Not by any definition of the term that I've been able to find. Microevolution is defined as change over a short and observable period of time. A few generations, for example. Macroevolution is defined as evolution over a much longer period of time which spans geologic time or which results in the creation of new species. The fossil record of the evolution of a horse spans over 50 million years and multiple branches, most of which died out.
The only problem with this is, the fossil record doesn't support this expectation. What it shows, remarkably, is stasis, the very opposite of evolution: the tendency of species to remain unchanged, even over the course of hundreds of millions of years.
It shows nothing of the kind, as this link explains.
The "evolution" of the modern horse from its precurser forms eohippus – mesohippus would seem to be an example of microevolution. So what if the earlier precurser forms died out. Perhaps in a couple million years the modern horse as we know it will look a lot different than it does now.
This is the best definition of microevolution I've ever come across, from Doron Aurbach, Professor of Chemistry at Bar Han University, Israel:
Micro-evolution is a reality that is experienced in life and documented by reliable scientific experiments and observations…. It includes observation of speciation in some kinds of birds and insects, due to the interrelationship between genetics, environment, and adaptation. In fact, the genetic code of all living species allows for certain degrees of freedom and change for any property that is inherent in these species. These degrees of freedom are in part intrinsic, that is, they are part of the genetic code itself, and may be caused by mutations, or, in layman’s terms, by sporadic and occasional changes in the genetic code. This freedom of the genetic code is of critical importance because it allows for the adaptation of life to environmental changes and for all the wonderful diversity that is seen in life on earth, enabling human beings, for example, to be distinguished from one another, by appearance, as well as by unique identities and characteristics. This adaptive ability of genetic codes … is nothing more than a fine tuning of basic properties. ["Intelligent Design vs. Evolution Theory," Divine Action and Natural Selection, Singapore: World Scientific, 2009, p. 687]Do you have a problem with that definition? If so, please tell me what it is.