I have seen some gourd vines to split or have cracks too.
If the spilt/crack is on the ground, cover is with some straw/hay, to prevent too much dehydration. If it is off the ground wrap it loose;y with something like strip of and old cotton t-shirt.
Even without these measures the vine may survive fine.

With the rats, you have to put rat baits and traps(use chunky peanut butter). Also feed them a mixture of corn meal, sugar, powdered aspirin, baking soda, plaster of paris. If they eat that stuff eventually will die of digestion problems.

Thank You for all of your great advice. Things are looking GREAT for my pumpkins. I did everything you guys told me to do. These are Big Max pumpkins and I live in Southern California, so here is the whole story. I trapped as many Rats as I could and I have been spraying with Repels All, (the stuff stinks!), but works. I lost my first round of pumpkins, however the second round came out twice as large. My vine is growing on our putting green, (artificial grass).My largest Pumpkin is about 30 pounds right now, and I have two more 20 pounds.It has been about 100 degrees every day, so I have them protected from the sun. I hope to get a 100 pounds by Halloween. I have the whole neighborhood rooting for me.I just want to Thank All of You who have helped me on my journey. I will enclose photos at Harvest.
Irene aka Mommybean