Conclusions
Given that our studies found no differences in whole-body protein
synthesis when threonine was supplemented, the findings indicate
that the threonine supplementation for weanlings receiving this
commercial concentrate and a quality grass forage or adult horses
at maintenance on a diet composed of 60% grass forage and 40%
concentrate is most likely not warranted. However, threonine supplementation
can affect amino acid metabolism and additional research
is needed to determine how these changes in metabolism affect long
term growth and athletic performance. Additional research is also
needed to determine amino acid requirements in horses.