She’s gonna Blow!!
Most, if not all of us Cattleman are looking forward to warmer temperatures and green grass. As temperatures begin to warm, (Yes believe I or not it will eventually happen), cool-season grasses and legumes begin a rapid growth phase resulting in the production of large amounts of lush, palatable, green pasture.
Unfortunately, early in the growing season, these forages are very high in moisture content and nutrients are diluted. The result is that it is difficult for animals to eat enough dry matter to meet all of their nutrient requirements even if you provide dry/baled free-choice hay. Two important problems are commonly seen early in the grazing season, grass tetany and bloat. And until Gas-X produces a really big tongue strip for cattle, you’ll need to wean your cattle onto fresh grass so they don’t blow up!
Grass tetany, sometimes called "grass staggers", is a metabolic disorder in cattle related to a deficiency of magnesium (Mg). Early lactation cows are the most susceptible, with older cows considered more susceptible than heifers with their first or second calves.
Grass tetany usually occurs when animals are grazing lush pastures in the spring, but it can occur during the fall and winter too. Grass tetany is typically seen in early lactation cows grazing fresh, green, early/cool-season grasses after having been accustomed to eating dry hay all winter. Rapidly growing, lush grasses create the greatest problem. But this condition isn’t only limited to grazing legumes in early spring, it has been documented that it has occurred on Orchardgrass, perennial ryegrass, timothy, tall fescue, crested wheatgrass,
Bromegrass, Kentucky bluegrass, annual ryegrass and small grain (wheat, oats, barley, triticale
and rye) pastures too. The risk of grass tetany decreases on pastures that contain over 30% legumes
(examples: clovers, alfalfa, birdsfoot trefoil) or animals wintered on grass-legume hay.
The greatest risk for grass tetany is when pastures soils are low in available magnesium, high in available potassium and high in nitrogen. Pastures where a significant amount of manure has been applied often have this mineral imbalance and are considered more vulnerable. That alone is a good enough reason to not spread manure on your pastures and hay fields. I have always discouraged other producers from this practice because it just doesn’t seem logical to "infect" especially your hay fields with manure. Its bad enough that we can’t potty train our cattle to go in one localized area of their pastures so they aren’t "contaminating" the entire pasture. Obviously I’m kidding about the potty training. Nobody has time to train their cattle to do that, even if it were possible.
Signs & Symptoms
Unfortunately in many cases of grass tetany, symptoms are not immediately noticed and the only evidence is a dead cow. In mild cases, milk yield of dairy cattle is decreased, and the animal appears nervous. These signs
indicate the need for preventive measures. Animals affected by acute grass tetany may suddenly stop grazing, appear uncomfortable, and show unusual signs of alertness, such as staring and keeping their heads and ears in an erect position. Cattle may also have a staggered walk, have twitching skin, especially on the face, ears, and flanks, and lie down and get up frequently. Once cows get to this point, they are easily excited and any stimulation may lead to startling reactions, such as continuous bellowing or running. A staggered gait pattern typically develops followed by collapse, stiffening of muscles and violent jerking convulsions with the head pulled back. And the most obvious sign is they look really pregnant when their not. Like their gonna blow!!
Animals often lie flat on one side with periodic foreleg paddling, twitching of the eyes and ears, and a chewing motion that produces froth around the mouth. Between convulsions, the animal may appear relaxed. During this phase, any sound or touching of the animal, such as when administering treatment, may result in violent reactions. Animals usually die during or after a convulsion unless treatment is given.
This info. Isn’t meant to scare you beginning farmers & ranchers from grazing your cattle, but just be mindful of conditions before just turning your cattle out on fresh, green, spring pastures for the first time this coming season. There is actually a lot of thought and planning that should come first.