Radiographic Analysis of the Beef Cattle Digits Slaughtered after 114 Days of Confinement

Foot disorders are responsible for up to 5% of confinement losses. Identifying the cause of lameness and applying the correct treatment are crucial measures. The possibility of determining the probable origins of digital lesions, their extension, and assistance in cases in which it was not possible to reach a definitive clinical diagnosis demonstrates that the radiographic evaluation provides information of great importance on cattle digits. Thus, this study aimed to investigate possible radiographic changes in the hoof, bone structures, and soft tissues of the digits of Nelore bulls at the end of the confinement period. Regarding the main signs, 100% (n = 24) showed proliferation of enthesophytes and osteophytes and irregular contours, 62.5% (n = 15) enlargement of vascular channels, 37.5% (n = 9) osteolysis, 33.4% (n = 8) gas content in the white line region, 20.84% (n = 5) gas content in the dorsal lamina region, and 4.16% (n = 1) presented palisade periosteal reaction. Ten (41.7%) out of 24 (100%) animals evaluated at the end of the confinement presented lameness, three animals of score three, four animals of score two, and three animals of score one. The higher the score indicating the severity of the signs observed in the visual assessment of the radiographs, the higher the internal angle values (moderate correlation of 0.5 and p < 0.05). A higher prevalence of osteo-proliferative radiographic changes was identified at the end of the 114-day confinement period in the third phalanx of Nellore cattle even in animals that had no lameness.


Introduction
Intensive management favors the occurrence of infammatory or infectious foot disorders in cattle.Several factors, such as management [1,2], nutrition [3], facilities, and the type of foor where the animals are kept can cause morphological changes in the hoof, which infuences the distribution of forces on the hoof support surface [2].
Lameness clinical manifestation in beef cattle can generate serious economic consequences for producers.Foot disorders are responsible for up to 5% of confnement losses [4].In addition, lameness is associated with an unsatisfactory result of reproductive health in beef breeding bulls [5].
Identifying the cause as soon as possible and applying the correct treatment is crucial, as its origin is multifactorial [4].Foot diseases in beef cattle have been underestimated in several regions of Brazil and the world [1,6], which characterizes an important barrier for the detection and treatment of lameness [6].
Te absence of an early diagnosis in the feld may contribute to increase the severity and diversifcation of foot disorders [1].Inadequate control and prophylaxis measures relative to foot disorders demonstrate the importance of establishing adequate programs for preventing lameness in beef cattle [1,5,6].
Te adoption of radiographic examination for orthopedic evaluation in the clinical routine of cattle farming has been growing over the years.Radiographic examination in dairy cows has been widely used in the assessment of digits, helping in early diagnosis, determining prognosis, and directing efective treatments [7][8][9].Te possibility of determining the probable origins of digital lesions, as well as determining their extent and helping in cases whose defnitive clinical diagnoses could not be reached, demonstrates that radiographic evaluation provides information of great importance on cattle digits [7,[10][11][12][13].Approximately 30% of bulls that did not present lameness had radiographic changes and the digits were the most afected regions, with enthesopathy, septic arthritis, fractures, and degenerative joint disease among the most frequent radiographic changes [13].
A study carried out by Gantke et al. [10], including beef cattle breeds, identifed several radiographic changes related to laminitis and its sequelae.However, the misalignment of the third phalanx could not be objectively verifed due to the absence of radiographic measurements in normal hooves.Subsequently, Hage et al. [12] determined the radiographic pattern of normality of measurements and angles in digits of Nellore females.
Tis study aimed to investigate possible radiographic changes in the hoof, bone structures, and soft tissues of the digits of Nellore cattle at the end of the confnement period.

Animals and Management.
After confnement, 24 intact male Nellore cattle with an average age of 22 months were sent for slaughter in a slaughterhouse and the collection of thoracic and pelvic digits was authorized.Te project was previously approved by the Ethics Committee on the Use of Animals under protocol number 111/19 and carried out at the Experimental Confnement of Beef Cattle of the School of Veterinary and Animal Science of the Federal University of Goiás.
Te animals were confned for 114 days from July to October (dry period with the transition to the rainy period at the beginning of October) and allocated to three collective stalls (7.7 × 10 m), with eight animals being distributed per stall.Te animals had free access to water in 500 liter drinking troughs shared between two stalls and were fed with feed containing fresh sugarcane bagasse (11.18%), fnely ground corn (66.83%), soybean hulls (9.35%), proteinaceous corn meal (5.70%), soybean meal (3.34%), and mineral core (2.63%).
Lameness score was determined in the last week of the confnement, close to sending the animals to the slaughterhouse.Te pieces were collected from the carpometacarpal and tarsometatarsal disarticulation and stored in a freezer at 20 °C.
Te thoracic (n � 96) and pelvic (n � 96) limbs were thawed and sanitized with water, brush, and soap for further analysis of the digits and the hoof capsule.Te radiographic examination was performed after they were dry.

Lameness Score.
A locomotion scoring scale was adopted for lameness assessment with scores between 0 and 3 [14] (Table 1).Te evaluation was performed by one of the authors, who has experience in this evaluation.Te animals were led individually in a corridor beside the stalls with an earthen foor, without irregularities.

Radiographic Examination.
Te bony structures, hoof, and soft tissue topography of the third phalanx were examined using radiographs in the lateromedial, mediolateral, and palmar/plantarodorsal projections.Te examinations were performed using bags flled with sand for supporting and fxing the digits and a Philips fxed radiographic, computed radiography (CR), device model KL.74/20.40(Philips Heathcare ® , Biassono, Italy) with a capacity of 500 mA and 125 kVp, with the technique of 75 kVp and 30 mAs.
Te radiographic images were evaluated and interpreted by a single experienced radiologist, without knowledge of the lameness score information.Te images were evaluated using the free version of the Horos software (version 3-LGPL3.0)and interpreted for the presence of the following parameters [7,10,15]: osteophytes, bone lysis, bone remodeling, enthesophytes, cysts, and spiculated periosteal reaction.
Radiographic changes were classifed into scores according to lesion characteristics, location, and severity (Table 2).
Measurements were performed still using the radiographic images to verify the positioning of the third phalanx (3P) relative to the hoof capsule, as shown in the diagram of Figure 1.Te measurements consisted of the distance between the dorsal face of the 3P and the hoof wall [8,10], plantar/palmar distance of the 3P and solar face of the hoof [7,15], and angulation of the third phalanx relative to the hoof and dorsal wall of the 3P with the starting point on the solar face of the fexor tubercle [7,12].
In addition, measurements of the distances between the apex of the third phalanx to the apex of the hoof capsule in the plantaro/palmarodorsal projections of the medial and lateral digits of pelvic and thoracic limbs were proposed by the researchers of this study to estimate the hoof growth relative to the distal phalanges.

Statistical Analysis.
Descriptive results related to radiographic examinations of lameness were presented as a frequency [16].Lameness scores and objective and subjective radiographic evaluation were assessed to determine the existence of a correlation between them and statistical diference (Table 3) through analysis of variance (ANOVA), test of means, Scott-Knott (parametric data) and Kruskal-Wallis nonparametric data, and Spearman correlation [16][17][18].

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Results
Table 4 shows the individual and the mean values of measurements from the apex to hoof in palmaro/plantarodorsal projections and dorsal and solar distances, and internal and external angles.Te means shown in Table 4 were grouped and tested for lameness scores (Table 3).Te animals that presented a score of 3 for lameness had higher values in the measurements of dorsal distances and internal angles and lower values of external angles in pelvic and thoracic limbs.
Te radiographic evaluation showed that all animals had signs, the most prevalent being osteo-proliferative signs (Figure 2).Regarding the main signs, 100% (n � 24) showed proliferation of enthesophytes and osteophytes and irregular contours, 62.5% (n � 15) enlargement of vascular channels, 37.5% (n � 9) osteolysis, 33.4% (n � 8) gas content in the white line region, 20.84% (n � 5) gas   Veterinary Medicine International content in the dorsal lamina region, and 4.16% (n � 1) presented palisade periosteal reaction.Ten (41.7%) out of the 24 (100%) animals evaluated at the end of the confnement period had lameness, with scores of three (n � 3), two (n � 4), and one (n � 3) (Chart 4).A weak correlation with no statistical signifcance was observed between lameness and subjective radiographic evaluation.Table 5 shows the details of the signs and the classifcation of lameness and radiographic scores.Other 14 (58.3%)animals did not present lameness, but bone remodeling signs were observed in the third phalanx, with radiographic scores similar to those observed in animals with lameness scores from 1 to 3.
Te classifcation of radiographic scores showed that eight animals (33.4%) presented a score of 3, six (25%) animals a score of 4, two (8.4%) animals presented a score of 2, seven (29.16%) animals had a score of 6, and one (4.16%)animal had a score of 5.
Te correlation coefcients showed that the higher the score indicating the severity of the signs observed in the visual evaluation of the radiographs (proliferative and lytic, bone fssures, gas content in dorsal laminae, and spiculated periosteal reaction), the higher the values of the internal angles (moderate correlation of 0.5 and p < 0.05).
Te evaluation of the relationship between the measurements on the radiographic examination showed that longer apical distances in pelvic and thoracic limbs infuenced longer dorsal distances (strong correlation of 0.7 and p < 0.05).Te measurements of angles showed a strong correlation (0.7 and p < 0.05) between the internal and external angles in the pelvic and thoracic limbs.
EOBF and JSC: Enthesophyte and osteophyte bone formation with a jagged surface contour.
Te comparison between angles and distances showed that both the internal and external angles decreased as the apical distance increased in pelvic and thoracic limbs (strong negative correlation of −0.7 and p < 0.05).Only the external angle in pelvic and thoracic limbs presented a moderate negative correlation (−0.5 and p < 0.05) with the dorsal distance, indicating that the smaller the external angle, the longer the dorsal distance.

Discussion
Te identifcation of higher values in measurements of dorsal distances and internal angles and lower values of external angles in pelvic and thoracic limbs in animals with a score of 3 may be associated with pain, a factor that biomechanically alters or prevents normal movement and causes new injuries [19].It may be associated with the loss of mechanical stability of the third phalanx, which interferes with the structures of the suspensory apparatus, making it insufcient to absorb the impact of the third phalanx on the corium.Te third phalanx without adequate suspension and damping changes its position within the restricted space of the hoof capsule with all the weight supported by the limb [20].
Te fact that more than half of the evaluated animals presented no lameness detected by the locomotion score but had bone remodeling signs in the third phalanx can be explained by the chronicity of the lesions, as lameness may not be evident in cases of chronic laminitis, which presents hoof deformations.Te disease may progress silently for a long-term asymptomatic subclinical period [20].Tese fndings corroborate the information obtained by Barbosa et al. [21], who observed that the evaluated cattle presented no lameness even with radiographic signs and chronic lesions may not promote nociceptive signs in cattle locomotion.
Tus, the severity of radiographic fndings in the third phalanx may not be related to the locomotion score.Hoof lesions may return after some period, although corrective hoof trimming is performed on afected digits, leading the animal to lameness resolution or reduction [22].Tis information reinforces the importance of using radiographic examination to detect digital signs, which can evolve, worsen, and later afect the distal interphalangeal joint.
Te establishment of the score indicating the severity of radiographic signs by the researchers of this study confrms the one developed by Nouri et al. [22], who considered the presence of bone neoformation, osteitis, and the presence of gas content, three factors considered to assess the disease severity.In addition, the presence of bone lysis was considered a worsening factor in this study.
Veterinary Medicine International  6 Veterinary Medicine International Te directly proportional relationship between higher values of the radiographic score and higher values of internal angles can be explained by bone remodeling, observed with signifcant diferences between the lateral surface of the proximal and distal parts with the other surfaces [22].Remodeling of the third phalanx can occur as a result of bone necrosis by compromising the regional blood supply, afecting nutrition and oxygenation [8,20].
Te measures of internal and external angles decrease as the hoof elongates apically, which can be explained by the sinking of the third phalanx.Te cause of the 3P sinking can be attributed to damage to the chorion [8,23], which is further potentiated by this sinking, related to laminitis [19,24,25].Bone development in subclinical laminitis occurs mainly in an abaxial-axial direction, which refers to the narrowing of the space between the solar surface of the distal phalanx and the internal surface of the hoof capsule, which may lead to irregularity of the solar surface [19,26,27].Te fexor tubercle is the most important site on the solar surface for these alterations [19], which also supports the decision of the authors of this study to perform only one measurement on the solar surface with the fexor tubercle as the point of origin and the measurement in the apical region.
Te permanence in a confned environment and on an earthen foor may be one of the factors associated with the increase in the apical distance, as a thicker hoof wall was observed in confned beef cattle, causing a change in their external structure [2,24,25].

Conclusions
In the third phalanx of the Nellore cattle, without lameness, osteo-proliferative radiographic signs were identifed at the end of the 114-day confnement period.Te establishment of the radiographic lesion severity score, proposed in this study, may become a facilitating tool for the application of feld evaluations by buiatricians.
It is important to emphasize that these are experimental data, which can provide relevant information for the diagnosis of foot diseases in cattle, and require application in live animals.

Data Availability
All data used to support the fndings of this study are included within the article.Veterinary Medicine International

Figure 1 :
Figure 1: Radiographs of the third phalanx of the right pelvic limb of a Nelore bull in lateromedial (a), mediolateral (b), and plantarodorsal (c) exhibitions.Distance between the dorsodistal edge of the third phalanx and the dorsal wall of the hoof (Dd), distance between the solar edge of the fexor tubercle and the hoof (Sd), external angle over the silhouette of the dorsal edge of the hoof and the sole of the third phalanx (Ea), internal angle on the silhouette of the third phalanx (Ia), and distances between the apex of the hoof and the apex of the third phalanx in plantarodorsal (Ad).

Table 4 :
Means (Me) and standard deviations (SDs) of measurements of apical and dorsal distances (cm), internal and external angles ( °) of thoracic (TL) and pelvic limbs (PL) of the lateral (L), and medial digits (M) of adult Nellore bulls after 114 days of confnement.

Figure 2 :
Figure 2: Radiographs in plantarodorsal and palmarodorsal exhibitions, demonstrating the main radiographic signs observed in the third phalanx of Nellore cattle after 114 days of confnement: (A) osteophytes at the apex of the third phalanx (yellow arrow), (B) spiculated periosteal reaction (empty arrowhead), (C) axial enthesophyte (thick yellow arrow), (D) widening of vascular channels (white arrows), (E) irregular contours in the abaxial face and apex (full arrowhead), and (F) gas in the white line region (thick white arrows).

Table 1 :
Lameness score ranging from 0 to 3 in beef cattle.Normal Te animal walks normally, with no apparent lameness or change in gait.Te pelvic limbs land in a similar location to the thoracic limbs, with the back level 1 Mild lameness Te animal presents short strides when walking, lowering its head slightly.Te animal does not limp when walking.Tere may be slight arching of the back when walking 2 Moderate lameness Te animal has evident faccidity, favoring the afected limb(s) that still support the weight.A slight nod of the head is present when the animal walks.It may have back arching 3 Marked lameness Te animal applies little or no weight to the afected limb and is reluctant or unable to move.Te back will arch during the walk, with the head swaying and lameness detected.It may have an arched back when standing up and walking [14]ce: Zimpro[14].

Table 2 :
Score for evaluation of radiographic changes in the digits of Nellore cattle after a 114-day confnement period.
Proliferative signs (enthesophytes, osteophytes, and irregular contours) 2 Proliferative signs with bone remodeling and channel widening 3 Proliferative signs with bone remodeling, channel widening, and gas content in the white line, and lateroapical to the third phalanx 4 Proliferative and lytic signs, bone remodeling, and channel widening 5 Proliferative and lytic signs, bone remodeling, channel widening, and gas content in the white line 6 Proliferative and lytic signs, bone fssures, gas content in dorsal laminae, and spiculated periosteal reaction

Table 3 :
Parametric and nonparametric data with their respective medians and mean and tests of means.

Table 5 :
Description of radiographic signs associated with the claudication score (CS) and radiographic score (RS) signs.

Table 5 :
Continued., bone remodeling in apex 3P, widening of vascular channels, gas opacity in white line, and gas opacity in dorsal lamellae 6 12 0 EOBF and JSC, bone remodeling in apex 3P, widening of vascular channels, osteophytes in dorsal wall of the claw, and concave groove of the dorsal wall of the claw , bone remodeling in apex 3P, concave groove of the dorsal wall of the claw, osteophytes in apex 3P, and osteolysis in apex 3P 4 22 3 EOBF and JSC, bone remodeling in apex 3P, gas opacity in white line, jagged surface contour in fexor tubercle, widening of vascular channels, concave groove of the dorsal wall of the claw, and osteophytes in apex 3P EOBF and JSC, bone remodeling in apex 3P, gas opacity in apex, jagged surface contour in fexor tubercle, widening of vascular channels, and concave groove of the dorsal wall of the claw 3 24 3 EOBF and JSC, bone remodeling in apex 3P, osteophytes in apex 3P, osteolysis axial in apex 3P, and gas opacity in dorsal lamellae 6