In cattle, bloating is most often caused by the animal eating young and lush pasture, usually if the pasture has a high proportion of legumes(medicks, clover or lucerne (alfalfa)). Legumes contain foaming agents which trap air bubbles in the ruminant's rumen and prevent them from belching to relieve the pressure. This causes a build up of pressure in the rumen which manifests as an obvious swelling on the left side. Signs of bloat in cattle are distended left abdomen, stopping of grazing, lethargy, appearing distressed, difficulty in urinating or defecating, rapid breathing and staggering. In mild and moderate cases an antibloating agent will be administered orally or through a stomach tube and the ruminant should be exercised. In severe cases a wide bore trochar and cannula can be inserted into the rumen on the left flank to release the gas and liquid. In emergency cases of frothy bloat, this may not be enough and a 10–20 cm incision may need to be made in the animal’s side and the froth manually removed. Veterinary care is then needed to clean and stitch the wound and administer an antibiotic to the animal.
To treat this problem, there is often an incision made in the keiva of the cow and then stitched up. Is found a very interesting discussion about this issue in the new picture book on chulin by rabbi lach (page 146). The question is whether a hole that renders the animal a treifa can be fixed so that the animal is no longer a treifa. If once a treifa, always a treifa, any animal that undergoes such a surgery, even after it heals is a treifa rendering all it's milk to be non-kosher. The issue is based on an apparent contradiction in Rashi when he explains the gemara which says a "krum" - membrane that grows over a wound in the esophagus doesn't fix the hole and the animal remains a treifa. Rashi at first writes that even if it is thick membrane, it will not last, therefore it is as if the hole remains and the animal is a treifa - אפילו עלתה בו סתימה עבה אינה מתקיימת. According to this rationale, the problem is that the hole cannot fix itself properly, but when the hole is stitched up and heals properly, the animal will no longer be considered a treifa. However, Rashi continues by creating a rule that any holes that render the animal a treifa cannot be fixed even if it heals afterward, unlike a hole in the lung that if closed by the wall of the inside of the animal is kasher, because that seal was there originally. The implication of the second statement of Rashi is that once it is a treifa, it remains a treifa and even if repaired properly remains a treifa. The Pri Megadim (Mishbetzos Zahav - 33:4) understands from rashi that if the closure of a hole isn't present at the time the hole forms, it cannot be fixed by a membrane or healing afterward. The Pri Megadim explains that the fact that the closure or membrane will allow the animal to live, doesn't in anyway change it from being a treifa. The concept of a treifa not living 12 months is to be used as a siman to determine whether a safeik treifa is a treifa. But, when it is known that the animal is a treifa, even if it lives for many years, it remains a treifa. The pri megadim doens't explain how he would read the beginning of Rashi. Perhaps he understands that the statement of rashi - אפילו עלתה בו סתימה עבה אינה מתקיימת, is referring to the beginning of the healing process. Meaning, even if it begins to scab originally, that seal will not remain forever, therefore we give the animal a status of treifa. Once we give the animal a status of treifa, even once the hole fully heals, it no longer loses it's status since that is considered a closure that occurs later. This approach would seemingly invalidate even a hole in the stomach (since rashi asks from the lung and liver, and doesn't answer that this is a special din of the esophagus, it implies that the principle applies to holes in any organ).
Rav Belsky wrote an article available here being matir all milk. He explains that even if the procedure would render the animal a treifa, it would be mutar, and the suggests that one of the procedures doesn't render the animal a treifa based on many different rationales for this: 1. There are 3 linings to the stomach and the piercing of the needle is not at the same point through each lining. 2. Even if this hole could kill the animal, it would have a din misukenes but not treifa and since the hole is made to heal the animal it doesn't even qualify as a misukenes. There is another procedure which stitches the stomach of the animal to it's side. In this type of stitching there is definitely a how made straight through the stomach. Rav Belsky understands that the correct reading of Rashi is the first approach, that any closure which isn't a permanent fix doesn't work, implying that if it is indeed מתקיימת, it works to remove the status of treifa. The reason why rashi had to come up with the alternate explanation - דטרפות לא מהניא להו סתימה דסלקא בהו לאחר זמן is because it isn't obvious that these closures are permanent, but since they are there from the very beginning and remain there, they are considered closures. He then suggests that even if we take the stricter approach, the type of stitching called toggle bolt, would qualify as the hole being fixed immediately and not as something that only occurs later. He therefore concludes that the process done to milk cows qualifies as a סתימה המתקיימת and as a סתימה מעיקרא. He also elaborates to argue with the concept that a treifa cannot be fixed, that it is a rule that is contradicted from the gemara 68b. The gemara on 68b actually uses the term כיון שנטרפה שוב אין לה היתר, but Rav Belsky explains that it doesn't mean to say that every treifa, once it is assur can never be fixed. The gemara on 54 explains that any problem that can be fixed with medicine isn't part of the list of 18 treifos - this clearly implies that treifos can be fixed. Therefore, the gemara on 68b also means to say that the definition of treifa is a problem that can't be fixed. If it is possible to fix the problem, it no longer qualifies as a treifa. Even though the ability to keep an animal that has one of the 18 treifos alive wouldn't remove the status of treifa, the ability to fix the actual problem so that the hole is no longer present, Rav Belsky holds would help to remove the status of treifa.