Left Displaced Abomasum (LDA)

In this episode, Dr. Lottie talks about left displaced abomasum (LDA), how it develops, which cows are most at risk and what we should be doing to prevent it

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Timeline:
00:00 Intro
00:32 Case
01:30 Aetiology & Pathogenesis
06:04 Clinical Signs
07:06 Diagnosis
08:23 Treatment
14:43 LDA vs RDA
15:34 Prevention
16:49 Key Points
18:04 Outro

References

• Coppock, C.E. (1974) “Displaced Abomasum in Dairy Cattle: Etiological Factors,” Journal of Dairy Science, 57(8), pp. 926–933. Available at: https://doi.org/10.3168/jds.S0022-0302(74)84988-X.
• LeBlanc, S.J., Leslie, K.E. and Duffield, T.F. (2005) “Metabolic Predictors of Displaced Abomasum in Dairy Cattle,” Journal of Dairy Science, 88(1), pp. 159–170. Available at: https://doi.org/10.3168/jds.S0022-0302(05)72674-6.
• Shaver, R.D. (1997) “Nutritional Risk Factors in the Etiology of Left Displaced Abomasum in Dairy Cows: A Review1,” Journal of Dairy Science, 80(10), pp. 2449–2453. Available at: https://doi.org/10.3168/jds.S0022-0302(97)76197-6.
• Braun, U., Pusterla, N. and Schönmann, M. (1997) “Ultrasonographic findings in cows with left displacement of the abomasum,” Veterinary Record, 141(13), pp. 331–335. Available at: https://doi.org/10.1136/vr.141.13.331.
• Mueller, K. (2011) “Diagnosis, treatment and control of left displaced abomasum in cattle,” In Practice, 33(9), pp. 470–481. Available at: https://doi.org/10.1136/inp.d6079.
• Morrow, L. and Brennan, M. (2020) “Comparing survival times in cattle with a left displaced abomasum treated with roll-and-toggle correction or right pyloro-omentopexy,” Veterinary Record, 187(5), pp. 192–193. Available at: https://doi.org/10.1136/vr.m3308.
• Babkine, M. et al. (2006) “Ventral laparoscopic abomasopexy on adult cows,” The Canadian Veterinary Journal, 47(4), pp. 343–348.

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Creators and Guests

Host

Dr. Lottie Wilkinson

Creator and host of the Current Vet podcast

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Intro

[00:00:00] Hello, hello, and welcome back to Current Vet, the podcast that makes veterinary medicine simple. I'm your host, Dr. Lottie, and today we are talking about a bread and butter dairy condition that everyone needs to know about, and that is left displaced abomasum or LDA.

So let's walk through LDA properly, use a real world case, break down the physiology and talk through how you'd actually approach this in practice.

Case

So you called out to see a five old Holstein cow, who is 10 days post calving. She calved unassisted, but since then, her milk yield hasn't picked up the way that it should have.

The farmer tells you that she's eating but not finishing her concentrates. She's looking a little bit tucked up and her milk has dropped off quite suddenly over the last few days. She's also been treated for ketosis earlier in the week and on [00:01:00] clinical exam, she's bright enough. Her temperature, heart rate, and respirate are all normal.

But when you stand back, you notice she looks a little bit gaunt on the left hand side. You auscultate and percuss the left flank and hear a high pitched ping just behind the last rib. So already your LDA radar should be going crazy. Uh, but we're gonna come back to this cow as we go through the episode.

So let's talk about what LDA actually is.

Aetiology & Pathogenesis

In normal circumstances, the abomasum sits in the ventral midline of the abdomen slightly to the right, it is the cow's true stomach and responsible for acid secretion and enzymatic digestion. In LDA, the abomasum becomes a to, hypo, motil and gas filled.

Which allows it to float, dorsally, [00:02:00] and move to the left where it becomes trapped between the rumen and the left abdominal wall. Hence the name left Displaced abomasum. Crucially in LDA, the abomasum is displaced but not twisted, and that's why these cows are often systemically quite stable, and that is why it also behaves very differently to a right displaced abomasum and or ous.

So why does LDA happen? Basically, it's a multifactorial condition. It can be caused by many different things, but there are three key underlying factors that drive the condition. So first is reduced abomasal motility. So in early lactation, cows are typically in a negative energy balance.

They're often hypocalcemic and they can have concurrent diseases like metritis, mastitis, that kind of thing. Calcium is essential for smooth muscle [00:03:00] contraction, so even subclinical hypocalcemia can significantly impair abomasal motility. So that's thing number one. Thing number two is gas accumulation occurs.

So gas is produced normally in the abomasum, but when the motility is reduced, that gas is not being moved on throughout the rest of the digestive tract. So the abomasum becomes distended and it becomes buoyant. Thing number three is the postpartum anatomical changes. So after calving the uterus involutes rapidly, which basically means it just gets smaller after it's had a calf come out of it.

So dry matter intake is also usually reduced. Ru fill is decreased and suddenly between the decreased ru fill and the involuting uterus. You have a big space in the abdomen and the gas filled floaty abomasum now has room to [00:04:00] move. So put all of that together and you have your gas filled, poorly contracting abomasum that is floating up and becoming trapped on the left side.

And that is why LDA is most common in the first six weeks post calving. And it is also why it's so closely linked with other conditions like ketosis, hypocalcemia, metritis, and poor transition cow management.
So now we've got those three key factors. Let's talk about a couple of risk factors that can predispose LDA. And they fall into a few categories. So we've got metabolic and UR diseases, nutritional factors, management factors, and animal factors. So our metabolic and UR disease factors are gonna be, like we said before.

Ketosis, hypocalcemia, fatty liver disease, metritis, and retained fetal membranes. All of these conditions are going to make [00:05:00] the cow feel sick. They're gonna reduce feed intake, they're gonna impair, motility, or do a mix of all of those things. Your nutritional factors are gonna be feeding a high concentrate, low fiber diet, providing inadequate, physically effective fiber.

Sudden dietary changes around the calving period and overfeeding in the dry period, which leads to over conditioned cows. A couple of management factors are gonna be your poor transition, cow management, overcrowding, inconsistent feeding times, limited access to feed and stress around calving. Your animal factors are gonna be having a really high milk yield because that's gonna promote a negative energy balance in the postpartum period.

High parity cows and a previous history of LDA. So LDA is often the result of [00:06:00] management issues, especially if it's a recurring problem within one herd.

Clinical Signs

Now let's come back to what we're actually going to see in practice. So one of the most important things to understand about LDA is that the clinical signs are often quite subtle.

These cows are not crashing, they're not rolling, they're not that systemically unwell. They classic signs are gonna be a drop in milk yield, reduced appetite. Dullness, reduced room fill and fewer room contractions. And that characteristic left-sided ping that you hear on auscultation and that ping is basically just going to be, you are hearing the gas distended abma .

Cow feces are often normal, just reduced in volume, and importantly, vital parameters are usually within normal limits. So in our case, our cow with the sudden milk drop, the selective in inappetence, [00:07:00] recently ketosis, and the left-sided ping all obviously fits perfectly with LDA.

Diagnosis

So diagnosis of LDA is primarily clinical. Your biggest clues are going to be the timing In early lactation, the ment, typically high producing dairy cows, your history of milk drop, ketosis, UR diseases, reduced feed intake, and then your physical exam where you might be hearing your left-sided ping, seeing reduced room fill, that kind of thing.

That ping is caused by gas trapped in the abomasum because that abomasum is sitting directly underneath the body wall.

But it's important to remember that that ping is not gonna be pathognomonic. We could also hear a ping if we had a rumen gas cap, or rumen atony, that kind of thing. So remember, interpret it in context. ancillary diagnostics can be used to assess [00:08:00] concurrent disease, but typically not to confirm the LDA.
So on bloods you might see , hypocalcemia ketosis, uh, mild electrolyte abnormalities, which are probably gonna be reflective of any concurrent diseases and UR conditions.

In most cases though, if the history exam and ping all lined up, you can be pretty confident you're dealing with LDA

Treatment

the aim of treatment is to return the abomasum to its normal place, fix it in place to prevent recurrence, and to obviously address the underlying drivers of the condition.

Surgery is going to be the treatment of choice in the majority of cases, because it returns the abomasum to its place and we can fix it in place with an abomasopexy. Also means that there is gonna be a really low recurrence rate when it is done properly. So we have a couple of approaches that we can use.

First up is the right paralumbar [00:09:00] approach with an omentopexy or a pyloropexy, and this is the most commonly used technique in practice. The cow remains standing. The surgeon approaches from the right paralumbar fossa. The abomasum is decompressed with a needle and tubing, you manually reposition it and then you fix it either by suturing the omentum or the pylorus to the right body wall where you made your incision. This is often the first choice approach because it gives you excellent visualization of the abdominal organs. Your view isn't being obscured basically by the massive rumen on the left hand side and allows you to assess for concurrent pathology.

You can reliably fix the m to ensure low recurrence rates. It's really practical and it avoids casting or dorsal recumbent for the cow. Our second approach is a bilateral paralumbar [00:10:00] approach, and this is basically an extension of the right-sided approach, but a second incision is made on the left paralumbar side as well, allowing a surgical assistant to.

Access the displaced Abomasum, help decompress it and pass the omentum and the abomasum across to the right hand side. You might choose this approach if the abomasum is difficult to reach from the right hand side on its own. If you have really short arms, for example, and you just can't reach, or if any adhesions are suspected, which means that the abomasum is difficult to move out of its displaced position, or if you want maximal abdominal visualization. The downsides are obviously gonna be that it requires more time, it needs more people, and it has a higher cost.

We then have the left only paralumbar approach, which is known as the URE method. This technique accesses the abomasum directly from the left side with the cow [00:11:00] still standing. After you've decompressed the abomasum and repositioned it, long sutures are placed through the abomasal fundus and secured to the ventral abdominal wall.

This method is used because it gives really good access to the displaced abomasum itself. It allows breakdown of adhesions and obviously it has really low recurrence rates when performed correctly. But it means that you have a limited visualization of the rest of the abdomen and less flexibility if a different pathology is also present.

It basically needs. The surgeon to be really comfortable with the technique, or it is used in cases where direct abomasal access is really useful.

We then have the right paramedian approach with an abomasopexy. So this technique requires the cow to be cast and placed incumbency, and a ventral incision is made just right of the midline. The abomasum [00:12:00] is decompressed, repositioned, and fixed directly to the ventral body wall.

This technique gives a really secure fixation. Pretty good visualization of the abdomen. But it's pretty stressful for the cow. It requires rolling and restraint, and you have pretty poor visualization of the rest of the abdomen. We could actually do it laparoscopically as well for a minimally invasive option. The Caroma is standing. Small portals are used on the left side. The abomasum is deflated, allowed to reposition passively on its own, and then it is fixed using a right paramedian abomasopexy technique.

This obviously minimizes tissue trauma. It means that there's a rapid recovery. You can get pretty good visualization with the laparoscope, and it has low recurrence rates, but it requires specialized equipment and training, has higher costs, and is less suitable if [00:13:00] extensive abdominal exploration is needed.
Finally, I do wanna mention the toggle pin fixation method. This is a blind fixation of the abomasum to the ventral body wall. Once you have rolled the cow, it is pretty quick, it's inexpensive, and it's very useful in a low resource setting, but you don't get visual confirmation of what you are fixing.

You have a risk of peritonitis of. Puncturing organs that you don't mean to puncture. And actually a risk of damaging the milk vein, which can then cause a massive load of hemorrhage. There's also no opportunity to assess the abdomen. So this technique can work well, but it requires really careful case selection and you need to be pretty confident at what your toggle pinning to the body wall.

If surgery isn't an option, you could just roll the cow [00:14:00] on its own. This contemporarily correct the displacement, but recurrence rates can actually reach up to like 70 or 80% if the abomasum isn't being fixed surgically to the body wall. So rolling should really only be used as a temporary measure or when combined with fixation.

Regardless of how you are correcting the displacement, supportive care is essential. So consider calcium supplementation, ketosis management, fluids, electrolytes, NSAIDs for your pain and inflammation and nutritional support to get their feed intake backup. If you are not addressing these factors, the risk of recurrence is much higher.

LDA vs RDA

Just briefly, it is worth contrasting LDA with RDA, so RDA and abomasal. volvulus involves a rotation. This then compromises the blood [00:15:00] supply and leads to rapid systemic deterioration. These cows are often tachycardic, painful, dehydrated, and very, very sick. It is much more comparable to a gastric dilatation and volvulus.

So GDV, like we see in deep chested dogs, and that is because that volvulus, that twisting of the stomach or abomasum is happening in LDA. Our cows are usually. Stable because there is a minimal systemic involvement unless there is a severe concurrent condition.

Prevention

So prevention.

Prevention is all about our transition. Cal management. The biggest risk factors in this period are gonna be poor, dry matter intake over conditioning. So basically having a really fat cow. Inadequate effective fiber hypocalcemia and ketosis. So [00:16:00] prevention is gonna focus on maximizing feed intake, maximizing their fiber.

Pre and post calving to really boost their ruen fill and make sure that we don't have just random gaps in the abdomen that are floating. abomasum can take up. You wanna avoid sudden dietary changes, avoid stress, manage the dietary cation and ion difference appropriately. And this is gonna help mobilize calcium from the bones and prevent hypocalcemia.

You wanna reduce overcrowding, reduce their stress, and monitor your fresh cows really closely for changes in their appetite, for changes in their demeanor. If you reduce metabolic disease, if you manage a transition cows properly, you reduce the risk of LDA.

Key Points

So before we wrap up, let's summarize the key things that you should know about LDA. [00:17:00] So left displaced Occurs when the gas filled atonic abomasum floats and becomes trapped on the left side of the abdomen between the rumen and the body wall, it most commonly affects high producing dairy cows.
In the first week or two after calving. The reduced abomasal motility is often due to ketosis, hypocalcemia, or other perran conditions, and these are gonna be central to LDA. Developing clinical signs are often subtle so a sudden milk drop, reduced feed intake, and a left-sided ping may be heard. Diagnosis is primarily clinical based on the cow's presentation. Treatment of choice is surgical correction with fixation of the abomasum to prevent recurrence. And the most common approach used is that right paralumbar fossa approach.

And then finally, your long-term success depends [00:18:00] on addressing underlying metabolic and management factors.

Outro

And that is LDA. So it's a condition you're gonna see again and again if you're in dairy practice and want to understand the physiology behind it. The diagnosis and management and prevention methods become much more logical.

Thank you for listening to this episode of Current Vets. If you found it helpful, follow or subscribe or like us, wherever you get your podcasts. Share it with a friend or colleague, and you can also find us over on Instagram and TikTok at Veterinary Vista. So if there's a topic you'd like us to cover next, then please just let us know.

We'll see you next time.