Sigmoid ansa

In most herbivores, the cranial part of the duodenum is longer in proportion than in carnivores and shows a sigmoid ansa (sigmoid inflection; Ansa sigmoidea) near the right liver lobe, particularly prominent in ruminants, barely visible in equids and pigs. This is the part where the bile duct (from the liver) and the pancreatic duct(s) open. However, embryological development differences mean that in some species, the pancreas has only one duct, which opens instead into the descending part (Cattle, Pig), or even at the beginning of the ascending part (Rabbit) of the duodenum.