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Discussion in 'Cattle' started by Tango, Sep 22, 2006.
Can someone tell me the symptoms and causes? Is there a bacteria involved? Thanks in advance.
Shipping fever pneumonia is a respiratory disease of cattle of multifactorial etiology with Mannheimia haemolytica and, less commonly, Pasteurella multocida or Histophilus somni (Histophilosis : Introduction), being the important infectious agents involved. Shipping fever pneumonia is associated with the assembly into feedlots of large groups of calves from diverse geographic, nutritional, and genetic backgrounds. Disease is typically seen in feeder calves 7-10 days after assembly in a feedlot. Morbidity can approach 35%; mortality is 5-10%.
The pathogenesis of shipping fever pneumonia involves stress factors, with or without viral infection, interacting to suppress host defense mechanisms, which allows the proliferation of commensal bacteria in the upper respiratory tract. Subsequently, these bacteria colonize the lower respiratory tract and cause a bronchopneumonia with a cranioventral distribution in the lung. Multiple stress factors are believed to contribute to the suppression of host defense mechanisms. Transportation over long distances serves as a stressor; it may be associated with exhaustion, starvation, dehydration, chilling and overheating depending on weather conditions, and exposure to vehicle exhaust fumes. Additional stressors include passage through auction markets; commingling, processing, and surgical procedures on arrival at the feedlot; dusty environmental conditions; and nutritional stress associated with a change to high-energy rations in the feedlot.
Thank you for the thorough explanation Dagwood. Is this the same "shipping fever" that I've commonly heard on these boards when transporting a new animal from farm to farm or from auction to farm? I've never come across it but even my neighbors talk about a "fever" when a new cow is transported form auction. Yesterday my new auction bottle calf had a fever in the afternoon and refused her bottle. Since she had a fever I gave her a shot of penicillin and tubed her with formula to keep her strength up. This morning she was fine and took her bottle willingly but this afternoon she refused again and was lethargic - no fever but I followed through with the penicillin.
Dagwood quoted the Merck Manual regarding shipping fever. It, and enzootic pneumonia are two parts of the bovine respiratory disease complex. They share similarities in infectious agents, etc. Enzootic pneumonia applies more to calves less than 6 months of age, while shipping fever is in older calves of feedlot age.
Of course, for any infectious disease to occur, you need an inusufficient immune response, and infectious agents. In shipping fever, the broken immune system is mainly caused by fear (releasing cortisol, an immune suppressant, from the adrenal gland) during weaning, crowding, shipping, running them through a chute to give shots, etc. Putting them in a new pen, with new feeders, watering systems, new kinds of feed, etc. Having to work out new pecking orders. A lot to handle all at once for a young animal, a lot of things we donât think about unless we put ourselves in their frame of mind.
Some try to spread out these stresses by separating the events, e.g. weaning well before shipping to feedlot, starting them on new feed, getting used to feed bunks, etc.
As my brother who worked in a feedlot said, âYouâre not a real cattleman until youâve got a dead pile.â I once read a vet say we shouldnât ask why some feedlot cattle die from the stress and disease, but we should ask why any survive. One more reason to raise your own and give them a better life.
In enzootic pneumonia of young calves, the disease can be the same as in shipping fever, but the broken immune system often results because they received too little antibodies from mom (didnât get sufficient or the right colostrum). This is called failure of passive transfer of antibodies. (Passive means they were given to you and will go away, active means you make your own antibodies continuously.)
Ideally you would vaccinate the cow who actively makes antibodies she dumps in the colostrum for the calf. Hopefully the vaccines are against the bugs the calf will run into when in a sale barn, or being mixed in a group.
Without the antibodies, treatment with antibiotics has much less chance of success. One problem with calves from sales are that you donât know how much colostrum they got, or whether their moms were vaccinated.
Anyway, that's my interpretation of what you can read here from the Merck Manual. There are more factors to consider, like quality of milk replacer, etc.
Thia is something I found that made it easy to understand.
Shipping fever, as the disease is more commonly known, affects calves about 1 week after they are transported from the cow and calf operations where they were born to the feedlots where they finish their growth. It is the biggest killer of beef cattle in feedlots.
The culprits are three different bacteria that are usually harmless--Pasteurella haemolytica, P. multocida, and Haemophilus somnus. Normally present in cows' nasal cavities, these bacteria usually don't cause problems--until the young animals are readied for shipment. Then the stress of handling and shipping takes a toll on their immune systems, and the bacteria move into their lungs and cause pneumonia.
Thank you for the further explanations DJ. It remains to be seen whether what my calf has is pneumonia. Her fever is down again this morning and she appears more alert. No doubt that all the stuff cattle people do is stressful, they completely strip the calf of any psychological and emotional need for their own purposes. That is the main reason I raise calves.