Grazing
Gazette
pennSt/
College of Agricultural Sciences
in coopcratioo with USDA/ARS
GRASS TETANY
Lawrence Muler
Profwr Of
Mry Science
Ptmm Male IMvenity
As pasture season starts, we
need to be concerned about piss
or magnesium (Mg) tetany. Gnus
tetany is a general term commonly
used to describe a condition of te
tany that occurs when cattle or
sheep are on pasture. It is caused
by low amounts of total or avail
able magnesium in the diet It is
sometimes called hypomagnesem-
ic tetany, lactation tetany, or grass
staggers.
Gnus tetany, as the name indi
cates, is most common when cows
are turned out onto lush spring pas
ture. The first 4 to 6 weeks of the
grazing season are of most concern'
to producers. The condition occurs
more often on grass pastures than
on legume pastures. Older cows
are more susceptible than younger
cows. Early lactation cows with
higher Mg requirements are most
susceptible.
In mild cases of grass
tetany, milk yield is de
creased and animals are
nervous. These signs
may indicate the need
for preventative mea
sures such as injection
of Mg solutions. In
more severe cases, af
fected cows have mus
cular incoordination,
aggressive and irritable
behavior, and excess
salivation. Finally, gen
eral tetany, convulsions,
and death can occur if
not treated.
Causes
The exact causes of
grass tetany are not
known, and the occur
rence within and be
tween herds is variable
and not predictable.
Grass tetany is most
common during cool,
cloudy, and rainy .
weather and often oc
curs when cool weather _
is followed by warm
weather. Changeable flBWt NrWfrniTl
weather lutwli lIIJIII
seem to trigger grass te- J
tany. It occurs most of- •
ten when cows graze
cool season grasses or _____ _ _ _____
small grain pastures. |Jfl|lC "if UCEI J
Some dairy producers lIWUI II ll t
have had limited or no
problems with grass te
tany. Others have prob
lems that vary between ,
years. Five years ago we
had one year with major
tetany problems. Other
years the occurrence of
tetany has been mini
mal. Affected cows
have low blood magne
sium levels caused eitfa-1
erbyadietcowinMgor I
one from which the MG i
is not absorbed into the
bloodstream. A normal
blood Mg level is 2 to
2.5 mg per 100 ml of &
hlood serum. Blood lev
els of Mg may drop to 1
mg per 100 ml blood or
less with grass tetany. w w^i
Plant and animal factors related
to the amount and utilization of Mg
are associated with grass tetany
problems. Factors thought to be re
lated to causing gnus tetany are:
• Low content of Mg in soil and
in pasture. The NRC recommenda
tion for lactating dairy cattle is that
Mg be fed at 0.20 t00.2S percent of
the total ration dry matter (DM). In
the spring, a Mg level of .30 per
cent or greater of the total radon
DM (forage and grain) is recom
mended. The Mg content of grass
es typically ranges Grom 0.17 per
cent to 0.23 percent, or less than
the needs of the high producing
cow. Legumes are usually higher
in Mg than are grasses and range
from 0.2 S to 0.30 percent Mg.
Magnesium levels are lowest in the
spring and increase during the
growing season.
• High rates of N and K fertiliza
tion and high amounts in pastures
interfere with Mg utilization.
Heavy N applications to pasture
increase the incidence of-grass te
tany. High K interferes with Mg
uptake by grasses. Many early
spring pastures contain 2S percent
protein (4 percent N) and in excess
of 3 percent K. The excess K not
THE END OF TEAT INJURY
ra K “NO SECRETS"
The “TEAT SAVER”
' pushes the udder & teat away from
r the dew daw. Apply two weeks prior
\C to freshening.
This product can be purchased at your local Farm Stores or Feed
Mills or by contacting your local animal health centers.
The TEATSAVER" supplied by
< J B - Supp'y Ltd.
/ Chetek Wisconsin 54728
i /Vv For Information Phono (715) 924-2136
Here's HOOF ROT Help!
Dr. Naylor Hoof 'n Heal la a naw topical antiaaptle aid In
the treatment, prevention and managemant of
HOOF ROT, FOOT ROT and FOULS
• SAFE
• COLORLESS
• EASY TO APPLY
Hoof 'n Heal wool harden or discolor treated hoofs, and it's labeled for use
on cows, so it's barn-legal. Simply spray Hoof 'n Heel liquid on affected
hoofs once or twice daily.
Available in your choice of packaging ... pint squeeze bottle ... one
gallon container... or as a powder concentrate for making a foot bathing
solution or preventive walk-through. Always read and follow all label
directions.
Or. Naylor Hoof 'n Heel is available now from your favorite animal health •
supplier. H.W. Naylor Company, Inc., Morris, NY 13808-0190. (607) 263- J
A
Dr. Naylor and Hoof ‘n Hoot ara ragiatarad tradamarks of tha
H.W. Naylor Company, Inc.
only is a factor in causing grass te
tany but can lead to imbalance in
cationstanions in dry cows which
can contribute to increased milk
fever.
• Grass tetany is more likely to
occur when Ca is low and when K
is high. When the ideal ratio of Ca,
K, and Mg is unbalanced, proper
nerve impulse transmitsioa foils,
and tetany occurs. The grain ntkm
or supplemental feeding needs to
be programmed to contain ade
quate Ca.
ControUag
Grass Tetany
Early lactation dairy cows re
quire about 0.13 pound or about 40
grams of Mg per day. A cow con
suming 28 pounds of pasture dry
matter per day will consume about
25 grams of Mg. Most grain ra
tions without supplemental Mg
contain about 2 percent Mg.
Therefore, grazing dairy cows
need an additional 10 to IS grams
of Mg per day foam supplemental
minerals.
Magnesium needs to be added to
the grain ration to increase tfve Mg
content of the total ration (pasture
plus grain) to at least .30 percent
• NON-TOXIC
• ODORLESS
• NO WITHHOLDING
Mg. Often, .35 percent Mg it re
commended. Magnesium oxide is
the most common source of sup
plemental Mg. This means the
grain ration may need to contain
about 0.5 percent Mg. Cows often
will not consume all the allotted
grain with lush spring pastures,
thus other supplemental methods
may be needed. Oral bolusing indi
vidual cows with 1 to 2 ounces of
magnesium oxide per day is effec
tive. Freechoice minerals with ele
vated Mg content can be consider
ed in addition to the Mg being
force-fed in the grain rations. Not
Top Lamb
LOWELL VILLE, Ohio
Buyers from eastern Ohio, central
and western Pennsylvania as well
as Maryland bid enthusiastically
at Yeo Farms’ eighth annual Club
Lamb Sale held at the farm Satur
day, April 22.
11m Basich of Leetonia, Ohio
successfully bid for the highest
priced iamb, which went for $lBO.
Other top-selling lambs were pur
LAND PRIDE
Quality equipment from
a quality company.
"TKI
>w
GROOMING MOWER
3-Spindle. 48”
48” Through 120”
&
*
ROTARY CUTTERS
48” Through 120”
48” Through 96”
Wa Ship Part*
UPS
Lancaster Faming, Saturday, April 29, 1995-A23
¥k u■n rf
only can Mg help prevent grass te
tany, but may help prevent a de
pressed milkfat test that often oc
curs on spring pasture. Providing 5
10 8 pounds per day of legume hay
high in Mg can be helpful in in
creasing Mg intake.
For cattle with gnus tetany, con
sult the local veterinarian for treat
ment Dextrose rotation with Ca
and Mg is a common treatment A
saturation solution of magnesium
sulfate Injected under the skin
places a high level of Mg in die
Mood in a short trial.
Takes $lBO
chased by A.F. Dussd Jr. of Kent,
Ohio; Bob Crawford of Lisbon,
Ohio; and Sherry O’Neill of Titus
ville, Pa. In all, 20 wether lambs
were sold in the afternoon auction
at an average price 27 percent
higher than last year's average.
The Lawrence County 4-H
Club provided a refreshment stand
for the event. Larry Gamer, of
Carrolton, Ohio, was the auction
eer.
42” Through 96”
PULVERIZERS
48” Through 84”
' ii ■ -ii -n
,v "’
OVER SEEDERS &
PRIMARY SEEDERS
48” And 72”
&
TILLERS
34” Through 76”
MONDAY
FRIDAY
7:30-6:00
SATURDAY
7:30-12:00