The newborn lamb was wrapped in a lot of jelly and yellow mucus, and the placenta of the ewe was not left. Could it be brucellosis?

According to the information you provided, it is impossible to determine whether this yellow mucus is caused by brucellosis. However, this situation needs attention, because it may be an abnormal symptom that newborn lambs are covered with mucus, which may require further examination and treatment.

First of all, I suggest you consult your local veterinarian for initial diagnosis and treatment advice. Veterinarians can check the symptoms of ewes and newborn lambs and conduct necessary laboratory tests to determine whether they have brucellosis.

If brucellosis is diagnosed, measures should be taken in time to prevent the further spread of the disease. This may include isolation, treatment and preventive measures to protect other animals from virus infection.

In addition, if brucellosis is diagnosed, it is suggested that medical examination and preventive measures should be taken for those who have come into contact with sick animals to prevent human infection.

In a word, this situation needs attention and timely measures to protect the health of animals and human beings.