YOU SAID:

I own one horse and two cows

INTO JAPANESE

私は馬を1頭と牛を2頭飼っています

BACK INTO ENGLISH

I have one horse and two cows

INTO JAPANESE

私は馬を一頭と牛を二頭飼っています

BACK INTO ENGLISH

I have a horse and two cows

INTO JAPANESE

私は馬と牛を二頭飼っています

BACK INTO ENGLISH

I have two horses and two cows

INTO JAPANESE

私は二頭の馬と二頭の牛を飼っています

BACK INTO ENGLISH

I have two horses and two cows