Left Displaced Abomasum
Surgery is needed when the cow's fourth stomach rotates to an abnormal position.
Start thinking of a left displaced abomasum if you hear a ping on percussion over the brown oval region on the cow's left side, especially if you feel a fullness high in the oval, where the hollow we call the paralumbar fossa is located.
Rory walked around his patient noting the left paralumbar fossa, the caved in space between the cow’s ribs and pelvis was empty. It’s the space where the rumen is supposed to be. He placed his hand in the fossa feeling for rumen rhythm and tone. A fossa is a depression behind the ribs, and this recession was deeper than usual because the rumen was not full. The cow was not eating or drinking.
Rumen contractions occur every 30 to 60 seconds. Today this cow’s contractions were fewer and weaker maybe two over two minutes which told Rory the rumen wasn’t working well; it was slow and deflated. He pushed his finger into the skin there trying to decide where the line of liquid ended in this fermentation bag called the rumen and where gas started.
"What did you find Doc?" Justin asked.
"This is what we call a hypotonic rumen it's not doing anything, just sloshing liquid back and forth about right here," he pointed midway along the fossa.
“The rumen's not as full as it should be. That tells me she’s quit eating too.” Rory pulled his arm from the rectum and stripped the plastic sleeve off. “I'm going to check for gut sounds,” He adjusted his stethoscope squarely in his ears and walked to the cow’s left side. Placing the head of the scope on the skin with his left hand he used his right hand to tap on the body wall.
“What are you listening to when you do that?” Jen asked.
“I’m listening for an LDA; a left displaced abomasum. Here we have a Holstein dairy cow which calved one, two, maybe three weeks ago and is eating poorly has scant feces and is producing little milk. Those are all cardinal signs of an LDA.”
“I thought it was bloat Doc,” David said.
“No, then this space here, the paralumbar fossa, would be bulging because the rumen would be too full. This is the opposite.”
“What the hell is an LDA?”
“You remember that cows have four stomachs, right?”
He nodded.“The last stomach in the cow is the abomasum. When it slips too much to the left, it’s called a left displaced abomasum, an LDA. Because this sac fills with air when it shifts to its displaced position we can locate its whereabouts by pinpointing the high-pitched pings when we tap our fingers on the side of her chest like this.”Jen's interest was piqued. She came closer to watch. “Can I hear? What are you listening to?”
The picture above is normal. The one below shows left displacement
“A ping sound is coming from right here Jen.” He pointed to a spot in the middle of the cow’s left side. He pulled the stethoscope from his ears and handed them to her showing her how to place the head of the scope between two ribs. “First you have to recognize if there is an abnormal ping. It’s a metallic sound like hitting crystal.”
He adjusted the stethoscope’s head between two rib bones. Pressing firmly on the tool for better hearing, he flicked the space just above the stethoscope with his finger.
“Hear that?” He asked, then flipped his finger onto hide two more times.“Doesn’t it sound like metal hitting crystal?”
Smiling, she nodded.
“It’s the abomasum under pressure because the displacement clogged it up, so it fills with gas like a balloon, and I can locate it by listening for the ping. Every time you snap your finger onto the skin pay attention to the change in the sound, it will tell you how big the air balloon is underneath this area. Usually, you can’t hear any sound because the fluid in the rumen dulls it out. But if the abomasum has slid over you hear a ping instead. Now move your snapping finger around to determine the shape and size of the gas pocket. With LDA the abomasum is trapped between the left body wall and the