264 ESSENTIALS OF VETERINARY LAW 
much stronger than that dividing two meadows. 
On the other hand, animals simply driven along 
the highway have neither time nor opportunity 
for discovering any but very apparent weaknesses 
in the enclosing structure. 
These general rules must often be altered to suit 
the locality or other conditions. Where cattle are 
permitted legally to wander upon the range, clear- 
ly every man must protect his own grain by fences. 
By agreement it is customary for the owners of 
adjacent property to unite in building line fences, 
or to agree that one shall keep up a certain por- 
tion, and the other another portion. This agree- 
ment should include a statement of the purposes 
for which it is erected. A fence which is entirely 
sufficient as a line fence would be improper for 
the restraint of animals; and a fence which would 
be good for horses would not restrain hogs, or if 
built for hogs it might not restrain cattle or horses. 
A man is liable for the trespass of his animals 
through that portion of the line fence which it is 
his duty to keep up, without regard to the char- 
acter of his neighbor’s portion.*® But, an owner 
of property cannot recover for trespass when the 
trespass was due to his own negligence, as in a 
failure to keep his portion of the fence in repair.*® 
‘‘Eivery unwarrantable entry by a person or his 
cattle on the land of another is a trespass, and a 
person is equally answerable for the trespass 
of his cattle as of himself.’’®° Where cattle 
48 Cooley, Torts, 399. v. Balzer, 47 Barb. 562; Duf- 
49 Carpenter v. Cook, 67 Vt. fees v. Judd, 48 Iowa, 256. 
102, 30 Atl. 998; Weide v. 50 Am. & Eng. Enc, of Law 
Thiel, 9 Ill. App. 223; Cowles (2nd Ed.), 345. 
