Int rate futures and options

Hello Sir, after watching the int rate risk management lecture I have a question about the int rate future and options As what you said at the start of the lecture, the int risk management is for cover/protecting the period before the transaction (borrow loan or deposit money)take place until a future date, which we either selling or buying the future contract at today and close out the position when the transaction takes place Why the future contract size bought need to be cover the period of the loan which is after the transaction date(date of beginning)? Although I know its only cover for 3 mths ,but my question is : is it not only protect until the beginning of the loan start but also for the whole borrowing period ? Thank you.