New U.S. Food and Drug Administration (FDA) regulations regarding the manufacturing and use of medicated milk replacers will take effect in 2010.

Last August, the FDA ruled that the combination drug of neomycin and oxytetracycline can no longer be used in its current 2:1 dosage in milk replacer. It must be sold in milk replacer as a 1:1 concentration and used at different dosages than originally approved.

The FDA has allowed a depletion period for medicated milk replacer currently in the market. Sources say it is likely to be completely removed from the marketplace by the fall of 2010.

The total amount of the drug combination fed for disease treatment will change to either 0.05 to 0.1 milligrams per pound of body weight and fed continuously or 10 milligrams per pound of bodyweight fed daily for 7 to 14 days. For the high dosage this means:

  • Calves weighing 100 pounds and fed 8 ounces of milk replacer powder twice daily will need to consume products containing 2,000 grams each of oxytetracycline and neomycin per ton
  • Calves weighing 100 pounds and fed 10 ounces of milk replacer powder twice daily will need to consume products containing 1,600 grams each of oxytetracycline and neomycin per ton

Calf-raisers who wish to continue to feed oxytetracycline and neomycin at the high dosage rates will only be able to feed it for a period of seven to 14 days. This new treatment level is expected to increase the cost of a finished bag of calf milk replacer by $4 to $5 per bag.

Tom Earleywine, director of nutrition services for Land O’Lakes Animal Milk Products, says there are some concerns with the new regulations. “It is possible that calf-raisers might feed the medicated milk replacer for five to six weeks, if they only purchase one type of milk replacer.” Feeding it past 14 days means the calf-raiser would be feeding the medication off-label.

From a conventional standpoint, Earleywine says a calf-raiser will need two different types of milk-replacer products, and he says in most operations, it’s not practical to manage both. 

Earleywine says there is the option for calf-raisers to use an “add-pack” dose for individual calves. “Calf-raisers could medicate individual calves with the ‘add-pack’ doses, but this leaves a lot of opportunity for under- or over-dosing calves,” notes Earleywine.

The question is whether this new ruling will impact calf health.

“Not much,” Earleywine says. “Over the last 10 years, we have run 11 different research trials, where we compared non-medicated milk replacer to the 2:1 medicated milk replacer,” he says. Seven of the 11 total trials showed a response of weight gain with neomycin and oxytetracycline in the milk. There was no affect on scours which is the expected response when feeding neomycin and oxytetracycline. But, upon further evaluation, the studies show that calves fed at a higher plane of nutrition responded only one-third of the time to the medicated milk replacer. Calves fed at the lower level of nutrition, responded 100 percent of the time to the medicated milk replacer. “Our research doesn’t show a big benefit to medicated milk replacer, if you’re feeding adequate nutrition,” notes Earleywine. “Nutrition trumps medication every day.”

Don Sockett, veterinarian at the Wisconsin Veterinary Diagnostic Laboratory, agrees with Earleywine. “The most common agents that cause neonatal diarrhea are Cryptosporidium parvum, rotavirus and coronavirus which are resistant to antimicrobial drugs. E. coli and Salmonella account for less than 10 percent of all the neonatal calf diarrhea cases submitted to our lab.”

There is a lack of peer-reviewed studies demonstrating the efficacy of neomycin and oxytetracyline when used for the prevention and treatment of neonatal calf diarrhea caused by E. coli and Salmonella, Sockett says.

The change in medicated milk replacer regulations gives calf raisers an opportunity to focus on preventing coccidiosis from day one, which they couldn’t do before, says Lance Fox, veterinarian and technical service manager with Alpharma Animal Health. Previous regulations did not allow for the combination of neomycin, oxytetracycline and anticoccidials in calf milk replacers. Anticoccidials are common in starter feeds offered to calves from day one, yet most calves are not consuming enough starter and therefore adequate levels of the medication until several weeks of age. This has left a gap in the protection against coccidiosis, says Fox. “Having the anticoccidial in the milk replacer along with the anticoccidial in the grain can effectively ‘bridge the gap’ for solid coccidiosis control.”

Earleywine offers the following advice to calf-raisers who are currently using medicated milk replacer.

  1. Look at feeding a higher plane of nutrition, if you’re not already.
  2. Decide if you really need medication. If it is needed, use another product such as lasalocid or decoquinate or feed neomycin and oxytetracycline at the new levels.