Introduction
In cattle, exungulation, or loss of the entire hoof capsule, can be either primary and associated with a traumatic event or secondary to dermal-epidermal disruption from acute laminitis, systemic diseases including vasculitis caused by Salmonella Dublin and foot-and-mouth disease, local digital infections (eg, interdigital necrobacillosis), or toxicoses (eg, fescue foot).1,2,3 Traumatic exungulation can result from accidents where the animal catches its foot in a gate, fence, or piece of farm equipment and the hoof is unintentionally removed when the animal struggles to free itself.1 Exungulation may be partial or complete in such cases. Reports of complete traumatic exungulation in cattle are rare and limited to a small number of animals.3,4
Clinical signs of traumatic exungulation in cattle include acute-onset lameness and bleeding from the affected digit or digits. Treatment typically includes regional anesthesia, cleansing of the region, administration of topical antimicrobials, fiberglass cast or bandage placement, and placement of a block on the hoof of the unaffected adjacent digit.1,5 Long-term outcomes including return to productivity and intended function have not been evaluated.
The purpose of the study reported here was to characterize complete traumatic exungulation in cattle and to describe treatment approaches and short- and long-term outcomes for affected animals. All ages and classes of cattle (eg, beef, dairy, and use [commercial production vs athletic performance vs pet]) were included to fully characterize the likelihood of affected animals returning to their expected function.
Materials and Methods
Case selection criteria
The medical records databases of the Oklahoma State University Boren Veterinary Medical Teaching Hospital and Colorado State University Veterinary Teaching Hospital were reviewed to identify records of cattle that were treated for complete traumatic exungulation between January 1993 and December 2018. Diagnosis of complete traumatic exungulation was made on the basis of clinical findings. Thirteen records were retrieved and reviewed. Two animals were subsequently excluded from the study because they had only partial exungulation, and 1 animal was excluded owing to an incomplete medical record. Thus, 10 cattle were included in the study (7 that were treated at the Oklahoma State University Boren Veterinary Medical Teaching Hospital and 3 that were treated at the Colorado State University Veterinary Teaching Hospital).
Medical records review
For each animal included in the study, information extracted from the medical record included signalment, history, and results of the initial physical examination and any ancillary diagnostic testing that was performed. Locomotor scoring was performed with each animal observed while walking in a large pen without being led by a halter as described by Greenough et al.1 Briefly, a score of 1 = minimal abduction or adduction and no unevenness or tenderness; 1.5 = slight abduction or adduction and no unevenness or tenderness; 2 = abduction or adduction present, uneven gait, and perhaps tender; 2.5 = abduction or adduction present, uneven gait, and tenderness of feet; 3 = slight lameness that does not affect behavior; 3.5 = obvious lameness, difficulty in turning, and behavior affected; 4 = obvious lameness, difficulty in turning, and behavior affected; 4.5 = some difficulty in rising, difficulty in walking, and behavior affected; and 5 = extreme difficulty in rising, difficulty walking, and behavior affected. The abbreviated version of this lameness scoring system was as follows: 1 = normal, not lame; 2 = slight abnormality; 3 = slight lameness, moderate and consistent lameness; 4 = obvious lameness that affects behavior; and 5 = severe, marked lameness.1
Also recorded were general treatment approaches (eg, antimicrobials, curettage, anti-inflammatories, analgesics, regional anesthesia, and bandage or cast placement), number of recheck visits, and number of days hospitalized. Outcomes were recorded including whether the animal survived to discharge. Information about long-term (≥ 9 months) survival and return to productivity or function was obtained from the medical record review or by telephone communication with the owner.
Statistical analysis
Descriptive statistics including the mean, median, and range were generated for all numerical variables with a spreadsheet program (Excel; Microsoft Corp). The small number of observations and nature of the data precluded more in-depth analyses.
Results
The 10 cattle enrolled in the study included 3 crossbreds, 3 Angus, 2 Holsteins, 1 Hereford, and 1 Longhorn. There were 5 bulls, 4 heifers, and 1 cow. Of the 5 bulls, 3 were beef bulls intended for breeding purposes and 2 were used as bucking bulls. The remaining 5 animals included 2 commercial dairy cows (1 was a heifer at the time of injury), 1 commercial beef cow (that was a heifer at the time of injury), 1 pet beef cow (that was a heifer at the time of injury) that was also maintained for breeding purposes, and 1 rescue pet cow (that was also a heifer at the time of injury). For all 10 animals at hospital admission, the median age was 2 years (mean, 2.4 years; range, 1 day to 10 years) and weight was 379.1 kg (mean, 413.2 kg; range, 30 to 909.1 kg).
For 7 of the 10 animals, the primary reason for examination was absence of the hoof capsule on at least 1 digit. Of the 3 remaining animals, 1 was presented for lameness unassociated with the exungulation, 1 for a hoof problem that turned out to be an exungulation, and 1 for swelling of the right forelimb unrelated to traumatic exungulation. One animal had concurrent diarrhea, fever, and respiratory distress in addition to exungulation. The duration of clinical signs prior to admission ranged from ≤ 24 hours (n = 6 animals) to 3.5 days (median, 12 hours; mean, 22 hours). The cause of exungulation was known for 5 animals; exungulation was associated with restraint in a chute or being tilted on a hydraulic chute for 3, occurred in a load alley at a rodeo for 1, and occurred when stepping on a bucking dummy for 1 (Figure 1). Treatments administered before hospital admission included ceftiofur sodium (n = 1), gentamicin (1), oral neomycin (1), and foot bandage application (1).
Body temperature at hospital admission was recorded for 5 of the 10 animals, of which 3 were febrile (reference range,6 38.1 to 39.2 °C). The body condition score (BCS) was recorded for 6 beef animals and ranged from 3/9 to 6/9 (median BCS, 6/9; mean BCS, 5.4/9). The BCS was 3/5 for the 1 dairy heifer. Heart rate was recorded for 4 animals and ranged from 90 to 180 beats/min (mean, 127.5 beats/min; median, 120 beats/min; reference range,6 40 to 80 beats/min). Respiratory rate was recorded for 5 animals and ranged from 24 to 160 breaths/min (mean, 78 breaths/min; median, 60 breaths/min). Four animals were tachypneic (respiratory rate reference range, 12 to 36 breaths/min).
A lameness score was recorded for 7 animals and ranged from 1.5/5 to 5/5 (mean lameness score, 3.1/5; median lameness score, 3/5). Six animals had exungulation of a forelimb digit, and 4 animals had exungulation of a hind limb digit. Complete exungulation occurred in 6 medial digits (right hind limb, n = 3; left forelimb, 2; and right forelimb, 1) and 5 lateral digits (right forelimb, 3; left forelimb, 1; and left hind limb, 1). Eight animals had complete exungulation of only 1 digit. One calf had complete exungulation of the lateral digit of the left hind limb and partial exungulation of the medial digit of the right hind limb. One calf had complete exungulation of both digits of a limb. Both of the bucking bulls had complete exungulation of the medial digit of the right hind limb. Only 1 animal had a traumatic injury in addition to complete exungulation (a laceration to the medial aspect of the thigh region of the same hind limb with the exungulation). Comorbidities were also rare and were limited to suspected viral pneumonia and diarrhea, which was subsequently confirmed to be caused by Cryptosporidium spp infection, in 1 calf.
Traumatic exungulation was diagnosed on the basis of clinical findings in all 10 animals. For 1 animal, radiographs were obtained during the initial examination to rule out additional traumatic injuries to the digits of the affected hoof. During the initial examination, a portion of the third phalanx (P3) was visible with variable amounts of solar, laminar, and parietal corium adherent to the exungulated hoof in 4 animals. The distal interphalangeal joint (DIPJ) capsule was also exposed in 1 of those 4 animals. The P3 was not fractured nor was there identifiable penetration of the DIPJ in any of those animals. One animal required vascular ligation to control hemorrhage. Only 1 animal had swelling of the affected limb recorded at the time of hospital admission.
Treatment information was available for 9 animals. Treatments administered included bandaging (n = 9), antimicrobials (9), anti-inflammatories (8), application of a hoof block on the unaffected digit of the affected limb (7), regional anesthesia (6), cast placement on the affected limb (4), curettage of P3 (3), regional IV perfusion of florfenicol (1), and local application of polymethyl methacrylate beads impregnated with ampicillin-sulbactam (1). Antimicrobials administered included florfenicol (n = 5), oxytetracycline (2), tulathromycin (1), ceftiofur crystalline-free acid (1), ceftiofur hydrochloride (1), ceftiofur sodium (1), sulfamethoxazole-trimethoprim (1), sulfadimethoxine (1), and enrofloxacin (1). Antimicrobials were administered for 2 to 30 days. All anti-inflammatories administered were NSAIDs and included flunixin meglumine (n = 6), meloxicam (2), and ketoprofen (1); some animals received more than 1 NSAID. All drugs were administered in accordance with established extralabel dosing regimens, and estimated withdrawal times for meloxicam and ketoprofen were determined by FARAD consultation.
All affected digits were cleansed of dirt and debris, debrided, and either bandaged (n = 5), bandaged initially and placed in a cast later (3), or placed in a cast (1). The type of bandage applied was characterized as a Robert-Jones bandage (n = 1), pressure bandage (1), or sterile bandage (1) or was unspecified (6). Topical antimicrobials applied on the affected digits included neomycin-bacitracin-polymyxin B ointment (400 U of bacitracin zinc/g, 3.5 mg of neomycin sulfate/g, and 5,000 U of polymyxin B sulfate/g; n = 2), cephapirin (mastitis tube with 200 mg of cephapirin sodium/tube; 1), oxytetracycline powder (100 g/lb; 1), and 1% silver sulfadiazine cream (1).
Three animals were sedated to facilitate treatment, and sedation included xylazine (IV or SC; n = 2), butorphanol (IV or SC; 2), detomidine (IV; 1), and ketamine (SC; 1). Regional anesthesia was administered by the use of lidocaine via regional IV perfusion (n = 5) or a ring block (1). A hoof block was applied to the unaffected digit of the affected foot for 7 animals. All traumatic exungulations were allowed to heal by second-intention healing. In general, bandages were changed daily 1 to 3 times if heavily contaminated or at 2- to 3-day intervals until healthy corium was present. For 4 adult animals, half-limb casts were applied at the discretion of the attending clinician to reduce the need for frequent bandaging and provide superior protection to the healing digit. One animal received a biotin-methionine hoof supplement (15 mg of biotin and 5 mg of dl-methionine) added to the grain on a daily basis for 2 months.
Pedal osteitis or osteomyelitis developed in 3 of the 4 animals that had full-thickness defects in the corium at hospital admission, as evidenced by failure of granulation tissue to cover visible bone after 5 to 7 days and discoloration and darkening of the exposed bone. One of those animals subsequently developed a sequestrum that was detected clinically during curettage. All 3 animals underwent regional IV anesthesia and curettage of P3. Long-term follow-up information was available for each of those animals, and each ultimately returned to their intended purpose (breeding bull, bucking bull, and pet cow).
For all 10 affected animals, the duration of hospitalization ranged from 0 to 33 days (mean, 9 days; median, 5 days) and the number of recheck visits ranged from 0 to 13 (mean, 3; median 1.5). Four animals were managed on an outpatient basis, 2 of which were primarily managed by the owner at home. The timing of permanent removal of the bandage or cast was recorded for 5 animals and occurred 20 to 83 days (mean, 55.2 days; median 58 days) after initial application.
Nine of the 10 animals were discharged from the hospital following diagnosis and treatment. One bucking bull, in which P3 of the affected digit was exposed, was euthanized after 4 days of hospitalization. One commercial dairy cow that was examined on an outpatient basis was transported directly to a slaughter facility following examination.
Long-term (≥ 9 months) follow-up was obtained from the medical record or by telephone communication with the owner for 7 of the 9 animals that were treated for complete exungulation. Long-term follow-up information was unavailable for 1 bull and the cow that went directly to slaughter. All 7 animals for which long-term follow-up information was available remained in their respective herds and returned to use for their intended purpose (2 breeding beef bulls, 1 bucking bull, 2 beef heifers, 1 dairy cow, and 1 rescue pet heifer). Six of those animals had no residual lameness reported. One bull had some residual lameness that was initially caused by a toe ulcer and abscess; however, it was still able to function as a pasture breeding bull. Three animals required regular hoof trimming of the affected digit but were not lame. The affected hooves of those 3 animals were described as being too long, slightly deformed, or having an axial deviation of the abaxial wall akin to corkscrew claw, necessitating corrective trimming.
Discussion
Overall, the cattle with complete traumatic exungulation evaluated in the present study had good long-term outcomes, with 6 of the 7 animals that were treated and for which long-term information was available returning to their intended purpose with no residual lameness. A potential factor contributing to the positive long-term outcomes for these animals was that most received medical care within 24 hours of the exungulation occurring. Additionally, a primary weight-bearing digit (ie, the medial digit of a forelimb or lateral digit of a hind limb) was affected in only 4 of those animals. The specific digit involved may not be a salient determinant of traumatic exungulation outcome as it can be for digit amputation.
The cause of complete traumatic exungulation was known for 5 of the 10 cattle evaluated in the present study. Interestingly, for 3 animals, the exungulation occurred while the animal was being moved through or restrained in a chute (1 during a routine bull breeding soundness examination, 1 as the animal was walking into a chute for a lameness examination, and 1 while the animal was being restrained in a tilting hydraulic chute for treatment of a subsolar abscess). For the other 2 animals, traumatic exungulation was associated with moving or bucking in an arena (rodeo bull). Thus, it may be prudent to inform owners of the risk for traumatic exungulation when an animal is being moved through or restrained in a chute for any reason.
For the cattle of the present study, the basic tenets of treatment included preventing or controlling infection of the exposed soft tissues and bone, establishing and maintaining a healthy bed of granulation tissue for subsequent dermal recovery and expansion, protecting the affected digit from weight-bearing and other contusion during healing, and controlling pain. Broadly, this entailed systemic and sometimes local antimicrobial administration, anti-inflammatory and analgesic treatments, hoof block application to the unaffected adjacent digit, bandaging, and sometimes surgical curettage of P3. All drugs were administered at the discretion of the attending clinicians, and the dosing regimens varied substantially among animals. Therefore, drug dosages were not provided for the cattle of the present study. However, all drugs were administered in accordance with regulations regarding extralabel drug use in food animals. For some cattle, a half-limb cast was applied once a healthy and confluent bed of granulation tissue formed over the affected digit to reduce the frequency of restraint and bandage changes.
Florfenicol, oxytetracycline, and ceftiofur (administered at the label dose and route) were the systemic antimicrobials most frequently administered to the cattle of the present study because of their respective spectrums of activity, label approval for the treatment of interdigital phlegmon (foot rot), and longer duration of activity to avoid the need for daily injections (which was advantageous for the treatment of mature or bucking bulls). Regional IV perfusion of antimicrobials was reserved for animals in which bone involvement was suspected. The duration of systemic antimicrobial administration ranged from 2 to 30 days for treated animals.
For cattle with complete exungulation of a digit, treatment of the exposed corium with topical antimicrobials could be beneficial prior to bandage placement. For the cattle of the present study, neomycin-bacitracin-polymyxin B, cephapirin, oxytetracycline powder, and silver sulfadiazine were the topical antimicrobials most frequently used for that purpose. We recommend topical antimicrobial preparations that are noncaustic and promote formation of granulation tissue for this purpose. Some topical antimicrobial formulations impede epithelialization and delay wound healing in other species7; therefore, bandaging materials containing polyhexanides or colloidal silver topical preparations are recommended. Bandaging of the affected limb varied for the cattle of the present study. In our experience, a pressure bandage, such as a Robert-Jones bandage, is applied initially to help reduce local swelling. Once local swelling is resolved, a nonadherent dressing, stretch gauze, and a self-adherent wrap are generally used and protected by several layers of scrim-backed pressure-sensitive tape with a polyethylene coating to keep the bandage dry. Bandages are used to prevent trauma to and contamination of the corium as well as the underlying bone and synovial structures. In our experience, the affected foot remains bandaged until keratinization of most or all of the exposed corium is achieved. Alternatively, once any local infection of the corium or underlying bone is resolved, a half-limb cast can be applied to the affected limb to reduce the need for bandage changes.
For each of 2 animals of the present study, the owner was able to perform most patient management at home following the initial examination at the hospital. Both of those animals recovered and returned to their intended function. Despite the acute traumatic nature of complete exungulation, control of hemorrhage was rarely necessary for the cattle of the present study. Three animals developed pedal osteitis or osteomyelitis, which required intensive management. One of those animals developed a sequestrum. All 3 of those animals underwent curettage of P3, and 2 also received local antimicrobial delivery. Two of those animals had the longest hospital stays (31 and 33 days). One was managed on an outpatient basis and had the greatest number of recheck visits (n = 13). All 3 animals (1 pasture breeding bull, 1 bucking bull, and 1 rescue pet cow) ultimately recovered and returned to their intended use, although 1 had residual lameness attributed to a toe ulcer that progressed to an abscess during the healing process, leading to an abnormal hoof shape for the affected digit. However, evidence of DIPJ capsule exposure, penetration, or sepsis; fracture of P3; or existing pedal osteitis-osteomyelitis in addition to complete exungulation might prompt clinicians to consider digit amputation, slaughter, or euthanasia, particularly for patients with owners with limited economic resources.
Both calves with exungulation of multiple digits (1 calf with exungulation of both digits of a forelimb and 1 calf with exungulation of 1 digit in both hind limbs) had successful long-term outcomes, with one becoming a productive beef cow and the other a productive dairy cow. A mare with non–weight-bearing lameness resulting from traumatic exungulation of a hoof was supported with a custom-made sling on a daily basis to limit stress on the contralateral limb.8 Slings were not used in the management of any of the cattle in the present study.
Amputation of a digit following traumatic exungulation is a potential treatment alternative for cattle9 and may be an option for animals with concurrent fracture of P3, persistent pedal osteitis or osteomyelitis, or penetration or sepsis of the DIPJ. Heavy cattle and cattle with exungulation of a primary weight-bearing digit, particularly a lateral digit of a hind limb, may not be ideal candidates for digit amputation. Results of another study10 suggest that the likelihood of a positive outcome following digital amputation is only 27% for cattle weighing ≥ 682 kg. Use of a methyl methacrylate prosthesis to protect hoof wall defects in cattle with exposed corium has also been described as a potential treatment.1,5
A Holstein bull with exungulation of a hoof secondary to foot-and-mouth disease was successfully treated with autologous skin grafts.2 That bull reportedly had a fully formed and normal-appearing hoof 20 weeks after the grafting procedure.2 Those results seem extraordinary given the number and locations of the grafts. Nevertheless, the use of grafting techniques for treatment of exungulation in cattle warrants further investigation. The published literature contains few descriptions of digital skin grafts in large animal species; however, digital cushion and frog corium punch grafts have been successfully used to protect the digital stump in horses with limb amputations and subsequent prostheses.11
For the cattle of the present study, the cast or last bandage was removed at 20 to 83 days after initial presentation to the hospital. Unfortunately, the extent of epithelialization and keratinization of the corium at the time of cast or bandage removal was not clearly defined in the medical records. In practice, we generally keep an exungulated digit bandaged until the corium is of normal thickness and appears healthy and at least 75% of the degloved surface has evidence of epithelialization. The hoof block on the adjacent unaffected digit is generally left in place until most of the surface of the exungulated digit is keratinized. In cattle with partial or complete primary exungulation, it reportedly takes 8 to 12 weeks for cornification of the affected digit.3 In horses that underwent surgical stripping of a hoof wall, developed neoepithelium of the lamellae was present at 10 days and complete keratinization of the site was achieved by 4 months after surgery.12 Of the 10 cattle evaluated in the present study, only 1 required medical management for 10 months after traumatic exungulation. That bull was atypical because it developed numerous complications including a toe abscess and a persistently misshapen abaxial hoof wall.
Following exungulation, each portion (perioplic, parietal, laminar, and solar) of the surviving corium produces a unique form of epithelium to cover the wound surface, representing different regions of the hoof capsule. Initially, approximately the distal two-thirds of the newly forming hoof will be composed of laminar keratin or horn. The hoof wall proper grows from the more proximally situated parietal corium and grows distally at approximately 0.5 cm/mo,5 so there are many months after recovery begins before a normal hoof wall can be expected to reach the sole. If weight is borne on the healing digit during this time, considerable forces will likely be applied to a portion of the new hoof capsule composed of laminar horn that is not anatomically designed for weight-bearing. This can damage the dermal-epidermal junction, leading to an associated inflammatory response and pain and potentially delaying wound healing. It takes many months of wound repair before the hoof wall lamina will regain the anatomic structure and, most importantly, the strength necessary to provide appropriate suspension and support of P3 in the newly formed hoof capsule. Weight-bearing prior to complete healing of the lamina corium and associated wall predisposes the sole corium to traumatic injury because the P3 suspensory function is inadequate.
Digital angiography is a contrast radiography imaging modality used to evaluate the vascular structures of the foot. It is used more frequently in horses than in ruminants.13 Digital venography (retrograde venous angiography) in equids is useful for evaluating the progression of laminitis, and serial venograms can help assess response to treatment and inform prognosis.14 The procedure is fairly simple and inexpensive to perform and helps clinicians assess the severity of the pathological changes within the hoof.15 In bovines, digital angiography of some foot disorders, including osteomyelitis with avascular necrosis of a portion of P3, has been described.16 Digital angiography may be useful in cattle with traumatic exungulation, particularly in those that do not follow the expected timeline for resolution of lameness or keratinization of the hoof wall and sole. However, to our knowledge, digital angiography has not been performed or evaluated in cattle with exungulation.
Some of the cattle of the present study required corrective hoof trimming following recovery from exungulation. Two animals required corrective hoof trimming on a routine basis; however, lameness was not evident in any of the animals once the primary injury had healed. It may be prudent to advise owners of cattle with complete traumatic exungulation of the potential for abnormal hoof regrowth that might require frequent hoof trimming and care.
Results of the present study suggested that cattle with complete traumatic exungulation often have a good chance of recovery and return to intended use, even those with multiple affected digits or that develop complications such as P3 osteitis or osteomyelitis. For cattle with uncomplicated exungulation, medical management is fairly straightforward and can be economically feasible for owners who are willing and able to invest time into treatment on the farm. Owners of affected animals should be advised of potential complications (eg, pedal osteitis or osteomyelitis and sequestra) that may develop during healing and informed that regular hoof trimming may become necessary following recovery.
References
- 2. ↑
Demirkan I. Surgical treatment of a sloughed hoof by skin grafting in a young bull. Can Vet J. 2004;45(5):418–420.
- 3. ↑
Stanek C. Primary complete exungulation in cattle. Article in German. Berl Munch Tierarztl Wochenschr. 1981;94(7):126–128.
- 4. ↑
Deuri B, Singh CK, Nath PJ, Sarma KK, Rosangzuali. Hoof avulsions and their management—a report of two bulls. Intas Polivet. 2012;13(2):208–210.
- 6. ↑
Terra RL, Reynolds JP. Ruminant history, physical examination, welfare assessment, and records. In: Smith BP, Van Metre DC, Pusterla N, eds. Large Animal Internal Medicine. 6th ed. Elsevier; 2020:2–13.
- 7. ↑
Farstvedt E, Stashak TS. Topical wound treatments and wound care products. In: Theoret C, Stashak T, eds. Equine Wound Management. 2nd ed. Wiley Publishing; 2009.
- 8. ↑
Jackson LL. Regrowth of an equine hoof following traumatic removal. Iowa State Univ Vet. 1969;31(2):44–46.
- 9. ↑
Van Amstel SR, Shearer J. Biomechanics of weight (load) bearing and claw trimming. In: Manual for Treatment and Control of Lameness in Cattle. Blackwell Publishing; 2006:115.
- 10. ↑
Pejsa TG, St Jean G, Hoffsis GF, Musser JM. Digit amputation in cattle—85 cases (1971–1990). J Am Vet Med Assoc. 1993;202(6):981–984.
- 11. ↑
Vlahos TP, Redden RF. Amputation of the equine distal limb: indications, techniques and long-term care. Equine Vet Educ. 2005;17(4):212–217.
- 13. ↑
Santos IF, Hussni CA, Rodrigues CA, Watanabe MJ, Alves AL. Digit venography in ruminants—a review. Vet Q. 2016;36(1):22–29.
- 14. ↑
Baldwin GI, Pollitt CC. Progression of venographic changes after experimentally induced laminitis. Vet Clin North Am Equine Pract. 2010;26(1):135–140.
- 16. ↑
Gogoi SN, Nigam JM, Singh AP. Angiographic evaluation of bovine foot abnormalities. Vet Radiol. 1982;23(4):171–174.