Trichostrongylus colubriformis is a very small threadlike worm and is the most predominant small intestinal worm. It is found in goats throughout the United States but seems to thrive better under more cool and wet conditions similar to T. circumcincta. However, in the southeastern United States, this worm is the next most common and important after Haemonchus. On some farms it can cause considerable problems. As with Telodorsagia, this worm feeds on nutrients in mucous and interferes with digestive function, resulting in diarrhea. It is called the "bankrupt worm" because death is seldom the end result, and animals just become poor doers, leading to loss of production and income.
Nematodirus spp. are relatively large worms that are easily visible and can be found in goats throughout the United States, although usually in rather small numbers. Problems are rare in the Southeast, but in cooler areas of the United States there is a possibility of greater numbers of worms accumulating. The eggs of this worm have a high tolerance for freezing temperatures. If heavy infection occurs, production and income losses will result, similar to that of T. colubriformis. Female worms lay eggs that are substantially larger than those of other abdominal and intestinal worms.