The climax of a story usually occurs at the same time as the crisis or turning point. This is when a character makes a choice which will determine the outcome of events and once done, the consequences are irrevokable.
Mr. O'Flynn obviously has the last 'say-so' concerning Curly since it is his steer and he knows Johnny is attached to it as a pet. When denial over Curly's fate breaks down and Johnny understands that Curly will be evenetually slaughtered, he could decide to make an exception in Curly's case, but he doesn't. He needs the money; cattle are his livelihood. Besides, his son needs to learn to be realistic in life.
When Johnny's sister tries to convince her father to do otherwise ("Dad! Do something!"), he resolves to put an end to this "nonsense," although he is not indifferent to his son's feelings.
- This is evidently not about the same short story as the other one which has comments! Same title, different story...