Introduction
Long a staple in poultry and swine production, biosecurity has seen only limited adoption in milk production.  But the same factors that drove acceptance in the other livestock industries now affect dairying. . . expanding farms, intensified management, higher capitalization, increased reliance on purchased replacements, and less margin for risk. Your dairy clients are growing amenable to a proactive approach to dairy herd medicine -- a HerdSecure focus that by necessity involves the practitioner.

Pfizer Animal Health, maker of CattleMaster, Bovi-Shield, UltraChoice, 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 in the future.

Focus: HerdSecure™ Biosecurity Strategies
Ideally, dairy clients would in most cases prefer to expand their milk string by either raising all their replacements or by buying weaned heifers that can be quarantined with relative ease. But in the practical rush to expand and fill the milk string, about one in five dairies introduce cows already in lactation, according to USDA -- only 5 percent of which go into any kind of quarantine. That situation demonstrates that keeping disease agents off the farm in only one prong of the three-pronged approach that comprises a biosecurity protocol. When prevention of disease can’t be assured, the practitioner can nevertheless prevent infectious disease by using vaccination to increase immunity, as well as by setting up monitoring, containment and eradication programs to control its spread inside the herd. 

Suggest these steps for your clients to use in their milk-herd biosecurity program.

• If animals can’t be quarantined and tested before entering the lactating herd, only bring in animals from herds in which the health status is known.

• Bring in animals only from herds with a known effective vaccination program -- preferably one that closely matches the client’s own. 

• Advise clients to limit purchase of cows from unknown sources or animals that have been mixed with other animals. 

• Offer to review the source herd production records for potential problem areas such as high somatic cell count. This becomes especially critical during herd expansions, when the scramble to fill the string may tempt producers to short-cut one link in the biosecurity.  

• Promote a preventive mastitis-control program that controls the spread of contagious mastitis by using proper milking hygiene and culturing suspect cows. 

• Suggest maintaining a fresh-cow herd separate from the hospital pen. Newly-fresh cows under stress are under increased risk of developing disease after exposure. 

• Vaccinate. If a definite and provable vaccination record isn’t available on new purchases, animals should be treated as unvaccinated. Whenever possible cattle should be vaccinated before arrival with the last dose in a vaccination regimen administered at least a week before shipment. The minimum should include BVD, IBR, BRSV, 5-way Leptospirosis, Campylobacter (if using aged clean-up bulls). Others to consider include Clostridia, Pasteurella haemolytica, Haemophilus somnus, scours vaccines and E. coli mastitis vaccines. Help ensure that all annual boosters are given regularly and on schedule.

• Advise test-and-cull strategies. Testing and then separating animals into pens accordingly can be a valuable strategy for BLV and PI BVD, in particular. Doing so helps raise disease-free replacement heifers.
• Advise use of sterile, single-use disposable needles for all injections.
• Suggest protocols to rinse and disinfect instruments used for tagging, castrating, tattooing, removing teats and dehorning.
• Consider using bloodless dehorning options, such as an electric tools or caustic paste.
• Suggest tagging, dehorning and teat removal while calves are still housed individually.
• For calves from positive dams, prevent contact with other animals until they have been tested.
• Use separate equipment for feed and manure handling.
• Make sure employees scrub and disinfect boots when moving from one production area to another. 

Focus: Johne's Risks
Michigan State researchers conducted a cross-sectional study in 1996 to identify risk factors for herd-level M. paratuberculosis infection. Data collected from 121 herds identified five risk factors significantly associated with infection status:

• History of Johne’s on the farm within the past three years.

• Using an exercise lot. Because cattle face much higher density and more manure in “stomp lots” than they do on true pasture, exercise lots increased risk of Johne’s by three times.

• Washing udders. Udder washing before parturition increased the risk of herd infection.  Washing udders indicates excessive fecal contamination, the authors suggested, and moistening dried feces in fact may actually facilitate infection of neonatal calves before dam removal.

• Not cleaning calf housing. Cleaning calf hutches and pens risk infection risk by three-fold.

• Not liming pasture. Lime application reduced infection risk by 10 times, possibly by limiting ability of M. paratuberculosis to compete for available soil iron.

Source: Johnson-Ifearulundu, U.J. & J.B. Kaneene, AJVR 60(5):589-596; 1999.

Focus: BVD Risk Assessment
The confusion surrounding the epidemiology of BVD leaves many dairy producers confused about effective control. That confusion often shows up in these actual vaccination mistakes that end up increasing their risk. Assess your clients’ practices for these risky practices: 

• They don’t vaccinate for BVD.
• They vaccinate, but don’t know whether the vaccine contains BVD. 
• They faithfully vaccinate cows once-even twice-per year with killed vaccine, but they never initially give a primary vaccination followed by la booster two weeks later, per label directions. 
• They initially vaccinate calves at six months of age but never re-vaccinate before they enter the breeding herd. 
• They fail to ensure that purchased cattle or boarders have been given a primary series before including them in the herd’s vaccination program. 
• They refuse to vaccinate without laboratory confirmation of infection. 
• They neglect vaccinating bulls.
• They leave a few cows unvaccinated -- typically dry cows, planned culls or heifers. 
• They don’t ensure that calves receive a full gallon of colostrum from immune cows within 12 hours of birth.

Source: Alves D., CEPTOR, Dec. 1994

• Clients know and routinely meet milk quality standards.
• Production per cow consistently improves with each lactation.
• Cattle attend shows, use community pastures or share fencelines with neighbors, or go to performance centers.
• Clients purchase, borrow, or use loaner bulls.
• Animals only come from a Johne’s-certified farm.
• Purchases are limited to open heifers.
• Clients collect DHIA somatic-cell counts from the seller’s herd.
• Clients faithfully booster against lepto, IBR and BVD. All incoming animals are vaccinated for IBR, BVD, P13, BRSV and lepto before arrival.
• Clients actively test and cull PI BVD carriers.
• Clients test for BLV and Johne’s infection.
• Clients understand the importance of limiting spread by discarding needles and sleeves between animals.
• Cows are blood tested for Salmonella dublin annually. Carriers are culled. 
• Purchased feed is tested for Salmonella annually, or purchased from certified mills.
• Access to feed by birds, rodents, cats and strays is controlled on the dairy

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 CattleMaster®, Bovi-Shield™, UltraChoice®, and ScourGuard 3™ (K)/C please call 1.800.829.5528.

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