Freemartin is a female calf that is born as a twin to a bull and has been connected to its brother through circulation during pregnancy. As a result of this connection, the sexual development of the cow twin is disturbed and it is sterile. Freemartinism causes detectable anatomical changes, but early diagnosis by clinical examination is difficult due to heterogeneity of the developmental aberrations. Another result of the joined circulations is chimerism: both of the twins have permanently got cells derived from the other twin. The presence of bull cells in the freemartin can be easily detected by studying e.g. blood leukocytes. Even if not directly connected with the developmental defect, the blood cell chimerism can be used in diagnostics. The aim of this stydy was to develop a method for detecting freemartinism based on genomic in situ hybridization. Bull cells containing the Y chromosome were visualized among leukocytes from calf blood, using a specific DNA probe. Individual Y chromosome containing cells could be identified. The results indicate that chimerism can be reliably detected by in situ hybridization. 94 of the 100 calves included in the study had Y chromosome positive cells in their blood, 6 were negative. The proportion of Y chromosome bearing cells determined by counting was between 5 and 90 % in the positive samples. When samples from cow-bull twin pairs were studied, it could be shown that in most cases the level of blood cell chimerism was approximately the same in both twins. In conclusion, in situ hybridization is a precise and reliable method for detection of heterosexual chimerism in freemartin cattle.
This article is the first of two articles describing recent advanced studies performed by Katri Halinen at the Department of Basic Veterinary Science, Faculty of Veterinary Medicine, University of Helsinki. In Finland, forensic respectively legal medicine, is in itself not a discipline in the curriculum of veterinary students. However, veterinarians deal frequently with forensic or veterinary jurisprudence issues even in every day duties. Basing on the features of forensic human medicine, this first article defines forensic veterinary medicine. Beside autopsies and paternity investigations, issues from normal clinical work, like marking of animals, belong to legal medicine. Insurance companies are mass consumers of veterinary legal medicine both when they take insurances in and when they recompensate loss due to damage. With March 2002, a law for the setting up of a Board of veterinary malpractice came into force; this is supposed to serve as an opinion giver. Furthermore, animal welfare work which basically implies the supervision of the interests of animals, belongs to veterinary jurisprudence. The second article in the series will deal with anti-doping work in veterinary medicine, as well as with certificates given by veterinarians. It will outline the legislation and laws which regulate veterinary jurisprudence. The series of articles does not represent a comprehensive review of Finnish veterinary jurisprudence but will serve to figure out its characteristics on the basis of selected examples.