra cost of getting them bred.”
Data from the study, conducted from November 2015 to February 2017, are still being collected, so results and analysis aren’t definitive.
For Giordano, the bottom line for farmers is finding a method they feel most comfortable with and improving conception rates.
“There are many options,” he said. “You can do whatever you want. Just breed your heifers.”
Paul Post is a freelance writer in eastern New York. He can be reached at paulpost@nycap.rr.com.
Source: Lancaster Farming
Link: http://www.lancasterfarming.com/farming/dairy/should-you-speed-up-conception-rates-on-dairies/article_d00dc5a7-88b3-5ef4-9cbd-da429af61702.html