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There are two types of staggers, these are grass staggers and ryegrass staggers. Grass staggers is a metabolic disease in cows caused by a magnesium deficiency. By giving cows extra magnesium in their diet, you can prevent health issues like grass staggers and milk fever, which can help increase milk production. It's important to discuss with a vet before starting because there have been cases of salmonella infections linked to magnesium supplementation. Ryegrass staggers is a nervous disorder in cows caused by high levels of certain chemicals in pasture. You can manage this with specific diet and grazing practices.
Grass staggers is a metabolic disease caused by magnesium deficiency. It is also called hypomagnesaemia. The cow is dependent on the amount of magnesium supplied in her diet, and from supplements.
Supplementing cows with extra magnesium (Mg) in late pregnancy and early lactation has become routine on most farms since the 1970’s. Mg supplementation helps prevent animal health problems, such as milk fever and grass staggers (tetany), and potentially increases milk production.
Mg plays an important role in nerve and muscle function and functioning of the immune system. Although cows have significant stores of Mg in the bones, little of these stores are available to maintain levels in the blood. Therefore, the cow is dependent on the Mg supplied in the diet and from supplements to maintain blood levels. Blood and urine tests can confirm Mg deficiency. Consult your vet.
There have been reports from New Zealand and Australia of Salmonella infections occurring in dairy cows that had received Mg supplementation, delivered as granules, prills, pellets, powder and via the drinking water.
Before starting Mg supplementation for your dairy herd, consult your veterinarian to discuss the potential risks and to determine if there are any health or environmental factors that should be taken into consideration to reduce the risk of the development of Salmonellosis.
The initial symptoms of Mg deficiency are nervousness, ears pricked, nostrils flaring, eyes alert and head held high. Movement is stiff, like a cow is walking on stilts, and she will stagger when forced to move quickly. Cows suffer loss of appetite and reduced milk production. Death results from a “tetany”, where the muscles contract uncontrollably, including the heart.
It is recommended that dry cows receive a diet containing 0.35 percent Mg, and lactating cows 0.28 percent Mg.
There are a number of different sources of magnesium, and methods of adding these into a cow’s diet. Common methods include drenching, pasture dusting, hay slurries, through water, and as magnesium bolus. Each method has its own limitations and advantages, so it is up to each farm how they choose to supplement their magnesium.
Factors that increase Mg requirements of cows during the winter/spring period are:
For more information, refer to the Farmfact below.
Table 1. Dietary magnesium concentrations and quantity of supplementary Mg required (grams/cow/day) for different types of dairy cattle.
|Cow status||Mg requirement(% of diet)||Supplementary Mg (g/cow/day)|
Table 2. Quantities of magnesium sources to supply the required amounts of pure magnesium (down the cow's throat).
|Magnesium source (% Mg)||Example product||Magnesium required (g/cow/day)|
|12 g||14 g||16 g||18 g||20 g|
|Mg Oxide (55%)||CausMag||22||25||29||33||36|
|Mg Sulphate (10%)||Epsom salts||122||142||162||182||202|
|Mg Chloride (12%)||Mag chloride||100||117||134||151||167|
Note: If dusting magnesium oxide on pasture, the quantities above need to be at least doubled, possibly tripled, to allow for field losses. When mixing with feed, double the rates above.
Table 3. Amount of magnesium oxide dusted on pasture (g/cow/day).
|Magnesium source (% Mg)||Rate||Magnesium required (g/cow/day)|
|12 g||14 g||16 g||18 g||20 g|
|Mg Oxide (55%)||Double rate||44||50||60||66||72|
Ryegrass staggers is the nervous disorder animals suffer from as a result of eating pasture containing high levels of the ryegrass endophyte chemical Lolitrem B.
Ryegrass staggers symptoms are most likely seen in stock which graze seed heads or graze into the base of the pasture where the endophyte chemical is concentrated. Symptoms start with tremors in the neck and head, followed by heavy tremors and stiff legs. Seriously affected animals often fall over when disturbed. Calves appear to be more susceptible to ryegrass staggers than older stock.
Outbreaks of Ryegrass staggers occur from late November until the end of April, but the problem is sporadic and tends to be worst from late January to early February. Animals are at most risk when a sustained hot, dry spell is followed by rain, especially when pastures are over grazed.
Wild-type endophytes in New Zealand perennial ryegrass pastures produce a toxin that causes ryegrass staggers. Over the past 20 years, new endophytes have become available that do not produce this toxin, while still protecting the plants from disease. Depending on the age of your pasture, and what was sown, will determine the risk of Ryegrass Staggers on your farm.
Specific management will vary with the farm business goals, pasture type, season and locations. However, some general principles can be used.
The highest levels of endophyte toxins are in the ryegrass leaf sheath, seed head and seed. Management that increases the leaf content of ryegrass and reduces intake of seed head and plant parts near ground level will reduce the chance of ryegrass staggers.
Supplementary feeding with high quality pasture silage is the most practical way for most dairy farmers to manage ryegrass staggers by substituting supplement for pasture.
Seriously affected stock should be:
For badly affected calves consider a 100% supplement diet. Depending on calf weight, 4 kg dry matter per head will be required, some of which may need to be a high quality feed such as meal or brassica crops.