Chimerism in cattle
Mayr, B.; Hager, G.
Deutsche Tierärztliche Wochenschrift 85(5): 170-173
1978
ISSN/ISBN: 0341-6593 PMID: 348442 Document Number: 133266
Chromosomal analyses were performed on blood and testicular cell cultures from 254 cattle to assess the frequency of chimerism. In six cases (4 males and 2 females) a chimerism of blood cells was established, being born as heterosexual twin pairs. The male fetus had a crown-rump length of 92 mm and the freemartin a length of 85 mm with freely distributed vessel anastomoses; the male embryo was clearly the more dominant. Female blood cells in the four males were found at a frequency of 5, 16, 20 and 90%. The absence of XX cells was observed in the testicles of one male which exhibited a positive blood test. About 10% of the heterosexual female twins were considered to be fertile. Gross examination of the freemartin showed well developed genitalia and a moderately enlarged mammary complex; a small, thin mammary complex was observed in male fetuses. The tubuli of the freemartin contained only a few 'spermatozoa' whereas those of the male twins were rich in these cells.