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Newsletter of Penn Dutch Cow Care August 2005

Hi Folks,

The topic for the regular installment of this month's Moo News is Heat Stroke. Although we ended July "in the green" regarding crops, we really went through an intensely hot and humid time which dramatically impacted the cows on many operations. The hot and hazy weather can definitely happen again in August and into early September. So I'd like to discuss heat stroke a bit.

What is heat stroke? The condition involves the increase of body temperature to an extreme point. Unreasonably high temperatures, in an animal which seemed completely healthy a few hours previously, would be above 106°F. Therefore, on a very hot and humid summer day, it would be wise - indeed, necessary - to check an animal that is down or otherwise depressed to see what her temperature is. Most times, a "typical" heat stroke will be 106-108°F. If the temperature is much above 108°, like 109-110°, the cow or horse will not recover since brain damage is occurring. A heat-stressed cow or horse (compared to a more serious heat stroke animal) will shows signs of open mouth panting and quickened breathing but can still stand while a heat stroke cow will usually be down and not rise. A heat stroke cow usually has shallow, rapid respirations and usually appears depressed or even comatose - much like a milk fever cow. The pupils of the eyes will be dilated. The animal will feel hot to the touch. She may or may not be sweating. If you do a rectal on her, she will feel like she is burning up internally (which she basically is). Heat stroke animals tend to not drink water, while a heat-stressed animal will. Basically the difference between a heat-stressed cow and a heat stroke cow is that the heat stroke cow will have lost control of normal functions (cannot stand, won't drink, non-responsive or comatose). Unfortunately, milk fever cows and coliform mastitis cows show these signs as well -so you must check the quarters for watery secretions and take into account if she is just fresh and an older cow (suspicious for milk fever/low calcium). To add to the possible confusion, it entirely possible that a milk fever cow or a coliform cow also has heat stroke. While milk fever and coliform mastitis are treated with fluids, heat stroke and heat-stress animals are primarily treated with hosing down the animal with cold water for a continuous 20-30 minutes, head to tail with attention paid to hosing the back of the head since this is where the cow's temperature regulation center is. Heat-stressed cows will often freely stand still to be hosed down. IV fluids are definitely indicated for heat stroke but are secondary to using a hose. If a hose is not available, quickly move the cow on a 4 x 8 plywood board or a tractor bucket to an area where a hose is. Although the intentions are good, a sponge bath or lugging out a few buckets of cold water and dumping them over the cow will be ineffective. If a cow is deemed to have both milk fever and heat stroke, treat IV for the milk fever (do NOT put liquids into an animal which is weak and down - never!!). When an overly hot animal is hosed down for a good 20-30 minutes, the temperature will often drop to about 103°, (just above normal) which is an excellent sign that your hydrotherapy treatment worked.

How do we prevent heat stroke and heat stress? Pay close attention to your entire herd during really steamy days, but especially the fresh cows and the springing animals as they are much more stressed in general. Reduce feeding of high carbohydrate/starchy rations (i.e. grains) during hot spells since they tend to "heat up" the rumen generally and replace grains with haylage/grass silage, hay and evening grazing. Tunnel ventilation is excellent and is essentially "bovine air-conditioning" . For draft horses, be very careful of excessively hot and humid afternoons, especially of any horses that have not been up to par for whatever reason. Horses will work themselves to heat stroke/exhaustion while mules will stop before overheating. Ironically, the farms which actually make use of pasture need to keep in mind what folks driving by may see in relation to a down cow. The area large animal protection officer has gotten in touch with me to treat animals that are seen obviously ailing by people driving by. As long as the animal receives prompt veterinary attention, the officer will not levy a fine. Preventing down cows in a field on very hot days is worth considering bringing in the cows at noon to be cooled by fans (of any sort) and/or grazing only during the evenings during a really hot stretch. Lastly, hosing down hot animals is always a good thing to do.

For Bovinity Health, information on functional alternatives to antibiotics see:

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