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This issue of The Ranch Hand contains several articles dealing with toxicity problems and newly harvested feeds. This is a particularly pertinent topic at this time of year. Also take note of the schedule for the Dickinson Research Extension Center Research Roundup coming up October 3.
Greg Lardy Feeding Newly Harvested BarleyDr. Chip Poland, Area Livestock Specialist Dickinson Research Extension Center Since coming to North Dakota, I have received several inquires regarding the utilization of newly harvested grains as livestock feed. After investigating this topic for two years, I was directed to the following web information maintained by Ag Canada in Alberta . "Newly harvested barley, whether dry or high moisture, should always be stored about 4 to 6 weeks before being fed to any class of livestock. This storage period is often called a sweat period. Serious losses in cattle, pigs, and poultry have been attributed to feeding newly harvested grain. There is some evidence that certain compounds in the newly harvested grain may be toxic to livestock. In storage, such compounds undergo chemical changes that make them non-toxic. Processing newly harvested barley for feed apparently does not eliminate the problem of toxicity. A rest or sweat period is necessary." Simple enough and straightforward, but contrary to other information/conversations I gathered in my fact-finding mission. Most everyone has heard this caution in the use of newly harvested feed grains, but I have had trouble finding someone who has actually experienced a problem. The recommendation seems to emerge from anecdotes or testimonials where a producer encountered a problem when the base feed in a ration was abruptly switched from old-crop to new-crop grain. In most cases, conclusive evidence suggesting the source of the problem is lacking and other management-related explanations are typically available. Dr. Bob Harrold, NDSU nutritionist, and others have tried to systematically study this problem. However, they were unsuccessful in creating a problem by feeding new-crop barley. To my knowledge, there are no accounts of anyone being able to produce feeding problems that could be attributed specifically to some deleterious or toxic component in newly harvested grains. This is not to suggest that grains do not go through a transitional state early in the storage period. A "sweating" period seems to occur due to continued cellular respiration in the grain resulting in water formation and translocation to the seed coat. This moisture or "sweat" must be removed with proper ventilation to maintain a proper grain storage environment. This sweating process should last less than a week, and certainly does not continue for 4-6 weeks. Some seeds apparently do undergo physiological changes after harvest (i.e. during storage). Germination potential seems to be the most obvious indicator that seeds are not physiologically quiescent during storage. Many types of seeds experience higher germination potentials as time after harvest is increased. This suggests that some type of inhibitor may be affecting early germination potential and the effect of this inhibitor is diminished with time. The possibility of a toxic component that exists in newly harvested grain which undergoes some chemical change during short-term storage is conceivable. However, unless the problem can be reliably induced experimentally, it is difficult to explain the basis for the original recommendation. There are individuals who have fed newly harvested grains without any adverse incidents. Rick Corbett (the individual who maintains the nutrition-related internet information for Ag Canada in Alberta) is one of them. He isn't sure who posted this information on their web site. In his opinion, this information is conjectural at best and based entirely on anecdotal observations. He has submitted a proposal to Alberta's equivalent of a barley council to study this concern over the safety of feeding newly harvested grain to livestock. Although not a major problem today, if North Dakota develops an aggressive feeding industry the feeding of new-crop grain could become an important factor. Until more is known about the feeding safety of newly harvested grains, perhaps a more appropriate recommendation would involve treating the new-crop grain as a "new" feed in the ration. This would suggest gradually diluting the new crop grain into the diet in place of the existing grain over a series of days. This recommendation acknowledges that there may be problems associated with the abrupt use of newly harvested grain, but that with appropriate feeding management, these problems can be avoided. This recommendation would not preclude the use of newly harvested grain. Careful management of feed grain inventories can be used to capitalize on seasonal lows in feed grain prices. However, producers who are able to utilize new-crop grains must be prepared to manage available feedstuffs in such a way as to avoid possible problems associated with rapid ration changes. Prussic Acid Poisoning And Emergency ForagesGreg Lardy Extension Beef Cattle Specialist Many producers have planted alternative or emergency forages in order to provide winter feed in areas of the state affected by drought. Producers need to be aware of potential problems associated with grazing or haying sorghum-sudan and related species. Prussic acid poisoning is a concern with these forages. Prussic acid, also known as hydrocyanic acid or hydrogen cyanide (HCN), can accumulate under a number of growing conditions. Sorghums and related species have a cyanogenic molecule in their epidermal cells. When leaves are damaged by freezing, chewing, or rumen fermentation, HCN is released. Why is prussic acid toxic? - Once these plants are eaten, cyanide is absorbed into the bloodstream and binds to enzymes in the cell. This complex prevents hemoglobin from transferring oxygen to individual cells. The animal dies from asphyxiation. Prussic acid can kill animals very quickly, often within minutes. Symptoms include excess salivation, difficulty breathing, staggering, convulsions, and collapse. Clinical signs include blood which is bright cherry red and which clots slowly. Animals can be treated with simultaneous injections of sodium nitrate and sodium thiosulfate. Sodium nitrate releases cyanide from the cell where it is bound with sodium thiosulfate and excreted. Please contact your local veterinarian for diagnosis and treatment. Factors Affecting Prussic Acid ConcentrationPlant Species - Plant species most commonly associated with prussic acid poisoning are sorghums, sudangrass, and Johnson-grass. Grain sorghums are potentially more toxic than forage sorghums or sudangrass. Hybrid pearl millet and foxtail millet generally have very low levels of cyanide. Indian grass, chokecherry, and flax can also cause prussic acid poisoning. Plant Age and Condition - Young, rapidly growing plants generally have higher levels of prussic acid. Higher concentrations of cyanide are found in young leaves than in old leaves or stems. New forage growth following drought or frost is dangerously high in cyanide. In general, any stressful condition that retards plant growth may increase prussic acid content. Cyanide is released when plant leaves are damaged by cutting, crushing, trampling, chewing, or wilting. Plants growing in high nitrogen, low phosphorus, low potassium soils, tend to have high cyanide concentrations. Animals - Most losses occur when hungry or stressed animals graze young sorghum growth. Feeding grain or hay to animals before turning them unto a pasture reduces the rapid intake of forage and diminishes the amount of cyanide consumed. Animals do not develop immunity to cyanide, but they can detoxify LOW levels. Turn them out late in the day, as prussic acid levels are highest in the early morning. Harvest Technique - Fresh forages have higher concentrations of prussic acid than silages or hay. However, if the forage had extremely high concentrations of prussic acid before cutting or if the hay was not properly cured, dangerous levels of prussic acid can remain. Hay and silage should be analyzed for cyanide before feeding. Guidelines
46th Annual NDSU Livestock Research Roundup - Dickinson Research Extension CenterDickinson State University West River Ag Complex Dickinson, North Dakota October 3, 1997Morning Session - Moderator, Josh Dohrmann, Dunn County Extension Agent10:00 am Welcome 10:05 am Production of selected rotation crops for livestock - Pat Carr, Agronomist, DREC; Roger Ashley, Area Agronomist, DREC 10:30 am Pork production using alternative crops - Doug Landblom, Swine Specialist, DREC 10:55 am Alternative crops in beef cattle production - Marc Bauer, Beef Cattle Nutritionist, Animal and Range Science Department, NDSU 11:20 am Integrating cattle and annual forages - Chip Poland, Area Livestock Specialist, DREC 11:40 am Grazing and haying of CRP in southwestern North Dakota - Jim Nelson, Animal Scientist, DREC 12:00 pm Noon Lunch - Sponsored by Steffan Feeds and Vigortone Ag Products Afternoon Session - Moderator, Carmel Miller, Bowman County Extension Agent1:00 pm Current issues in animal health - Jim Clement, DVM, Mandan Veterinary Clinic 1:40 pm Effects of drought conditions on grassland management strategies - Llewellyn Manske, Range Scientist, DREC 2:10 pm Protein supplementation of grazing cattle - Greg Lardy, Extension Livestock Specialist, Animal and Range Science Department, NDSU 2:40 pm Dataline and Retained Ownership - Conception to Consumption - Kris Ringwall, Director, DREC 3:00 pm Supreme Champion Competition - Kris Ringwall, Director, DREC 5:00 pm Supper in Multi-Purpose Arena Sponsored by Dickinson Ag Committee Contact Chip Poland at 701-227-2348 for further information. |
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