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AAES Research Series 488
incidence of morbidity, serum vitamin B12 concentrations,
and number of antibiotic treatments were analyzed using the
GLM procedure of SAS (SAS Inst. Inc., Cary, NC). The
model included block and cobalt supplementation.
Results and Discussion
Average daily gain for the entire 42-d study (Table 2)
was not affected (P > 0.10) by dietary supplementation of
cobalt. Gains during the period from d 8 to 14 tended to be
greater in calves supplemented cobalt (P = 0.07) compared
with those fed no supplemental cobalt; however, from d 15 to
28 control calves tended to have increased ADG (P = 0.09).
Stangl et al. (1999) found that a cobalt deficiency did not
have any significant effect on energy metabolism in calves
fed a cobalt deficient diet for 43 weeks. These authors did
find that there was a marked reduction in serum triodothryonine.
The ADFI (Table 2) for d 1 to 42 did not differ (P >
0.10) among treatments. These results are consistent with
those of Mburu et al. (1992) who found that cobalt deficiency
had no effect on feed intake of small east African goats.
Supplemental cobalt did decrease feed/gain (P = 0.06) from d
8 to 14 ; although, from days 15 to 28 control calves had a
lower feed/gain (P = 0.07) compared with calves fed supplemental
cobalt.
Percentage morbidity was not affected (P > 0.10) by
supplemental cobalt (65%) vs. control (76%). Supplemental
cobalt also had no effect (P > 0.01) on medication costs,
$12.37 for cobalt supplemented calves vs. $12.57 for controls.
Plasma vitamin B12 was not affected by cobalt supplementation.
Judson et al. (1997) found that plasma vitamin
B12 concentration was increased for up to 28 weeks due to
the supplementation of a single cobalt pellet over that of
control cows.
Implications
Supplementing cobalt in the present study did not
improve growth performance or lower medication costs for
stressed heifers. In addition, cobalt supplementation did not
improve plasma vitamin B12 concentrations.
Acknowledgments
The authors acknowledge J. A. Hornsby, G. Carte, and
J. Sligar for the management and care of the experimental
animals.
Literature Cited
Judson, G. J., et al. 1997. Aust. Vet. J. 75:660.
Mburu, J. N., et al. 1993. Internat. J. Vit. Nutr. Res. 63:135.
NRC. 1996. Nutrient Requirements of Beef Cattle. 7th ed.
Natl. Acad. Sci., Washington, DC.
Stangl, G. I., et al., 1999. Internat. J. Vit. Nutr. Res. 69:120.
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