There are several things that could be causing this. Brown ejaculate could be caused by blood in the semen, or left-over blood in the urethra from bloody urine. It would be best to see a doctor.
ejaculation is the come out the semen from the penis. brown ejaculation is the one kind of disorder of the man reproductive system. if one's kidneys are not properly working then brown colour semen is appear rather then white colour. due to presence of red blood cell, it may occur.
There is nothing to worry to much about the color of the ejaculation. But, if the color is very much different from the usual color that you have had before ,it is better to consult a doctor and you should make sure about the fitness of your body.
Anytime you have ejaculation that is of an off color and not normal you should consult with your doctor to rule out any diseases. This way you can get treatment as soon as possible and not spread anything to your partners, as well as prevent any thing worse from occurring.
No need to worry about brownish semen. This is caused by blood and is caused from ejaculation and should clear up in a few days if not see your doctor.