Adding to the Reproductive Toolbox

Activity monitors can help determine proper breeding time. ( Wyatt Bechtel )

Reproductive success is only attained when a live calf is on the ground, but before that can happen the mother needs to be bred in as few services as possible.

Recently, activity monitors have become a more attractive option to achieve this goal.

Activity monitors are a tool producers can use to aid in getting cows and heifers bred in a timely manner, says Matthew Haan, Extension dairy educator at Penn State University. 

Optimal Breeding Time

Haan performed a study in 2016 to find the optimum time to breed cows with activity monitors at a Pennsylvania dairy with 104 lactating Holstein cows housed in a tunnel-ventilated tiestall barn.

Each cow was fitted with an activity monitor and the system identified when the peak activity occurs for breeding, starting a countdown to zero. Hours of ovulation were recorded to help determine the prime time to breed. The study looked at firstservice AI.

Cows bred nine hours or earlier into ovulation had the worst success with 16 breedings and only one pregnancy. Waiting longer for ovulation at 20 hours or more had fewer breedings at just four, but resulted in 50% pregnancy. The best results occurred at 17 hours from ovulation for seven breedings with 57% pregnancies. The next best results were seen at 12 hours (eight breedings) and 15 hours (13 breedings) from ovulation with 38% pregnancies.

Haan notes for this farm, the best time to breed appears to be from 10 to 17 hours from ovulation, but this could vary for other operations and monitoring systems. “Remember, an activity monitor is only a tool to help manage breeding of dairy cows, and like any tool, it has to be used to achieve the desired results,” Haan says. 

Part of the Toolbox

Stephen LeBlanc, research program director at the University of Guelph’s Veterinary College in Canada, also believes activity monitors are a tool dairy producers should consider for their reproductive toolbox.

“Getting cows bred in an economically favorable interval is difficult,” LeBlanc says. “Relying on estrus detection, by whatever means, can be challenging, particularly when using visual observation.”

The peak window for fertility to breed in estrus is 6 to 24 hours. To catch a cow in a standing heat where she is being ridden only occurs 0.0015% of the time during a three week breeding cycle. At less than half a minute of riding during a standing heat, LeBlanc says it is difficult to determine estrus visually.

A study done by the University of Guelph looked at four commercial dairies in Canada using two different activity monitoring systems. Both monitoring systems submitted data when cows entered the parlor. LeBlanc says newer monitoring systems have technology that submits data live which helps increase the data accuracy versus those that would only get data the two to three times cows are milked per day.

Cows were bred using activity monitors between 55 and 80 days in milk. After 80 days cows were bred off of timed AI along with activity monitors.

Of the 1,014 cows in the study, 83% were detected in estrus by day 80. Only 3% of those cows had low progesterone levels, meaning they were not ready to breed. 

Ovsynch Plus Activity

Another study in Canada looked at a Double Ovsynch breeding program versus two different monitoring technologies on two Canadian dairies milking more than 500 cows each.

The study found on first-service AI there were 33.9% pregnancies with Double Ovsynch and 29.3% pregnancies for activity monitors. When stretching the breeding window to 88 days in milk the activity monitors had an advantage at 40.1% compared to 33.9% for Double Ovsynch.

“While one can gain quite a bit of ground with this technology, it is not realistic or economically favorable to rely on it exclusively,” LeBlanc says. He thinks producers will still need to use other breeding tools like fixed-timed AI or Double Ovsynch as insurance when using activity monitors in their reproductive program.

To hear more on activity monitors watch the following webinar form the Dairy Cattle Reproduction Council featuring LeBlanc:


Note: This story ran in the March 2018 magazine issue of Dairy Herd Management.