Thursday, November 13, 2014

A Tale of Grass Tetany


                   

                    
                        Everyone should have a hero.  Mine is James Herriot of the All Creatures Great and Small book and television series.  If you’ve ever thought of being a veterinarian, you probably read these books or watched the shows; it is practically mandatory.  I gained a great deal of knowledge from them.  Now I don’t want to say I learned more about being a veterinarian from James than I learned in college, but it's probably pretty close, and I strive to be like him- the hero in almost every story.  I’m afraid, though, I may have turned out more like Tristan, James’ partner’s not-so-bright, trouble-making, “goof off,” younger brother.  Most of my co-workers would probably agree with that.

                        Life is full of stories.  Some end happily; some do not.  That is part of the adventure. Veterinarians’ lives are like that.  My other columns have been more of the fact-filled, “do this, do that” format.  This time I wanted to try something different.  Here is my attempt at an educational, and true, “James Herriot” story.

                        It was a perfect October day.  The air was clear and crisp, and the trees were in their autumn glory.  My patient was a “down” Angus cow at the far end of the pasture just in front of a woods.  From afar, the cow appeared to be dead, but as my truck bounded across the grass toward her, I could see that she was breathing.   The closer I got, the more agitated she became; she was now paddling her legs in wild convulsions.  When I got out of the truck and approached her, she threw her head at me in an aggressive manner.

                        What I have just described are the classic signs and presentation of a cow suffering from hypomagnesemia or “grass tetany.”  This is a metabolic condition that arises from low blood magnesium levels.  “Grass tetany” is commonly seen in cows, and sometimes in sheep, that are grazing lush grass pastures, usually in the spring or the fall of the year.  The rapid growth of the grass along with cool weather conditions results in decreased uptake of magnesium into the plants, making the plants deficient in this nutrient.

                        My assistant for this call was an extremely thin and elderly man who lived in an old house at one end of the pasture.  The owner of the farm had told me on a previous visit that this old man was deaf and could not speak.  Nevertheless, he proved to be a very capable helper.  I placed a nose lead, a tong-like device, in the cow’s nose to keep her head still, and my assistant held the rope to which it was attached.  I then administered a bottle of a calcium/magnesium solution intravenously, being careful not to give it too rapidly as this could kill the cow.  My friend did a good job of keeping just the right amount of tension on the rope, thus preventing the cow from thrashing about.  I would ask him to do things, and he seemed to understand, but I’m sorry to say that I couldn’t understand any of the sounds he would make in response.

                        Following the intravenous bottle, I gave the cow a second bottle of the same solution under the skin on the side of her ribcage.  With our treatment completed, my assistant gently removed the lead from the nose, then neatly wound the rope around the tongs and handed them to me.  I reached out to take them, pinching his fingers between the metal pieces in the process.  It was at this time that our communication problem ceased.  “Ow…you got my finger!” was spoken as clearly as I had ever heard anyone speak.  I apologized profusely and thanked him very much for his help.

                        The occurrence of grass tetany can be prevented by increasing the consumption of magnesium during the critical pasture seasons.  The recommendation is two ounces per head per day for cattle and one-third ounce per head per day for sheep, either incorporated into the grain mix or in molasses-containing blocks.

                        A few minutes after our treatment, the cow gingerly arose and headed into the woods with her calf.  After making certain my new friend’s finger wasn’t badly damaged, I thanked him again and was on my way.

Author:  Dr. John Jones
Image courtesy of Mister GC at FreeDigitalPhotos.net

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