It sounds like your little puppy may be suffering from a condition called Ascites. This occurs when there is an accumulation of fluid in the abdomen, causing distension and discomfort. In the case of your puppy, it seems that the accumulation is quite significant if it is measuring in kilograms.
Some possible causes for Ascites in dogs include liver disease, heart disease, cancer, or even an injury to the abdomen.
It is important to take your puppy to a veterinarian as soon as possible to determine the underlying cause and begin appropriate treatment.
In the meantime, you can help your puppy by providing a comfortable and quiet space for them to rest. It may also be beneficial to feed them smaller meals more frequently to ease any discomfort caused by the fluid buildup.
Source: ViacomCBS Inc.
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