That kind of looks like the same thing I have on some of my White, Red, and Austrian pines and some of the spruces and does not appear to be of any concern here.
Pines do loose needles from the last year or so after this years needles grow out and take over. That is normal unless the needle loss is at the tips of the branches.

It sure looks like the kind of damage that the pitch moth larvae make, but I don't believe that you'll find them in Texas. How about a call to your local extension office to find out if there have been any trends with insect infestations in Loblolly Pines. If they are of no help, and these trees are important to you, you may want to consider calling on a ISA Certified arborist for a consultation. I stress the certified aspect strongly....diagnostic work should never be done by untrained 'tree guys'.

Also, can you think of any change in environmental factors for your trees? Nearby construction, grade change, drought, flooding, etc.?

You might also post your picture and description over in the Tree Forum, where several other experts might get a chance at some arm chair diagnosing. ;-)

I'd like to see more images, too. How about one showing more of the trunk, not just the close up? You'd be surprised at how much we learn from seeing pictures of the trunk, the canopy, the base of the tree, etc.

Well, now I've consulted a master gardener and 2 certified arborists. They all agreed that the growths were galls produced by the tree because of some kind of damage - one said fungal, one said probably borers, one said probably old damage from Ike. Who knows? They also all said the tree was otherwise healthy and could probably last another 5-10 years or longer. I think we may go ahead and replace it now, though, rather than wait and see and have to replace it around the time when we may be trying to sell the house (5 -10 years...). The only environmental factor I can think of would be 6 weeks without rain, but surely it's weathered that before...

I had a number of photos to post, but could only figure out how to post one...

I typically think of canker diseases (caused by a Fusarium fungus) as being higher up on the tree than what you've described, but I'm really not certain of that. The symptoms (the appearance) of pitch canker and certain beetles or borers can be very similar. Though someone who knows how to diagnose either one of those should be able to do so in person.

If you are going to replace it with another Loblolly (and I'm all for that), please know that both disease AND insect problems can be invited into a host plant by physical damage to the tree. Inspect the tree for improper pruning, scrapes or dings to the trunk, etc. Avoid any weedeater or mower damage by mulching the tree after planting so that you don't have to keep the grass down around it.