This barbecue battle (a ritual well-known to suicidal animals) isn't proceeding along conventional lines. Comparing this with some other examples of the form (here and here), we see one obvious difference: The pig is not approaching the sacred contest with the requisite solemnity. It's a breach of protocol that the cow will not tolerate!
The pig's heart is filled not with a trembling awe, the proper expression of religious fervor, but instead with… happiness. And in his inappropriate mirth, he has insulted the very basis of the animals' supposed worldview! Who knew one belly laugh could upend an entire way of life? It's the guffaw heard 'round the world, and the cow—presented here as the culture's Old Guard—can only look on in shock and annoyance.
The pig, doesn't he realize what's at stake? Doesn't he know that by their deaths, the animals renew their very world? Here he is, laughing at his funeral, seemingly unmindful of the import, the honor that has been bestowed upon him. Like a holy clown, he chuckles, so glad is he to die. As the Sacred Wiener made from his flesh is proffered, he neither prays in gratitude, nor kneels in humble acceptance. Nor does he brace for combat. No, the fool laughs! A decent pig would hide his joy at death's impending caress, a joy—let's be frank—as natural as it is mysterious. He would act out his role with a little dignity. To enjoy death, but not to overenjoy it. This is what is required.