kotiti

1. (of animals) to give birth; to have young
   Zečevi se kote nekoliko puta godišnje. — Rabbits have litters several times a year.
   Naša mačka svake godine koti mačiće u podrumu. — Our cat has kittens in the basement every year.
2. derog. (kotiti se, of people and things) to multiply; to breed
   Kladionice se kote u svakom kraju grada. — Betting shops are multiplying in every part of town.

Used both transitively (koti mačiće) and with se (mačka se koti); the perfective is okotiti.