Page 17 - MWC 4-23-20s

GRASS TETANY: The Midwest Cattleman · April 23, 2020 · P17

Now Is the Time to Prepare

By Adele Harty, SDSU Extension Cow/Calf Field Specialist
The warmer spring tem- •Various combinations of
peratures have been a wel- the above factors result-
come reprieve from the cold ing in low blood Mg or Ca
experienced across the re- Older, lactating cows with
gion in 2019. With warmer calves younger than 2 months
temperatures and significant of age have the greatest sus-
soil moisture, ranchers need ceptibility to tetany. Mature
to be proactive in mitigating cows are more susceptible
grass tetany risk. Cool sea- because they are less able to
son grasses are beginning to mobilize Mg from bones to
green up, posing a risk for maintain the necessary Mg
cows with young calves. As level in their system. Also, ty and adequate intake can contained (i.e., water tanks),
the temperatures continue to cows within two months after be challenging, resulting in soluble Mg salts can be added.
increase, cool season grasses, calving have increased milk some animals consuming an Some examples of soluble Mg
such as crested wheatgrass production which requires inadequate amount of min- salts are magnesium acetate,
will grow rapidly, increasing additional Ca and Mg. Steers, eral on a daily basis. Ensure magnesium chloride, and mag-
the risk of grass tetany. Hav- heifers, dry cows, cows with all animals have access to nesium sulfate (Epsom salts).
ing a solid understanding of calves older than 4 months of the supplement prior to and The most common form of Mg
the risk factors and how to age and bulls are less suscep- while grazing tetany-prone found in supplements, magne-
mitigate risk will be key. tible. pastures to help decrease the sium oxide, is not soluble in
Grass tetany is a metabolic Prevention is key to mini- occurrence. water and therefore cannot be
disorder associated with graz- mizing risks associated with Another option is to provide used for this purpose.
ing lush pastures, resulting lactating cows grazing lush hay while cattle are grazing A long-term approach is
in low concentrations of blood pastures. If possible, delay lush pastures; however, they to incorporate more legumes
magnesium, which results in turn-out until plants are 4 are not likely to eat hay un- into pasture mixes. Legumes
nerve impulse failure in an- to 6 inches tall. This will re- less forced to. Dry forages can have higher levels of Mg and
imals. With adequate mois- duce the occurrence of tetany act as carriers to provide ad- Ca than do immature grass-
ture and warm temperatures, in addition to giving pastures ditional Mg and Ca at critical
grasses will grow rapidly. more rest and recovery. Un- times. If the water source is continued on page 32
Grass tetany isn’t normal- fortunately, reality is that
ly seen until May but taking many pastures are needed
steps now to prevent it will be when grasses begin to green-
more effective in the long run. up and the risk for tetany is
It is never too early to plan highest.
and ensure proper manage- If delayed turn-out is not
ment practices are in place. an option, other management
Understanding the factors tools should be utilized. First,
that influence the progres- always provide a high mag-
sion of grass tetany will help nesium (Mg) supplement con-
one manage risk. These fac- taining 8-12% Mg at 3-4 oz.
tors include: intake. For a cooked molasses
•Low magnesium (Mg) cou- product with a recommend-
pled with high potassi- ed intake of approximate-
um (K) content of rapidly ly 1 pound, the guaranteed
growing forages analysis for Mg should be
•High crude protein content approximately 4%. Read the
of forages label to ensure adequate
•Bad weather, storms, Mg levels and recommend-
stress, etc., that cause ed intake. Magnesium sup-
cattle to be “off feed” for plements need to be offered
24-48 hours two to three weeks prior to
•Lactation due to losses of turn-out or before tetany is
Mg and calcium (Ca) in likely to occur. Palatabili-
milk