Cows fed Se-yeast have higher
concentrations of Se in almost all tissues than do
cows fed selenite. Much of this Se is in proteins as
Se-met. As proteins in the body are turned over,
Se-met is released and if broken down can provide
Se for selenoenzyme synthesis. Cows fed selenite
have a much lower body reserve of Se than cows
fed Se-yeast. This could be beneficial in periods of
high Se demand and in unexpected periods of low
Se supply. Increased body reserves may be
especially beneficial for newborn calves. Calves
borne from cows fed Se-yeast have higher
concentrations of Se in tissues and often much higher
GSH-px activity than when cows are fed inorganic
Se. In addition, colostrum from cows fed Se-yeast
contains more Se than colostrum from cows fed
selenite, thereby increasing the difference in Se status
of the calves. Feeding cows some Se-yeast during
the last 60 days of gestation may have beneficial
effects on calf health by improving the Se status of
the calf.