Longhorn and Cowhorn are different varieties. I’ve grown both for seed though it has been 11 years since I grew Longhorn. Longhorn is slightly fatter than Cowhorn and gets tough just a little bit sooner meaning you have to be diligent to pick it while still tender. Most okra will stop setting new pods once 3 or 4 have formed on the plant. Cowhorn will keep setting new pods though it eventually slows down usually with 15 to 20 pods maturing seed. I’ve been working on a strain of Cowhorn for 34 years.
Here is a photo of young Cowhorn okra plants just as they start heavy production.
This is a picture of a Cowhorn plant with 22 pods of okra. This plant is 15 feet tall. I was holding my camera as high as I could reach to take the picture.
If you want to grow some okra just to figure out what you like, here are a few to try:
Cowhorn - tall, very heavy producer, can harvest up to 6 inches long
Granny Franklin - My overall favorite okra because it is so versatile
Heavy Hitter - very high production, but has to be harvested daily
Jing Orange - very good production, red/orange color, good fried
Lee - developed for shorter but still productive plants
There are another dozen that I could suggest, but the above gives a broad range of growth types and uses.