As spring nears and grass begins to show inexperienced, producers are anxious to get cows out to grass. Nonetheless, cool season predominate areas are inclined to have lush spring development which might result in grass tetany in cows. Whereas there are remedies for cows caught fast sufficient, prevention is at all times one of the best coverage.
Why are cows liable to grass tetany within the spring?
Grass tetany happens when circulating Magnesium (Mg) is low within the beef animal. Signs embody staggering, convulsions, excitability, twitching, and can lead to loss of life. Whereas it may possibly have an effect on rising cattle, it typically impacts older lactating cows. The Mg requirement within the pregnant cow is 0.12% of the weight loss program on a dry matter foundation and jumps to 0.20% with lactation. Furthermore, the Mg in colostrum is 3 instances what it’s within the milk the remainder of the lactation. Thus, threat is highest early in lactation.
Moreover, not like another minerals, Mg just isn’t saved and mobilized within the tissues for instances when it’s poor within the weight loss program. Magnesium is absorbed throughout the rumen wall and the way a lot Mg is circulating within the blood is very dependent upon how a lot was consumed.
Along with the truth that the Mg requirement will increase with lactation, feed that’s excessive in potassium (Okay) or nitrogen (N) like lush quickly rising cool season forages can lower Mg absorption. So, extra magnesium must be consumed when cows are grazing lush cool season pastures to get the identical quantity of magnesium into the blood. Moreover, cool, cloudy days related to moist springs typically instances enhance the chance of grass tetany.
Utilizing free selection minerals to forestall grass tetany
To assist forestall points with grass tetany, producers ought to begin offering a excessive Mg mineral to cows a few month earlier than turning out on lush pasture to get them used to consuming it, and proceed to supply excessive Mg complement till grass begins to elongate and mature and the chance of grass tetany is low.
Mineral mixes are sometimes formulated for two oz or 4 oz consumption. At 2 oz consumption, 100 cows ought to eat 87.5 lbs of mineral combine per week and 175 lbs/week for a 4 oz mineral combine. If they’re consuming extra, then including extra salt will typically lower consumption. Nonetheless, the salt will dilute the combo so general consumption (salt plus mineral combine) needs to be better than the preliminary goal. Maintain observe of the particular mineral combine consumption to make sure goal intakes are reached. When utilizing a free selection mineral combine to supply magnesium, don’t present separate salt as offering separate salt will scale back consumption of the mineral combine.
To forestall grass tetany, a superb goal for a 4 oz goal consumption free selection mineral is 10 to 13% Mg. If including magnesium to an present mineral, then 9 lbs of magnesium oxide per 50 lbs of mineral combine could be wanted. Nonetheless, magnesium oxide is bitter and should scale back consumption. If consumption is low, then including 1 lb of dried distillers or soybean meal could assist enhance consumption.
Utilizing a hand fed complement to forestall grass tetany
If utilizing a hand-fed vitality or protein complement, then 5 lb of Magnesium oxide per 100 cows would should be added. Sodium deficiency can enhance the chance of magnesium deficiency, so if utilizing a mineral fortified complement that’s supplied every day, equivalent to a cake (and never a free-choice mineral) ensure that free selection salt is supplied.
Whereas offering excessive Mg mineral helps scale back the incidence of grass tetany, producers ought to speak to their native veterinarian and have a therapy plan in place for cows who do succumb to grass tetany, as therapy should happen rapidly in these cows.
For extra data on assembly the mineral and vitamin wants of beef cows, see G2340 Formulation Concerns for Mineral and Vitamin Dietary supplements for Beef Cows https://extensionpublications.unl.edu/property/html/g2340/construct/g2340.htm
