I have used Cydectin, but have gone back to Ivomec.
I worm spring and fall. Timing depends on the weather. As long as the grass blades are getting wet with dew cattle can get reinfected. I usually treat in mid April and again after frost. The Extension Vet from A&M says if you are going to treat once a year, best time is mid July.
I've used Cydectin and like it- altho the last couple years have used Ivomec since the generic is so cheap...I usually pour my cows in about Jan or Feb- month or so before calving- or just when the lice get started good...I think I will probably use Cydectin next time-- they say you should switch off every few years so you get the bugs that have built up an immunity to the other.......
