Coccidiosis in goats and sheep
Coccidiosis is a serious problem that commonly causes death in kids and lambs. Knowing the facts about coccidiosis can help producers develop a plan for prevention and/or treatment of the disease.
Coccidiosis is not caused by a bacteria, virus or roundworm but by single cell protozoa. There are multiple coccidia species that are found in the environment. Some of these are non-infective, some moderately infective and others are highly infective. Strains of coccidia are animal species specific with some very limited crossover between sheep and goats.
The following are some coccidia facts:
- Coccidia are always present in the herd or flock, and most adult animals carry coccidian but are immune to clinical disease.
- Immunity occurs more in sheep than in goats.
- Lambs and kids develop immunity about four weeks after exposure.
- The protozoa are present in the small intestine, and young animals are most susceptible (30-60 days of age).
- Stress can trigger severe infections that can result in death.
- Chronic infections result in “poor doing” lambs/kids and create long-term intestinal damage.
The life cycle of coccidia is quite complicated and has many stages of development. The cycle is 21 days in length and proliferates inside the epithelial cells of small intestine, which causes damage to the cells of the small intestine. Oocytes (eggs) from adult protozoa are released via feces into environment. These oocytes go through a process called sporulation (hatching), which is enhanced by warm, moist conditions. Early development during the first 16 days following ingestion initiates damage without clinical symptoms. Clinical symptoms, diarrhea with or without blood, occur after day 18. Other symptoms can include stomach pain, decree sed appetite, dehydration, rectal straining (can lead to prolapse) and chronic poor doers as a result of small intestine damage. Animals are infective 14 to 17 days after ingestion. Animals begin to excrete eggs after day 22. The implications of this life cycle are that there is a gap between symptoms (diarrhea) and egg excretion so fecal egg counts are not always a good indicator of infection, as shedding of eggs only occurs at the end of the infection period after the damage has been done. Michigan State University Extension recommends post mortems as the best way to confirm coccidiosis.
In conclusion, coccidiosis is preventable in sheep and goat herds. Knowing the facts of how it is transmitted, and the lifecycle will help producers maintain their herds health.