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The very popular and educational Kentucky State University “Third Thursday” program this month is devoted to goat- and sheep-related production issues. As always, the program is free and open to the public. There is a meat and dairy tract in the morning with presentations on marketing, raising dairy kids for the meat market and lactation nutrition. Other topics include factors affecting carcass quality in meat goats, fabrication of goat carcasses for market and home, and an update on other research underway at KSU. In the afternoon there are hands-on selection activities, so participants should be prepared to go to the barn. The program starts at 10 a.m. and should conclude around 3:30 p.m.
The program is at KSU Research Farm and Conference Center, 1525 Mills Lane in Frankfort. For more information and complete program details, call Dr. Ken Andries, KSU animal science specialist, at 502-597-5094 or email firstname.lastname@example.org.
Forages and Frost. It’s that time of year when the first frosts are expected, and we begin to receive calls from livestock producers concerned about potential toxicity to livestock with some forage crops. Two potential problems can develop: prussic acid poisoning and nitrate toxicity.
Prussic acid can build up to toxic levels in the leaves of a number of plants including johnsongrass, sorghum, sudangrass, sorghum-sudangrass hybrids and wild cherry. It is most likely to build up to toxic levels immediately after a frost. Young tender, fast-growing plants are more likely to be toxic than older, more mature plants.
Prussic acid causes death by interfering with the oxygen-transferring ability of the red blood cells, causing animals to suffocate. Symptoms include excessive salivation, rapid breathing, and muscle spasms, and may occur within 10-15 minutes after the animal consumes forage containing prussic acid. Animals may stagger, collapse and eventually die.
Prussic acid and nitrate poisoning are not the same. Toxic levels of nitrates result from heavy nitrogen fertilization followed by severe drought stress or wet pastures during cool, cloudy weather. Unlike nitrates, prussic acid deteriorates with time. To be safe, avoid grazing when frost is possible. After a frost, grazing or feeding greenchop should be avoided for at least a week after the last green material has been frosted. Hungry cattle should not be turned into potentially toxic pastures or those containing wild cherry trees. Livestock never should be given access to limbs trimmed from wild cherry trees.
Nitrate toxicity typically is more of a concern after drought stress, but it also can occur on wet pastures during cool, cloudy weather. Forage plants with the most potential to accumulate nitrates are sudangrass, sorghum-sudan hybrids, pearl millet, corn, wheat and oats. Certain weeds also may accumulate toxic levels of nitrates and thus pose a threat, especially in hay: pigweed, smartweed, ragweed, lambsquarter, goldenrod, nightshades, bindweed, Canadian Thistle, and stinging nettle. The application of some herbicides such as 2-4D also can increase nitrate levels in plants.
Nitrates induce symptoms including labored breathing, muscle tremors, and a staggering gait after which the animal collapses, gasps for breath, and dies.
Animals grazing suspect pastures should be watched for symptoms. Supplemental grain feeding can reduce the risk through a dilution effect. A veterinarian can treat the condition if it is diagnosed early enough. Some contaminated feeds can be mixed and diluted with safe forages and fed, but toxicity levels need to be measured and monitored.
For more information on either of these forage related problems, call the Hardin County Cooperative Extension Service, 270-765-4121. This information was provided by Dr. Garry Lacefield and Southern Forages, Fourth Edition.
Douglas W. Shepherd is a Hardin County Extension Service agent for agriculture and natural resources. Reach him at 270 765-4121 or email@example.com.