Skip to main content

Florida Scientist: Calves Conceived in Winter Perform Better

Cows and humans have something in common: If you take better care of the mother during pregnancy, her children are likely to be healthier – and this impact should last a lifetime, a University of Florida scientist says.

In the case of cows, cool conditions are key. A new UF/IFAS study shows calves conceived during winter went on to produce more calves and milk.

That’s a critical finding for dairy farmers and for people looking for a nutritious glass of milk because each Florida cow produces an average of 2,408 gallons of milk per year.

“This is important to figure out because maybe we can improve the conditions from conception on in order to get an animal to do as well as possible throughout its existence,” said Albert De Vries, a UF/IFAS associate professor of animal sciences. “The current thinking is that the environment plays an important role from at least conception on.”

Florida has about 124,000 dairy cows, the study said.

For the study, researchers examined 667,000 cow lactation records for the years 2000 through 2012 from the Dairy Herd Information Association database. They obtained weather data from the National Oceanic and Atmospheric Administration. Scientists considered a heat and humidity index higher than 68 to cause heat stress in the cows.

Through these records, De Vries and lead author Pablo Pinedo of Colorado State University documented effects of heat stress during conception on the calf’s performance when it becomes a cow. A calf grows into a cow about two years after birth.

They found that calves conceived in the cool season fared better from day 1 of their pregnancies. Now researchers want to know whether the biological mechanism that causes that effect on day 1 or later.

“Perhaps we can do something during early gestation, even if the mom is still under heat stress,” De Vries said.

The study is published in the Journal of Dairy Science.

Be Aware of Drug Testing Changes

By Gabe Middleton 

Preventing drug residues in milk continues to be a key area that dairy producers should focus on, but starting on July 1, 2017, that prevention will develop another layer. The tetracycline screening pilot program will begin, and no less than 1 out of 15 tanker loads of milk will be tested for oxytetracycline, chlortetracycline, and tetracycline. The tolerance level for the drug will be 300 ppb.

This testing pilot program represents an opportunity for dairy producers to re-evaluate how the tetracycline class of drugs is used on the farm. Oxytetracycline injectable is labeled for the treatment of bacterial pneumonia and infectious bovine keratoconjunctivitis (pinkeye).

Many producers may use oxytetracycline in an extra-label indication for treatment of mastitis, metritis, or topically for the treatment of digital dermatitis (hairy heel warts). Under the direction of your veterinarian, extra-label drug use is legal as long as established withdrawals periods are adjusted when necessary.

Many producers, veterinarians, and hoof trimmers use the tetracycline class of drugs to wrap feet affected by digital dermatitis. This represents a risk of milk residue under the upcoming tetracycline screening pilot program.  Wrapping a foot with tetracycline (powder or injectable) and not withholding milk puts the producer at risk for a milk residue violation.

FARAD (Food Animal Drug Residue Avoidance Databank) recommends a 24-hour milk withhold when a cow’s foot is wrapped with tetracycline. While tetracycline foot wraps aren’t directly affected by the veterinary feed directive legislation, the powder tetracycline product switched from over-the-counter to prescription status on January 1, 2017.

Tetracycline powders are only available with a veterinary prescription and a valid veterinary/client/patient relationship.  Anyone applying tetracycline to a foot wrap should pay close attention to the amount of the drug they apply. More drug creates more risk for milk residue. Only a small amount should be applied directly to the lesion. Experts have suggested that a 2 gram dose is the maximum that should be applied to a wrap.

Small herds more vulnerable

Smaller herds need to be even more diligent in monitoring and obeying milk withhold guidelines due to the lack of dilution factor. While larger herds may be at less risk, they should still obey the withhold guidelines on all tetracycline products to maintain the integrity of the milk they sell. Ultimately, the dairy industry can’t justify improper drug withholds based simply on dilution.

This program should also renew the producers’ commitment to lameness in general and digital dermatitis specifically. This is an excellent time to review footbath protocols and scrutinize heifer facilities. We know that it’s critical to prevent hairy heel warts prior to first calving. Often times, cleanliness is a critical step in preventing digital dermatitis in heifer facilities.

While producers may view this new testing protocol as additional level of regulation, consider it another step in improving the quality and safety of the product that the dairy industry has to offer. Antibiotic use needs to be transparent on our dairies.

This program is another way for the industry to open the blinds and let the public see what we are doing to care for cows and provide a safe product. As long as the tetracycline class of drugs are used properly, the dairy industry will have nothing to hide.


Using antibiotics responsibly, part 1

PARSIPPANY, N.J. — When we do need to use antibiotics, we know that we need to use them responsibly (in both animals and people) to help keep them effective and available for decades to come. What are some of the steps to help make this happen? In caring for cattle, responsible use of antibiotics involves many things and people, but there’s one person who should continue to be part of these decisions — a veterinarian.

Veterinarians strive to prescribe antibiotics in a responsible way.

“As veterinarians, we have an ethical responsibility to make sure that we preserve the efficacy of antibiotics for future generations and ensure continued access to certain classes of antibiotics in food animals,” said Robin Falkner, DVM, managing veterinarian at Zoetis. “We use our medical training when we prescribe these medicines to restore or maintain animal health and well-being, and we take the responsibility of using them very seriously.”

Veterinarians strive to prescribe antibiotics in a responsible way to not only help treat infections but also to help reduce the unintended risk of antimicrobial resistance. This includes helping producers:

  • Decrease the need to use antibiotics. Doing things to help keep animals from ever getting sick is our top priority, Dr. Falkner said. This means looking at disease management and making tweaks that can help prevent disease outbreaks.
  • Ensure antibiotics are used only when they are needed. Antibiotics are only effective against bacterial infection. Veterinarians help identify if a bacterial disease is present or likely to be present, and then can recommend the right antibiotic to help address the disease challenge. For instance, there are four key bacterial pathogens associated with bovine respiratory disease, and we can recommend an antibiotic that will be effective against these pathogens, Dr. Falkner said.
  • Reduce the need for additional antibiotic treatments. Animals sometimes get sick, so when we do need to treat these animals, our priority becomes getting the highest treatment success, Dr. Falkner said. There are different classes of antibiotics that work in different ways. For example, a triamilide macrolide, such as DRAXXIN®(tulathromycin) Injectable Solution, works by interfering with protein synthesis in target pathogens, and a cephalosporin, such as EXCEDE® (ceftiofur crystalline free acid) Sterile Suspension, kills bacteria by destroying cell walls. If you have the right antibiotic that works the first time, you can use fewer antibiotics and have fewer animals exposed to multiple classes of antibiotics.
  • Avoid antibiotic residues in meat. Proper administration and following label instructions are important to ensure product efficacy and safety. This means reviewing treatment protocols with your veterinarian about the correct dose, route of administration and adhering to proper withdrawal times.

See the results of a good relationship.

“What I find is, when the veterinarian understands what’s important to the producer in the long-term, the veterinarian can make recommendations beyond just treating the immediate animal that’s sick,” Dr. Falkner said. “It takes effort, and the intent of both parties, to develop that type of relationship and see the results that this relationship can bring.”

For Brenda Paul, owner at Timberlawn Farm in Paris, Kentucky, it means she can keep making improvements. Having a veterinarian’s input enhances animal health decisions that can help maintain the responsible use of antibiotics.

“An outside opinion is a very helpful thing to have,” Paul said.  “We’re constantly evaluating what’s working, what’s not working and what changes we need to make.”

Her veterinarian helps in evaluating data to see if they’re heading in the right direction, if there’s a treatment need, or if they need a change in the protocol.

“We’ve been working together on developing this program over all the years we’ve been in the business,” Paul said. “And that will continue for many years.”

Next up: Did you know that the effectiveness of an antibiotic also plays a role in responsible use? Part 2 of this series will explore the relationship, so stay tuned. In the meantime, keep working with a veterinarian on the responsible use of antibiotics and find more information at

IMPORTANT SAFETY INFORMATION FOR DRAXXIN: DRAXXIN has a pre-slaughter withdrawal time of 18 days in cattle. Do not use in female dairy cattle 20 months of age or older. Do not use in animals known to be hypersensitive to the product. See full Prescribing Information.

IMPORTANT SAFETY INFORMATION FOR EXCEDE: People with known hypersensitivity to penicillin or cephalosporins should avoid exposure to EXCEDE. EXCEDE is contraindicated in animals with known allergy to ceftiofur or to the ß-lactam group (penicillins and cephalosporins) of antimicrobials. Inadvertent intra-arterial injection is possible and fatal. Do not use in calves to be processed for veal. Pre-slaughter withdrawal time is 13 days following the last dose. See full Prescribing Information.


– See more at: