Charlie Carslake BA BVSc MRCVS, Molecare Veterinary Services
Turn out is a time to look forward to but there is one, sometimes fatal disease you must be prepared for.
What is it?
Hypo-magnesia, more commonly known as Staggers, is due to a lack of magnesium.
Why does it happen?
Magnesium has a controlling, inhibitory effect on nerve and muscle activity and is essential for normal neurological function. If a cow or sheep does not get enough magnesium the lack of inhibition can result in severe convulsions know as Staggers. Unless treated, Staggers usually results in death.
Lush pasture is especially low in magnesium and the sudden change from winter ration to pasture means that magnesium intake can plummet. This is especially true in bad weather where cattle may be sheltering rather than grazing. Unfortunately, the body has no readily available store of magnesium and is unable to mobilise reserves sufficient to make up this shortfall which results in staggers. Lactating dairy or suckler cows are at high risk for 6-8 weeks after spring turnout.
What does it look like?
Signs can vary depending on the severity of the shortfall in magnesium. Severe grass sickness is quite impressive. After a period of dullness they will go down convulsing, violently paddling their limbs, salivating and if no treatment is administered, may result in death. Signs for sub-acute cases are vaguer. They may appear withdrawn, reluctant to be milked or herded, have reduced dry matter intake and poor milk yield. Dairy cows with subclinical hypomagnesaemia can lead to hypocalcaemia so may be worth considering if your cows are suffering from milk fever. Talk to your vet if you are suspicious of subacute hypo-magnesia.
What action should I take?
Firstly, call your vet. They will advise you on a treatment plan such as the following:
For cattle; immediately give 1 bottle of calcium containing magnesium (i.e. Calciject 5 40CM) into the vein and 1 bottle of magnesium (i.e. Magniject 9) under the skin. DO NOT give magnesium into the vein, it will kill the cow by stopping the heart. Don’t risk getting kicked. You may need to wait for the vet to sedate the cow.
For sheep; give 100ml of calcium containing magnesium (i.e. Calciject 6 20CMD) immediately into the vein with a further 100ml under the skin. Again, it is best to call the vet to administer medicines into the vein as quickly as possible.
How can I prevent it?
As always prevention is better than cure! Firstly make sure you have a ready supply of magnesium and calcium in your medicines drawer. Better to not use it than find yourself short when you need it most.
Prevention in a group can be achieved giving magnesium in the ration. This can come as Calcined Magnesite (MgO) in the ration, Magnesium Chloride (MgCl2) in the water. Unfortunately, most cases occur when animals are out at grass and receive no additional feeds. It may be the case that if problems are bad enough buffer feeding or ruminal boluses should be considered. Mineral licks are an unpredictable solution because often only a few animals consume most of the bucket.
Long term management of troublesome pastures can lie in grassland management, with focus on grass types and fertilizer practices. Please consult your vet for options if you are concerned or if a group has been showing sub-clinical signs.
For more information phone Molecare Vets on 01392 872934