ARSBC 2018: Impact of fly control on cattle performance

Brandon Smythe
New Mexico State University

Three species Smythe works on:

• Horn flies
• Stable flies
• House flies

House flies become an issue when we upset our neighbors. Dairy in New Mexico dealt with litigation from their neighbors.

Everyone knows that flies are horrible.

Both horn fly males and females feed on blood. Horn flies feed 30 to 40 times a day. Stable flies feed once or twice and then find a place to rest. Horn flies almost never leave a cow. Only time they leave is to lay eggs on a manure patch.

There can be 200 to 1000 flies per animal. Flies are reproductively efficient. Flies lay 10 to 200 viable eggs per female. This reproduction efficiency allows for population surges.

Horn flies are a warm weather pest, thus during cattle breeding and growing. Flies go dormant in winter months.

Horn flies reduce performance in feed efficiency, growth and milk production. Horn flies are number one in causing production losses.
We see a $5 to $8 return for every $1 we spend on fly control.
We need to interven when we see >200 flies per animal.

Horn flies don't affect reproductive outcomes.

We need to rotate fly control methods. Need to have seasonal rotations, and even better is intra-seasonal rotations. If you notice that flies are coming back earlier than the previous year, you probably need to rotate fly control method.