YOU SAID:

i have 1 dog and 3 cats

INTO JAPANESE

私は犬1匹と猫3匹を飼っています

BACK INTO ENGLISH

I have a dog and 3 cats

INTO JAPANESE

私は犬と猫を3匹飼っています

BACK INTO ENGLISH

I have 3 dogs and 3 cats

INTO JAPANESE

私は3匹の犬と3匹の猫を飼っています

BACK INTO ENGLISH

I have 3 dogs and 3 cats