XX/XY chimerism and freemartinism in a female llama co-twin to a male

XX/XY chimerism of blood cells and freemartinism may be identified in femal e llamas born co-twin to males. Females of opposite-sex twins should be exa mined at birth for vaginal patency. Freemartinism should be suspected in female llamas with undeveloped interna l genital organs even if they were apparent single births, because a male t win may have been conceived but died during gestation.