Worming calves & Anaplasmosis OK cow/calf

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Well-known member
Jan 20, 2007
LaRue, Ohio

The Newsletter

From the Oklahoma Cooperative Extension Service

May 9, 2008

In this Issue:

Early Summer Deworming of Nursing Calves
Glenn Selk, OSU Extension Cattle Reproduction Specialist

Anaplasmosis Prevention
Glenn Selk, OSU Extension Cattle Reproduction Specialist

Early Summer Deworming of Nursing Calves
Glenn Selk, OSU Extension Cattle Reproduction Specialist

Five deworming trials were conducted at the Eastern Research Station located near Haskell, Oklahoma during the 1990’s. Crossbred cows and their Charolais sired calves were sorted by sex of calf, calf age and cow age, then randomly allotted to one of four treatments:  1) non-dewormed control, 2) deworm calf only; 3) deworm cow only; and 4) deworm cow and calf.  Two or three treatments were applied each year including one control group.  Each treatment was applied two or three years. Cows and calves were individually identified and weighed in early June.  Treated animals received label-recommended dosages of ivermectin pour-on.  Pairs grazed in rotation seven bermudagrass pastures overseeded with clover at a stocking rate of 2 acres per cow-calf pair during the 144 to 181-day trials. Initial studies indicated that a low worm infection rate was present in the first two years.  At that time fecal egg counts ranged from 0 to 28 eggs per 3 gram sample of feces.  Deworming cows in late spring had no significant effect on cow summer weight gains up until calf weaning time.  Treating cows but not their calves resulted in a small advantage in average daily calf weight gains (0.1 pound/day); while treated spring-born calves had significantly greater daily weight gains (0.14 pound/day) while nursing non-treated cows. In other words, just deworming the calves resulted in a 21 pound weaning weight advantage over non-treated controls.  Treated calves nursing treated cows had significantly greater average daily weight gains (0.17 pound/day) than the untreated calves nursing untreated cows.  Over the approximate 150 day period this weight gain advantage would total about 25 pounds additional weaning weight to calves in this treatment group.  In this series of studies, deworming spring-born nursing calves in early summer resulted in summer weight gains of 21 pounds.  Deworming both cow and calf  resulted in an increased summer weight gain of 25 pounds versus non-treated controls (or 4 pounds more than when the calf alone was treated.)  In these studies, reproductive performance was quite high for both treated and non-treated cows, and no difference was noted.  Different results may occur in different climates and under different stocking rates. 

Anaplasmosis Prevention
Glenn Selk, OSU Extension Cattle Reproduction Specialist

Anaplasmosis is an infectious disease of cattle caused by a blood-born organism.  Anaplasmosis causes a severe anemia because of the destruction of red blood cells.  Poor performance, abortion, and even death can result from anaplasmosis.  The organism that causes anaplasmosis is moved from animal to animal by transmission of infected blood.  In most cases, anaplasmosis is spread by biting insects that take on a blood meal from an infected animal and then move to a susceptible animal.  Insects are not the only cause of anaplasmosis transmission.  Unclean vaccination needles, and surgical tools (such as dehorners) have also been shown to cause outbreaks of anaplasmosis.

Make sure that equipment is cleaned of all blood between uses. Medicated mineral mixes have been useful in reducing the risk of anaplasmosis on Southern Plains ranches.  Chlortetracycline (CTC) consumed at the rate of 0.5 mg / pound body weight daily during tick and horse fly seasons will help prevent sickness due to anaplasmosis.  CTC may be administered in medicated feed; salt-mineral mixes offered free choice, and medicated blocks.  Most producers will choose to purchase commercially prepared medicated mineral mixes or blocks for use during the vector season.  They certainly want to read and follow the label instructions closely.  Read the label to see that it is in fact "labeled" for anaplasmosis control.  A consistent and appropriate intake of the mineral is critical to a successful anaplasmosis prevention program.  Cow calf operators will want to monitor mineral consumption closely to be certain that the recommended amounts are being consumed by the cattle. 

Placement of mineral feeders and blocks can aid in achieving optimum mineral intake.  Place them in areas where cattle spend a lot of time. Minerals should be placed in loafing areas, near water sources, in shady areas, or any other location that tends be a popular place for the herd to congregate.  Summer often becomes a busy time of year for ranchers (especially during haying season).  Don't forget to check the mineral feeders or blocks to be certain that they are supplying the minerals that your cows need.  If you suspect that an animal in your herd has anaplasmosis, call your veterinarian for help with treatment.