Hey, good evening everyone, and thank you for joining us for tonight's webinar with the webinar vest. Hope you're all, sat nice and cosy with a nice cup of tea ready for for this. So tonight's webinar is by Paul Wood.

And Paul graduated from the Royal Veterinary College in 2005, and he spent 18 months working in a mixed practise across Her Hertfordshire, Bedfordshire and Buckinghamshire. He then moved around doing some small animal and exotic animal locum positions before starting a year-long MSC in wild animal health with ZSL in London. After completing this degree, he returned to the RVC as a farm animal clinician working in both the ambulatory and referral practises.

After 3 years at the RVC, Paul had a brief foray into industry, and he was providing maternity cover as an area veterinary manager for Pfizer Animal Health. In 2012, he joined the farm department at the University of Cambridge, where he developed the ambulatory referral and consultancy services that were offered. During this time he completed his.

Postgraduate graduate diploma in veterinary education. Since October 2016, Paul has taken up a role as a principal clinician and senior lecturer in farm animal practise at the Royal Dick School of Veterinary Studies at the University of Edinburgh. Paul's interests lay in obstetrics and fertility.

Surgery, veterinary education and student support. And tonight's going, tonight Paul will be talking to us about the basics of large animal surgery. So over to you, Paul.

Thanks Caroline and welcome to everyone, thank you for for attending the webinar. So, today I'm gonna talk about large animal surgery, sort of the basics of surgery. Now, I realise, as with most of farm animal, there are a number of ways of different ways that people do different procedures.

So this is really covering sort of the ways that I, not only teach how to do them, but the, the, the ways that I tend to, do them, after all my years in practise. That's not to say they are necessarily the best way for every situation. And I think as farm vets, we have to alter how we approach things depending on the situation that we find ourselves in.

So the content of the webinar, I'm gonna talk a bit about restraint and preparation, but then also talk about anaesthesia and analgesia for different procedures, including sedation, epidurals, and some local anaesthesia blocks. Then the sort of the common or or basic, if you like, surgeries that I'm going to cover, a digit amputation, tail amputation, nucleation, vasectomy, and then talk a bit about flank laparotomy, but I'm sure you can appreciate that, doing a webinar including all the different flank surgeries and abdominal surgeries is probably a bit beyond the scope of a, a one hour session. They're gonna talk a little bit about complications and then because it's always at the forefront of everyone's mind, a little bit about antibiotic use, and what some surgical principles might suggest about how we use antibiotics when we're doing surgeries on farm.

So the first thing I always like to say if you are doing anything with large animals and no matter what procedure is being performed, we need to make sure that ourselves er and the animal and everyone around us is safe. So for that reason, we need the animal suitably restrained. I ideally would like the area to be well lit with the floor that I am unlikely to slip on.

Obviously, that all changes once we have blood and and other items on the floor around us. Now that restraint could be physical, so in a crush or in a, behind a caesarean gate, it could just be halted, or it could be chemically restrained. But whichever way you feel more comfortable and safest, I, I think is the best way to go.

If you know you're on your way to an elective procedure, or you know you have a, a bit of a drive before you get there, there's nothing wrong with asking the farmer to sort of start to prepare the animal before your arrival. So this might just be that they can initially clip and clean the area, or if it's an elective surgery of more than sort of 24 hours, you could ask them to keep the animal on a, a clean bed in a small pen. If it's abdominal surgery, you might ask them to starve the animal for 24 hours.

Then once we get there, particularly if it's a fractious animal, then sedation will be useful in most of the cases of surgery that I'm going to describe. We do need to be aware There are the potentials for overdose, but also the risks of respiratory collapse or recumbency, in different species depending on the anaesthesia protocol that we decide to go with. So I'm not gonna do a lot of discussion about the, the different regimes that are out there.

Obviously we have a very few licenced preparations in cattle in the UK. Apologies to if there's anyone here from from overseas. But I'm mostly gonna be speaking about the, the products that we have available in the UK.

I'll try to do it by, the drug, within the product rather than by their trade name. So. We probably most commonly use Xylazine as a sedative, but you can achieve recumbency, with the, with the larger doses of Xylazine.

And we also have domidine available as well, licenced for, for cattle. . Depending on what effects you want, we can give different doses and we can sort of make the effect, quicker, the time to effect by by giving these doses intravenously.

Although not licenced by intravenous use, ylazine can be given IV. I tend to work on the give a third of the IM dose, IV, depending on the level that you want to, to get that calcated to. With small ruminants, we need to be aware that they are much more sensitive to the effects of alpha 2s.

So xylazine can be used, but at a much lower dose, and these are the recommended doses to use in sheep. And again, we can get similar steps, step up levels to cattle. I would never give xylazine IV in a, in a small ruminant, just because of how sensitive they are.

I think giving IM, you get a smoother, time to effect. With goats, there are stated volumes of domidine, so the cattle are licenced doomidine, but obviously the concentration means that it's actually very small volumes. The one of the main reasons that we have to be careful with xylazine in small ruminants is that it does have significant negative cardiopulmonary effects.

And again, it is unlicensed to use reversal agents, but, if you start to see a small ruminant going blue following Alpha 2 administration, it's very hard not to, reach for a reversal if you have it handy. Just be aware that we need to make the farmers aware of withdrawal times. With camelids, I'm sure in the UK and around the world we are all seeing a few more camelids.

This is a range of different, protocols, and I've included all of these those protocols in the lecture notes. My favourite is using this sort of stunt sedation where you just combine your xylazine, your ketamine and your buorphenol, I, into one syringe and then give it IV. And that generally will give you around 30 to 40 minutes of sort of stunt sedation.

Depending on the procedure you're doing, you will probably want to use local anaesthesia as well. And all of these products are not licenced, in camelids in the UK. For those of you working with pigs, I think there isn't much that we would do with commercial pigs, but with smallholders and pet pig owners becoming more prevalent, then these are some doses of some different protocols that are sort of suggested.

Be aware that a zapperone on its own is probably quite a poor sedative agent. I've used high doses just to do foot trimming and sales, but I wouldn't want to do anything more involved than that just on a zapperone. And actually just adding a little bit of ketamine can make quite a difference.

Again, this is my favourite or preferred protocol. 2 migs per kg of zapperone, 5 mg per kg of ketamine, and 2 mg per gig of Xylazine, all given together IM. Generally I see a time to effect of about 5 minutes, and then you get about 30 to 35 minutes of recumbent anaesthesia.

I give these all I am together again using a long needle and going in the muscle behind the ear, to make sure that we're not just injecting into fat. So moving on to some local anaesthesia techniques, I'm sure all of you are well aware about epidurals and how to perform them in cattle, where we're looking for that hinge joint at the sacral and coccyal, joint just at the base of the tail. I tend to use an 18 gauge, 1.5 inch needle.

After prepping and clipping the skin, I will put the needle perpendicular to the skin. Fill the hub with a small drop of local, the hanging drop technique, and then advance it. And when that drop disappears, we know we're in the right place.

You can just redirect the needle to 60 degrees, pointing toward the cow, and that should advance quite easily. Once you're in that space, then we can infiltrate the rest of the local, and it should flow quite easily. If it doesn't, I sometimes think when you reconnect the syringe, you advance the needle slightly, so just withdrawing the needle, a tiny amount might make the local flo flow better.

Volume wise, I use anywhere from 3 to 5 mils depending on the size of the of the cow. And I've always used procaine, the preparations we have in the UK will have adrenaline in, which according to the data sheet is contraindicated for epidurals. But, I'm not aware of any other products, that we have that are available, or that we would, routinely carry in, in the car.

And not wanting to tempt fate, but I've never had any issues, using the products with the adrenaline in. We can do epidurals in small ruminants, generally recommended about 0.5 mg per kg of local, again preparing the sacred coccygeal area, slightly smaller needle, maybe just using a 1 inch needle, and.

Recommended to insert at an angle perpendicular to the slope of the tailhead or about 20 degrees to the horizontal plane. The hanging drop doesn't always work in small ruminants, so we have to rely on the ease of administration and that the needle isn't contacting bone. You could also put a little air bubble in the syringe, and as long as the air bubble isn't compressed and, you know that that anaesthetic is flowing easily.

We can add xylazine to into our local, again, very small amount, about 0.7 0.07 mg per gig, and that will increase the duration of the effect and increase the duration of the pain relief.

So it can be quite useful for certain procedures. Epidurals are described in camelids, using 0.1 to 0.5 migs per gig of local, again, preparing the sacred rosy gill area and inserting the, the needle at an angle perpendicular to the slope of the tailhead.

You can use a hanging drop in in camelids. It works quite well in llamas. But again, we could just rely upon ease of administration and no compression of a of an air bubble in the in the bottom of our syringe.

So as well as epidurals as local anaesthesia, we might use other forms of local anaesthesia to provide An adequate level of of anaesthesia without the need for sedation or general anaesthesia. The success of that is gonna depend on the accuracy of the block, the volume that we administer, and the time before the procedure, making sure that we leave long enough for the, the blocks to work, but don't leave them so long that we're narrowing our, our window before those blocks become ineffective. Generally speaking, local in infiltration of anaesthetic around any site will provide anaesthesia for most basic surgeries, and that can be administered in any means, really.

So talking about some specific nerve blocks, and we'll mention a little bit about what they might be used for. So in regards to the surgeries that I'm gonna talk about, for digit amputations, you can perform a ring block, which we can perform around the whole limb at the same level. So we can inject local anaesthetic at several sites around the leg, above the area that we're gonna perform the surgery on.

We want it to be deep and superficial to the flexor tendons, and also adjacent to them. We want it immediately and laterally to the extent of tendons, and we're basically trying to form a circle around the leg. So for most digit amps, we're looking at doing this at a level of the junction of the proximal and middle thirds of the metacarpus in the forelimb or the metatarsis in the hind limb.

Other surgeries that we might use ring blocks for would be any tee surgeries where we would perform the ring block around the the base of the tee up near the other. Another option er for the digit amputation would be intravenous regional anaesthesia and this is my method of choice, . You will read in the textbooks about which vein which veins we're aiming to inject.

My rule of thumb is when you've put a tourniquet on, whichever vein that raises below your tourniquet, you can inject the local into there and it will provide adequate IVRA. I don't think we need to worry about which specific vein, we are using and in my experience, that is the case. So when we inject that, I I tend to.

Adult cow inject around 15. I do use the products with adrenaline in, and always have done. However, again, intravenous use is contraindicated according to their data sheet.

Some people also describe if you're performing IVRA to with, remove the amount of blood, that you are going to replace with the local. So if you're going to inject 15 mLs of local, first of all, you remove 15 mLs of blood, from, from the vein. My theory to not doing that is the more pressure there is is in that vein, the more it's gonna push through into the tissues around it.

However, that is purely speculative, and I have no evidence behind that. When we're performing a nerve block, sorry, a a nucleation, there are lots of blocks available. The first block we probably will want to perform is an arriculop palpebril block.

This is to stop the blinking of the eyelids. It's located in the same area as the corneal block that you would apply for disbudding. And I generally use around 5 mLs of local anaesthetic.

the nerve runs a little bit more superficially than, than the way we would block for horn buds. But 5 mils is generally adequate and anaesthetizes the eyelids. This then allows us to suture the eyelids together, so form a tarsserafi, using a simple interruptive pattern.

For the axolar nucleation, obviously just desensitising the eyelids is is not adequate, so we may want to perform a retrobulbar block. This can be done by placing a needle basically at the medial canthus or, or ventral to the eye, just a straight needle under the under the eyeball, to the back of the eye. And then injecting between sort of 10 or 15 mLs of local in an adult bovine.

Reducing the amount, in small ruminants and other species. Something that you can do if you feel a bit nervous, just putting a straight needle in that close to the eye, is you can curve a spinal needle and then use that to follow the border of the orbit er to the back of the eye. Another alternative to the retrobulbur is the 4 point retrobulbur, which basically we place needles at the 12, 36, and 9 o'clock positions around the eye.

So the median and lateral canthus and through the top eyelid and through the bottom eyelid, and inject around 5 to 10 mLs of local anaesthetic at each and including about 2 mLs as we withdraw the needle. Again, you can use this curved spinal needle for this, but there is actually quite a lot of space to get a straight needle behind behind the eye. A block that is also described, I've used twice and not been hugely convinced that it's provided adequate anaesthesia, so I've then done a retrobulva on top, is the Peterson block.

And what we're doing with the Peterson block is we're aiming to block the ocular motor trochlear, abduence and three branch of the trigeminal nerve as they emerge from the orbital tendum at the back of the eye. You can see, . Showing in that picture on the top right.

So we're gonna place our needle, and advance it, so place it in the notch form by the zygomatic arch and the supraorbital process. Direct it slightly ventrally and posteriorly, and then advance about 3 to 4 inches until it strikes bone. We can then inject 15 to 20 mLs at this location.

As we withdraw our needle, we can then redirect up toward the horn base and inject the 5 mils to block the urecular palkebral nerve at that point. If we're talking about flank surgeries, again, there are lots of different, local anaesthetic procedures that we can do. Line block, the pros being it's quite quick and easy, might provide some hemostasis in the local area due to the effects of the adrenaline.

However, it is described that some of the, the negatives to this method would be that it can cause maceration of the muscle, may lead to poor healing. If you need to, you haven't, blocked enough area that you can extend the incision. And we also might get incomplete anaesthesia of the peritoneum.

An inverted L block, again, it's quite quick and easy. However, it does use a large volume of local, depending on which product you are using, but if you're using a, a lidocaine product, performing an inverted L block, with about 20 mLs at each site, each injection site, you are probably approaching in an adult bovine, toxic levels of lidocaine. If you're doing a two-sided abdominal approach, then you're definitely going to approach those, if you're using an L block.

The other option would be pervertible, and there are two options, the proximal and the distal. The benefits of these are they do block all the muscle layers and the peritoneum. It's a relatively low volume of local required, and it's quite easy to, see when the flank is anaesthetized rather than sort of just sticking your needle into the flank to see if the cow reacts or the animal reacts.

It is a more difficult technique, er, and in cows, it can make them a little bit unsteady on their hind legs. The vasodilation that occurs can also lead to increased haemorrhage around your surgical site. My general advice for when you're opting for which block to use is to use the method that you are most comfortable with, particularly in an emergency situation.

But if you have the chance to use practise on cadavers or to accompany colleagues who use alternative techniques, then that is a good way to practise and become more confident with the landmarks and the volumes needed to use the different techniques. So just a diagram to show the inverted L block. I tend to use a blocker, put the needles in at about 7 sites to perform an L block .

And in a cow I cow I will use 20 to 30 mLs at each site. So I do sort of 5 sites down the long arm of the L and then 3 sites along the top, but obviously the top left corner one is the same, so it doesn't need to be repeated. If I'm doing a line block, generally I'm, I use 5 sites and I space my needle insertions roughly 1 inch apart, sometimes up to 1 inch and a half, just thinking about how much local I've, I've injected.

So the previous picture showed the landmarks, generally, it's fairly similar in all species. In a cow, I go about a hand span width, behind the last rib and down from the transverse processes, and then just reduce that according to the size of the animal for sheep and goats. I'll tend to use a 1.5 inch needle in cattle and a 1 inch in small ruminants.

The tissues tend to be much thinner. If you are gonna perform one of these blocks, er, it's advisable to surgically prepare the skin before and after administration of the blocks that we don't introduce any bacteria with our needles when we're performing the block. We're gonna infiltrate the local throughout the tissue at each point of the chosen block, and I tend to sort of fan, go in deep, fan upwards, fan, cranially and fan downwards.

As I said, cattle I tend to use 20 to 30 mLs at each site, and then for small ruminants, we can dilute, say 10 mLs of local with 10 mL of sterile water, and then that gives us a larger volume to use, for the infiltrative, anaesthesia. And then we can safely use larger volumes, which otherwise we may reach toxic levels sooner. Performing a para vertebral block, I've always preferred to do the proximal block, where you're going in from the, the dorsal aspect, and the aim is to block T13, L1 and L2.

Some people will also, aim to block L3, which does sort of the cranio, sorry, the, the caudal ventral area of the flank. What we look to do for the anatomy of this is locate L5. This is the transverse process that is directly cranial to the tubercoccy.

It can be more prominent in thinner cattle and actually quite hard to identify in well conditioned cattle, so not always the easiest to do in, in big beef cows. I will then clip count for. Good to L1 and L2, and clip and prep an area over the middle of the transverse process of L1 and L2.

Put a little blab of local anaesthetic over the middle of that transverse processes, then using an 18 gauge spinal needle in a cow or a 19 gauge 2 inch needle in a small ruminant. Push that through the blab until you hit the transverse process. We then by withdrawing slightly the needle and pushing it back in, we're gonna walk the needle off the cranial edge of L1 until we feel a little pop as we go through the interspinous ligament.

You can use a hanging drop, so if you enter the abdomen, you'll get negative pressure and you'll lose that drop, so you can just withdraw a little bit. In a cow, I'd inject 15 mLs at this site, and a further 5 mLs as I withdraw. In a small room, I would use 5 mLs and then 3 mLs as I withdraw.

We don't withdraw the needle completely through the skin on this first area, but back to the centre and then walk the needle off the back of L1. Then we're gonna go on to L2 and just walk off the back of L2. So the diagrams at the bottom sort of show what we're aiming to do, and we're aiming to block the nerves before they split.

What's quite nice with these para vertebrals is once the side that you have blocked relaxes, you get this curving of the spine, so quite a good visual representation. I still go and test the flank where I'm gonna make my incision with a needle, but, generally you can rely on that as a, as an effective way of showing that your block has worked. The other method is the distal paravertible or the Magda technique, and here we are going above and below the transverse process.

As shown in the diagram, and here we are blocking the nerves after they er after they split. Again, we're probably using about 10 mils below and above each transverse process, but the key here is we are gonna go above and below L1. L2 and L4.

But we're still blocking the same T13, L1 and L2 nerves. In small ruminants, as kind of alluded to, again, those and ewes are particularly susceptible to the toxic doses of local anaesthetic, so particularly lidocaine. So paravertebr may be better as it uses lower doses and therefore might be safer.

It is suggested that we limit lgnicaine to 6 mg per kg, in small ruminants. So for an 80 kiloe, this is only sort of 24 mLs of a 2% lignnicaine. So as I said, we can dilute that volume with sterile water to increase the volume we've got.

Available for diffusion. OK, so That's kind of an overview of all the local anaesthetic techniques that we generally will use for some of these surgical procedures. I will talk about vasectomy slightly differently.

So now we're gonna move on to some of the actual surgical procedures. The first one I want to talk about is digit amputation, and the general indications for this would be an unresolved lameness or if we have an infection tracking up the limbs. The technique would be provide your local anaesthesia either by IVRA or ring block.

I tend to then, once I know that the block has worked, and I, I've clipped and cleaned prior to my, prior to my nerve block, clip and clean the areas as well as you can, stick the foot in a bucket and using a brush to really get all the fil all the muck off before, we, we prep it surgically. I will then incise between the claws, especially if there's fibrous tissue or swelling, so incise the front between the claws, even all the way down to the heel bulb and up the back of the heel bulb, so that we can set a wire that we can use for the amputation in nicely. I generally aim to, get the wire to come out at distal, P1 shown by the blue line in the bottom right diagram, but a lot of people will aim just for it to come out of mid P2 shown by the red line in the diagram.

Once we have removed that digit, we can then put a compression bandage on initially, and discuss with the farmer about when we need to see it later. In an ideal world, before we do those digit amputations, we perform radio radiographs just to see which bones were involved. So in the radiograph on the right, we can see that actually P2, the distal part of P2 is probably infected.

So actually removing this at the level of mid P2 may not solve the problem. So in this one, following a radiograph, I would be aiming to come out distal P1 to make sure we're in healthy bone. As a general rule of thumb, if your wire is set between the digits and your and you aim for it to come out of the skin just below the accessory digits, you are gonna end up in distal P1.

Obviously, even restrained animals are gonna move about, and that can sometimes mean we end up a bit lower. By taking radiographs and planning our surgeries based on them, we can probably offer a better prognosis to the farmer. One thing to be aware of is if we, when we're performing this amputation, if we end up coming through a joint space, we need to be aware that we need to remove that joint surface surface.

So that it doesn't produce joint fluid going forward. So just a few pictures. Here we have a, a, a solar, well a toe ulcer that is not healing.

Cow is restrained in a whopper box, with a tourniquet, midcarpus. And this is IVRA being used using a butterfly catheter, just in case there's any movement. In these rare cases where I'm doing a digit amp, I may actually use the leg band of the Whopper box as a second tourniquet further up.

The instrument of choice is probably your embryostomy wire, . With an assistant, whether that's a farmer, available to sort of put some pressure on the toe you're amputating as you get to the end of, of the amputation. The last thing you want to be doing is when you're putting a lot of effort into doing the amputation, when you come through the skin, you fall backwards, potentially injuring yourself.

What we're aiming for is this at the end of the surgery, so nice clean tissue. If there was swelling up the leg or infection, we may see purulent material here. If you think that purulent material is going up the tendon sheath, then that's obviously gonna mean a slightly poorer prognosis.

But what I have done in the past is using a metricu plastic catheter and some sterile saline, put that catheter up the tendon sheath and flush some of that fluent material out. As long as you don't do it under too high a pressure and force material upwards, that can help clean, clean as well. We're then gonna put an initial compression bandage on, and again, different surgeons will have different preferences as to how they will change the bandages.

I prefer to put on quite a tight bandage for 24 hours, then go back, remove it, place another bandage on, leave that for 5 days, take that off, after 5 days, and then leave the cow B. If at the second change, there's a lot of pure material or a lot of malodorous material there, I will sometimes do an iodine wet to dry dressing. So 5 swabs soaked in a concentrated iodine with 5 dry swabs behind, the, the wet swabs placed onto the the amputation site and then bandaged in.

This tends, I find tends to clean the air really nicely. We can obviously do digit amputations in small ruminants as well, but it's often best to do these recumbents, with under some sedation, and then IVRA on top. It makes it a little bit easier for us, as the surgeons and it's a bit less stressful for the animal.

But again, we're aiming for the same kind of technique and the same landmarks. With all of these procedures, I would strongly recommend giving anti non-steroidal anti-inflammatories prior to the procedure. And antibiosis depending on on the surgery that we're doing and the individual case, and we'll talk a bit about antibiotics a little bit later.

So moving on to tail amputations, reasons that we may need to perform a tail amputation would be damage to the tail through trauma. I've seen a lot due to automatic scrapers catching tails in dairy cattle, but they could be caught on anything. It could be.

Tail amputations can be performed under cordal epidural and anaesthesia, and we know that that's worked when the tail is nice and floppy. But again, we can use a needle just to test the, the sensation of the skin, around the site where we're gonna make our amputation. What I tend to do is plan which joint I'm going to to separate the tail at and place a needle crudely represented in the picture by my by my .

Clip art, place it across through the joint space straight across the tail. Then when I do my V shaped incision, I can use that needle as a landmark for the base of my V on both the top of the tail and the back aspect of the tail. You can apply tourniquets on the tail to reduce bleeding.

I generally don't, unless it's a big edematous adult sheep tail or something that's traumatised. Generally in cattle, I, I have never needed to apply a tourniquet. But this is quite a quick procedure, so you're not gonna cause any damage by doing that.

Once we've made our V-shaped incision through the skin, we can undermine the soft tissue to reveal the bone, and we want to reveal the bone to the base of our V, above and below. You can see in this next picture that rather than blunt dissection, I've actually decided to use a scalpel blade. I've regretted this once when I, accidentally cut off the flap on the base of the tail, which wasn't a problem because I was able still to stitch over, the flap from the top.

So it's much safer to use, scissors and blunt dissect underneath. Once we've undermined those V flats, we can cut through the bone or disarticulate at the level. Where our needle was, remember to remove the needle.

And then all we're gonna do is close the soft tissue, the skin over the bone end to prevent bone necrosis and reduce potential infection at the site. I generally start at the base of the V and then so at the point of the V sorry, and then fill in the gaps to the bottom, so cranial up the tail, proximal up the tail. Choice of suture material, you can use a non-absorbable, but probably, should remove it.

Or you can just use absorbable even if you're going to just place cruciates or or continuous, suture patterns. Really depends on the suitability of whether you're going to want to remove that or whether the cow is gonna go back into the field, never to be seen, again for any treatment. Antibiotics I will use according to the infection that's occurring at the time.

Obviously there is a risk of contamination due to the sight of the tail just behind the, the, the, the rear end, . Bandages generally are, in my experience are not successful on tails, they just fall off, so I don't tend to, to use bandages. OK, so moving on to a nucleations.

The main indications for performing an a nucleation would be if there's damage to the globe, if there's a severe infection or there's been severe trauma, or there's neoplasia associated with the eye. As we've mentioned before, probably gonna use an orricular palpal block and then one of the blocks to block the actual orbit in the eye. So the first thing I do, once I've performed my block, is switched to the eyelids closed.

This diagram shows a cow that actually had sort of chronic abscesses around the eye where she had received, . I suppose they were intended to be subconjunctival injections, but I think they actually led to damage of the eyelids. So clean, a big, prepped area.

This cow is sedated. I think it's always advisable to sedate cows that you're doing iron nucleation on and actually small ruminants as well, . Once the eyelids are blocked, suture the eyelids closed, we've got a cadaver specimen in the top corner which shows it a bit clearer.

I tend to leave quite long ends on my sutures as this gives us the opportunity to use the sutures to add tension when we're removing the eye. We're then gonna make an elliptical incision just outside where we've placed our sutures, or if there is infected or tissue with tumours around the eye, we want to make that elliptical incision around the tissue that we want to remove. We're then gonna undermine the skin, to the bony edge to the orbit using a combination of blunt dissection, you may need sharp dissection, particularly at the medial and lateral canthus.

And we're just gonna slowly edge our way around the orbit. I regularly using, my gloved hand just to feel where, where, where the eye is and where the orbit is. We're gonna keep using blunt dissection through the fascia, the attachments in the orbit.

Aiming to try and keep that eyeball in its little sack. By putting gentle tension on the long suture ends, we will eventually, it can be a slow process, the eye will eventually tease itself out. You can put a slight rotational torsion on the eyeball within the socket, .

And then we can bluntly dissect some tissues behind. Be very careful, putting a lot of tension on the eye as it is described that if you put too much tension when removing one eye, you can damage the optic chiasm which can lead to blindness in the in the other eye. As you can see, eventually we are gonna manage to get the eye out, still in its sack.

This may be by rotating it in in different directions, . As we've put that slight portion on, we may have reduced haemorrhage by putting torsional pressure on the blood vessels, but generally when I get to the back there, I will just use scissors to cut straight across the tissue remaining. I'm not too worried if the, if, if the, if it bleeds, because once we've got the eye out, we're just gonna suture the, tissue, closed.

And once we've sutured that tissue closed, it's gonna form a watertight seal. Any haemorrhage that is occurring is eventually gonna fill up the orbit, and then that's gonna put pressure on those blood vessels leading to hemostasis. I don't think it matters what suture pattern you use to close the eyes, the eyelids, sorry, .

But do think about removal, and how easy that's gonna be. As I said, we can try and control the bleeding with a torsion on the blood vessels as we remove it. It is described using forceps with a 90 degree bend to clamp, and then we can ligate the optic vessels.

I've always found this very awkward, to actually do that. It is also described to pack the socket with gauze or swabs prior to closure and then leave a little corner out when you close the eyelids. That you can then remove them after a few days.

My concerns with this is that it's gonna lead to, swabs, impregnated with blood, which is a great culture medium, and then we've left a little window for potential bacterial infection to get in. Remember that no matter how sterile and how well we prepare for these surgeries. We are never gonna make them 100% tile.

So there is always risk of us having introduced infections, so the minimal amount of foreign material that we leave behind, I think, is the best. Innucleations can be done on small ruminants, they can be done on camelids. I've never heard of one being done on a pig, but again, I would use a similar procedure.

But with all the other species, I would potentially consider using a sedation or general anaesthesia so that they are recumbent when we do it. Moving on to talk about vasectomies, so again, quite a common procedure that we might be doing in practise. I think it's most commonly done on, on tups and rams, but it is a similar technique whether we're doing it in sheep, in bulls, or in bulls.

Why are we doing it? We're doing it to produce teaser animals, which can help, farms with their heat detection and therefore their pregnancy rates. But it does introduce some health to biosecurity issues.

Because in teaser animals, they can still achieve full intermission of the penis, so there is a risk of spreading venereal diseases. So when we choose the animal that we're gonna vasectomise, we want a healthy animal, and we ideally want it from our own herd or flock or from a closed herd or flock with good disease and biosecurity histories. We generally recommend keeping a vasectomis male away from females for 6 weeks post the op.

It is described about using electrical ejaculation, however, I suppose this is probably a questionable, ethically and probably against the welfare of those animals that sort of use electroejaculation to, to clear them out following surgery. Vasectomised animals will still show masculine traits, so can show aggressiveness and need to be treated, similarly to entire animals. Like tyre balls and working balls, they can lose their libido if they're overworked, .

So we need to make sure that we are using the right animal, that it's healthy, it's good confirmation that it's gonna have good longevity, has no signs of arthritis or other issues that might stop it mounting, has a normal penis and prep use and a norm normal testicular tissue. And also if we can test the libido first, good to see that they actually are interested. So vasectomies in bulls, typically we choose a beef cross calf, 6 to 9 months of age.

In younger animals, the testicles and epididymis are probably too small to allow easy handling. But gras present a risk and an increased cost of surgery. As we said, they need to be healthy animals, so that we get good longevity out of them.

Generally, to provide continuity of the bull use, it's necessary to prepare about one animal every 12 to 18 months for every working teaser on the farm. So a vasectomy in a bull is 100% effective in prevention of fertilisation, like an epididymectomy, which I'll briefly mention it in a bit. It's described as being done standing, makes me a bit nervous.

I think that it is easier if you've got the bull in lateral recumbency, but obviously there are the risks involved in knocking down a big heavy animal. You can induce the recumbency with a large dose of xylazine. You can use a high volume sacrococcygeal epidural, which will also take them off their back legs.

So I would sedate them with xylazine before doing that so that they don't, react to that, recumbency. We then will pull the upper hind limb cordially or cranially using ropes, to give us access to the scrotum. If you did want to perform a high volume, called epidural anaesthesia, then 3 to 4 gigs per gig of Linor came with adrenaline, .

Plus or minus some xylazine to prolong the effects, but also like I said, gives some xylazine parentially to sedate the animal. Once we have our sedated animal, we're gonna inject local anaesthetic into the distal spermatic cord, or just into the, subcutaneous tissue at the incision site. My preference is to do it just below the, the skin, cause I don't want to damage, the cord, and potentially cause problems.

A cranial approach is preferred, but it can be done by a quadrilateral or a full full caudal approach, and obviously if you're doing this standing, in a bull, you would probably use the the caudal approach. We can incise through the skin and the tunicadatus to expose the spermatic cord. Dissect that free from the surrounding tissues, then locate the vas deferns, which is within that vaginal tunic.

It's the bow in a bull 3 to 5 millimetres in diameter and it feels quite firm. In a RAM, I always describe it as feeling like a, a pencil lead flicking between your fingers, and it's the same in a ball. When we found it, we can incise through the vaginal tunic to expose the vas deference.

Be careful that we don't incise any of the vessels. We can then clamp it at both ends. And Remove approximately a minimum of 5 centimetres, it's described as up to 10 centimetres in a bull of vast deference.

You can ligate the ends of the remaining vas deference, and some people also describe suturing one end outside of the tunic before closing the tunic. That's to prevent recantalisation. We would then suture the skin closed.

And make sure that bull isn't going to the cows, like I said, preferably for 6 weeks, as they, he may still have sperm reserves along the reproductive tract. Corbal epidi, I always struggle with this word, epididectomy, is also described, and the advantages are that it can be easily performed in the standing animal. It's quite simple, it's quite straightforward and also allows a 100% effective prevention of fertilisation.

How is this performed? Well, what we're aiming to do is to remove the tail of the epididymis, xylazine sedation, but we want the ball to remain standing, and then some local anaesthesia infiltration in the tail of the epididymis and subcutaneous in the scrotum. We're then gonna incise lateral and midline over the bubble at the bottom of the scrotum, when the testicle is tense down through a 5 centimetre, and then we're then gonna extend our incision to 5 centimetres incise through the tunics to expose the tail of the epididymis.

So a couple of videos that hopefully will work and hopefully the sound won't be beyond. So once we have injected the local. Just into the base.

Very similar to how some people will perform castrates. We're then gonna make our incision, and when we've made our incision through the skin, we're gonna get the, the caudal epididymi, it's just gonna pop out of the scrotum, within the tunic. We're then gonna penetrate the ligament of the tail of the epididymis with sharp artery forceps and spread the jaws to create a large opening.

This turns the tail of the epididymis into a U-shaped structure. Which we can then lie gate on both sides of the loop, clamp and lie gate. We can then excise with the scalpel blade and generally just remove the clamps after one minute, just for a bit of added hemostasis.

We can then just suture the skin, close with absorbable material. If you want to, you can repeat for the other side, however, it's also described that you could just do a unilateral castration and just leave 11 testicle present. So on a cadaver specimen.

Just showing the tail of the epididymis, where we're gonna place our forceps and then just open up. To form a loop, or a U shape. So, as I said, the actual vasectomy procedure is similar, whether it's in a bull, a ram or a bore.

With rams, some people will use zylazine as a sedation plus the local, some people will use lumbosacral epidurals. My preference is, if you have a good person to, to hold the ram, it's just to sit them on a chair or on a bale of straw, and then just place local, in the neck of the scrotum where we're gonna make our incisions. Again, we're gonna identify the cord, and we're gonna identify the vast deference within the cord before making an incision and bluntly dissecting in the ram aiming to remove 3 to 5 centimetres.

In a bore, the procedure is very similar, again under my preferred xylazine, ketamine, and zaprone sedation. Again, local anaesthetic infiltration, just cranial to the scrotum, caudal to the base of the penis, remembering that the anatomy of bore testicles is slightly different, but just subcutaneous, infiltration. And again, we're just identifying the cord and identifying the vast deference.

And again, I aim to remove about 5 centimetres. I'm not gonna go into huge details about flank laparotomy because there are a number of reasons we can do it. And the approach and the flank side that we're gonna use will be determined by what our aims of surgery are.

So a left-sided approach would be indicated for LDAs, for caesareans, for traumatic reticular . Pericarditis, for a rheinotomy, for rumen or bloat, but we can also use it as part of an ex-lap to check the left border of the liver, the left kidneys, the ovaries and the descending colon. A right-sided approach can be used for an LDA or for an RDA for sequel dilatation with or without torsion, for an intestinal interception, but as well as part of an ex-lap we can look at the large intestine, the small intestine, the liver and the kidneys.

Local blocks that you select will depend on the area of anaesthesia that you require, but again, the animal should be suitably restrained, and I, I, especially for a for a exploratory laparotomy, will give a really wide clip and a thorough surgical prep. I also like to see sort of, and I think that there is no reason why we shouldn't prepare ourselves the surgeons, drape the animals, follow the best principles of surgery that we can, just because they're farm animals and are a little bit more forgiving, doesn't mean that we shouldn't be aiming for, for better practise. Any flank incision, we're gonna go through the external and internal abdominal oblique muscles and the transverse abdominal muscle, and then into the peritoneum.

And we're gonna get that very, sudden sucking in of air when we go through the peritoneum. We're then gonna do whatever procedure we need to do, and then closing up, I tend to do it in sort of two layers with the transverse muscle and the peritoneum together and then the two obliques together and then finally close the skin. My preference is to use continuous absorbable for the muscle layers and then I tend to do a forward interlocking with a non-absorbable for the skin.

The picture on the right shows that how sometimes it can be useful to use power revertibles as we had to extend this incision by about 4 or 5 inches along the bottom. And also shows why a very wide clip is is quite useful. What do we do if the cow goes down?

Don't panic. I would generally then sedate the cow, use some assistance to reposition the animal, and then continue the procedure with the cow recumbent. Trying to get the cow to stand can cause more stress for everyone.

And all we need to do is, if we're worried about contamination, lavage the, the surgical area in the abdomen, . As thoroughly as possible and then maybe make sure that we're monitoring that cow well following surgery. Post-op see, obviously the post-op care will depend on the surgery performed.

Whatever surgery, I tend to clean the surgical field straight after the op so that we've not got a lot of dried blood, drying and maybe causing irritation. We may apply wound dressings and we need to let the farmer know when we want to change those. We may need to think about fly control, and the potentials of where that incision may get contaminated.

We may want to limit movement depending on on what surgery is being performed. We want to think about some ongoing analgesia. We may want to continue or start antibiotics.

We may want to give fluids if we feel that the animal has lost a lot of blood. And then we want to just discuss with the farmer, how are they gonna manage that animal, and when do we want to revisit. The common complications following any surgery would be infection or peritonitis, wound breakdown, subcutaneous emphysema, seroma or abscess formation, and there may well be, no matter what surgery has happened, an effect on production.

In the worst cases, we may get a sudden death, and generally a sudden death will be due to a catastrophic catastrophic event such as a haemorrhage or endotoxemia. I want to finish with some slides on antibiotic use. I'm not gonna preach to people.

I think that as farm vets we can make our own decisions about what is prudent use. But I just want to talk a bit about sort of the surgical principles that we may may need to consider. So even on farm animals, we can think about the wound classification and even surgical wounds or surgical incisions and how we classify those surgeries.

So clean, clean contaminated, contaminated or dirty. And this really depends on the procedure, the technique, the viability of the tissue and the infection that's there. And even in clean surgeries, we, with no known risk factors, there is still a 2% expected rate of surgical site infection.

Clean contaminated, we expect 5 to 15%, contaminated greater than 15%, and dirty greater than 30%. So We should think about perioperative prophylaxis, er if there is a risk of infection, or if a subsequent development of infection could have disastrous consequences. So generally surgeries considered clean, it would be ones where respiratory or gastrointestinal and neurogenital tracts are only entered under controlled conditions, and there's been no major breaks in aseptic techniques and no acute inflammation.

Clean, we have clean contaminated, a, a, a slightly different, followed by our contaminated surgeries and our dirty. Now, with the dirty surgeries, it talks about the presence of Frank Frank Passwell, a lot of our iron nucleations, our digit amputations, maybe even our tail amputations, there possibly will be infection and infla inflamed, traumatised, devitalized tissue present. So most of those we could consider dirty and therefore antibiotics might be advisable.

I generally will always give antibiotics for flank surgeries, because despite how clean I try to make the area myself, it's not always possible. So I think we need to, to be careful of what we're doing, but also to consider and discuss with the farmer. Appropriate use, really includes three elements.

So we need to choose appropriately, the appropriate drug, how we're gonna give the first dose, and when are we gonna discontinue it. So in small animal cephalosporins are the preferred prophylactic antimicrobial for most surgical procedures. However, as we all know, we have restrictions on using these without cultural sensitivity in farm animals.

So we need to think, we want to choose a product that is gonna give gramme negative and gramme positive, and also anaerobic, so. Really unless we're using in combination therapies, potentially amoxicillins tend to be quite a good bet. We want those antibiotics to be in the tissues at the start of the surgery and an effective concentrations to be maintained throughout.

The problem with the licenced products we have available is it can Take 2 to 3 hours to reach TMax, so realistically, I don't think we're gonna get farmers to give these drugs 2.5 hours prior to us starting surgery. From the data with potentially amoxicillin, we could extrapolate that following the first dose, we should give another dose every 1.5 hours after that first dose.

Which again is not really realistic. And again, surgical texts will say that really we shouldn't be administering 24 hours post surgery unless there's been a major break in the sterile technique. Or there's been an unexpected change in the contamination status.

And to be perfectly frank, I think most on-farm procedures or procedures that then go back to farm, there is going to be a change in the contamination status and the risk of that incision getting contaminated. So, I don't think it's necessarily a bad choice to give a course of antibiotics. One interesting thing that I would say is that it is suggested that giving once daily, so following the manufacturer's guidelines for potentiated amoxicillin in cattle, is probably underdosing and actually giving it 2 or 3 times maybe better therapeutically.

However, that is off licence use. And it is also going to increase the amount of antibiotics that we use. So I know that's a bit of a whistle stop tour, but I'd like to thank you for your attention and if there are any questions, I, I'd be happy to see if I can answer them.

Thank you very much, Paul. That was really interesting. So if, does anyone have any questions?

I've just sent a little message out to everyone just to see if there were any questions, and you can head over to the question and answer box. We'll give you a couple of minutes, a little second just to add any questions into, into there, and we can, call will kindly answer them for us. Nothing's coming through yet, Paul, I think you might be.

Yeah, if anyone does think of any questions that, you know, I'm sure that my contact details are available or they can find them through the Edinburgh website and I'm happy to take questions by email if people would prefer. Oh, I've had one come through, so, . It's I think from John and says thank you for a really nice presentation.

Do you ever do, oh gosh, epididiectomy in RAMs? So it's, it's not actually a technique that I've, done even on bulls, . There's no reason why you couldn't.

I just think with RAMs that actually the, the vasectomy is quite straightforward, particularly as I do it without sedation and just under local. And I find it quite a quick procedure to do a, a, a normal vasectomy. So it isn't something that I have done, but there's no reason why you couldn't do it.

Cool. Thank you very much. Well, we've had no other questions come through, so I would like to thank, thank you, Paul for a really interesting talk that I hope everyone who's attended this evening will be able to take, take some stuff away from the, from this, to be able to use in practise, especially with all the doses and everything being given and the, handouts as well.

So thank you very much, Paul, and thank you Phillip in the background for doing all of the technical stuff for us. And thank you everyone else again for attending this evening and I hope you have a lovely rest of the evening. Take care, bye.