PHYSICAL EXAMINATION

Clinical signs can often dictate the specific target of a physical examination. However, any thorough examination should evaluate the respiratory and cardiovascular systems. The focus of the exam should be on both the morphology of the relevant anatomical structures and evidence of physiological dysfunction of each of these systems.

When the animal is approached, indications of respiratory system dysfunction can be appreciated by noting respiratory characteristics such as rapid, shallow breaths, coughing and open-mouth breathing, which are all signs of impaired ventilation. Determination of respiratory rate is not as important as noting the pattern and ease of respiratory effort. Upper respiratory sounds can increase or be abnormal in cases of upper airway obstruction. In addition, other vital signs such as heart rate and body temperature are very important in assessing a patient. These can often help determine the likelihood of involvement of a septic process. Body condition and knowledge of the duration of the problem can help in determining potential success when considering surgical therapy.

The upper respiratory tract can be evaluated relatively readily via palpation, percussion, and auscultation. The nares of cattle should be moist and readily and regularly cleaned by the tongue; therefore the presence of even serous nasal discharge is abnormal. The openings of the nares do not flare or move as much as those of horses. Patency of the nares and nasopharynx can be readily accomplished by placing cupped hands in front of the nares and assessing the volume of air flow or, in cold climates, observing the condensed expired air. Inspiration is difficult to assess, but the relative volume of expired air can be readily determined. Symmetry of air flow may be the most important aspect of expiration to be determined at the nares. The nature of any fluid at the nares should be examined. Expired air should be evaluated for odors that may be indicative of an infectious and/or necrotic process. Any abnormal sounds associated with inspiration or expiration should also be noted. Audible whistles, gurgles, or other abnormal sounds can be indicative of upper airway compromise.

Facial symmetry should be assessed and any distortion may indicate underlying disease disrupting upper airway anatomy. Percussion of the nasal passages and paranasal sinuses can be performed with fingers or with a plexometer. Placing a stethoscope over the percussed region may help determine the presence of abnormal tissue or fluid presence in otherwise air-filled spaces. The sounds can be augmented by opening the mouth during percussion.

The ventral aspect of the head should be visually examined and palpated. The intermandibular space should be examined for swelling and painful response to palpation. Congenital malformation, trauma associated with bawling gun injury or foreign body penetration may result in a perilaryngeal mass that can compromise the upper respiratory tract at the pharynx, larynx and proximal trachea. These can be suspected by detection of proximal cervical swelling (see Figure 10-14). The cervical locations of palpable lymphatic tissues should be closely examined visually and by hand. The trachea should be auscultated with attention to airflow, or abnormal sounds indicating the presence of fluid. The trachea and tracheal region should be palpated. Subcutaneous crepitation should be noted. Tracheal sensitivity to pressure and the ease of eliciting a cough should also be determined.

Figure 9-14 Arytenoid chondritis in a calf. Note left arytenoid cartilage on the midline with enlarged right arytenoid cartilage. There is a mass on the axial surface of the right arytenoid cartilage.

The thoracic cavity should be evaluated by observing the overall condition of the patient as well as the basic movements of the thoracic wall during respiratory efforts. A decline in body score and abnormal respiratory movements can indicate a primary disease process in the thorax. Auscultation is important in evaluating the thorax. Careful attention and assessment of ventilation and lung sounds should be performed. This should include notation of the location or regionalization of abnormal findings. Abnormal lung sounds can indicate different pulmonary diseases, which may or may not need surgical therapy. Thoracic and cardiac surgical diseases are suspected by the absence of respiratory sounds or muffled normal sounds, which indicates a need for further diagnostic procedures. In conjunction with auscultation, percussion of the thoracic wall should be performed. A normal bovine thorax should have air-filled resonance throughout the thorax except for sites of closest cardiac association. Fingers or a plexometer used in a dorsal-to-ventral direction in the intercostal spaces can help detect loss of resonance associated with accumulated fluid or solid tissue in the pleural space. Notation of the interface between resonant and dull percussing regions can often indicate the relative level and severity of abnormal pleural fluids. This can also help when deciding if thoracocentesis will be of value.

Other physical manipulations can also assist when assessing the thorax of cattle. Hand pressure can be applied to the dorsal aspect of the spinous processes over the thorax or from the ventral aspect of the sternum. Observation while applying pressure can reveal a pain-avoidance response (grunt test), which can indicate an intrathoracic disorder that may require surgical treatment.

ENDOSCOPIC EXAMINATION

Endoscopy is a very useful tool for evaluating the upper respiratory tract. Endoscopy is certainly most familiar in equine practice, yet the same general techniques can be applied to cattle. Standing restraint is necessary and is likely best in a stanchion or substantial head catch. Although anatomy can be evaluated with any form of restraint, normal upper airway function can only be assessed in a nonsedated animal. Therefore physical restraint alone is encouraged. Nose tongs can help gain control of the head. If these are used, care should be taken not to occlude passage of an endoscope through the nares into the nasal passages. It is advised to evaluate each nasal passage, which requires passing the endoscope though the left and right sides. Anatomical variation from the more familiar equine upper airway includes the following:

Figure 9-1 Endoscopic view of the nasopharynx; note the caudodorsally tapering nasal septum in the caudal third of the nasal passage.

Figure 9-2 Endoscopic view of the nasopharynx: note the nasopharyngeal septum.

Figure 9-3 Endoscopic view of the nasopharynx: note the right nasopharyngeal opening of the auditory tubes (arrows) located dorsolateral to the nasopharyngeal (NP) septum.

Figure 9-4 Endoscopic view of the larynx: note the triangular epiglottis with rounded borders and very prominent rounded corniculate processes of the arytenoid cartilages.

Figure 9-5 Endoscopic view of the nasopharynx and larynx in a Jersey cow; note the irregular, dark pigmentation of the mucosa of the pharyngeal and laryngeal structures.

If sedation is deemed necessary to complete an endoscopic evaluation of an individual’s upper airway, care should be exercised in choosing sedative agents. Xylazine can substantially alter the anatomic position of laryngeal structures and reduce response to stimuli. Therefore assessments of laryngeal function may be inaccurate. Acepromazine appears to result in much less interference with evaluation and may be preferable over xylazine if time and the animal’s demeanor allow use of this agent.

IMAGING EXAMINATION

Ultrasonography can be a very helpful tool in evaluating the airway for disease. It should be recalled that sound waves reflect from gas or air; therefore the aerated aspects of the respiratory tract cannot be satisfactorily imaged. However, a great deal of indirect information can be obtained with ultrasonography. Soft tissue facial distortion, peritracheal swelling, and pleural space fluid accumulation can be readily assessed. Ultrasonography is indicated anytime soft tissue or fluid-associated abnormalities are evaluated in and around the respiratory tract of cattle.

Radiography can also be critical in imaging the respiratory tract of cattle. The upper airway is best imaged with lateral and dorsoventral radiographic projections. However, various oblique views can certainly assist in defining mass lesions and lesions associated with fluid accumulation. With the increasing availability of three dimensional imaging, computed tomography (CT) and magnetic resonance imaging (MRI) can assist the clinician in completing diagnoses in cattle. However, animal size and economic considerations will likely limit the practicality of these imaging modalities. The lower airway can also be imaged with radiographs (Figure 9-6); however, animal size often interferes with the ability to identify abnormalities. It should be assumed that radiographic detail will be lost as body size increases. When one is considering the caudal thorax and cranial abdomen, positioning the bovine patient may be an important for successful radiographic assessment. Metallic foreign material that penetrates the reticulum and entering the thoracic cavity may be more easily identified radiographically with the patient in dorsal recumbency rather than standing (Figures 9-7 and 9-8). This allows for reduced tissue thickness and better detail of reticular and pericardial structures with the gas content displaced in the ventral aspect of the reticulum. Care should be exercised as some animals do not tolerate casting or the sedation needed for this position. Dorsal recumbency is not advised for very sick and/or debilitated animals or animals with impaired ventilation.

Figure 9-6 Pleural fluid accumulation in a cow with septic pleuritis.

(Courtesy of Dr. A. Yeager, Cornell University.)

Figure 9-7 Radiograph of the caudal thorax and cranial abdomen in a mature cow with traumatic reticuloperitonitis and pericarditis. Note the metallic foreign body sticking out of the confines of the reticulum in the caudal thoracic area.

(Courtesy of Dr. N. Dykes, Cornell University.)

Figure 9-8 Radiograph of the cranial abdomen in a mature cow in dorsal recumbency: note the improved visibility of the reticulum in comparison to Figure 9-7.

(Courtesy of Dr. N. Dykes, Cornell University.)

NASAL OBSTRUCTION

Nasal obstruction in cattle, as in other animals, is typically marked by respiratory noise, which is readily localized to the upper airway. Unilateral obstruction can usually be detected with cupped hands near the nares to evaluate symmetry of expiration. Bilateral obstruction is accompanied by severe dyspnea and often with labored open-mouthed breathing. Disease entities most commonly associated with nasal obstruction include congenital malformation—such as conchal cyst (Figure 9-9) and choanal atresia—and acquired conditions, such as granulomas, polyps, and neoplasia (i.e., adenocarcinoma).

Figure 9-9 Lateral radiograph of a 7-month-old heifer calf with nasal conchae cysts. Note oblong opacity in the nasal cavity.

(Courtesy of Dr. N. Dykes, Cornell University.)

Physical and endoscopic examinations in combination with radiography can usually delineate the presence of a discrete mass lesion (see Figure 9-9). This is desirable when surgical treatment is considered, as a specific target helps in formulating a surgical plan. Some small and pedunculated nasal masses can be resected with transendoscopically-guided long instruments, wire loop (with or without cautery), or laser. Small masses may also be amenable to traditional trephination approaches and therefore can be removed in standing cattle. It is pos-sible to resect membranous choanal atresia using a laser (Nd : Yag or diode) under video endoscopic guidance, but a well vascularized membrane can hemorrhage and obstruct vision of the surgery site.

Nasal flap elevation is typically necessary to reach larger masses in the nasal passage or bony choanal atresia of affected animals. Often nasal masses come to veterinary attention after the size and potential invasiveness of the primary disease process indicates a need for general anesthesia and performance of a large facial flap procedure.

The typical preanesthetic preparations (including acceptable antibiotic and antiinflammatory therapies), induction and maintenance of general anesthesia are recommended (see Chapter 6). Orotracheal intubation is essential to allow surgical manipulation within the nasal cavity. Lateral recumbency with the affected nasal side uppermost is usually a satisfactory position for unilateral disease. On rare occasions, sternal recumbency is desirable to reach bilateral lesions from a single incisional approach. A flap should be designed to allow as complete exposure as possible without potentially damaging vital structures. It should be noted that many—if not most—facial flaps will enter the paranasal sinuses. This is especially true in the caudal region of the nasal passages. The maxillary and frontal sinuses are often the first cavity entered in an approach to the nasal cavity.

A curvilinear skin incision is made over the underlying bone and soft tissues that require elevation. Periosteum should be sharply incised, gently elevated, and moved from the line of incision into bone. An oscillating bone saw is ideal for this procedure; however, an osteotome and mallet can also be successful in producing a bone flap. The rostral, caudal, and axial aspects of the bone flap should be completely osteotomized. The dorsal and rostral aspects should be “notched” at the corners to allow the flap to be gently hinged away from the normal position. This generally produces good exposure to allow needed manipulations of diseased tissues in the nasal cavity. The nasal passages and paranasal sinuses are highly vascular regions, and extensive hemorrhage should be expected with aggressive manipulations. Hemostasis is difficult to obtain without direct packing of gauze into the affected airways. With unilateral surgical procedures, firm packing of the affected airway with continuous rolled gauze is very effective in controlling bleeding. In our experience, nasal bleeding is not as marked in cattle in comparison to horses. If bilateral disease is present, a tracheostomy should be placed. The gauze packing can be exited from the nares and secured to the skin. Alternatively, the packing can be exited from the lateral aspect of the incision. This usually requires removal of a corner of bone with a rongeur forceps or osteotome. The bone flap can be repositioned and manually pushed back to its normal position. Periosteum, subcutaneous tissues, and skin are then closed. The facial bone of the flap can be wired to the parent bone, but this is rarely necessary if the overlying soft tissues can be successfully closed.

Gauze packing should be left in place for 24 to 72 hours. The gauze can usually be readily pulled from the airway without chemical restraint. Some form of confinement housing is probably best for several days after surgery. During this time, continued antibiotic and antiinflammatory therapy is usually indicated. Benign nasal polyps, foreign bodies, and infectious or allergic granulomas usually respond well to surgical removal and supportive medical management. Alternatively, some granulomatous masses can be treated or managed with repeated injection of formaldehyde (neutral buffered 10% formalin) (one should consult with your regulatory veterinarian, as this may vary between countries). Nasal neoplasia is often very difficult to completely excise; therefore surgery is, at best, palliative, and recurrence is common.

DISORDERS OF THE PARANASAL SINUSES

Disease of the paranasal sinuses is most commonly marked by discharge from the nares or a site of previous dehorning or fracture. The frontal or maxillary sinuses or both can be affected. The sinuses can be primarily affected—usually with infectious, congenital, or neoplastic disorders—or secondarily a disease process extension from a distant or near site. The most common cause of infectious sinusitis is extension of a septic complication after dehorning. Other causes of sinusitis are trauma, sinus cysts, and parasites. Sinus disease should be considered with unilateral or bilateral nasal discharge; facial distortion; and signs of abnormal head posturing, which possibly indicates pain. Other clinical signs may include foul breath odor, dullness upon sinus percussion, fever, anorexia, depression, weight loss, or decreased production.

Diagnosis of paranasal sinus disease is based upon physical examination findings and imaging studies. On physical examination, bulging of the sinus and purulent exudates at the site of dehorning or nasal discharge are typical of sinusitis (Figure 9-10). Endoscopy may help rule out other sources of nasal discharge, but the best definition of sinus involvement is obtained with radiography. Lateral and dorsoventral radiographic projections will delineate abnormal soft tissue and fluid components within the airspace and walls of the sinuses (Figure 9-11, A and B). Occasionally, oblique projections may be necessary to more fully understand the extent of the disease process. Final etiologic diagnosis depends on microbial culture, cytology, and/or histology of the abnormal tissues within the affected sinus. This may be obtained from sinus centesis and aspiration after a small trephine hole is produced with a Steinmann pin (4 mm or 5/32 inch). Actinomyces pyogenes is commonly isolated after dehorning, and Pasteurella multocida is often associated with sinusitis unrelated to dehorning.

Figure 9-10 Young bull with sinusitis. Note purulent drainage at the right nostril.

Figure 9-11 A, Right lateral radiograph of the frontal sinus in a 3-year-old Jersey cow. Note the fluid line in the left frontal sinus. B, Rostral to caudal radiograph view of the frontal sinuses. Note complete opacification of the left frontal sinus.

(Courtesy of Dr. Anthony P. Pease, Cornell University.)

Refractory or chronic infectious sinusitis is best treated by open drainage and lavage of the affected sinus. This is most directly performed with 1 or 2 trephine holes positioned to allow drainage. The site of trephination for each sinus is indicated in Figure 9-12. This can be done with physical restraint and local anesthesia. Generally, the site of drainage is localized in the middle of the bulging frontal or maxillary bone. The frontal sinus is the most commonly affected sinus, and one needs to effectively drain the postorbital diverticulum. The drainage site is 4 cm caudal to the caudal edge of the orbit just above the temporal fossa (Figure 9-12A). The rostral site of the frontal sinus can be drained by trephining 2.5 cm from the midline on a line passing through the orbit center (Figure 9-12B). The turbinate part of the frontal sinus can be drained by trephining just caudal to the nasal bone divergence point, again 2.5 cm from midline (Figure 9-12C). The main part of the frontal sinus can also be trephined if it bulges (Figure 9-12D). A ¾-inch (19 mm) trephine is recommended. Additional trephine holes may be required, depending on individual needs. The maxillary sinus can be opened with a trephine hole immediately dorsal and caudal to the facial tubercle. It may be necessary to place this hole more dorsally in younger cattle to avoid the maxillary teeth. After trephination, large volume lavage with sterile fluid is often necessary to remove exudate and debris. Saline (0.9%), lactated Ringer’s, or tap water with povidone iodine solution can work well. Occasionally, debridement will be required to completely remove inspissated material and necrotic tissue. This can be performed though the trephine holes or a more aggressive sinus flap. The technique is the same as described for the various approaches to the nasal passages. Flaps should be elevated toward midline with sufficient exposure to accomplish the necessary excision or debridement. General anesthesia is usually required when large flaps are considered. Complete curettage and aggressive lavage are easier to perform via a sinus flap. Voluminous hemorrhage is more likely after creation of a flap and aggressive intrasinus manipulation. Therefore packing the sinus with gauze may be required before flap closure. Creating portals for lavage and drainage is recommended before closing the flap. Removing one or two corners of the facial bone flap allows easy access for subsequent lavage. This is essential to resolve septic disease pro-cesses in conjunction with systemic and local antibiotic therapy.

Figure 9-12 The circles indicate the site(s) of trephination for each sinus, and shaded areas are the frontal and maxillary sinuses.

In cattle with dental disease as the primary cause of sinus involvement, dental extraction is required. Often oral extraction of the affected tooth can be successful. Because the tooth root is shorter in cattle and the disease process is usually chronic, oral extraction is easier than it is for horses. The crown of the affected tooth is grasped with a forceps and rocked back and forth until it loosens and can be extracted. Postextraction drainage through the mouth with, or without, lavage usually resolves the problem. Alternatively, either a trephine hole over the affected tooth or a sinus flap can be effective in providing access for tooth repulsion. A general-purpose acrylic or special dental putty should be placed into the oral aspect of the dental alveolus to prevent oral contamination of the sinus. Plaster of Paris can be used for this purpose as well. The packing is an effective temporary barrier and is usually extruded (or removed) when sufficient granulation or fibrous tissue forms to occlude the mouth from the sinus. Treatment of the sinusitis with local lavage as described earlier is also required.

Cattle with infectious sinusitis appear to respond well to surgical treatment if it is performed prior to general debilitation and development of deteriorating secondary clinical signs. If a neoplastic disorder causes the sinusitis, treatment (surgical debridement of an affected sinus) is palliative, but long-term prognosis is poor because complete excision is usually not possible.

DISORDERS OF THE NASOPHARYNX

Localized infectious disease is the most common disorder of the bovine pharynx. Trauma from puncture or laceration can be problematic and can also result in abscess, hematoma, or granuloma formation in the pharyngeal and retropharyngeal tissues (see Figure 10.1-4). Lymph node abscesses can also result from delivery of bacteria to lymphatic tissue in this region. Pharyngeal polyps and various neoplastic disorders have been reported in cattle but are rare. Finally, cleft palate is occasionally seen in cattle (see Figure 10.1-20). Most cleft palates are congenital, but injury during oral administration of medi-cation can occasionally result in iatrogenic palate laceration. Animals with cleft palate typically present with nasal regurgitation of milk, water, and food material immediately after eating. They are likely to have secondary aspiration pneumonia, and signs of lower airway disease may be present.

Clinical signs associated with trauma to the pharynx can mimic those of other regions of the upper airway. Nasal discharge with foul breath may be the mildest sign noted. The spectrum of clinical signs can progress to dyspnea and dysphagia, fever, and systemic fluid and electrolyte derangement. Diagnosis can usually be made from a thorough physical examination, which includes a speculum-assisted visual and manual oral examination. Endoscopy can also be helpful to inspect suspected lesion sites more closely. Ultrasound examination can reveal an abscess or thickened perilaryngeal tissue with edema or fluid/air around the larynx, which indicates cellulitis. Radiography can also delineate an abscess location and dimensions. Close attention should be given to the systemic repercussions of pharyngeal obstruction because respiratory and gastrointestinal malfunction (such as ruminal bloat) may initially require treatment before the primary pharyngeal lesion is addressed. For example, if an animal cannot swallow, marked dehydration and acidosis can occur associated with the loss of fluids and bicarbonate through the saliva.

Pharyngeal trauma that does not result in abscess formation rarely requires surgical treatment. Instead, systemic antibiotics, analgesics, and medical therapy (appropriate fluid and electrolyte supplementation) can often lead to resolution of lacerations, hematomas, and granulomas. However, if cervical cellulitis (see Section 10.1) and/or a pharyngeal abscess develops, surgical drainage is the most expedient means of returning to normal function (see Section 10.1 for management of cervical cellulitis secondary to oropharyngeal disease). An abscess can cause significant upper airway obstruction and requires immediate attention to prevent suffocation. Depending on the degree of airway compromise, a temporary tracheostomy may be needed before surgical intervention. Abscesses in—or very near—the pharyngeal wall can often be incised and drained into the pharyngeal cavity. Retropharyngeal and perilaryngeal abscesses are more common than abscesses directly in the pharyngeal wall. These abscesses usually result from trauma or esophageal rupture or develop in regional lymph nodes. As for pharyngeal abscesses, the diagnosis is usually based on clinical signs that can vary from local swelling to dyspnea, anorexia, excessive salivation, and dysphagia. Ultrasonography and radiography can help more accurately define the location, structure, and quantity of abscesses (see Figure 10.1-6, A). These imaging techniques can also confirm the presence of foreign material that requires removal. The treatment of retropharyngeal abscesses is also based on establishing good ventral drainage.

Drainage of both pharyngeal and retropharyngeal abscesses can be readily accomplished in standing cattle with physical or chemical restraint. Drainage can be obtained through the nasopharynx, oropharynx, or proximal cervical area. An incision adequate enough for complete drainage is important. Debridement and lavage may assist in completing drainage but may not be essential to a good outcome. The incision should be left open to heal by second intention.

This drainage is best accomplished with a carefully restrained, standing, and occasionally sedated animal after infiltrating the surgical site with local anesthesia. Sedation must be used with great caution because sedation relaxes the nasopharynx musculature, which can accentuate the degree of upper airway compromise. Nasopharynx drainage is done with endoscopic guidance by using either laser incision or cautery. Oropharynx drainage is performed, after placing an oral speculum, using a scalpel blade, guarded by hand, introduced into the mouth. The abscess can be incised and drained, either blindly or with endoscopic guidance. Ideally, incisions should be located ventrally and be large enough to allow continuous drainage. When possible, the abscess cavity should be explored digitally for blunt debridement of fibrinous and fibrous septa, which can interfere with complete decompression. After surgery, oral or pharyngeal lavage can be attempted, but the practicality and efficacy of this may be frustrating.

A large retropharyngeal abscess that extends near the skin surface in the cervical area may require a cervical approach for surgical decompression of the ventral pharyngeal and laryngeal regions. Because many perilaryngeal and pharyngeal structures (linguofacial vein and artery; parotid glands; facial, vagal, and pharyngeal branch of the vagal and hypoglossal nerves) are important, great care should be used during surgical exploration. Cellulitis or periabscess fibrosis can greatly diminish the ability to recognize these vital structures. The authors have found the following procedure minimizes the risk and morbidity associated with drainage of these abscesses. First, (preferably under ultrasonographic control) a 6-inch (15.24 cm), 14-gauge needle is placed into the abscess. A 2-cm skin incision is made adjacent to the lesion, and the needle is left in place. A curved Mayo scissors is advanced a few cm into the incision and the blades opened to bluntly to separate the tissue. This procedure is continued until the scissors penetrate the abscess, and the needle is loosened. The abscess cavity is then probed digitally, and if necessary, the tract is enlarged one to two more centimeters. A draining fistula should be enlarged conservatively where adjacent vital structures cannot be identified. Depending on the extent and location of the lesion, a midline incision, or a lateral incision below the linguofacial vein, is used to drain a pharyngeal abscess and reach a quicker resolution.

Finally, a pharyngotomy can be used to provide limited surgical access for addressing pharyngeal abscesses, polyps, or tumors. Most polyploid and neoplastic disorders of the pharynx will not be resolved by surgical resection. A caudal ventral midline skin incision can be made between the basihyoid bone and thyroid cartilage. The incision is extended toward the pharynx using a combination of sharp and blunt dissection to enter the ventral aspect of the oropharynx. As described under Transhyoid Pharyngotomy, the basihyoid bone can be transected with an osteotome to increase visibility of the oropharynx. The authors prefer to close the oropharyngeal mucosa with simple continuous sutures. If the basihyoid bone has been split, a number 2 or 5 stainless steel suture is used to stabilize the basihyoid bone. The sternothyrohyoid muscles are reapposed over the basihyoid bone only, and the remainder of the incision is left open to heal by second intention. If the pharyngeal and laryngeal aspects of the upper airway are still compromised to the point of dyspnea, a temporary tracheotomy may also be required.

Persistent dorsal displacement of the soft palate is an extremely rare cause of upper airway obstruction in farm animals. Unlike horses, dorsal displacement of the soft palate results in respiratory noise that is most evident on inspiration, although it is apparent on expiration as well. Diagnosis is suspected on the basis of upper respiratory noise and confirmed by endoscopy. If the upper airway obstruction is significant, strap muscle resection has been shown effective in relieving DDSP. The procedure can be done with the animal standing, head tied-up, and the middle cervical infiltrated with local anesthetic. Alternatively, general anesthesia can be used. After aseptic preparation of the area, a 10-cm ventral midline incision in the cranial cervical region is used to expose the sternohyoideus and sternothyroideus muscles at the ventral and ventrolateral aspects of the trachea. These muscles are elevated and transected, and a segment (10 cm) of each muscle is resected. The subcutaneous tissues and skin are closed separately. Normal husbandry and function as well as reduction of respiratory noise have been reported within 24 hours of surgery.