Wearable animal monitoring technology helps some farms identify when cows are in heat and ready to be inseminated. The data collected from these devices can also highlight differences between cows and their estrus cycles.

Using this data, researchers have shown that the duration and intensity of estrus does make a difference when it comes to getting cows bred. Ronaldo Cerri, a professor at the University of British Columbia, shared the results of a few studies during the December Hoard’s Dairyman webinar.

Researchers found that cows with low estrus intensity have a lower pregnancy rate per artificial insemination (A.I.). On the flip side, cows in these studies with high estrus intensity were consistently 10 to 12 percentage points higher for pregnancy per A.I. “You do have a notable bump in pregnancy per A.I.,” Cerri emphasized.

He also pointed out the connection between high estrus intensity and lower pregnancy losses. More than a dozen studies have shown that relationship, Cerri noted.

Estrus intensity also impacts the success of embryo transfer work. He shared the results of an observational study in which donor cows that expressed high intensity of estrus had a higher percentage of viable embryos. Meanwhile, the recipient cows that had high estrus intensity had a greater pregnancy per A.I. rate compared to cows with lower estrus intensity.

In another study, heifers were superovulated prior to flushing. The intensity of estrus did not affect the quality of the embryos, but the number of embryos collected grew as estrus intensity increased.

“Estrus is important for fertility, but not all estruses are equal,” Cerri summarized. “The intensity of estrus and duration, captured by activity monitors, can have a direct association on pregnancy per A.I.” To learn more, watch the Hoard’s Dairyman webinar, “Using technology to understand fertility in dairy cows.”