Bringing heifers back to the dairy
Wednesday, May 05, 2010
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Posted by: Dairy Calf & Heifer Association
By Roy Williams, 2010 Leadership Class member
For many dairy operations, sending young calves to a custom grower until they are ready to calve is routine procedure. Heifers returning to the dairy after being at a heifer ranch, and purchased heifers, can present health challenges. In this article, we'll briefly review some of the issues that you may face with these heifers.
1. Biosecurity
There is always a risk that new variations of common diseases, parasites (protozoa and worms), or highly infectious diseases (Johnes, BVD, BLV)(1) will enter your dairy along with these heifers. While the risk is low, there is always the possibility of a major and serious disease outbreak. More likely, the flow of animals into the dairy imports just enough pathogens and parasites to increase the morbidity and mortality rates in the milking herd by a few percent.
There are some things you can do to minimize the risks.
a. Quarantine arriving cattle for two weeks; keep as much physical distance as possible between arriving cattle and the rest of the dairy.
b. Sanitize equipment moving from the quarantine area to rest of the dairy.
c. Monitor arriving cattle closely for two weeks.
d. Immediately isolate sick animals away from other animals.
e. Keep arriving groups of animals separated from each other.
2. Pneumonia (shipping fever)
Shipping fever(2) is a well-known problem in feeder cattle, due to stress in combination with multiple opportunistic pathogens. Shipping fever causes 64% of deaths in feedlots in Colorado. Shipping puts extreme environmental stress on the animals; livestock trailers can be hot, cold, drafty, dusty, rainy or damp, very crowded, and often very unsanitary.
Your first defense against shipping fever is an appropriate vaccination program, so be sure your heifers are properly vaccinated before they are shipped. There are at least six respiratory disease pathogens(2) for which vaccines are available. Vaccinations do not "work" immediately - usually two weeks or more are required for the immune system to respond completely to vaccine, and many vaccines require two doses, so be sure vaccines are given far enough in advance of shipping to allow for effective protection.
Respiratory bovine coronaviruses (RBCV) is an "emerging disease," first isolated in 1993. One study found that RBCV was significant factor in shipping fever(3). Ask your veterinarian for advice on how to combat RBCV in your herd.
Some field research suggests that some feeding programs can reduce the incidence of shipping fever, but this is too complex a topic to discuss here(4) (talk to your nutritionist).
References
1. Brouk MJ. Contract Growing Dairy Heifers: The Good, The Bad, and The Ugly. s.l.: Dept. of Animal Sciences and Industry, Kansas State University.
2. Bagley CV. Bovine Respiratory Disease. Utah State University. s.l.: Extension Beef Cattle Resource Committee. publication number BCH-3505.
3 Storz J, et al. Coronavirus and Pasteurella Infections in Bovine Shipping Fever Pheumonia and Evans' Criterial for Causation. 9, s.l.: American Society for Microbiology. Journal of Clinical Microbiology. Sept. 2000; 38: 3291-98.
4. Galyean ML, Duff GC. Recent advances in management of highly stressed, newly received feedlot cattle. s.l.: American Society of Animal Science. Journal of Animal Science. 2007; 85: 823-840.
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