As announced on August 4, 2021, Chiru (female), an Domestic Pig Domestic Pig kept at "Children's Zoo STEP," had cancer spreading throughout her body. We have been working to treat her and reduce her suffering to maintain her quality of life (QOL), but since recovery is not expected and her suffering is likely to increase, we regret to inform you that we have had no choice but to euthanize her.

Treatment history to date

January 2019
A surgical removal was performed due to suspected pyometra (a condition where pus accumulates in the uterus), and cancer was discovered. At this point, no obvious metastasis was observed, and the patient was placed under observation.

February 2021
Due to a significant increase in the white blood cell count, a CT scan and cytology examination were performed at the zoo's animal medical center, revealing lesions in multiple organs, including the lungs and kidneys, that appeared to be metastatic cancer.

However, because the cancer had spread throughout her body, surgical treatment was not possible. We also considered chemotherapy, but we thought that it would require continuous intravenous administration while restricting her movement, and given the severity of the expected side effects (nausea, vomiting, diarrhea, anemia, loss of appetite, etc.), it would actually worsen Chiru's quality of life in the future. Therefore, we focused on alleviating the cancer pain with analgesics and managing her as quietly as possible so as not to disturb her rest, so that Chiru could continue living her life as before.

Around July 2021
We continued administering painkillers, but gradually the animal's respiratory abnormalities and unsteadiness increased, and its activity level decreased. In addition, its appetite worsened, and it spent most of the day sleeping, leading us to suspect that the painkillers were reaching their limit. We took great care to create a safe and comfortable environment for it to rest in, and encouraged it to forage by actively offering its favorite foods.

Decision and implementation of euthanasia

August 2021
After reviewing the current situation and the projected future course of events, we concluded that it is impossible to alleviate Chiru's current suffering through treatment, and that it would likely worsen. Therefore, we determined that euthanasia, rather than prolonging her futile suffering, would ensure Chiru's animal welfare.

Surgical methods such as cancer removal are not possible.
- Medication is unlikely to reduce the size of the cancer that has metastasized throughout the body, and chemotherapy would impair Chilu's quality of life in the future.
The decrease in activity and food intake is presumed to be due to pain caused by cancer, and the effectiveness of painkillers has reached its limit.
The patient's breathing is becoming labored, and respiratory distress is expected to worsen.
It is likely that the patient will soon become unable to stand, and in that case, there is a high probability that bedsores will develop, leading to new pain and sepsis.

September 6, 2021
The euthanasia procedure was performed in a manner that took care to minimize the animal's suffering.

from now on

Immediately after treatment, an autopsy is performed to investigate the lesions and other conditions. The valuable information obtained from the autopsy will be used to improve veterinary medicine in order to save more animals in the future.
The two Domestic Pig currently being cared for at "Children's Zoo STEP" are also getting old, but we will continue to prioritize the animals' health in their care.

Please note that, as a measure against COVID-19, we have suspended accepting offerings such as flowers for animals. We apologize that we are unable to provide a place for you to express your feelings.

We are deeply saddened to have to deliver this news, and we hope you will understand.


"Chirū" Domestic Pig (Domestic Pig)
◎Related News
・ Introducing the native breeds of beef cattle "Mishima Beef" and native breeds of pigs "Domestic Pig" and "Ayo"! (December 12, 2008)
・ Domestic Pig has a new member joining the family! (October 23, 2009)
・ About Domestic Pig kept at "Children's Zoo STEP" (August 4, 2021)

[Ueno Zoo Education and Outreach Division]

(September 6, 2021)