**4.3 Histopathological features**

Arteriovenous shunts (AVs), disruption of the dermal-epidermal junction, rupture of the vascular wall, vascular thrombosis and vascular proliferation were the main histological changes frequently observed in the claws with laminitis and the laminitis-related lesions. Other histological changes observed but rare included oedema in the dermis of the sole, connective tissue oedema, thickened arterial wall, degeneration and necrosis of the connective tissue that supports the distal phalanx, damage of the epidermal cells, spongiosis of the stratum basale and stratum spinosum, corium haemorrhages, connective tissue degeneration and enlargement of veins (**Table 3**).

Arteriovenous shunts (**Figure 10**) were observed in 40 and 50% of the corium specimens from claws with subclinical laminitis and chronic laminitis, respectively. Vascular wall damage (**Figure 11**) and dermal-epidermal junction disruption (**Figure 12**) were each observed in 30 and 50% of the corium specimens from claws with subclinical and chronic laminitis, respectively. Spongiosis was seen in 30% of

#### **Figure 7.**

*A rounded (missing) apex of the pedal bone (bold arrow) making the bone look shorter than the ipsilateral pedal bone as shown (dotted line) in A and B. The projected apical part of the ipsilateral pedal bone is slightly irregular with serrations (dashed arrow). These radiographic changes were observed in dairy cow claws that had laminitis.*

**47**

*Kenya.*

**Table 3.**

*Macroscopic, Radiographic and Histopathologic Changes of Claws with Laminitis…*

*A small fracture-like fissure (arrow) observed in three pedal bones from dairy cow claws that had laminitis.*

*Pedal bones showing radiolucent areas representing bone lysis (arrows). The areas look similar to medullary cavity, which is normally absent in normal pedal bones. This was observed in one dairy cow claw that had* 

Arteriovenous shunts 40 50 Vascular wall damage 30 50

Vascular thrombosis 40 100 Vascular proliferation 30 30

Vascular wall thickness 30 10 Connective tissue degeneration 0 30 Corium haemorrhages 10 20 Spongiosis 0 30

*The claws were collected from Kiserian abattoir of Kajiado County and Wangige slaughter slab of Kiambu County,* 

*Histopathological changes observed in the corium tissue specimens harvested from dairy cow claws with* 

**laminitis (n = 10)**

30 50

20 20

**Prevalence (%) in chronic laminitis (n = 10)**

**Histopathological lesions Prevalence (%) in subclinical** 

*DOI: http://dx.doi.org/10.5772/intechopen.81255*

**Figure 8.**

**Figure 9.**

*chronic laminitis.*

disruption

tissue

Dermal-epidermal junction

Oedema of corium and connective

*subclinical laminitis and chronic laminitis.*

*Macroscopic, Radiographic and Histopathologic Changes of Claws with Laminitis… DOI: http://dx.doi.org/10.5772/intechopen.81255*

#### **Figure 8.**

*Veterinary Anatomy and Physiology*

**4.3 Histopathological features**

veins (**Table 3**).

**Figure 6.**

phalanx. The fissure was small and the part that appeared like bone fragment was still aligned to the entire bone (**Figure 8**). One distal phalanx was found to have osteolysis, which was clearly manifested by radiolucency of the bone appearing like the bone has a large medullary cavity (**Figure 9**), which is naturally absent in the pedal bone.

*Narrowed pedal bone (arrow) whose extent of tapering is shown (brace). The pedal bone of the ipsilateral claw is normal width. This radiographic change was observed in dairy cow claws with laminitis.*

Arteriovenous shunts (AVs), disruption of the dermal-epidermal junction, rupture of the vascular wall, vascular thrombosis and vascular proliferation were the main histological changes frequently observed in the claws with laminitis and the laminitis-related lesions. Other histological changes observed but rare included oedema in the dermis of the sole, connective tissue oedema, thickened arterial wall, degeneration and necrosis of the connective tissue that supports the distal phalanx, damage of the epidermal cells, spongiosis of the stratum basale and stratum spinosum, corium haemorrhages, connective tissue degeneration and enlargement of

Arteriovenous shunts (**Figure 10**) were observed in 40 and 50% of the corium specimens from claws with subclinical laminitis and chronic laminitis, respectively. Vascular wall damage (**Figure 11**) and dermal-epidermal junction disruption (**Figure 12**) were each observed in 30 and 50% of the corium specimens from claws with subclinical and chronic laminitis, respectively. Spongiosis was seen in 30% of

*A rounded (missing) apex of the pedal bone (bold arrow) making the bone look shorter than the ipsilateral pedal bone as shown (dotted line) in A and B. The projected apical part of the ipsilateral pedal bone is slightly irregular with serrations (dashed arrow). These radiographic changes were observed in dairy cow claws that had laminitis.*

**46**

**Figure 7.**

*A small fracture-like fissure (arrow) observed in three pedal bones from dairy cow claws that had laminitis.*

#### **Figure 9.**

*Pedal bones showing radiolucent areas representing bone lysis (arrows). The areas look similar to medullary cavity, which is normally absent in normal pedal bones. This was observed in one dairy cow claw that had chronic laminitis.*


*The claws were collected from Kiserian abattoir of Kajiado County and Wangige slaughter slab of Kiambu County, Kenya.*

#### **Table 3.**

*Histopathological changes observed in the corium tissue specimens harvested from dairy cow claws with subclinical laminitis and chronic laminitis.*

#### **Figure 10.**

*Arteriovenous shunts shown by branching out of the wall of the artery (bold arrow) and inclusion of veins within the arterial wall boundaries (thin arrows) and the position of capillary-beds (curved arrows). These changes were seen in the corium of dairy cow claws with laminitis. (H&E stain, ×400).*

#### **Figure 11.**

*A vein showing damaged wall (thick arrow) and a thrombus attached to the wall (thin arrow). This was a common feature in the corium of dairy cow claws with laminitis. (H&E stain, ×400).*

#### **Figure 12.**

*Dermal-epidermal junction disruption shown by areas where the cells are not in contact and continuous with each other (short arrows). Intracellular oedema (spongiosis) (long thin arrows). These were common findings in cases of claws with laminitis. (Toluidine blue stain, ×400).*

the specimens from claws with chronic laminitis (**Figure 12**), but it was not seen in claws with subclinical laminitis. Vascular wall damage was seen more regularly in the arterioles and venules than in the larger blood vessels. Endothelial disruption was seen more frequently than damage of the rest of the vascular wall. Rupture of the entire thickness of blood vessel wall followed by haemorrhage into the surrounding tissues was seen in 10 and 20% of the corium specimens from claws with subclinical and chronic laminitis, respectively. All the histological changes

**49**

**Figure 14.**

**Figure 13.**

*Macroscopic, Radiographic and Histopathologic Changes of Claws with Laminitis…*

mentioned above were more common, extensive and severe in the corium specimens from claws with chronic laminitis than in those with subclinical laminitis. Vascular thrombosis (**Figure 13**) was found in 70% of all corium specimens. All the corium specimens from claws with chronic laminitis were found to have vascular thrombosis, but only 40% of the corium specimens from claws with subclinical laminitis. Thickened vascular wall particularly of the arteries was found in 40% of the specimens, 30% from claws with subclinical laminitis (**Figure 13**). The vascular layer that appeared more prominently thickened was tunica media and in some of the specimens, it was evident that this thickening was due to oedema. Degeneration of the connective tissue that supports the distal phalanx was observed in 40% of the specimens, all of which were from claws with chronic laminitis. Oedema in the dermis of the sole and in the connective tissue (**Figure 14**) was found in 40% of the specimens, half from claws with subclinical laminitis and half from claws with chronic laminitis. Evidence of haemorrhages in the corium was found in 30 and 10% of the specimens from claws with chronic laminitis and subclinical laminitis, respectively. Mild degeneration of the sole connective tissue was seen in 30% of the specimens from claws with chronic laminitis (**Figure 15**). In 20% of all the specimens of claws with subclinical laminitis and chronic laminitis, the veins had

*Thickened arterial wall (double-headed arrow), disrupted arterial endothelium (curved arrow) and a thrombus in the lumen of the artery (single-headed arrow) (H&E stain, ×400). This was a feature observed in* 

*Connective tissue oedema (arrows) seen in the corium of dairy cow claws with laminitis. (H&E stain, ×400).*

*the corium vasculature of dairy cow claws with laminitis. (H&E stain, ×400).*

*DOI: http://dx.doi.org/10.5772/intechopen.81255*

enlargements that appeared like dilatations.

### *Macroscopic, Radiographic and Histopathologic Changes of Claws with Laminitis… DOI: http://dx.doi.org/10.5772/intechopen.81255*

mentioned above were more common, extensive and severe in the corium specimens from claws with chronic laminitis than in those with subclinical laminitis.

Vascular thrombosis (**Figure 13**) was found in 70% of all corium specimens. All the corium specimens from claws with chronic laminitis were found to have vascular thrombosis, but only 40% of the corium specimens from claws with subclinical laminitis. Thickened vascular wall particularly of the arteries was found in 40% of the specimens, 30% from claws with subclinical laminitis (**Figure 13**). The vascular layer that appeared more prominently thickened was tunica media and in some of the specimens, it was evident that this thickening was due to oedema. Degeneration of the connective tissue that supports the distal phalanx was observed in 40% of the specimens, all of which were from claws with chronic laminitis. Oedema in the dermis of the sole and in the connective tissue (**Figure 14**) was found in 40% of the specimens, half from claws with subclinical laminitis and half from claws with chronic laminitis. Evidence of haemorrhages in the corium was found in 30 and 10% of the specimens from claws with chronic laminitis and subclinical laminitis, respectively. Mild degeneration of the sole connective tissue was seen in 30% of the specimens from claws with chronic laminitis (**Figure 15**). In 20% of all the specimens of claws with subclinical laminitis and chronic laminitis, the veins had enlargements that appeared like dilatations.

#### **Figure 13.**

*Veterinary Anatomy and Physiology*

**Figure 10.**

**Figure 11.**

**Figure 12.**

**48**

the specimens from claws with chronic laminitis (**Figure 12**), but it was not seen in claws with subclinical laminitis. Vascular wall damage was seen more regularly in the arterioles and venules than in the larger blood vessels. Endothelial disruption was seen more frequently than damage of the rest of the vascular wall. Rupture of the entire thickness of blood vessel wall followed by haemorrhage into the surrounding tissues was seen in 10 and 20% of the corium specimens from claws with subclinical and chronic laminitis, respectively. All the histological changes

*Dermal-epidermal junction disruption shown by areas where the cells are not in contact and continuous with each other (short arrows). Intracellular oedema (spongiosis) (long thin arrows). These were common findings* 

*Arteriovenous shunts shown by branching out of the wall of the artery (bold arrow) and inclusion of veins within the arterial wall boundaries (thin arrows) and the position of capillary-beds (curved arrows). These* 

*A vein showing damaged wall (thick arrow) and a thrombus attached to the wall (thin arrow). This was a* 

*changes were seen in the corium of dairy cow claws with laminitis. (H&E stain, ×400).*

*common feature in the corium of dairy cow claws with laminitis. (H&E stain, ×400).*

*in cases of claws with laminitis. (Toluidine blue stain, ×400).*

*Thickened arterial wall (double-headed arrow), disrupted arterial endothelium (curved arrow) and a thrombus in the lumen of the artery (single-headed arrow) (H&E stain, ×400). This was a feature observed in the corium vasculature of dairy cow claws with laminitis. (H&E stain, ×400).*

#### **Figure 14.**

*Connective tissue oedema (arrows) seen in the corium of dairy cow claws with laminitis. (H&E stain, ×400).*

#### **Figure 15.**

*Connective tissue degeneration manifested by deeply stained degenerated fibroblasts (bold arrows) and fibres (dotted arrows) in the histological sections of the corium of dairy cow claws with chronic laminitis (Toluidine blue stain, ×200).*
