Zebra injury

Note the difference between the two stomachs of the zebra. The one behind is more square and when I asked the cause, this was the reply I received: Thanks Dr. Peter Buss! 

“Thanks for sending me the photograph.  It is always difficult to give definitive answers based only on a photograph. However, the enlargement on the zebra’s abdomen, which appears to be localized, suggests three possibilities. a) a hernia of fat and other tissue through a small tear in the muscles of the abdomen to below the skin. The original injury resulting in the tear may have been a kick from another zebra; b) localized infection resulting in an abscess; c) soft tissue growth.  The most likely is an abscess as it is an unusual place for a hernia, and growths (cancers) are not common in wildlife. The thickened vein running from the area, which is visible in the photo, suggests an increased blood supply to the area and possibly an active lesion which would be consistent with an abscess. It is also possible the mass may be blocking the vein causing it to appear enlarged.”