SB 10.19.1

śrī-śuka uvāca
krīḍāsakteṣu gopeṣu
 tad-gāvo dūra-cāriṇīḥ
svairaṁ carantyo viviśus
 tṛṇa-lobhena gahvaram
Word for word: 
śrī-śukaḥ uvāca — Śrī Śukadeva Gosvāmī said; krīḍā — in their playing; āsakteṣu — while they were completely absorbed; gopeṣu — the cowherd boys; tat-gāvaḥ — their cows; dūra-cāriṇīḥ — wandering far away; svairam — independently; carantyaḥ — grazing; viviśuḥ — they entered; tṛṇa — for grass; lobhena — out of greed; gahvaram — a dense forest.
Translation: 
Śukadeva Gosvāmī said: While the cowherd boys were completely absorbed in playing, their cows wandered far away. They hungered for more grass, and with no one to watch them they entered a dense forest.