With cow values at an all time high, it is crucial that farmers should take action to safeguard their cows against the occurrence of tetany before clinical signs or losses appear. When turning out freshly calved cows it is often advisable to supplement them with silage or hay and gradually increase grass intake. In addition, on cold wet nights cows should have access to shelter.
If cows get cold, then their appetite will reduce and intakes will be depressed.
Fertilisers
Avoid using fertilisers that contain high levels of K at springtime as this can increase the level of potassium in the grass which will reduce the ability for the cow to absorb magnesium from their diet.
Feeding
Adding salt to the diet can increase the level of magnesium absorption.
Feeding nuts or rations containing minerals will supply additional dietary magnesium to cows and may help to reduce the risk or the severity of a grass tetany problem. However, farmers should pay particular attention to cows’ appetites while feeding concentrates. The level of minerals in many concentrates will not provide full protection against grass tetany. It is, however, a help to reduce the speed of onset of the disease.
Tips to reduce the risk of tetany
Feed hay or silage to cows at grass.Give concentrates containing minerals to cows at grass.Ensure cows are not cold and have shelter during cold wet nights (house at night with access to silage or hay).Supplement cows with a source of magnesium.Blood sample cows to identify mineral levels in the blood.Pay particular attention when grazing fields that are shown to be high in K.Methods of magnesium supplementation
There are several methods of magnesium supplementation open to farmers, but care should be taken with each method.
Dusting over silage
This may only be suitable for some farmers where cows are house at night and out at grass by day. Calcined magnesite is the product most commonly used for this. Farmers should follow the feeding guidelines on the bag closely to ensure adequate supplementation. It can be difficult to guarantee the required intake by each cow. Cow intakes should be monitored as scouring can occur at high intake levels.
Magnesium boluses
Magnesium bullets are given orally and provide slow release of magnesium, giving protection for 20 to 40 days, depending on the product. Farmers should be aware that this method is not foolproof as cattle can cough up the bolus. If this is missed by the farmer, then they will not realise that the animal is not protected against grass tetany. Farmers should consult the instructions carefully as some products require just one bolus, while others may require two boluses to be administered.
Magnesium licks
Mineral blocks or licks containing magnesium are a popular method of supplementation. These can be placed in fields and moved regularly to avoid poaching due to cattle crowding around them. These should be checked regularly and replaced as soon as eaten to ensure the cows have continuous access to magnesium. Problems can occur as some cows may tend to eat more of the lick than others, while some cows may not eat the licks at all. Where excessive levels of magnesium are ingested by cows, scours may occur.
Magnesium added through water
This is a quite a common practice around the country. However, farmers should bear in mind that in times of high rainfall, or when grass dry matter is low, appetite for drinking water may be reduced. In addition, cows are most at risk from grass tetany during wet cold nights/days in the spring and autumn. On a cold wet day, the cow’s appetite for water will most probably be reduced.
Read more
Click here for part one of this series
With cow values at an all time high, it is crucial that farmers should take action to safeguard their cows against the occurrence of tetany before clinical signs or losses appear. When turning out freshly calved cows it is often advisable to supplement them with silage or hay and gradually increase grass intake. In addition, on cold wet nights cows should have access to shelter.
If cows get cold, then their appetite will reduce and intakes will be depressed.
Fertilisers
Avoid using fertilisers that contain high levels of K at springtime as this can increase the level of potassium in the grass which will reduce the ability for the cow to absorb magnesium from their diet.
Feeding
Adding salt to the diet can increase the level of magnesium absorption.
Feeding nuts or rations containing minerals will supply additional dietary magnesium to cows and may help to reduce the risk or the severity of a grass tetany problem. However, farmers should pay particular attention to cows’ appetites while feeding concentrates. The level of minerals in many concentrates will not provide full protection against grass tetany. It is, however, a help to reduce the speed of onset of the disease.
Tips to reduce the risk of tetany
Feed hay or silage to cows at grass.Give concentrates containing minerals to cows at grass.Ensure cows are not cold and have shelter during cold wet nights (house at night with access to silage or hay).Supplement cows with a source of magnesium.Blood sample cows to identify mineral levels in the blood.Pay particular attention when grazing fields that are shown to be high in K.Methods of magnesium supplementation
There are several methods of magnesium supplementation open to farmers, but care should be taken with each method.
Dusting over silage
This may only be suitable for some farmers where cows are house at night and out at grass by day. Calcined magnesite is the product most commonly used for this. Farmers should follow the feeding guidelines on the bag closely to ensure adequate supplementation. It can be difficult to guarantee the required intake by each cow. Cow intakes should be monitored as scouring can occur at high intake levels.
Magnesium boluses
Magnesium bullets are given orally and provide slow release of magnesium, giving protection for 20 to 40 days, depending on the product. Farmers should be aware that this method is not foolproof as cattle can cough up the bolus. If this is missed by the farmer, then they will not realise that the animal is not protected against grass tetany. Farmers should consult the instructions carefully as some products require just one bolus, while others may require two boluses to be administered.
Magnesium licks
Mineral blocks or licks containing magnesium are a popular method of supplementation. These can be placed in fields and moved regularly to avoid poaching due to cattle crowding around them. These should be checked regularly and replaced as soon as eaten to ensure the cows have continuous access to magnesium. Problems can occur as some cows may tend to eat more of the lick than others, while some cows may not eat the licks at all. Where excessive levels of magnesium are ingested by cows, scours may occur.
Magnesium added through water
This is a quite a common practice around the country. However, farmers should bear in mind that in times of high rainfall, or when grass dry matter is low, appetite for drinking water may be reduced. In addition, cows are most at risk from grass tetany during wet cold nights/days in the spring and autumn. On a cold wet day, the cow’s appetite for water will most probably be reduced.
Read more
Click here for part one of this series
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