DENVER (AP) -- The spread of a venereal disease that can cause cows to lose their calves appears to be slowing in Colorado.

Agriculture officials plan to strengthen policies to keep it that way.

Trichomoniasis, or "trich," is of particular concern in the West, where grazing associations and permits for grazing on public land allow cattle to co-mingle.

Dozens of Colorado producers were hit with trich last year. So far this year, 13 facilities in eight counties have been quarantined in Colorado.

The spread in Colorado was blamed on what one expert called a "perfect storm" of drought, blizzards and low levels of testing.

Texas, the nation's largest cattle producing state, adopted trich prevention regulations April 1.

At least 15 other states in the West, including Colorado, New Mexico and South Dakota, have their own programs.

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On the Net: Colorado Department of Agriculture-Disease Information:

http://www.colorado.gov/cs/Satellite/Agriculture-Main/CDAG/1176829232393

American Veterinary Medical Association-Texas program: http://www.avma.org/onlnews/javma/apr09/090401o.asp 

Colorado State University Extension-Trichomoniasis Prevention: http://www.ext.colostate.edu/pubs/livestk/01628.html 

(Copyright 2009 by The Associated Press. All Rights Reserved.)