kitztack wrote:as an only son im the only one here to help my father, so i'd like to know what the sutta's say about obligation to one's parents
Paraphrasing AN I, 62-63:
The Buddha taught that there you can never physically repay your mother and father even if you were to carry them upon your shoulders or give them rulership over the whole world. The only way to repay them is to teach them Dhamma: establish the unbelieving in faith, the immoral in morality, the stingy in generosity, the ignorant in wisdom.
If your parents are supportive of you going and living off on your own or if they don't absolutely need you, I would leave with all due respect to them. If they absolutely need you on the farm to help them, that is tricky. On the one hand you want to follow the Buddhist path and not have wrong livelihood. On the other, you have an obligation to help your parents which involves slaughtering animals. You could try reducing guilt by reminding yourself that you only live in such a way to help your parents. Time will pass and eventually, one way or another, you will be freed from your obligations and at that time you will be able to choose the right path for yourself.
In the meantime, I'd do the best I could to extricate myself from having to slaughter animals directly.