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Use of an experimental high-magnesium tall fescue to reduce grass tetany in cattle

Crawford Jr, R.J. and Massie, M.D. and Sleper, D.A. and Mayland, H.F. (1998) Use of an experimental high-magnesium tall fescue to reduce grass tetany in cattle. Journal of Production Agriculture. 11:491-496.

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Grass tetany (hypomagnesemia) continues to be a problem
for the livestock industry. An experimental cultivar of tall fescue
(Festuca arundinacea Shreb.) selected for high Mg concentration,
HiMag, was compared against four other cultivars for
its ability to increase serum-Mg and reduce the risk of grass
tetany. Forage from HiMag contained 22% more Mg, 183%
more Ca, and 9% more P than other cultivars; K levels were
not different. Regardless of cultivar, concentrations of Ca and
Mg were lower while K and P were higher during the spring
than the autumn. The tetany ratio IK/(Ca + Mg) on basis]
was lower for HiMag than for other cultivars (1.34 vs. 1.65); all
cultivars had a higher ratio during spring than autumn (1.91
vs. 1.31). In cattle (Bos taurus) grazing trials, blood serum from
steers grazing HiMag contained 8% more Mg in autumn 1993
but was not different in spring 1994. Blood serum Mg was not
different for cows (either dry or nursing calves) during autumn
grazing, but approached significance (P = 0.09) during the
spring 1995 calving season (2.32 vs. 2.07 mg/dL for HiMag
vs. other cultivars). Except for differences between calves on
HiMag compared with Kentucky-31 in autumn 1995 (58 vs. 43
lb, respectively), animal weight change was not affected by cultivar.
Normal forage Mg concentrations (>0.20%) and tetany
ratios below 2.2 for all cultivars in every season except spring
1995 may explain the lack of consistent animal response. No
clinical symptoms of grass tetany were observed at any time
during these studies. However, the higher Mg concentration
and lower tetany ratio suggest that HiMag could provide a
means of reducing the incidence of grass tetany in livestock
during periods when risk of the disorder is high.

Item Type: Article
NWISRL Publication Number: 0971
Subjects: Animal > Animal health
Irrigated crops > Grass forage > Chemistry
Mass Import - autoclassified (may be erroneous)
Depositing User: Dan Stieneke
Date Deposited: 20 Nov 2010 21:54
Last Modified: 18 Nov 2016 15:57
Item ID: 702