===First reading=== 
 *In the lead section, you need to be careful to be consistent as to whether "Mérens" is singular or plural. For example you say "In the past, the Mérens was ..." and in the next sentence "Today they are mainly used as saddle horses ..." 
 *"In the second half of the 20th century, the population sharply declined, as mechanization transferred work in the cavalry and agriculture fields to machines." - The word "fields" is not ideal here. Are you referring to fields on a farm or uses such as for cavalry work and agricultural work? 
 *"... between 1975 and 1985 their population rebounded, leading them to be considered an example for the conservation of rare breeds." - I guess its not the horses that are the example but the conservation methods used. 
 *"... and recommends efforts focused on its preservation." - perhaps "... and recommends that efforts should be focused on its preservation." 
 *"The head a straight or slightly concave facial profile, a flat forehead, and wide, short ears." - This sentence lacks a verb. 
 *The article needs to be consistent about the breed's name. It starts off "Mérens" and changes to "Merens". 
 *"Merens are found mostly in northwestern Italy, in the provinces of Cuneo and Turin, but in the past years it has spread to other mountain regions ..." - Confusion over singular and plural again. 
 *"In 1950 in Senegal, the Merens was used in attempts to create a horse tougher than the native M'Bayar, but it was not enough to revive the Merens." - To what does the "it" in this sentence refer? 
 *"He moved the efforts of farmers towards breeding a pony, ..." - This needs clarification. 
 *"A few members of the breed are bred for their milk, ..." - This is rather awkwardly expressed. 
 **That's all for now.