Abstract: Antiwithdrawal agents and veterinary antiwithdrawal agents are disclosed which contain lipopolysaccharide (LPS) representatives which have the following physical properties:LPS1 Dominant molecular weight: 5,000.+-.1,000 as determined by SDS-PAGR method______________________________________ Phosphorus number: 2 .+-. 1/5,000 (m.w.) Hexosamine number: 9 .+-. 1/5,000 (m.w.) KDO number: 2 .+-. 1/5,000 (m.w.); ______________________________________LPS2 Dominant molecular weight: 6,500.+-.2,500 as determined by SDS-PAGR method ______________________________________ Phosphorus number: 1 to 2/5,000 (m.w.) Hexosamine number: 7 .+-. 1/5,000 (m.w.) KDO number: 1 to 2/5,000 (m.w.); and ______________________________________LPS3 Dominant molecular weight:6,500.+-.2,500 as determined by SDS-PAGE method ______________________________________ Phosphorus number: 2 .+-. 1/5,000 (m.w.) Hexosamine number: 5 .+-. 1/5,000 (m.w.) KDO number: 2 .+-. 1/5,000 (m.w.