Introduction
Dairy-herd biosecurity is turning out to be a best-management practice not just for dairies, but for clinics, as well. By adopting a proactive approach to dairy herd medicine, biosecurity by necessity involves the practitioner in almost all elements of profitable dairying, from conception to culling. Producers want the best plan that will: 1) keep disease out of a herd, 2) contain and control disease once it enters the herd, and 3) can be easily implemented. This requires the assistance of a knowledgeable dairy practitioner. Hence, regular veterinary involvement becomes the norm, not the exception. 

Pfizer Animal Health, maker of Bovi-Shield, CattleMaster, One-Shot, Ultrabac, ScourGuard 3 (K)/C, and other dairy animal health products, brings you this ongoing HerdSecure series on Biosecurity to help today’s practitioner adopt preventive biosecurity strategies for their progressive dairy operations. Next up: Biosecurity for the lactating herd.

Focus: HerdSecure™ Biosecurity Strategies
Maintaining profitable biosecurity in regard to post-weaned heifers requires vigilance on two fronts. First, one of the most stressful times for the dairy animal is when farm-raised heifers are weaned and then transferred into group housing, where social stress, environment, and nutrition all challenge the animal and result in a decline in immunity. It’s a time when respiratory diseases often break, and a time when you can suggest management changes that can ease the transition. Second, off-farm-raised heifers often introduce biosecurity risks to the existing herd because they’re coming back from a custom raiser or they’re being purchased as replacements.

Here are some foundations for your clients to use in their replacement heifer biosecurity controls. 

• Help evaluate the economic considerations of purchasing open or bred heifers in lieu of close-up replacements. Although a cash-flow squeeze or lender reluctance often force producers to purchase replacements ready to calve, heifers that are several months out offer biosecurity benefits. They give the dairy producer better control over the vaccination program, as will as time and flexibility to quarantine and test. 
• Help evaluate replacement heifer sources. Increasing emphasis on biosecurity has convinced many dairy producers to avoid commingling purchases from heifer lots and sale barns. Instead, they have the desire to go directly to tiestall barns and deal with cow people. However, they may not have the means of finding enough sources to draw from. Your wide-ranging contacts in the industry make you an ideal liaison. Plus, by offering to conduct consultations between you and the selling operation’s veterinarian, you can help present a better idea of the overall status of the herd being purchased from, as well coordinate vaccination programs.
• Help clients set up and follow rigid buying requirements as well as quarantine and test protocols. Because they’re not milking, heifers are relatively easy to quarantine.  Isolate purchased animals and animals returning from show or other farms in a designated quarantine area for at least a month. Quarantine should prevent heifers from sharing air space, food or water with the resident herd. It not only protects the herd from introducing disease, but protects the investment in the replacements by protecting them from organisms circulating in the home herd. Replacements should, at minimum, be tested for:
  • Brucela
  • Tuberculosis
  • BVD, including PI animals
• Optional tests include:
  • Johnes
  • Bovine leukosis
  • Mastitis cultures
  • Salmonella, as tests become available
• Help establish protocols for handling new arrivals:
  • Footbath makeup, placement and maintenance
  • Penning for isolation periods
  • Vaccination protocols and timing
• Help troubleshoot potential stressors. For hauling replacements, suggest tips to minimize stress by avoiding extremely hot or cold days, overcrowding animals and unclean trailers. For farm-raised heifers, get into the pens to help troubleshoot comfort problems. Evaluate fly control.  
• Control traffic. Advise farms to set up a separate location of haulers to pick up animals -- if possible, transport animals in farm-owned vehicles. Clean trucks between uses, and if someone else hauls the farm’s cattle, demand a sanitized truck. Suggest dairies limit visitor access to animal facilities, as well. All visitors should only be admitted by appointment. Signs forbidding admittance without permission should be posted. Offer disposable boots for use by visitors entering barns.
• Improve nutrition. Poor nutrition, particularly poor micro-mineral nutrition, will decrease immune response. Ensure that selenium, copper, iron, zinc and vitamins A and E are in adequate supply. Blood assays are usually necessary to get an accurate picture for the operation. It’s difficult to make meaningful decisions simply from the ration. And make sure that clients feeding animal proteins have confirmed they come from a mill which has been certified salmonella-free.
• Take any opportunity while clients are working heifers to conduct a visual examination.  Examine her udder for teat condition, quarter condition and mammary fluid.
• Help control people movement inside the farm. Dairies may call upon you to devise plans concerning the employees on the diary, including defining lines of responsibility for each employee.
• Be proactive in supporting replacement heifer biosecurity management.

Focus: Effective Vaccination
Effective vaccination is the final safeguard in a biosecurity program. Remind clients of the “three golden rules” for designing a herd vaccination program, says Pfizer’s managing cattle veterinarian Victor Cortese: First, prevent catastrophic death loss. Second, prevent reproductive losses. And third, prevent additional diseases which cause economic hardship. 

Even herds that raise their own replacement heifers can benefit from an effective, planned, strategic vaccination program for those animals. For open herds, once you help clients establish a vaccination program, you can then coordinate it with replacement sources. 

Vaccination of young stock is an important component for building a well-protected herd.   Even if calves are vaccinated early, it’s important to vaccinate at 4-6 months with Bovi-Shield when the immune system is more mature in order to prepare calves well in anticipation of the stress of weaning and group housing. 

Irrespective of the young calf vaccination program, at least one, and preferably two, modified-live 4-way viral vaccines should be given between 5-6 months, when the immune system is nearly fully mature, and prior to breeding. Disease exposure can occur prior to 8 months of age, so if producers wait until 12 months to vaccinate, they can be too late. 

Additionally a vaccination program should include vaccines against both leptospirosis and clostridial diseases. Vaccination for Leptospirosis is best given between 4 and 6 months and followed up with a booster in 4 weeks in an attempt to prevent the development of the hardjo carrier state that can result in prolonged shedding. Clostridial diseases tend to be sporadic but inevitably fatal, and so including a clostridial vaccine with booster into the pre-breeding program is a worthwhile investment of both dollars and time. 

Other available vaccines, such as Haemophilus should be included in the vaccination program based on the need of the particular operation. If the farm is using aged clean-up bulls, Campylobacter may be warranted as well. 

For purchased replacements without a definite vaccination history, including vaccine type and dates administered, clients should assume animals are unvaccinated and vaccinate them accordingly. Whenever it’s possible, purchased replacement heifers should be vaccinated before arrival with the final dose in a vaccination regimen administered at least seven days prior to shipment. Whenever possible, clients should do the vaccinations at the farm where the animals were purchased. If vaccination on arrival is the only option, it should be postponed until animals have been in the pen for at least 24 hours.

• Biosecurity plan begins with you?
• Consulted with the seller’s veterinarian?
• All animals permanently identified?
• Source herds/custom growers’ biosecurity, vaccination and testing programs known?
• Written, strategic vaccination plan drawn up for dairy?
• Ideal vaccination timing and type of vaccine identified?
• See that animals that die of unknown causes are posted?
• 30-day quarantine followed for all cattle, including post-shows and test stations?
• Quarantine prevents sharing air space with healthy animals, touching of cattle, sharing of feeders and waterers?
• All vaccination histories known on replacements?
• Avoiding mixed-origin cattle?
• Transporting animals in farm-owned, clean trailer?
• Providing a medicated foot bath?
• Limiting people’s access to pens?
• Posted keep-out signs?
• Providing clean boots and coveralls for visitors?
• All outgoing animals, including deads and downers, picked up at a site isolated from the herd area?
• Replacement heifers kept separate from milk herd for at least six months?
• Replacement heifers have their own separate source of fresh water?

For More Information
As a company devoted to the dairy industry, Pfizer can help you assist clients in protecting their dairy herds through sound biosecurity management practices and vaccination programs designed with their needs in mind. For reprints of this article, additional HerdSecure™ biosecurity management information and information on Pfizer Animal vaccines, like Bovi-Shield™, CattleMaster®, One-shot®, Ultrabac®, and ScourGuard 3™ (K)/C please call 1.800.829.5528.

Calf-Guard™ and ScourGuard™ are registered trademarks of Pfizer Inc. HerdSecure™ is a service mark of Pfizer Inc. 

This series is brought to you by Pfizer Animal Health. www.pfizer.com/ah