CALF_News_April_May_2019

22 CALF News • April | May 2019 • www.calfnews.net CALF ANIMAL HEALTH Chuteside Manner EXPLORING THE FRONTIER OF ANIMAL HEALTH Abomasal Impaction By Patti Wilson Contributing Editor S ome of the most frustrating issues we deal with in regard to livestock health are those that cannot simply be vacci- nated against. Many of these can be trig- gered by severe weather, where we have no control over the resulting problems. All we can do is prepare and watch the livestock closely. A good example is the buller steer, which has been previously covered in Chuteside ( June/July 2016). Like the buller, abomasal impaction is a completely environmental mishap. It is not brought about by any microbe or misstep in vaccinating protocol, it just happens. Consequently, we are left to deal with it ourselves; scientific experimentation cannot produce it in a lab and cannot prevent it. The only means of knowledge in treatment comes from real-world experience and, mostly, veterinarians with their boots in the field. What is it? Abomasal impaction is, basically, the impaction of dry feedstuffs in the abomasum. It is commonly associ- ated with cold weather, therefore most research found on the subject comes from Canadian Universities. Thanks and recognition go to R.A. Ashcroft, Depart- ment of Veterinary Clinical Studies, Western College of Veterinary Medicine, University of Saskatchewan, and Dr. Ron Clarke, in a March 2018 article written for the Canadian Cattlemen . The Merck Veterinary Manual is also an excellent source of information. Information coming from Canada was obtained by necropsy reports on cattle in the Saskatoon area. It was compiled from 1975 to 1982 on bovines diag- nosed with abomasal impactions. Although cold can be a factor, impac- tion happens even in temperate weather. So, what are the factors triggering a possible problem? First, temperatures below 14 degrees Fahrenheit can trigger beef cows and stocker calves to plug up. The reason, as the thermometer drops, cattle eat more to stay warm. Cows and stocker calves eat mostly lower quality, dry forages, slowing digestion further. It is estimated that energy requirements for cattle increase 10 percent for every 10-degree drop in effective temperature below their comfort zone. Many winter forages increase the risk of impaction as quality decreases. There- fore, the feeding of straw, for example, needs to be supplemented with alfalfa or higher-protein feedstuffs to help digestive flow. This is a critical factor; Canadian winters are so abysmal that up to 15 percent of cows can be affected during an outbreak. Interestingly, cattle in finishing lots are very seldom affected by impaction because of high-feed quality and grain intake. Beef cattle are more prone to impaction than dairy, and European breeds more likely than British. Preg- nancy status has no effect either way. Cattle, particularly cows on winter stalks or range, have less trouble when they carry a body condition score (BCS) of 3 or higher. They can simply stand more weather. Access to shelter is help- ful; this means windbreaks in nearly all cases. Fresh water needs to be available at all times – one of the most impor- tant and difficult factors to manage for livestock in extremely cold, prolonged weather. Sandy soil seems particularly egregious, especially when cattle are grazing turnips as a cover crop or winter feed source. Sand causes serious gut problems. Canadian winters start in October and are brutal. In the United States, where cattle feeding is a larger business, abomasal impaction can occur more frequently in backgrounding and stocker operations. The fall and winter feeding of dry, chopped forages is conducive to impaction. Abomasal impaction can strike any age and any class of cattle. Although the specific trigger is unknown, some factors can include cold weather, low-quality forage, increased feed consumption and inadequate access to water.