Grass Tetany - signs and symptomsProvide well-balanced supplementation to make up for nutritional shortcomings.

By Kris Ringwall, Beef Specialist, NDSU Extension

The change in the weather has brought much excitement to the north country.

Pasture sorting for the appropriate turnout day is underway, but use caution.

Why the hesitation after the long wait for turnout? Well, fast-growing, lush grass may create a problem in supplying the daily requirement for magnesium (Mg) in the lactating cow. Physiologically, the strain of peak milk production on the cow’s system can create a metabolic shortfall with disastrous consequences.

The common issue is grass tetany, a difficult-to-detect problem that makes its presence known often simply by a dead cow. So visit with your local cattle nutritionist and make sure the cows are adequately supplemented with a proper, well-balanced spring mineral program with magnesium. Stay alert, but better yet, stay ahead of the issue.

Often, magnesium deficiencies show up when cattle are moved or worked. The deficiency is treatable but response time is very short because a cow that may seem slightly nervous and irritable can digress quickly.

Also, in the back of one’s mind, cows need to be ready for rebreeding prior to grass turnout. Well, that is a “too late” thought, but it still is real.

However, spring pasture turnout is an excellent opportunity for those poorer-conditioned cows. The hope is that changing to pasture will be gradual, giving the rumen time to adapt to changing intake, which is why old-growth grass often is advantageous for early turnout pastures. The old growth helps adapt the rumen from the high dry-matter diet of forage pre-grazing to the low dry-matter pasture and actually slows the digestive process, allowing for more time for the cow to utilize what she eats.

Each cow’s needs are a little different, thus the inclusion of a good mineral supplement. Many times, producers have more questions than answers, and they have no time for mistakes.

Every day on the cow calendar for rebreeding is booked. If you want the cow that calved this year on April 15 to calve next year on April 15, assuming gestation is 283 days, producers have only 82 days remaining in which to have the cow start lactation, prepare to rebreed and conceive a calf for next year. Therefore, making sure to meet all the cows’ nutritional requirements as they move to spring pastures is important.

In reality, now is the last check to make sure the cows and bulls are in good condition for the upcoming breeding season. Opportunities for cows on the thin side are limited at this time. So remember, assess the herd now and take some good notes as to what deficiencies are present and plan managerial changes for next year.

But for today, the cows need to go to grass. When grass is good, the cows are good, but let’s make sure to avoid grass tetany as cows transition to grass. A good spring pasture mineral supplementation that has Mg included can minimize the development of grass tetany.

Grass tetany also is associated with low blood calcium, thus the connection to higher-milking cows, and any indication of instability in a nursing cow is an emergency situation. Ketosis (sometimes confused with milk fever at calving) and hypomagnesaemia tetany (commonly called grass tetany or grass staggers) are serious metabolic disturbances in cattle, and given the setting and time, often are fatal without veterinary intervention.

Ketosis generally is associated with reduced intake of carbohydrates or, more simply put, inadequate feed to support the nutritional requirements of a lactating cow. But like many problems, the root cause is a combination of issues expressed as a crisis.

Serious outbreaks can occur if cattle are borderline deficient on calcium, stressed while producers are working calves and moved from the calving pasture to a lush pasture where dietary Mg absorption cannot meet the daily maintenance of Mg plus the daily lactation requirement for Mg.

The cow does not have a good way to store Mg, so daily intake is critical. The result of a lack of Mg is dead cows in the morning. Critical response is imperative.

Nothing about feeding cows is unique. Monitor your cows and provide well-balanced supplementation to make up the shortcomings. Keep in contact with your local cattle nutritionist and veterinarian in advance, be prepared and offer a well-balanced spring mineral program.

Every stage of cattle production brings with it the opportunity to acknowledge if the cattle operation is meeting production, financial and economic goals while generating enough cash to keep moving. Most often, the bigger points already have been decided and implemented.

But at the day’s end, the small points often tip the balance between success and failure. As was noted, producers often have more questions than answers, but when the sun sets, a mineral supplement is better than a dead cow.

Source: NDSU BeefTalk