They are also able to discriminate between familiar individuals, and among humans. Cattle can tell the difference between familiar and unfamiliar animals of the same species (conspecifics). Studies show they behave less aggressively toward familiar individuals when they are forming a new group.  Calves can also discriminate between humans based on previous experience, as shown by approaching those who handled them positively and avoiding those who handled them aversively.  Although cattle can discriminate between humans by their faces alone, they also use other cues such as the color of clothes when these are available. 
The cheapest expense of being a bulldog owner would be the purchase price of the dog. This is what my family went through: we bought a cheap bulldog for $1500 seller said he was last of litter and just wanted to get rid of him to a good home. We were naive to the breed at the time and bought him. Within 2 weeks he was deathly ill with aspiration pneumonia which is quite common in the breed due to short squishy faces, his cherry eye popped out, and he had demodectic mange. The first vet we rushed him to was ready to put him down after a couple of courses of the wrong antibiotics. We didn't want to hear this so we took him back home where my husband and I gave him water from a syringe for hydration and desperately searched for a vet who had knowledge with this breed. We watched our Sammy struggle to breathe as he laid his chin on our couch to keep his head upright, very painful to watch. Then we found our vet we have now who saved Sammy's life. He was hospitalized for almost two weeks with iv antibiotics, breathing treatments every 2 hours, and steroids. Our cheap bulldog ended up costing us almost $10,000 in vet bills between the first vet that didn't have a clue to our current vet who specializes in bulldogs. Very hard and expensive lesson learned! Please be cautious of cheap bulldogs!!