Following the death of her father, Sir Leopold Cust in 1878, Aleen was forced to leave her birthplace at Cordangan Manor, Tipperary, Ireland, where she had spent an idyllic childhood, and move with her mother and siblings to Shropshire, England. Encouraged by a family friend in her aspirations to pursue a career, Aleen began training as a nurse at the London Hospital, but feeling more empathy towards animals, she left nursing and much to her mother’s dismay, decided to follow a career as a veterinary surgeon. After gaining the necessary qualifications at university in Edinburgh, she was accepted into the New Veterinary College, where despite winning several medals and having passed the four-year curriculum with distinction, she was refused by the Council of the Royal College of Veterinary Surgeons to sit her professional exams, because she was a woman.
In 1900, Aleen returned to Ireland where she worked as an assistant to William Augustine Byrne, at his veterinary practice in Roscommon. Unopposed to women entering the veterinary practice, William Byrne played a huge part in Aleen’s acceptance into the veterinary profession and through his recommendation she became part-time veterinary inspector to Galway County Council, a position that publicised the admittance of women into the profession. Aleen had become highly respected in her profession and pressure was mounting against the RCVS to lift their restrictions regarding women.
When William Byrne died suddenly in 1910, Aleen continued running his practice until the outbreak of the First World War in 1914. Keen to offer her veterinary skills in the horse hospitals set up at the Western Front, she drove her own car all the way to Abbeville in France. As she was still unqualified on paper, Aleen could not work officially with the Army Veterinary Corps, so she volunteered with the Young Men’s Christian Association (YMCA) and unofficially worked in the field veterinary hospital. During the last year of the war, she signed up for the Queen Mary’s Army Auxiliary Corps as a bacteriologist in the laboratory researching the diseases responsible for the deaths of many of the war horses. Aleen left France a month before Armistice Day.
The passing of The Sex Disqualification (Removal) Act in 1919, prohibiting the exclusion of women from any occupation because of their gender, forced the RCVS to lift their restrictions regarding women and in 1922, twenty-two years after completing her training, Aleen finally received her diploma, becoming Britain’s first qualified female veterinarian. With her health declining, she retired to a quiet village in the New Forest, Hampshire, but often assisted in the work of the RSPCA. In 1937, she was visiting friends in Jamaica and had just finished treating their injured dog, when she collapsed suddenly and died.