Grass tetany
Encyclopedia
Grass tetany or hypomagniesemic tetany is a metabolic disease of dairy cows grazing on lush pastures, of rapidly growing grass
, especially in early spring
.
The pathognomonic symptom is tetany
seen in the neck of the recumbent cow. But, before this stage, the animal had a staggering gait. Hence, the common appellation of "grass staggers".
A similar disease can occur in sheep.
content of involved grass. However, there are also low blood calcium
levels, as in milk fever
.
, the disease occurs after winter housing. But in Australia
and New Zealand
, where the cows are not housed, the disease occurs in similar conditions, when the animal enters lush, grass-dominant pastures.
Intravenous mixed calcium and magnesium injection are used. Subcutaneous injection of magnesium sulphate (200 ml of 50% solution) is also recommended.
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
, especially in early spring
Spring (season)
Spring is one of the four temperate seasons, the transition period between winter and summer. Spring and "springtime" refer to the season, and broadly to ideas of rebirth, renewal and regrowth. The specific definition of the exact timing of "spring" varies according to local climate, cultures and...
.
The pathognomonic symptom is tetany
Tetany (medical sign)
Tetany is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disease or other conditions that increase the action potential frequency...
seen in the neck of the recumbent cow. But, before this stage, the animal had a staggering gait. Hence, the common appellation of "grass staggers".
A similar disease can occur in sheep.
Etiology
The disease is related to low magnesiumMagnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
content of involved grass. However, there are also low blood calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
levels, as in milk fever
Milk fever
Milk fever, post-parturient hypocalcemia, or parturient paresis is a disease, usually of dairy cows, characterized by reduced blood calcium levels....
.
Epidemiology
In Northern EuropeNorthern Europe
Northern Europe is the northern part or region of Europe. Northern Europe typically refers to the seven countries in the northern part of the European subcontinent which includes Denmark, Estonia, Latvia, Lithuania, Norway, Finland and Sweden...
, the disease occurs after winter housing. But in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, where the cows are not housed, the disease occurs in similar conditions, when the animal enters lush, grass-dominant pastures.
Treatment
The affected cow should be left in the pasture, and not forced to come back to stall because excitation can darken the prognosis, even after adequate treatment.Intravenous mixed calcium and magnesium injection are used. Subcutaneous injection of magnesium sulphate (200 ml of 50% solution) is also recommended.