Salvete Dashydog,
the North Caucasus archaeological site Klin-Yar info can be gotten here -
http://www.rdg.ac.uk/archaeology/resear ... n-Yar.aspx - but this site is very old and includes both Koban (Russian:????????? ????????) culture - eg horse tack from 8th c BC
http://www.arcaucasica.ru/_images/gold_ ... 47_48f.jpg and late antiquity/early medieval Alanic strata.
Actually horses would be of various sizes and bone structure - eg Pazyrk kurgan finds with horses from 130 to over 150cm at withers, from steppe coarse type to Akhal-teke type - Pontic-Caspian steppes had plenty of horseflesh since the 4rd millenium BC, eg Anthony in Wheel, Horse and Language underlines the size of ancient steppe horses that Soviet archaeologist found in the Western Asian steppes, over 15 hands at withers was not infrequent.
The Caucasus region has had some of the finest horse breeds in the world - in the north it is especially the Kabardian, a medium size mountain horse of some very ancient pedigree eg
http://kabardians.com/
Smaller horses are all about the economy, hardiness, endurance and agility -
Polish armies ventured into the Russian winters many times, returning with their horses et al, especially during the 16-17th centuries. Our sources write plenty about eating twigs, tree branches and actual tree leaves when no grass, hay nor other fodder was available - several times during prolonged sieges they actually fed horses a mixture of chopped raw meat with straw and a bit of gunpowder, supposedly horses became very fiery ( siege of Zbaraz 1648 AD) . Americas' native horsemen, of the llanos and prairies, never fed their horses other food but what was available near their camp during the winter months, since they wintered in the river valleys then they fed their horses smaller tree branches and twigs, eg cotton tree branches being very popular amongst the Upper Missouri tribes. Horses can dig the dried grass from under the snow 50cm deep, while sheep and cows die of hunger unable to paw the snow to grass and herbs underneath.
Having said that I do not think Polish armies, mostly made of cavalry, preferred to fight in the winter, it was the condition of the war theater - bogs, swamps, wetlands, numerous rivers, streams, and lakes - of the Western Russian Plain that forced winter campaigning. There were no roads, highways, while forts, cities and strongholds were built near or on the lakes, riverbanks, etc, thus easier to attack in the winter... but the suffering for the horses and men must have been terrible and I dare to say beyond our understanding...
I would also venture to say that Western Sarmatian tribes or confederacies (3rd century BC to 3rd c. AD) had a bit different horse than later Hunnic -Xioung-nu's long, angular horse. Usually it is thought that they came to the Pontic steppe during 4th century BC. I think they had plenty of time to breed horses for various uses, from food to warfare and parade, espcailly since they brought fine and reguilar horses from Central Asia, and had at their disposal (through trade, gifts and raiding) many ancient Armenian, Thracian, Scythian, Persian etc bloodlines. Again comparison can be made, perhaps very far fetched, with the America's native horsemen. Around 1810-20s these American warriors - Cheyenne, Crow, Comanche, Nez Perce, Cayuse etc - achieved possession of horse herds comparable with the nomadic Sarmatians and then they selected, trained, and used their horses based on their war, racing and hunting needs and their mounts' predisposition for such various needs. A wealthy warrior had several horses dedicated only for war and hunting, while the rest of his herds were sort of 'split' between being part of his social status and his family economic needs. Sarmatian warrior must have had many types of horses to select from...
sorry for this longish entry
ps
...intersting article about the crucible steel sword blades from Alani strata of Klin Yar
http://home.att.net/~moltenmuse/examination.htm