Umbilical cord from and contains remnants of the yolk sac and allantois. It forms by the fifth week of development, replacing the yolk sac as the source of nutrients for the embryo. The cord is not directly connected to the mother's circulatory system, but instead joins the placenta, which transfers materials to and from the maternal blood without allowing direct mixing. The length of the umbilical cord is approximately equal to the crown-rump length of the fetus throughout pregnancy. The umbilical cord in a full term neonate is usually about 50 centimeters (20 in) long and about 2 centimeters (0.75 in) in
Tritrichomonas foetus Tritrichomonas foetus Tritrichomonas foetus is a species of single-celled flagellated parasites that is known to be a pathogen of the bovine reproductive tract as well as the intestinal tract of cats. In cattle, the organism is transmitted to the female vagina and uterus from the foreskin of the bull where the parasite is known to reside. It causes infertility, and, at times, has caused spontaneous abortions in the first trimester. In the last ten years, there have been reports of "Tritrichomonas foetus" in the feces of young cats that have diarrhea and live in households with multiple cats. "Tritrichomonas foetus"