Why is it that diagnosing a parasite infection can be difficult in some cases? What factors would make it challenging?

the sphincter muscles at the end of the digestive tract is the anus.

common management practices in dairy and poultry farming are: (i) proper shelter facilities and their regular cleaning. (ii) some basic hygienic conditions such as clean water, nutritious food, etc. (iii) animals are kept in spacious, airy, and ventilated place.