Final answer:
Pregnant ewes and does should be vaccinated against Clostridium perfringens, which can cause enterotoxemia, and Clostridium tetani, responsible for tetanus. Vaccination helps protect the health of both the animals and their offspring.
Step-by-step explanation:
Pregnant ewes and does should be vaccinated against certain diseases to protect both the mothers and their offspring. Among the options provided, Clostridium perfringens, known for causing a type of food poisoning and mild gastrointestinal illness, is a common bacterium that pregnant farm animals should be vaccinated against. It is part of a group of bacteria that can cause enterotoxemia in sheep and goats, which can be fatal, particularly in times of stress such as during pregnancy and birth. Vaccines against Clostridium tetani are also important since tetanus can be a life-threatening condition affecting muscle function, which farm animals can contract from contaminated environments.