09 Feb Why is my cow walking in circles?
By: Special Areas Board Agricultural Fieldmen
We’ve made it through another summer of debilitating drought and we’re still standing. PHEW! But wait. There’s more.
The effects of multiple years of drought are still being felt in the cow herd and may become more obvious this winter. There are a few warning signs producers should watch for in their herds this winter. If you suspect any of these conditions consult your veterinarian. Be sure to test your feed and water sources when managing livestock nutrition.
NITRATE TOXICITY
Nitrate is one of two plant available forms of nitrogen. Normally, a cow’s rumen bacteria converts this nitrate from plants it consumes into nitrite, which is then absorbed as ammonia in the blood and excreted in the urine. When certain plants are stressed (drought, hail, etc.) nitrates are immobilized in the plant, accumulating in the above ground tissue. If a cow consumes too much of this high nitrate feed, it causes oxygen starvation of cells basically your cow suffocates. Symptoms to keep an eye out for this winter include respiratory distress, sudden death, weakness, muscle tremors, difficulty walking, downers, blue/grey mucous membranes.
Some crops that can be susceptible to nitrate accumulation from drought include: cereals like barley, wheat, oats & rye; canola plants; sorghum; and flax. Beyond crops, you may also want to watch for weeds of concern mixed into your feed. Weeds like kochia, Russian thistle, bull thistle, Canada thistle, lamb’s quarters and mustards can also be susceptible to nitrate accumulation. Legumes do not accumulate nitrates as nitrogen fixing nodules self-regulate the amount of nitrogen the plant produces. Test your feed and use a nutritionist/veterinarian to determine safe levels of nitrates. For helpful tips on how to interpret that nitrate concentration on your feed test listen to the Beef Cattle Health & Nutrition Podcast Dec 22/23 episode.
VITAMIN A DEFICIENCY
Vitamin A is abundant in green leafy forages and is a fat soluble vitamin stored in the liver and fatty tissues of a cow. It can only be stored for up to 4 months. This vitamin does not cross the placenta, so newborn calves get all of their Vitamin A from colostrum.
Waldner & Uehlinger (2017) published a study that indicates calves with low serum vitamin A (<0.14ug/ml) were 2.8 times more likely to die.
Drought grown hay, bleached pasture, weathered forage, harvested crop residues and prolonged feed storage all contribute to vitamin A deficiency in your herd. Symptoms include blindness, neurological symptoms (including circling), stillborn/ weak calves, poor conception rates, immune deficiencies and abnormal bone development. For more on Vitamin A and other key nutrients visit BCRC’s Nutrition in Beef Cattle page.
SULFUR TOXICITY
Canola and other cruciferous crops typically contain excess sulfur, as well as weeds like Canada thistle, kochia and lamb’s quarters. Blending canola straw has been an economical option for many Special Areas ranchers this winter to prolong feed stocks. But be sure to test your feed and water for sulfur content first. Sulfur toxicity symptoms include wandering, circling, cortical blindness, incoordination, head pressing, seizure activity and more. Sulfur toxicity induces polio in cattle.
OXOLATE TOXICITY
Oxalic acid is a common constituent of some plants, most notably in our area in kochia. This anti-nutrient binds calcium, magnesium and iron. If a cow were to consume too much oxalic acid in its diet, they would essentially starve their bodies of calcium and magnesium. Symptoms of calcium deficiency include interference with normal bone growth, rickets and slowed growth & development in young cattle and weak & brittle bones in adult cattle. Symptoms of magnesium deficiency include staggering, muscle twitching, convulsions and death.
LISTERIOSIS
Listeriosis is a bacterial disease usually associated with feeding poorly preserved silage with a pH greater than 4.0, allowing Listeria bacteria to grow.
Poor compaction, high pH and/or oxygen in the silage favor the growth of this bacteria. Baled silage is more commonly affected due to inadequate sealing. While listeriosis is relatively uncommon, many producers in Special Areas have been trying their hand at bale-silaging salvage crops to bring the cost of feed down during the drought, so this may be one to look out for. Since the Listeria bacteria affects the central nervous system, symptoms include circling, uncoordinated movements, leaning against objects and progressive paralysis. It can also cause abortion and stillbirths.
For information feed sampling and winter nutrition, see the BCRC article Key Takeaways from the Nutrition Webinar Series for the Winter-Feeding Season