Roland W. Dixon qualified as a veterinarian (MRCVS, London) in March 1886. He arrived in South Africa in December 1893 as one of four veterinarians appointed by the Cape Government at the request of the Colonial veterinary surgeon, Duncan Hutcheon*. In 1894 he studied an outbreak of geeldikkop among sheep and goats in the Karoo. Though he found evidence that it might be caused by ingesting the duwweltjie (Tribulus terrestris), he was later unable to reproduce the disease during feeding tests. The work was reported in an article, "Geeldikkop in sheep", in the Agricultural Journal of the Cape of Good Hope (1895). From February to May 1897 he assisted with rinderpest research at the laboratory set up by Robert Koch* in Kimberley. The next year he and J. Spreull* conducted experiments on hearwater in sheep and goats, and redwater in cattle, and studied the life history of different ticks, on a farm near Fort Beaufort. The work was described in the Agricultural Journal as "Heartwater experiments" (1898, Vol. 12, pp. 754-760; 1899, Vol. 15, pp. 790-792) and "Tick experiments" (1898, Vol. 13, pp. 691-695). In 1899, stationed at Beaufort West, his feeding experiments contributed to Hutcheon's conclusion that Cotyledon sp. causes krimpsiekte in goats. That same year he reported in detail on his "Geel-dikkop investigations" (Ibid, Vol. 14, pp. 862-873), describing the symptoms, postmortem findings, and his unsuccessful inoculation experiments. In later years he reported in the same journal on wireworm in sheep and goats (1907), catarrhal fever of sheep (1909), East Coast fever (1910) and further on heartwater in sheep and goats (1910). During the next few years he published articles in the Agricultural Journal of the Union of South Africa on East Coast fever (1911) and wireworm (1913). His most important contribution was to the study of hearwater.
Dixon was stationed at Kimberley (1901-1903) and at East London (1904-1907) where he was in charge of the border districts. He was then promoted to senior veterinary officer in charge of the Cape Western Division, and stationed in Cape Town. After the formation of the Union of South Africa in 1910 he became senior veterinary officer of the Cape Province. The next year he undertook one or more dipping lecture tours. In 1916 he was an examiner in veterinary science for the newly established BSc Agriculture degree of the University of the Cape of Good Hope. He was promoted to assistant principle veterinary officer for the Union of South Africa in 1921.Three years later he represented the country at a conference on east coast fever held at Bulawayo.
Dixon was a founding member of the Cape of Good Hope Veterinary Medical Association in 1905, served on its council during 1907-1909, and then as vice-president to at least 1913. He later joined the South African Veterinary Medical Association and was still listed as a member in 1927. By 1929 he resided in Cape Town.