SHINNERY OAK POISONING OF RANGE CATTLE

SHINNERY OAK POISONING OF RANGE CATTLE It has been a long time since I wrote an article on this issue, in fact it was on a 51/2 floppy disk so I had to start from scratch. This is a recurring problem on the east side of Eddy County and other sandy range sites in the southwest and west Texas. In drought periods, particularly in the spring and fall cattle and other classes of livestock will consume oak leaves, buds, catkins (flowers) twigs, and in the fall acorns. They don’t have to consume very much to reduce their performance and depending on the year to cause death. Some years are not as bad as other, my personnel observations have been that when plants are under stress, either by drought, cold, or growing too fast (when it rains) the negative effects of oak browsing are increased. The chemicals responsible are called tannins. Tannins can be either condensed or hydrolysable. Condensed tannins are broken down only in strong acids, like that of the digestive system, hydrolysable are easily degraded and can be absorbed into the blood stream. As the chemical classification suggest the presence of water makes this occur. From personal experience we often find cattle that are suffering toxic injection near water. Since I took poisonous range plants and toxicology in college there has been a significant amount of research on how these toxic chemical affect the digestive track of livestock, by the USDA poison plant lab. Texas A&M, Texas Tech, and NMSU. If you are interested in the specifics, I will be glad to give you the citations. As Producers we are generally interested in symptoms, and prevention/treatment. Long before the producer will see the toxic effects on their livestock the livestock performance has been reduced. In the spring the catkins can contain 18-20% tannins while the leaves are only 2-6%. It takes a much smaller percentage of the diet if catkins are present and being consumed. Several days after consuming oak the producer may notice dark, dry feces and mucus and blood, reduced appetite or not ranging out, and constipation. A few days later bloody diarrhea, frequent pungent urination and animals staying close to water. The final stages the hair coat will be rough, muzzle dry, urine reddish and often watery swelling on the underbelly. On steers and bull misdiagnosed as water belly or urinary calculi. Symptoms usually last 3-10 days, the animal will recover or die. When eating catkins again personal observation symptoms appear much faster as little as one day and toxicity progress much faster as short as 3-5 days they are dead. Prevention, poisoning occurs when oak is the main source of forage, drought, when spring green up is delayed or does not occur. The first 30 days after oak leaves emerge are the most critical, tannins are forming and are concentrated as well as catkins. If oak have been chained, dozed or damaged by equipment, and or frost that also increased tannin production. I could not find any information about toxicity following herbicide treatment. Nursing calves can receive the tannin from the mother milk as well as consuming it directly. The best prevention is avoidance if possible, of course. Back in 1966 NMSU and Texas A & M suggested supplementing calcium hydroxide at 10% of total intake as a preventative measure, and that still works. Calcium hydroxide seem to prohibit tannin absorption by forming insoluble complexes which are not digested. Manny producer are able to supply high-energy and high-protein feeds. If there is some green forage this will prevent use of the oak. NMSU recommendation is a supplement of 54% cottonseed meal, 30% alfalfa, 10% hydrated lime and 6% fat, for a one-ton mix that is 1,040 lb. Cottonseed meal, 600 lb. alfalfa, 200 lb. hydrated lime and 160 lb. vegetable oil. Start feeding preferably two weeks before you anticipate leaf emergence of oak and continue to feed this for the first 30 days’ oak is in leaf. Treatment of livestock affected is first remove them from grazing oaks, give them a laxative to flush the digestive track of undigested oak forage then feed with a quality alfalfa hay or similar forage until better. Roughly 85% of all cattle that demonstrate symptoms die. Of the 15% that survive there is no research as to why. Subscribe to Eddy County Ag news at: http://nmsueddyag.blogspot.com/ Eddy County Extension Service, New Mexico State University is an equal opportunity/affirmative action employer and educator. All programs are available to everyone regardless of race, color, religion, sex, age, handicap, or national origin. New Mexico State University, U.S. Department of Agriculture, and the Eddy County Government Cooperating.