A topical localized formulation for use in the treatment or prophylaxis of parasite infestation in animals which comprises an effective amount of at least one isoxazoline compound of the Formula, wherein R 1 = halogen, CF 3, OCF 3, CN, n = integer from 0 to 3, preferably 1, 2 or 3, R 2 = C 1 -C 3 -haloalkyl, preferably CF 3 or CF 2 Cl T = 5- or 6-membered ring, which is optionally substituted by one or more radicals Y, Y = methyl, halomethyl, halogen, CN, NO 2, NH 2 -C=S, or two adjacent radicals Y form together a chain CH-CH=CH-CH, N-CH=CH-CH, CH-N=CH-CH, CH-CH=N-CH, or CH-CH=CH-N, HC=HC-CH, CH-CH=CH, CH=CH-N, N-CH=CH Q = X-NR 3 R 4 or a 5-membered N-heteroaryl ring, which is optionally substituted by one or more radicals; X = CH 2, CH(CH 3), CH, CO, CS, R 3 = hydrogen, methyl, haloethyl, halopropyl, halobutyl, methoxymethyl,methoxyethyl, halomethoxymethyl, ethoxymethyl, haloethoxymethyl, propoxymethyl, ethylaminocarbonylmethyl, ethylaminocarbonylethyl, dimethoxyethyl, propynylaminocarbonylmethyl, N-phenyl-N-methyl-amino, haloethylaminocarbonylmethyl, haloethylaminocarbonylethyl, tetrahydrofuryl, methylaminocarbonylmethyl, (N,N-dimethylamino)-carbonylmethyl, propylaminocarbonylmethyl, cyclopropylaminocarbonylmethyl, propenylaminocarbonylmethyl, haloethylaminocarbonylcyclopropyl, wherein Z A = hydrogen, halogen, cyano, halomethyl (CF 3); R 4 = hydrogen, ethyl, methoxymethyl, halomethoxymethyl, ethoxymethyl, haloethoxymethyl, propoxymethyl, methylcarbonyl, ethylcarbonyl, propylcarbonyl, cyclopropylcarbonyl, methoxycarbonyl, methoxymethylcarbonyl, aminocarbonyl, ethylaminocarbonylmethyl, ethylaminocarbonylethyl, dimethoxyethyl, propynylaminocarbonylmethyl, haloethylaminocarbonylmethyl, cyanomethylaminocarbonylmethyl, or haloethylaminocarbonylethyl; Or R 3 and R 4 together form a substituent selected from the group consisting of: and a veterinary acceptable liquid carrier vehicle wherein the liquid carrier vehicle comprises N,N-diethyl-3-methylbenzamide as a solvent and wherein the formulation comprises 10 to 40% w/v of the isoxazoline compound of formula. R 1 = halogen, CF 3, OCF 3, CN, n = integer from 0 to 3, preferably 1, 2 or 3, R 2 = C 1 -C 3 -haloalkyl, preferably CF 3 or CF 2 Cl T = 5- or 6-membered ring, which is optionally substituted by one or more radicals Y, Y = methyl, halomethyl, halogen, CN, NO 2, NH 2 -C=S, or two adjacent radicals Y form together a chain CH-CH=CH-CH, N-CH=CH-CH, CH-N=CH-CH, CH-CH=N-CH, or CH-CH=CH-N, HC=HC-CH, CH-CH=CH, CH=CH-N, N-CH=CH Q = X-NR 3 R 4 or a 5-membered N-heteroaryl ring, which is optionally substituted by one or more radicals; X = CH 2, CH(CH 3), CH, CO, CS, R 3 = hydrogen, methyl, haloethyl, halopropyl, halobutyl, methoxymethyl,methoxyethyl, halomethoxymethyl, ethoxymethyl, haloethoxymethyl, propoxymethyl, ethylaminocarbonylmethyl, ethylaminocarbonylethyl, dimethoxyethyl, propynylaminocarbonylmethyl, N-phenyl-N-methyl-amino, haloethylaminocarbonylmethyl, haloethylaminocarbonylethyl, tetrahydrofuryl, methylaminocarbonylmethyl, (N,N-dimethylamino)-carbonylmethyl, propylaminocarbonylmethyl, cyclopropylaminocarbonylmethyl, propenylaminocarbonylmethyl, haloethylaminocarbonylcyclopropyl, wherein Z A = hydrogen, halogen, cyano, halomethyl (CF 3); R 4 = hydrogen, ethyl, methoxymethyl, halomethoxymethyl, ethoxymethyl, haloethoxymethyl, propoxymethyl, methylcarbonyl, ethylcarbonyl, propylcarbonyl, cyclopropylcarbonyl, methoxycarbonyl, methoxymethylcarbonyl, aminocarbonyl, ethylaminocarbonylmethyl, ethylaminocarbonylethyl, dimethoxyethyl, propynylaminocarbonylmethyl, haloethylaminocarbonylmethyl, cyanomethylaminocarbonylmethyl, or haloethylaminocarbonylethyl; Or R 3 and R 4 together form a substituent selected from the group consisting of: and a veterinary acceptable liquid carrier vehicle wherein the liquid carrier vehicle comprises N,N-diethyl-3-methylbenzamide as a solvent and wherein the formulation comprises 10 to 40% w/v of the isoxazoline compound of formula.