This article from the Auckland Star (1 February 1916), describes the purchasing of horses in Waikato during the First World War. The horses had to be between five and 10 years old; thoroughbreds were preferred, and as few mares as possible were bought.
'Purchasing Waikato horses for war', URL: https://nzhistory.govt.nz/media/photo/purchasing-waikato-horses-war, (Ministry for Culture and Heritage), updated 17-Sep-2013
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