Cattle, including bulls, are generally quiet at night. However, when something stirs them up enough to make them call out for some reason or other, they would make the same noise or sound as they would in the daytime. The call a bull makes does not change with respect to photoperiod.
There are several ways to spell the sound a frog makes. The most common spelling is 'ribbit.' Sometimes, when referring to the sound a bull frog makes, the word 'croak' is used to refer to the deep, throaty, cracked groan bullfrogs make.