"One of the most important sources of weed infestation in agricultural crops is related to manure applied as biological fertilizer, when livestock growers don`t process it and don`t store it in order to be weeds - free. In manure there are lot of weed seeds from animal fodder, livestock bedding and also from animal excrements. On the pasture, when grazing fresh food, animals eat also the inflorescences with weed seeds. Ones of these seeds could pass through the digestive tract of animals while keeping their ability to germinate. The aim of this study was to record the weed species that can cross over the digestive tract without losing their germination, to note which weed species are more adapted to do this, which animal species are able to perform the endozoochory process and under what environmental conditions. Trials were conducted under laboratory conditions. The content of excrements taken from four animals species (cattle, goats, sheep, horses), from four distinct South – East areas in period 2019-2020, were mixed with sterilized soil and put to germinate under controlled conditions of temperature and humidity. Following the assessments, weed seeds were found to be able to cross over the digestive tract of animals maintaining their germination. The highest frequency was in cattle and the lowest was in horses. There was at Pasărea where the largest number of weeds was found and animals grazed on untillaged land (hences, fallow lands). The dominant weed species were Setaria sp., Chenopodium sp., Amaranthus retroflexus and Polygonum aviculare."