Belt-shaped placenta (placenta zonaria) is a type of placenta in which it is located around the neck of the fetus, forming a wide belt. This type of placenta is found in several animal species, including dogs, cats, cows and pigs.
A belt-shaped placenta has several advantages over a regular placenta. Firstly, it ensures more efficient delivery of oxygen and nutrients to the fetus. Secondly, it allows the fetus to be in a more comfortable position, which can reduce the risk of complications during labor. Third, it may be more resistant to infection than a regular placenta.
However, the belt-shaped placenta also has its disadvantages. It may be more difficult to remove after delivery, which may increase the risk of complications. In addition, it can restrict fetal movement and create difficulties during labor.
Overall, placenta girdle is an interesting option for animals where it may improve fetal health and reduce the risk of complications during pregnancy and birth. However, for each type of animal it is necessary to take into account individual characteristics and choose the appropriate type of placenta depending on their needs and living conditions.