Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: WEDNESDAY, April 14, 1993 TAG: 9304140074
SECTION: BUSINESS PAGE: B6 EDITION: METRO
SOURCE: SANDRA BROWN KELLY STAFF WRITER
DATELINE: LENGTH: Medium
DEVICES CUT OUT GUESSWORK WHEN IT'S CATTLE-BREEDING TIME
Now that cattle breeding depends more on farmers armed with vials of semen than bulls with roving eyes, how do the farmers know when?They watch.
Cows that are ready fidget and fool around.
But watching for cows in estrus is an inexact science, and the window of opportunity is brief.
The estrus, when estrogen production increases, is only a few hours long, said Raymond Nebel, extension dairy science specialist at Virginia Tech.
And 70 percent of the time that opportunity comes between midnight and 6 a.m. when few farmers are watching their cows.
"On average, about 44 percent of the cows are caught at the right time," Nebel said.
This means on average a cow has a calf every 13.7 months, Nebel said. With better detection work, that could be cut to nearly 12 months.
Enter such devices as pedometer ankle bracelets and mount meters, which can pinpoint estrus almost all the time.
Last fall, Tech tested the mount meter on its 102-cow dairy herd.
Nebel said Tech students and staff watching the herd missed 30 percent of the ready cows; but the meter missed only 2 percent.
Cows in estrus mount other cows and allow themselves to be mounted. A radio transmitter in the meter relays the frequency and duration of the mounts to a computer. When the activity peaks, it's prime time for the cow allowing the mounting.
Each morning, the farmer checks the computer to determine which cow is in the mood.
Nebel is going to test the pedometer - which monitors the increased walking of cows in estrus - and mount meter together beginning this fall. He also said the devices are designed to aid in reproduction management but won't replace the need to watch the cows.
The pedometer ankle bracelets have been marketed since November under the trade names of Heat-Seeker and Afikim. The heat mount meter will be marketed soon under the trade name Heatwatch.