THE VET'S ADVICE: Identifying grass tetany in cattle
May 26, 2023
WITH the days getting warmer grass is finally beginning to grow (at long last!) but with that so does the incidence of grass tetany for lactating cows.
Grass tetany also known as grass staggers, lactation tetany or spring tetany is a metabolic disease caused by a magnesium deficiency usually after grazing lush grass.
Magnesium is needed for proper muscle and nerve function so low levels in the blood cause ‘tetanic spasms’ where muscles contract uncontrollably.
Grass that has been fertilised will have highly digestible covers increasing the risk as cows do not have the ability to store this trace element.Slurry or fertilizer
Grass that has had slurry or high potassium content fertiliser should not be grazed for approximately two weeks after treatment.
Signs and symptoms of grass tetany include but are not limited to: drop in milk yield, frothing at mouth, isolating themselves from the herd, muscle twitching, incoordination and staggering often leading to collapse thrashing.
If a cow is identified as having grass tetany a calcium magnesium solution should be administered intravenously followed bymagnesium sulphate given under the skin, usually around the neck area.
It is sometimes useful to administer in a few areas along the neck so it can be absorbed quicker.
Before administering it is important to warm them to body temperature in a bucket of warm water.
Do not attempt to move the animal as stress can exacerbate the symptoms.
Provide magnesium to lactating cows especially those in new, lush pastures.
This can be in the form of magnesium licks, boluses or whichever form suits your herd.
If using lick buckets a general rule of one bucket per ten cows in a grazing herd should suffice but it is important to note that not all cows will favour a lick bucket and may need alternative supplementation.
Rotating grazing is also important.
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