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Respiratory management trends, progress and next steps

Tom Shelton Published on 30 April 2013

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Bovine respiratory disease (BRD) is one of the most important management issues on dairy farms and calf ranches.

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It’s the most common disease in calves more than 30 days old and has long-term effects on the life of the animal.

To monitor how the industry is doing when it comes to managing BRD, we identified trends, progress and next steps by comparing the National Animal Health Monitoring System (NAHMS) “Dairy Heifer Raiser” survey in 2011 with our respiratory survey of 775,000 dairy calves in 2010.

The most notable respiratory heifer health trends found in both surveys include an increase in large heifer-raising operations, an increase in recorded health events and the continued emphasis on respiratory disease vaccination.

Mitigating biosecurity risks and testing for transmissible disease are other important trends to note. The overall challenge moving forward for the dairy industry is to increase production efficiencies while reducing the potential for disease transmission.

The survey results demonstrate the industry is advancing its respiratory management programs, but there’s always more progress to make in raising healthier dairy calves and heifers.

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Custom heifer-raising
According to NAHMS, raising more heifers at an off-site location is a practice that is increasing in the dairy industry. Not only does this free up space in dairy operations for lactating cows, it’s an effective way to focus on the health of individual animals at the calf facility.

Though custom heifer growers have been a part of the dairy industry since the 1990s, NAHMS notes that the majority of them are newly established, having been in business for less than 10 years. As movement and commingling of animals increases, so does the need for biosecurity planning and management.

Dairy heifer exports
Dairy heifer exports have increased during the past decade as a result of increased global demand for dairy products. Turkey, Mexico and Russia are the top three import countries for the U.S. Dairy producers exporting heifers need to consider both national and international biosecurity issues, as well as opportunities for future heifer production.

As part of identifying and mitigating biosecurity risks, testing for infectious diseases and attention to commingling will help ensure maximum respiratory health is maintained.

Colostrum management
Dairy producers recognize a healthy start for dairy calves starts with effective colostrum management.

One gallon of high-quality colostrum should be administered within the first two to three hours of birth. NAHMS’ measurement of adequate passive transfer on the quantity, quality and timing of colostrum administration is similar to our findings of 41 percent.

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Larger dairy heifer facilities (more than 1,000 heifers) were more diligent in testing for passive transfer.

Calf nutrition and housing
In addition to recognizing colostrum as an essential part of calf health, producers understand the need to provide fresh water, calf starter and adequate amounts of milk. Without ample nutrition and stress-free housing, dairy heifer production becomes inefficient.

It’s been noted that respiratory problems have been reduced under stressful situations by increasing the amount of milk fed to calves during critical time periods, such as extreme weather. The frequency also can be increased to three feedings per day.

Diagnostic testing
Determining the cause of dairy respiratory sickness continues to improve. Advances in diagnostic molecular testing, like polymerase chain reaction, go hand-in-hand with well-established necropsy procedures, as well as veterinarian and nutritionist input on rations, vaccination and health management.

Diagnostic testing minimizes the risk of disease being spread among heifers from different farms. Our survey found that 24 percent of dairies surveyed were testing for BVD and persistently infected (PI) neonates upon arrival. Thirty-seven percent of dairy heifer producers participating in the NAHMS survey tested for PIs.

NAHMS reported the overall mortality rates of pre-weaned, weaned and pregnant heifers at 4.2 percent, 1.6 percent and 0.2 percent, respectively.

Respiratory causes of death in dairy heifers were more than twice the digestive causes. That compares favorably to our survey results for combined dairy losses associated with respiratory causes.

Reported necropsies performed by NAHMS to determine cause of death was half of the dairies surveyed, with the majority being large facilities (more than 1,000 cows). Our survey results suggested a 57 percent rate with medium to large dairies using necropsies most frequently.

Heifer ID and record-keeping
Another key component to dairy respiratory health is heifer identification and record-keeping.

The radio frequency identification (RFID) tags associated with various software programs now allow for not only source and age (to facilitate export), but also can provide a health and performance history to better understand the effects of calf-raising procedures. This includes future milk production and reproductive efficiency.

By using RFID tags, keeping comprehensive health records will become a more essential tool for respiratory disease management.

More than 70 percent of operations recorded individual treatments administered to sick heifers and kept written growth rates and other information. Records of individual animals treated with antibiotics are especially important for avoiding residue and ensuring food safety.

As the industry gets better at recording health event data and subsequent milk production in heifers, we see a connection between the two. Combined with genetic testing, our window into the future performance of these animals increases.

Offsetting this benefit to some degree is the fact that this trend is exacerbated by ever-larger facilities with increased chance of transmission of pathogens and management bottlenecks.

Proactive vaccination treatment
Vaccination against infectious disease still remains central for the control and prevention of the numerous infectious diseases of young cattle.

Surveys indicate that the majority of dairy heifer-raising facilities vaccinate for respiratory diseases. The few abstainers were all from small dairies (less than 100 cows) where commingling may be less of a health factor.

Cow comfort and stockmanship
In addition to providing proactive vaccinations, one of the essential components of dairy heifer respiratory management is practicing good cow comfort and stockmanship.

Providing adequate food, water, nutrition and a clean environment is critical to the health and well-being of all dairy animals.

Future dairy heifer respiratory management
The goal of respiratory management is to raise heifers that can deliver the maximum genetic potential, remain free of endemic disease and meet all the export testing demands to support that growing market.

This will require updated nutritional and growth benchmarks, enhanced record-keeping, environmental hygiene, quality control testing for infectious diseases, housing management and cow comfort.

While managing respiratory disease continues to improve on dairy farms, these studies point out several additional opportunities to advance the respiratory health of our dairy calves and heifers. Taking even small steps to improve respiratory health can make a big difference during the life of an animal. PD

Dr. Shelton is a dairy technical services manager for Merck Animal Health. He lives in Utah and can be contacted by email or by calling (208) 867-3502.

Photo by PD staff.

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Tom Shelton
Dairy Technical Services Manager
Merck Animal Health

Respiratory health best management practices for replacements

• For calves and heifers raised off the dairy, identify biosecurity risks and develop a biosecurity plan.

• Feed 1 gallon of colostrum within two hours of birth and another gallon 12 to 15 hours later.

• Provide fresh water, calf starter and adequate amounts of milk.

• Monitor colostrum quantity, quality and timing of administration.

• During critical time periods, increase the amount and frequency of milk fed to calves.

• Incorporate timely use of necropsies, BVD testing and other diagnostics.

• Consider use of RFID tags for better animal identification and record-keeping.

• Work with your veterinarian to establish effective vaccination protocols.

• Practice low-stress handling and maximize cow comfort.

The NAHMS report can be found online.

A news release about the Merck Animal Health study can also be found online.

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