The Cambridge specimen

The Cambridge aurochs is one of the complete aurochs skeletons that are on display. It was found in Burwell, England, and is mounted at the Museum of Zoology in Cambridge. It is the best-preserved British aurochs specimen, and of unknown age. For photos of the specimen, go here or here. 

The museum itself claims it was a bull. Indeed the postcranial skeleton looks masculine, with its robust bones and high shoulder spines. However, the skull reveals it was definitely a cow. The eye sockets are not very prominent, and the distance of the end of the frontal bone between the horns is considerably shorter than the distance between from eye socket to eye socket, while in male skulls the distance is about the same. A comparison between the skull of the Cambridge specimen (here) and skulls that are definitely male (f.e. here) shows its female nature. Furthermore, the withers height of the skeleton is only 145 cm (therefore the live animal must have been between 150 and 155 cm tall), see Frisch 2010. 

I did a reconstruction of the head of the specimen based on this photo: 

The horns resemble those of some Heck cattle from the Wörth lineage, go here and here for a comparison. The head of the specimen bears some resemblance to Sayaguesa and other primitive cattle.