The origin of SARS-CoV-2 has not been definitively identified but is suspected to be a Chinese horseshoe bat.¹ In late 2019, SARS-CoV-2 infection to and between humans led to a worldwide pandemic with rampant transmission. Widespread human infection led to increased exposure in domestic and exotic animals and experimental infection studies that resulted in the identification of numerous susceptible animal species. Cats, dogs, ferrets, mink, deer, Asian small-clawed otters, certain species of mice, various large cats, skunks, and many nonhuman primates are susceptible to natural infection.^2-10 Additional species, including a range of rodent species^11,12 and New Zealand white rabbits,¹³ have been experimentally infected. Cattle and pigs demonstrate poor experimental susceptibility to infection, suggesting that natural infection is likely of limited concern.^14,15 It should, however, be noted that viral mutation can potentially result in expansion in the host range. Care should be taken when stating a species is not susceptible.

Cats are both naturally and experimentally susceptible to SARS-CoV-2,^2,5,6,16,17 and transmission between cats has been identified experimentally.^18,19 Preliminary reports have identified high seroprevalence rates in cats (≥40%) with owners diagnosed with coronavirus disease (COVID-19).^4,6 Infection in cats most often appears subclinical; however, clinical disease has been reported.²⁰ Mild upper respiratory tract infection is likely the most common clinical presentation, but serious infection, including fatal disease, has been identified.²⁰ Although there are concerns about secondary myocarditis and cardiomyopathy,²¹ as occurs in humans, the risk in cats is currently unclear. Mild GI signs (eg, vomiting, diarrhea) may also occur.

Dogs may be relatively highly susceptible to infection but appear to rarely develop SARS-CoV-2 disease. Studies of dogs with owners diagnosed with COVID-19 have identified rates (≥15%) of seroconversion that tend to be lower than the rates identified in cats but are still suggestive of relatively common human-to-dog transmission.^4,6 It is debatable whether clinical disease occurs either naturally or in experimental studies as a result of SARS-CoV-2 infection.²² SARS-CoV-2 in dogs may be a mild, self-limiting upper respiratory tract infection, or patients may be presented with nonspecific signs (eg, lethargy).

It has been predicted that ferrets and mink (another mustelid species) may be highly susceptible to SARS-CoV-2 based on prior susceptibility to the original SARS virus (ie, SARS-CoV-1) and other human respiratory viruses.^9,10 In an experimental environment, ferrets and mink were highly susceptible to SARS-CoV-2,^23,24 and signs of upper (and sometimes lower) respiratory tract disease have been identified in both natural and experimental studies. Limited reports likely reflect limited testing and reporting. Transmission between ferrets has been documented experimentally²⁵ and in field conditions in mink.³

Although SARS-CoV-2 originated in animals, the COVID-19 pandemic is almost exclusively the result of transmission among humans. Widespread human-to-human transmission makes studying the potential and presumably minor role of zoonotic transmission difficult. Zoonotic transmission from mink to humans has been identified.^26-28 Cat-to-cat transmission has been documented in experimental studies^18,19 and may play a role in cat outbreaks in zoos, which raises concern for potential cat-to-human transmission. Dog-to-dog transmission has not been identified experimentally,¹⁹ and zoonotic risks from infected dogs are probably minimal to negligible. 

Although there were early concerns that cats and dogs could act as mechanical vectors (fomites) through haircoat contamination, it is now understood that surfaces (of any type) pose limited risk for transmission. Viable virus has not been found on haircoats of pets that had contact with humans with COVID-19,²⁹ and the potential risk from contact with a haircoat is likely negligible.

Two vaccines are currently available for animals: a recombinant spike protein vaccine used in North America in mink and certain exotic animal species (predominantly felids and nonhuman primates) and an inactivated vaccine developed in Russia and labeled for use in various species, including dogs and cats; no published studies exist for this latter vaccine. No licenced vaccines for dogs or cats are available outside of Russia. 

There is currently little to no indication that domestic dogs and cats should be vaccinated, given the mild nature of the disease, limited zoonotic risk from animals (especially when extensive human-to-human transmission is ongoing), and limited information about efficacy or safety. Cost and/or benefit decisions more clearly support vaccinating nonhuman primates and certain large cats because of their susceptibility and potential for severe disease, as well as for conservation. 

It may be more relevant to vaccinate pets if more serious disease is encountered or if evidence of reasonable risk for zoonotic transmission and reduction in viral shedding in vaccinated animals emerges. This is most likely related to emergence of a new variant with greater ability to cause severe disease.

Single-drug analgesia protocols can be effective in common surgeries, but a combination of analgesics can be more effective with a multimodal approach that targets multiple sites in the pain pathway.^1,2 There are many multimodal drug combinations designed to prevent and treat operative and postoperative pain, including opioids, NSAIDs, ketamine, alpha-2 agonists (eg, dexmedetomidine), local anesthetic agents, and oral agents not in previously mentioned drug classes. 

Following are the author’s 5 most frequently used and effective combinations of analgesics for common surgeries based on current trends and availability.

Use of an injectable opioid and injectable NSAID is common for perioperative analgesia and pain management.³ Pure mu-opioid receptor agonists (eg, morphine, hydromorphone, methadone, fentanyl) act on mu receptors at the spinal and supraspinal level and are highly effective analgesics. Pure mu agonists can manage moderate to severe pain and provide a moderate level of sedation.⁴ Butorphanol (a mixed agonist/antagonist) and buprenorphine (a partial agonist) also act at spinal and supraspinal levels; however, they are generally preferred for mildly painful procedures.¹ Butorphanol is also used for its reasonable sedative effects, commonly in conjunction with dexmedetomidine or acepromazine.

NSAIDs (eg, carprofen, meloxicam, robenacoxib) are also commonly used and effectively contribute to analgesia in acute painful situations (eg, surgery).^5-7 The primary mechanism of action is inhibition of COX enzyme activity and subsequent reduction in prostaglandin synthesis that reduces inflammation. Other non-COX–mediated anti-inflammatory and analgesic activities (eg, activity at the 5-lipoxygenase pathway, activities impacting other proinflammatory enzyme pathways) have been proposed to contribute to the overall effectiveness of NSAID pain management.⁶

Opioids and NSAIDs are effective analgesics when used alone but generally provide better pain management when coadministered. A recent study demonstrated inadequate early postoperative analgesia when dogs received only opioid premedication prior to surgery.⁸

Protocols that use a pure mu agonist (eg, methadone) can be applied to other soft tissue surgeries, basic orthopedic procedures, and longer procedures. Top-up doses of opioids can be administered midsurgery when the procedure is longer than the duration of the premedication agent. For example, premedication with hydromorphone (0.1 mg/kg IM or IV) can be supplemented intraoperatively with another dose (0.05 mg/kg IV) if the procedure lasts >2 hours. NSAID administration can be preoperative or intraoperative, but waiting until the patient has returned to normal physiologic status postoperatively can help avoid potential negative impacts on renal function during anesthesia-induced hypotension.

Dogs and cats undergoing ovariohysterectomy can benefit from opioid and NSAID protocols. Dogs can be given preoperative hydromorphone (0.05-0.1 mg/kg IM or IV) or methadone (0.1-0.25 mg/kg IM or IV), postoperative meloxicam (0.2 mg/kg SC), and at-home meloxicam (0.1 mg/kg PO every 24 hours) after the initial SC dose.

Cats can be given preoperative butorphanol (0.3-0.4 mg/kg IM, ideally followed by buprenorphine, 0.01-0.02 mg/kg IV, during or after surgery due to the mild impact of butorphanol on pain) or methadone (0.1-0.25 mg/kg IM or IV). Postoperatively, they can receive robenacoxib (2 mg/kg SC) and at-home robenacoxib (1 mg/kg PO every 24 hours for 3 days) after the initial SC dose.

Local anesthetic agents (eg, lidocaine, bupivacaine, ropivacaine) are particularly effective at providing pre-emptive analgesia because they block conduction of sensory nerve impulses via inhibition of voltage-gated sodium channels in neurons, causing complete blockade of nociceptive input from the surgical site. Local anesthesia can effectively reduce general anesthetic requirements during surgery.¹ 

Combination of a local or regional block with injectable analgesics (eg, opioids, NSAIDs) can provide a complete perianesthetic pain management plan (see When to Use Local Anesthesia). 

When using local anesthetics, it is important to calculate the total dose to avoid exceeding maximum recommended doses and to prevent toxicosis. In cats and dogs, the maximum dose of bupivacaine 0.5% is 2 mg/kg, and the maximum dose of lidocaine 2% is 8 mg/kg. Although the reported toxic dose of topical lidocaine 2% is up to 10 mg/kg in cats, there is some variability in the literature; the maximum dose ranges from 6 to 8 mg/kg. 

Dogs can be given preoperative hydromorphone (0.05-0.1 mg/kg IM or IV) or methadone (0.1-0.25 mg/kg IM or IV), as well as a preoperative incisional infiltration (ie, line block; lidocaine 2%, 4-8 mg/kg, or bupivacaine 0.5%, 1-2 mg/kg). After the procedure, meloxicam (0.2 mg/kg SC) can be administered.

Cats can be given preoperative butorphanol (0.3-0.4 mg/kg IM; ideally followed by buprenorphine, 0.01-0.02 mg/kg IV, during or after surgery due to the mild impact of butorphanol on pain) or methadone (0.1-0.25 mg/kg IM or IV). A preoperative incisional infiltration (ie, line block; lidocaine 2%, 2-4 mg/kg, or bupivacaine 0.5%, 1-2 mg/kg) can also be administered. Postoperatively, patients can be given robenacoxib (2 mg/kg SC).

Before surgery, dogs can be given hydromorphone (0.05-0.1 mg/kg IM or IV) or methadone (0.1-0.25 mg/kg IM or IV). Perioperatively, an intraperitoneal splash block on the ovarian pedicle and uterine stump (lidocaine 2%, 6-8 mg/kg, or bupivacaine 0.5%, 2 mg/kg; doses divided among sites) can be administered.¹³ Postoperatively, meloxicam (0.2 mg/kg SC) can be administered.

Cats can be given preoperative butorphanol (0.3-0.4 mg/kg IM; ideally followed by buprenorphine, 0.01-0.02 mg/kg IV, during or after surgery due to the mild impact of butorphanol on pain) or methadone (0.1-0.25 mg/kg IM or IV), followed by a perioperative intraperitoneal splash block on the ovarian pedicle and uterine stump (lidocaine 2%, 2-4 mg/kg, or bupivacaine 0.5%, 1-2 mg/kg; doses divided among sites).¹³ Robenacoxib (2 mg/kg SC) can be administered postoperatively.

For an intraperitoneal splash block, lidocaine 2% (2-4 mg/kg) or bupivacaine 0.5% (1-2 mg/kg) should be diluted to a total volume of 0.4 to 0.6 mL/kg. Addition of an incisional line block can improve the pre-emptive quality of analgesia. Total lidocaine 2% should not exceed 6 to 8 mg/kg, and total bupivacaine 0.5% should not exceed 2 mg/kg.

Dogs can be given preoperative butorphanol (0.2-0.4 mg/kg IM or IV), dexmedetomidine (1-3 μg/kg IV or 3-10 μg/kg IM), local anesthetic (lidocaine 2% or bupivacaine 0.5%, 0.25-0.5 mL) injected into the center of the testicle with the tip of the needle pointed at the spermatic cord,^14,15 and a line block (lidocaine 2%, 2-4 mg/kg, or bupivacaine 0.5%, 1 mg/kg) along the incision site.

Before the procedure, cats can be given butorphanol (0.3-0.4 mg/kg IM; ideally followed by buprenorphine, 0.01-0.02 mg/kg IV, during or after surgery due to the mild impact of butorphanol on pain) or methadone (0.1-0.25 mg/kg IM or IV), as well as local anesthetic (lidocaine 2% or bupivacaine 0.5%, 0.25 mL) injected into the center of the testicle with the tip of the needle pointed at the spermatic cord.^14,15

Administration of an opioid with an alpha-2 agonist for analgesia and sedation is common in short procedures and patients in which heavier sedation is indicated. Alpha-2 agonists (eg, medetomidine, dexmedetomidine) are commonly used to produce profound sedation; they also provide effective analgesia, presumably via modulation of nociceptive signals at the level of the spinal cord. Alpha-2 agonists have high dosage requirements and adverse effects that prevent their use as sole analgesic agents; however, their analgesic effectiveness is enhanced when combined with an opioid.⁹

Dexmedetomidine as part of an analgesia plan can range from 0.5 to 10 μg/kg IM or IV based on the level of sedation needed and patient status. Lower doses (0.5-5 μg/kg) are administered IV, and higher doses (5-10 μg/kg) are administered IM. The optimal approach is generally to maximize the opioid dose and adjust the alpha-2 agonist dose to fit the patient and level of sedation needed due to the lesser impact of opioids on cardiopulmonary function. Although alpha-2 agonists provide analgesia when used alone, they are not sufficient for most procedures, and an opioid should be included to maximize analgesic benefits.

It is important to note that alpha-2 agonist doses are in μg/kg, not mg/kg.

Preoperatively, local anesthetic (lidocaine 2%, 0.25-0.5 mL) can be injected into the center of the testicle with the tip of the needle pointed at the spermatic cord,^14,15 a line block (lidocaine 2%, 2-4 mg/kg, or bupivacaine 0.5%, 1-2 mg/kg) can be administered along the incision site, and butorphanol (0.2-0.4 mg/kg IM or IV) and dexmedetomidine (1-3 μg/kg IV or 3-10 μg/kg IM) can be administered. After the procedure, meloxicam (0.2 mg/kg SC) can be given.

A preoperative incisional infiltration (ie, line block; lidocaine 2%, 2-4 mg/kg, or bupivacaine 0.5%, 1-2 mg/kg) or perioperative intraperitoneal splash block on the ovarian pedicle and uterine stump¹³ (lidocaine 2%, 2-4 mg/kg, or bupivacaine 0.5%, 1-2 mg/kg) can be administered, along with preoperative methadone (0.25 mg/kg IM or IV) and dexmedetomidine (3-5 μg/kg IV or 5-10 μg/kg IM). Postoperatively, robenacoxib (2 mg/kg SC) can be administered.

For dogs and cats, a preoperative local infiltration of lidocaine 2% can be administered; it may be divided among multiple sites but should not exceed a total of 6 to 8 mg/kg in dogs and 6 mg/kg in cats. Preoperative butorphanol (0.4 mg/kg IV or IM for dogs or cats) and dexmedetomidine (3-5 μg/kg IV or 5-10 μg/kg IM for dogs or cats) can also be administered.

Intraoperative infusion of opioids or nonopioid analgesics as a single bolus or CRI can be a useful adjunct for common surgical procedures. For example, a patient responding excessively to traction on the ovarian pedicle during ovariohysterectomy will not have a rapid response to increased inhalant anesthetic gas. Although the simplest choice may appear to be administration of an additional dose of the premedication opioid, a small dose of ketamine (0.5-1 mg/kg IV) can provide additional analgesia and slightly deepen anesthesia without negatively impacting blood pressure or ventilation. 

Ketamine is an N-methyl-D-aspartate receptor antagonist that is mildly analgesic at subanesthetic doses and can work synergistically with opioids to improve analgesia during acute pain scenarios (eg, surgery). Ketamine can also be administered as a perioperative infusion alone or in combination with an opioid infusion (eg, fentanyl CRI). Lidocaine IV also has analgesic properties and can reduce inhalant requirements in dogs during surgery but is not recommended in cats.¹⁰ Most common surgical procedures are often not long enough to warrant CRI of these drugs.

When traction is placed on the ovarian pedicle or uterus during ovariohysterectomy, a single bolus of ketamine (0.5-1 mg/kg IV) can be administered and repeated every 20 to 30 minutes if a CRI cannot be performed.

If a patient is responding to surgical stimulation and increasing the inhalant is contraindicated due to hypotension, a single bolus of half the premedication dose of a pure mu agonist (eg, methadone, hydromorphone) can be administered.

To reduce inhalant requirements in fragile patients (ie, those sensitive to the negative cardiovascular effects of inhaled anesthetic agents) during longer procedures (eg, orthopedic), fentanyl (2-5 μg/kg IV) and/or ketamine (1-2 mg/kg IV) can be used preoperatively. Fentanyl (5-20 μg/kg/hour CRI) or ketamine (0.5-1 mg/kg/hour CRI) can be administered for maintenance.

Oral analgesia combinations are generally part of a postoperative analgesia plan, but they can also be used preoperatively in patients with painful pre-existing conditions. Potential interactions with perianesthetic analgesics should be considered. For example, buprenorphine oral transmucosal (OTM) likely reduces the initial effectiveness of pure mu agonists that are unable to bind to the receptor occupied by buprenorphine during the 6 hours following buprenorphine administration.

NSAIDs are anti-inflammatory and analgesic, but they are best used as part of multimodal analgesia with other classes of agents (eg, opioids) or other approaches (eg, local and regional anesthesia). NSAIDs are thus not optimal to manage most surgical pain alone. 

Buprenorphine (cats, 0.01-0.04 mg/kg OTM; typically started at 0.02 mg/kg) is particularly useful in cats as an adjunct analgesic that can improve postoperative pain management. This drug is also effective in dogs, but the analgesic dose (up to 0.12 mg/kg OTM) can be cost prohibitive in large dogs.¹¹ One cost-effective option is extra-label use of more concentrated buprenorphine (1.8 mg/mL); this article refers to the buprenorphine 0.3 mg/mL product.

Gabapentin (5-20 mg/kg PO every 8 hours) is an adjunct perioperative oral analgesic agent that can also be used as outpatient treatment in dogs and cats. The mechanism of analgesic action is not well understood but is thought to be via binding voltage-gated calcium channels.¹² Several studies have examined perioperative use of gabapentin for analgesia in dogs and cats, but none have demonstrated evidence of significant analgesia.¹² There is some evidence that gabapentin may improve analgesia when used as an adjunct with NSAIDs or opioids in small animals.¹²

The analgesic combinations described in this article are not mutually exclusive. Procedure type, invasiveness, and duration; pre-existing conditions; anticipated perianesthetic complications; and best practices for anesthesia management should be considered. Opioids, NSAIDs, alpha-2 agonists, other analgesic infusions, and other oral drug combinations should be selected to achieve optimal perianesthetic pain management, and local anesthesia should be part of multimodal analgesia when possible.

In the United States, canine gonadectomy has traditionally been performed at ≈4 to 6 months of age, after puppies complete their vaccine series. From a technical perspective, surgery at this age or younger is easy, fast, and safe because of small patient size, lack of body fat, and rapid recovery; however, recent studies suggest gonadectomy before skeletal maturity can have adverse effects, particularly in certain dog breeds.^2,4 More owners and clinicians are thus reconsidering their opinions on timing of gonadectomy and whether it should be performed. There are no randomized, controlled, lifetime studies to provide unequivocal evidence on appropriate timing of gonadectomies³; therefore, the decision as to when and if a patient should be neutered should be based on the individual patient, owner, and available data.

Conditions preventable or treatable by gonadectomy include testicular, ovarian, and uterine cancers; pyometra; prostatic hyperplasia; and endometrial polyps.^5,6 Gonadectomy also improves the chance for successful treatment of hormonally induced conditions (eg, prostatic abscesses and cysts,⁷ vaginal prolapse and hyperplasia,⁸ perianal adenomas⁹). Ovariectomy may contribute to control of diabetes mellitus¹⁰ and regression of vaginal leiomyoma.¹¹

Gonadectomy before sexual maturity reportedly reduces the overall risk for mammary tumor development^12-14; however, a systematic review found moderate to high risk for bias in published canine studies.¹⁴ 

The most quoted—and misquoted—study regarding mammary tumors and gonadectomy reported that dogs spayed before the first or second estrous cycle had 0.5% or 8%, respectively, of the risk of intact, multiestrous dogs, and that dogs spayed after 2 or more estrous cycles had a 26% relative risk.¹³ This information can be misinterpreted by assuming the actual rates of mammary cancer are 0.5%, 8%, and 26% of female dogs, depending on the timing of ovary removal; however, these numbers represent relative risk as compared with intact dogs. Application of these statistics therefore requires knowledge of mammary tumor incidence in intact females. For example, one study reported an annual incidence of 250 cases per 100,000 dogs, 73.4% of which were intact.¹⁵ Based on this study, the average annual incidence for intact females would therefore be 184 out of 100,000 (0.18%) dogs. Using the relative risk percentages from the study,¹³ the estimated annual incidence per 100,000 dogs spayed before their first, second, or third estrous cycle would be 1 (0.001%), 15 (0.015%), and 48 (0.048%), respectively, in that population. 

In patients in which risk for mammary cancer is the underlying reason prepubertal gonadectomy is recommended, breed predisposition to the disease should be considered. According to a Swedish insurance study of >260,000 female dogs, mammary tumors were most often reported in Leonbergers, Doberman pinschers, Bernese mountain dogs, Welsh terriers, English springer spaniels, American cocker spaniels, and boxers.¹⁶ For each of these breeds, the estimated likelihood of developing mammary tumors over a lifetime was ≥35%; conversely, estimated likelihood was ≤5% for basenjis, collies, Finnish Lapphunds, Lancashire heelers, Norwegian Buhunds, Norwich terriers, Pomeranians, pugs, and Siberian huskies.¹⁶ 

In another study of >7,000 female dogs in the United States, no mammary cancers were reported in intact or gonadectomized Bernese mountain dogs, boxers, miniature schnauzers, pugs, Saint Bernards, Shetland sheepdogs, or West Highland white terriers, but a high incidence was reported in American cocker spaniels and English springer spaniels.⁴ Based on these studies, owners of cocker spaniels and English springer spaniels may be counseled to consider ovariectomy before the first or second estrous cycle; however, mammary cancer may not play a decision-making role for owners of West Highland white terriers or Shetland sheepdogs. The discrepancy regarding Bernese mountain dogs could reflect differences in regional genetics or follow-up: the study of Swedish dogs¹⁶ followed patients to 10 years of age, whereas in the US-based study,⁴ mean age at follow-up was <6 years.

As with mammary tumors, timing of, or even need for, gonadectomy for pyometra prevention may depend on the breed of the patient.^16,17 Pyometra usually occurs in dogs >4 years of age and is therefore preventable with ovariectomy by this age in most breeds; however, Dogues de Bordeaux may be presented at a younger age (mean, 3.3 years).^16,17 Overall, ≈19% of intact females develop pyometra by 10 years of age, but the proportional hazard is ≥50% in Bernese mountain dogs, Bouvier des Flandres, bull terriers, Irish wolfhounds, keeshonds, Leonbergers, Newfoundlands, rottweilers, and Staffordshire bull terriers.¹⁶ Owners of high-risk breeds who believe there is no right time for gonadectomy may need to be counseled on the signs and complications of pyometra to aid in decision-making.

For some dog breeds, particularly large breeds, gonadectomy increases the risk for joint disorders by 2 to 5 times that of intact dogs.^4,17-20 For example, in golden retrievers, joint disease was diagnosed in 27% of males neutered before 6 months of age and in 5% of males left intact.^4,19 Rates of joint disease in male and female German shepherd dogs gonadectomized at <1 year of age were 21% and 16%, respectively, compared with 7% and 5% in dogs left intact.²⁰ 

Not all large breeds are affected equally. Neutering before 6 to 12 months of age was associated with significant increases in joint disorders in male Bernese mountain dogs, Labrador retrievers, rottweilers, and female Saint Bernards but not in collies, Doberman pinschers, Great Danes, or Irish wolfhounds.⁴ 

Effects of gonadectomy on the risk for joint disease can also be related to sex. For example, neutering before one year of age increased the risk for joint disease in male cocker spaniels, miniature poodles, and beagles but not in females of those same breeds.⁴

Although urinary incontinence does not directly cause death, it may result in euthanasia because of quality-of-life issues for owners. Urinary incontinence is most often reported in spayed, large-breed dogs and is rare in intact dams.^18,21-26 

A systematic review found that most canine urinary incontinence and timing of gonadectomy studies had a moderate to high number of errors that biased the conclusions; however, weak evidence indicated that ovariectomy, particularly before 3 months of age, increased the risk for incontinence.²³ In a more recent study, most cases of urinary incontinence occurred in dogs spayed at <1 year of age, with some breeds at significantly greater risk.⁴ For example, urinary incontinence was diagnosed in 25% of Doberman pinschers spayed before 6 months of age and in 19% of those spayed between 1 and 2 years of age.⁴ 

Other breeds with high rates of urinary incontinence after spaying included English springer spaniels, German shepherd dogs, rottweilers, Shetland sheepdogs, and West Highland white terriers.⁴ Predisposed breeds may benefit from longer hormone exposure with intact ovaries.

Other than tumors of the reproductive tract, it is difficult to determine whether gonadectomy increases the risk for cancer, as gonadectomized dogs often live longer, which increases the risk for cancer.^3,18 Some studies indicate that the effects of gonadectomy on nonreproductive cancer risks are breed- or gender-specific. For example, gonadectomized vizslas developed mast cell tumors at an earlier age than intact vizslas, and gonadectomized female golden retrievers were at increased risk, whereas males were not.^4,19,27

Some owners consider elective gonadectomy unacceptable or deforming; however, gonad-sparing surgeries to permanently prevent reproductive capabilities or adverse effects of estrus may still be requested. These convenience surgeries can have positive and negative effects. For example, male dogs can be vasectomized to prevent delivery of sperm during copulation. Although vasectomy is a simple surgery with few complications,^28,29 vasectomized dogs continue to have effects of testosterone, including libido-driven behaviors and prostatic hyperplasia.³ 

Ovary-sparing hysterectomy requires removal of the entire uterine horns and uterine body.²⁸ Resection of the cervix is also recommended because glandular endometrial tissue can extend into the cervix, which could result in vaginal discharge, endometritis, or stump pyometra.³⁰ Hysterectomy requires a longer incision than ovariohysterectomy because of the need for complete cervical resection, careful dissection to spare the urethra, and complete removal of the uterine horn tips. Ovary-sparing hysterectomy has no published long-term follow-up, but dams could suffer life-threatening conditions (eg, vaginal rupture, sperm peritonitis) if allowed to mate.²⁸ Vulvar and behavioral signs of estrus and attraction to males should be expected, and vaginal discharge could occur if glandular tissue remains. 

Delaying neutering increases anesthetic costs because of increased patient size. Ovariohysterectomy in adult dogs is more expensive and more difficult than in puppies, and complication rates are higher with larger patients and longer surgeries.³¹

Owners of dogs left intact may need counseling for managing libido-driven behaviors of males and isolating females during estrus. Owners may opt to place belly bands (ie, washable wraps that catch urine) on male dogs that mark indoors or diapers on female dogs that have vaginal discharge. Female dogs should not be taken to the park during receptive periods, nor should they be left alone in yards with low or electronic fences. Intact dogs should be leash- and crate-trained to provide extra control. Gonadectomized dogs have an increased risk for obesity and, therefore, need to be fed and exercised appropriately to prevent weight gain.³

Dogs should be allowed to reach musculoskeletal maturity (ie, be fully grown, with a fully functional urethral sphincter) before being neutered. Breed type and temperament should also be considered. 

Rottweilers provide an excellent case study for using research to determine timing of gonadectomy. In one longevity study, rate of mammary cancer in rottweilers was 7.9%, with a median age of 8.5 years at the time of diagnosis and a 37% case fatality; the rate of pyometra was 6.6%, with a median age of 5.4 years and case fatality of 7%.³² These results indicate that prepubertal or adolescent ovariectomy could improve outcome; however, ovary exposure >4.2 years was associated with a lifespan 17 months longer than for dogs with shorter ovary exposure.³² Life expectancy for females that developed mammary cancer was similar to the overall population. Bone sarcoma and lymphoma, however, had significant negative effects on life expectancy.³² 

Rottweilers have a 12.6% risk for bone sarcoma, and dogs that undergo gonadectomy before 1 year of age have an incidence rate of >25% compared with rates of 7.6% to 10.5% if left intact or gonadectomized after 3.5 to 5 years of age.³³ Because bone sarcoma has a mortality rate >90%, leaving a rottweiler intact for at least 4 years is worth the risk for mammary tumors. This also may decrease the risk for urinary incontinence. The rate of urinary incontinence was 1% in intact female rottweilers and 4% and 6% for those spayed at <6 months and 6 to 11 months, respectively.⁴ Research may not always be the deciding factor. In the author’s opinion, if a dog becomes aggressive during estrous cycles and attacks humans or other animals, the ovaries should be removed immediately and without hesitation.

Multiple factors, including breed and age of the dog and inclinations and needs of the owner, should be considered when determining whether to perform gonadectomy, as well as the appropriate timing. Whether a dog is neutered or left intact, owners should be informed of common breed and sex conditions, and the dog should be examined for those conditions on subsequent physical examinations. 

There is no single or definitive source of information on effects of gonadectomy for each breed, and most current articles have some bias. Current evidence should be evaluated and the positives and negatives should be considered for each patient and owner before a recommendation is made.

A significant percentage (78.5%) of dogs exhibit fearful behaviors during visits to the clinic.¹ Increasing patient comfort in the clinic is important to pet owners and clinicians; thus, prescribed anxiolytics and sedatives (extra-label) to be given before visits to the clinic have become increasingly common.^2-4

This randomized, crossover, double-blinded, placebo-controlled study* evaluated the use of oromucosal dexmedetomidine gel in the clinic to decrease stress in dogs. Study patients were known to have anxiety and/or fear when at the clinic. Aggressive dogs were not included. Owners, clinicians, and observers (who used an ethogram with predetermined stress-related behaviors to assess the dogs) were blinded as to which dogs received dexmedetomidine oromucosal gel (125 µg/m²) or a placebo control gel, which was identical in appearance to the dexmedetomidine gel. After a wait time of 20 minutes to allow the drug to take effect, interactions between each dog and the owner and staff were recorded on video. Dogs served as their own control, as they returned 14 to 21 days later and were given the alternative medication or placebo. Observers noted a significant decrease in signs of stress in patients, but owners and clinicians did not.

Key pearls to put into practice:

Owners and clinicians may not be familiar with all the signs of fear and anxiety in dogs and may miss subtle changes.

Dexmedetomidine may have a better effect when given at home (before arrival at the clinic), possibly because the 20-minute wait time for the drug to take effect can be stressful for patients in an unfamiliar environment.

In dogs known to be fearful, it may be beneficial to delay examination/treatment and send medication home to be administered before the next visit to the clinic.

Mandibular fracture repair in small animal patients, including reptiles, is difficult, as the procedure must balance repair stability with the patient’s ability to eat and maintain metabolism. 

This case series describes medical management and external coaptation of unilateral mandibular fracture in 2 bearded dragons (Pogona vitticeps). The author used principles of veterinary dentistry to facilitate bone healing. 

Analgesia and anesthesia were administered, fractures were aligned, and soft tissue defects were repaired in both patients. A metal wire (ie, section of a paperclip) was fashioned around the jawline to provide a base for stabilization. Dental acrylic was applied to adhere the wire to exterior mandibular skin. During treatment, additional dental acrylic was applied several times to re-adhere the wire to the skin.

A surgical tape splint was used as an adjunct to fracture stabilization. Because reptiles have a lower rate of metabolism, the splint was left on for the full duration of healing but was temporarily removed (and replaced) every 48 hours for tube feeding, which was continued until external stabilization was no longer necessary. Esophagostomy tube placement was not necessary. 

External coaptation was successful in both cases, and patients achieved functional healing in 7 to 9 weeks.

Key pearls to put into practice:

External coaptation using a metal wire and dental acrylic is a viable option for open, unilateral, simple mandibular fractures in bearded dragons.

Dental acrylics and ultraviolet healing lights for dentistry are increasingly common in veterinary clinics and are easily obtained from most veterinary suppliers.

Although reptiles typically heal more slowly than mammals, many fractures can be managed without direct surgical intervention.

Tube feeding is critical for meeting caloric requirements for basal metabolic rate and healing. Multiple commercial and home-prepared diets are available.

Microsporidiosis is an emerging zoonotic concern, and cats may have a role in the environmental dispersion of microsporidia and the epidemiology of human microsporidiosis.

This systemic review and meta-analysis evaluated the worldwide prevalence of microsporidia infection and genetic diversity of organisms among owned and stray cats. A systematic search was conducted to identify relevant literature: 30 studies representing 34 datasets were included.

In general, prevalence estimates varied by continent and detection method used. The highest prevalence estimates were derived from microscopy-based studies (29.7%), and then serology (11%) and molecular techniques (8.2%). Among molecular-based studies (n = 23), pooled prevalence estimates were the highest in Africa, followed by the Americas, Europe, Asia, and Oceania. The most commonly identified microsporidia species were Enterocytozoon bieneusi and, from there, Encephalitozoon intestinalis and Encephalitozoon cuniculi. Prevalence estimates did not significantly differ among owned and stray cats.

This systematic review highlights the paucity of data from both industrialized and developing countries in supporting evidence-based prevention and control recommendations. The epidemiology of microsporidia should be a continued area of research worldwide.

Key pearls to put into practice:

Although microscopic detection is commonly used, identifying microsporidia spores using this method can be difficult, and misdiagnosis may result. Molecular-based detection methods are thus considered the standard for detection and identification of microsporidia.

E cuniculi is a pathogen in rabbits commonly reported in this review that has been associated with uveitis and cataracts in cats; consideration should be given to this as a differential diagnosis.

Cats are a potential reservoir for microsporidia infections that may pose a health risk to humans, particularly those who are immunocompromised. Clinicians should work with physicians to provide guidance to immunocompromised owners on safely sharing their households with cats.

Rupture of the abdominal wall in cats is relatively uncommon and typically the result of trauma that causes damage to abdominal viscera, perforation of the abdominal wall, and potential injuries to other anatomic areas. 

This study describes a logical, comprehensive approach for management of traumatic abdominal wall rupture in cats in which evaluation and management should focus on assessment of internal injuries and stabilization. The entire cat should be examined for possible accompanying injuries of the limbs, thorax, head, and neck. Surgical repair is typically delayed until the patient is sufficiently stable to tolerate general anesthesia. Exceptions may include patients with internal organ injury, with extensive abdominal contamination, or that cannot be stabilized due to displaced viscera. 

Disruption of the abdominal wall can be diagnosed through physical examination, but imaging (eg, radiography, ultrasonography) is also often required. 

Surgical repair typically involves preplacement of monofilament absorbable or nonabsorbable sutures in an interrupted pattern. A tension-relieving suture pattern (eg, horizontal mattress) is commonly preferred. Because the abdominal defect often does not include structures with high connective tissue content, the defect is repaired by closing muscle layers; secure suture placement should be ensured. Synthetic mesh or muscle flaps may be needed to close the defect during repair of chronic abdominal wall rupture or if trauma has destroyed available local tissue. Muscle flaps are typically preferred due to the potential for complications (eg, infection, dehiscence, seroma) associated with synthetic mesh.

Key pearls to put into practice:

Systemic stabilization should be the highest priority in cats with acute injuries. Viscera displaced from the abdominal cavity can often be gently relocated and held in place, at least temporarily, with external bandages.

Diagnosis of traumatic abdominal wall rupture in cats, particularly in those with chronic rupture, may require imaging.

Repair of the defect can typically be achieved using local tissues. Transposition of muscle flaps or use of synthetic mesh may be required for larger defects.

In humans, neutrophil:lymphocyte ratio (NLR) and platelet:lymphocyte ratio (PLR) are prognostic markers in cancer and inflammatory processes. This prospective study evaluated whether NLR and PLR were correlated with severity and clinical outcomes in cats (n = 41) and dogs (n = 67) with acute pancreatitis. Diagnosis of pancreatitis was based on clinical signs, elevated canine or feline pancreas-specific lipase, and ultrasound findings. Days from diagnosis to clinical recovery were tabulated, and severity of disease was assessed using a standardized index adapted from human medicine. Study results demonstrated that NLR and PLR were significantly higher in dogs and cats with pancreatitis versus healthy control patients; however, there was no correlation with disease severity. Increased PLR was associated with a longer recovery time in both species. NLR and PLR may provide useful information regarding the course of pancreatitis in cats and dogs.

Hypertrophic cardiomyopathy (HCM) is the most common cardiovascular disorder in cats, affecting up to 29.4% of feline patients.¹ Cats with clinical signs of HCM are often treated with diuretics, angiotensin-converting–enzyme inhibitors, β blockers, or antiplatelet and anticoagulant medications.² However, evidence-based data supporting specific and ideal therapies for subclinical feline HCM are lacking. Diagnostic findings for subclinical HCM include thickened left ventricular walls and left atrial dilation in the absence of other disease (eg, congenital heart disease, hyperthyroidism, systemic hypertension).  

This study* evaluated pet owner-perceived quality of life and activity levels in cats with subclinical HCM and lifestyle-matched healthy controls, as well as owner-perceived quality of life, quantitative activity measurements, cardiac biomarkers, and echocardiographic variables in cats with preclinical HCM, with and without atenolol therapy.  

A total of 27 healthy cats and 32 cats with subclinical HCM were included. As compared with healthy cats, cats with subclinical HCM had significantly more arrhythmias, higher cardiac troponin I concentrations, and higher N-terminal pro-B natriuretic peptide concentrations. There was no difference in overall activity scores or quality of life scores between healthy cats and cats with subclinical HCM. 

Of the 32 cats with subclinical HCM, 16 were randomized and given atenolol (6.25 mg PO every 12 hours; dosage was the same regardless of body weight, BCS, or echocardiographic findings) and 16 were given a placebo. All HCM patients were reassessed at baseline and again at 6 months. Cats receiving atenolol had significantly lower heart rate and murmur grades compared with cats receiving a placebo. In cats with subclinical HCM, atenolol treatment did not significantly affect systemic blood pressure, echocardiographic variables, quality of life, or activity levels.  

Atenolol has been prescribed by veterinary cardiologists to manage HCM, with the main goal of prolonging the subclinical phase of disease while maintaining a high quality of life. Atenolol use in humans with HCM remains a mainstay therapy, with evidence of improved clinical condition. In the present study, some benefits were noted in cats that had subclinical HCM and were receiving atenolol, but there was no significant improvement in all areas assessed. More significant results may occur in cats with severe subclinical HCM if an alternative survey is offered or if higher doses of atenolol are administered.

Key pearls to put into practice:

Cats are often difficult to medicate. There are some benefits to atenolol therapy in cats that have subclinical HCM, but it is important to weigh the pros and cons of treatment and prescribe medications most likely to improve quality of life and longevity. Antiplatelet therapy can be prioritized in some cases.

Atenolol therapy may be most useful when given based on the patient’s body size and BCS and on the severity of echocardiographic findings.

Baseline diagnostics should be obtained prior to initiating medical therapy in cats with subclinical HCM. Recheck is needed after 6 months, and treatment should be adjusted to maximize positive effects.

Chronic allergic dermatitis in dogs can result in significant caregiver burden for pet owners. A previously published report¹ discussed the positive correlation between caregiver burden and severity of canine skin disease. 

The goal of the current study was to relate caregiver burden to both objective and subjective treatment complexity. Eighty-six participants were enrolled after completing an online survey about their dog with skin disease. An adapted 18-item Zarit Burden Interview validated for companion animal owners was used to assess caregiver burden, and a previously published measure was used to determine severity of skin disease. Complexity of treatment plans was subjectively determined using statements from the Pet Owner Adherence Scale. To decrease the influence of owner perception of difficulty, objective treatment complexity was determined by requesting the specific number of individual treatments required for management. 

A majority (ie, >80%) of enrolled dogs had moderate to severe skin disease that was positively correlated with caregiver burden. In addition, caregiver burden increased as the owner’s subjective assessment of treatment complexity increased, independent of disease severity. Objective analysis of treatment complexity was also positively correlated with the degree of caregiver burden.

Assessing caregiver burden is vital for successful management of dogs with allergic dermatitis. It is important to understand that as treatment complexity increases, compliance may decrease due to caregiver burden. Burden transfer to the clinician, in which owners overburdened with caregiving transfer their stress to the clinician, may also increase if the owner does not feel they can complete the treatments recommended for their dog.² Although multimodal therapy is paramount in the treatment of allergic dermatitis, starting with a simple, yet effective, treatment plan can yield lower caregiver burden.

Key pearls to put into practice:

Simple, effective treatment plans should be chosen, if possible, for dogs with skin disease. Additional therapies may be provided once the patient is comfortable, but caregiver burden should be assessed at each examination.

Compliance may be increased by limiting the number of treatment modalities and initially focusing on the most effective therapies.

Simplistic treatment plans may also decrease burden transfer to clinicians, as caregiver burden would decrease, potentially resulting in fewer treatment-related follow-up questions or confusion.

The increased frequency of emerging parasites, especially those of zoonotic concern, in the United States can be attributed to increased global travel. Nonnative parasite species translocated to a new geographic area can infect new host species and cause severe disease.  

Thelazia callipaeda (ie, oriental eye worm) is a nematode that reportedly infects dogs, cats, rabbits, wild carnivores (eg, red foxes), and humans.^1,2 T callipaeda requires Phortica spp drosophilid flies as an intermediate host in order to transmit to a new host and complete its life cycle. The flies feed on lacrimal secretions of an infected host, taking up first-stage larvae during feeding and depositing infective third-stage larvae after nematodes have developed.

This case report documented T callipaeda infection in an otherwise healthy 7.5-year-old Labrador retriever with no known travel history outside Dutchess County, New York. The patient was presented with a 3-week history of unilateral epiphora and blepharospasm unresponsive to treatment with a neomycin, polymyxin-B, and dexamethasone ophthalmic preparation. 

Nasolacrimal duct flush using gentamicin sulfate 0.3% and dexamethasone 0.2% in saline, followed by ivermectin (100 µg/mL) in saline allowed recovery of adult worms morphologically and molecularly identified as T callipaeda. Systemic ivermectin treatment eliminated the infection; no further treatment was required.  

This case report highlights an autochthonous infection of T callipaeda in the United States. T callipaeda is endemic in many Asian countries and has been documented in Europe since 2001.¹ Its zoonotic potential and ability to infect and use native Phortica spp as intermediate hosts in the United States make it a parasite of concern.^1,3 

In dogs and cats in Europe, documented ocular clinical signs of T callipaeda infection include conjunctival edema and hyperemia, conjunctivitis, epiphora, mucopurulent discharge, uveitis, and corneal abrasions.⁴ Additional studies of thelaziasis in dogs have suggested that moxidectin or milbemycin can be effective treatments.⁵

Key pearls to put into practice:

Travel history is not always an indicator of potential infection with novel or emerging parasites in the United States. Competent hosts for a variety of parasites can be found worldwide. It is therefore important to consider possible infection with atypical parasites.

Zoonotic potential should always be assumed when handling parasites unless true species identity is known. Many, but not all, parasites require an intermediate host for infection. Proper collection of parasites and safe handling of samples are important to ensure accurate diagnosis and safety of pet owners and clinic staff.

Controlling intermediate hosts like drosophilid flies is difficult. Owners should be made aware of how T callipaeda is transmitted, as knowing what to look for can help limit transmission to humans and/or other pets in the household.

Diagnosing osteoarthritis (OA) in dogs can be problematic due to the lack of early detection methods. Radiographic changes used to diagnose OA occur only in later stages of the disease. Inflammatory and degenerative biomarkers (eg, tumor necrosis factor alpha, interleukin-1 beta [IL-1 beta], tenascin-c [TN-C], matrix metalloproteinase-2 [MMP-2]) have been correlated with canine joint inflammation, and immunoassays are commercially available. Glucose, pH, and lactate metabolic biomarkers also increase in the synovial fluid of joints with OA, and tests for these biomarkers are simpler and less expensive. This pilot study of dogs with OA found that metabolic markers, pH, and glucose are significantly increased in OA-affected joints as compared with normal joints. They also found that synovial fluid lactate was significantly decreased in affected joints. Of the proinflammatory biomarkers, IL-1 beta, TN-C, and MMP-2 were significantly increased in OA-affected joints. None of the values correlated to radiographic findings, likely due to the difficulty of radiographically detecting OA in early stages of disease; correlations with MRI findings should be studied.

Symmetric dimethylarginine (SDMA) is a biomarker used to assess glomerular filtration rate in the diagnosis, classification, and monitoring of chronic kidney disease. Veterinary immunoassays have been developed for regular use in commercial laboratories and point-of-care laboratory equipment but have not been evaluated independently. 

This study attempted to identify intraindividual analytic performance goals (ie, imprecision, bias, total error) using both reference laboratory and in-clinic assay data and determine what internal medicine specialists considered to be acceptable analytical variability in SDMA values. Comparison revealed marked discordance between performance capability of the tests and clinician expectations for test performance; clinicians expected much less variability. 

Clinicians risk attributing significance to and overinterpreting small changes in SDMA that may reflect either normal changes in the individual patient or analytical variability. An individual patient may have a normal analyte result whether healthy or sick, but the population-derived reference cutoff points may not apply to that patient. Changes (ie, trends) in an individual patient may be more meaningful. Information regarding reference change intervals that can aid in interpreting results is available (see Suggested Reading).¹ In addition, breed variation is significant for SDMA, creatinine, glucose, and total protein values. Age variation has also long been recognized for numerous analytes.    This study evaluated SDMA, but biologic and analytic variations apply to all tests used in veterinary medicine.²

Key pearls to put into practice:

History, physical examination findings, and clinical insight may be more important than laboratory test results.

Trends in an individual patient may be more important than single measurements.

Regular screening in healthy and sick patients can generate meaningful data that can aid in making medical decisions.

In-clinic laboratory equipment should regularly undergo quality control.¹

This study examined biopsies from 12 dogs diagnosed with chronic inflammatory enteropathy (CIE) to quantify expression of the GI receptor for advanced glycation end products (RAGE), a pattern recognition receptor of the innate immune system. These biopsies were compared with expression from biopsies of 9 healthy dogs. Epithelial RAGE expression in the duodenum, ileum, and colon was higher in dogs with CIE, and several histologic and inflammatory lesion criteria as well as markers of inflammation (ie, serum C-reactive protein, fecal calprotectin concentration) were related to epithelial RAGE expression in these intestinal structures. These findings suggest that transmembrane RAGE expression and intracellular RAGE signaling are involved in the chronic inflammatory response of dogs with CIE. RAGE antagonization may present a novel therapeutic intervention for chronic GI inflammation.

The feline blood group system is defined as the AB system, with cats being type A, B, or AB. Type A is the most common blood type in cats, and type B prevalence varies by breed and geographic location. Cats are born with naturally occurring alloantibodies against blood types other than their own. Severe acute hemolytic reactions can occur if a type B cat receives type A blood; type B blood given to a type A cat has shortened red cell survival time. Discovery of the feline red cell antigen, Mik, raised further questions about red cell antigens outside the classic AB system and their clinical relevance.

This study aimed to estimate the prevalence of cats with non-AB red cell antigens and to begin identifying the number of potential non-AB red cell antigens. Blood samples were collected from 11 blood donor colony cats, 24 research colony cats, and 102 client-owned healthy or sick cats; 134 surplus EDTA blood samples were also collected from healthy or sick cats. AB blood typing was performed, and 13 type B and AB cats were excluded. The remaining 258 type-A cats were subsequently evaluated for the presence of non-AB alloantibodies. Extensive crossmatching revealed 18 cats with unidentified non-AB alloantibodies. Of these, only 7 cats were available to have new blood samples drawn for more extensive crossmatching, which identified 5 potential feline erythrocyte antigens outside the AB classification system.

Key pearls to put into practice:

Cats have naturally occurring alloantibodies against the blood type they do not express. Based on the AB blood type system, administration of type A blood to a type B cat can cause an acute hemolytic transfusion reaction.

There may be other unidentified non-AB red cell antigens that could lead to transfusion incompatibility. This study identified the presence of 5 potential red cell antigens outside the AB classification system in a low number (7/258) of cats.

Blood typing prior to any transfusion in cats is recommended. Crossmatching prior to transfusion can be considered to identify non-AB incompatibilities. Cats that have previously received a blood transfusion should be crossmatched prior to transfusion.

Tumors of the skin (eg, mast cell tumor), soft tissue (eg, sarcoma), or bone (eg, osteosarcoma) can occur along the tail. Depending on the location, adequate margins can be achieved via tail amputation (ie, caudectomy). Primary excision of skin tumors on the tail may lead to tension along the closure and can increase the risk for a tourniquet effect or dehiscence. Tail amputation should be considered for any malignant skin tumors to achieve both adequate margins and tension-free closure. 

Another common indication for tail amputation is repeated self-trauma (mostly seen in dogs) caused by hitting the distal tail, sometimes forcibly, on surrounding structures. These repeated incidents can create scar tissue and more friable skin and lead to increased risk for future trauma, bleeding, and a nonhealing wound. Tail amputation should be considered in recurrent cases in which conservative (eg, bandaging) or behavioral management does not allow the wound to heal or prevent recurrence. The goal for these cases is not to amputate the entire tail but to shorten it enough to preclude recurrent self-damage. 

Tail trauma in hunting dogs has been described.¹ Vehicular accidents can cause degloving wounds of the tail similar to appendicular trauma. Wounds can be sutured and closed in some cases, but if there is not enough skin to allow tension-free closure, tail amputation may be preferable.

Tail vertebrae are surrounded by closely attached dorsal (sacrocaudalis dorsalis lateralis and medialis), ventral (sacrocaudalis ventralis lateralis and medialis), and lateral (intertransversarius dorsalis caudalis and intertransversarius ventralis caudalis) bulky muscles. The main blood supply can be found on both lateral sides of the tail (lateral caudal arteries), with smaller dorsal (dorsolateral caudal arteries) and ventral (median caudal and ventrolateral caudal arteries) arteries. 

Complications of tail amputation include bleeding, dehiscence, and infection. Although infection and dehiscence are not common, they may necessitate revision of the amputation to a proximal level and require removal of more proximal coccygeal vertebrae. Bleeding in large dogs can be decreased with an intraoperative tourniquet, depending on its tightness. Temporary intermittent loosening of the tourniquet during surgery allows timely identification of vessels that can then be ligated (larger vessels) or electrocauterized. Alternatively, the tourniquet can be loosened prior to closure to check for appropriate hemostasis. A sterile, self-adhesive bandage can alternatively be placed over or adjacent to the intended incision site if there is enough proximal space. The bandage creates a tourniquet effect when applied tightly, and the incision can be extended into the bandaging. Judicious use of monopolar electrocautery when dissecting muscle off the bone and during muscle transection also decreases hemorrhage (aiding in identification of vessels) and can be used in addition to a tourniquet, especially in large-breed dogs. Individual hemostasis of vessels would still be needed. 

Tension-free skin closure reduces the risk for postoperative dehiscence; removal of an additional vertebra can be considered if there is tension. Perioperative placement of an anal purse-string suture can reduce the risk for fecal contamination, as does placing surgery drapes to only include the tail in the surgical field; however, in higher amputations (ie, sacrococcygeal caudectomies), draping the tail base and perineum typically cannot be avoided. Placing tape in a visible place (eg, top of the patient's head) with a reminder that a purse string was placed helps in remembering to remove the purse string postoperatively. 

Postoperative incontinence due to traction on the nerves is a concern with amputations at, or close to, the level of the sacrococcygeal junction. A small stump of several coccygeal vertebrae is ideally left to minimize the risk for incontinence; however, if the trauma or tumor are situated more proximally, care should be taken during dissection to avoid traction. 

Although postoperative bandaging can protect the tail stump from self-trauma and keep it clean, bandages can slip easily and are often unnecessary. If a bandage is placed, care is needed to not attach the more proximal part too tightly, as a tourniquet effect is possible.

• IV stand (or similar) to hang the tail during preparation 
• Soft tissue surgical pack
• Hypodermic needle
• Electrocautery
• 4- × 4-inch gauze
• Monofilament suture (based on patient size)
  • Polydioxanone sutures (or similar) for approximation of deeper tissue 
  • Absorbable monofilament sutures for subcutaneous closure  
  • External sutures (eg, nylon) or buried intradermal simple interrupted sutures (monofilament) for skin closure
• Tourniquet (optional): 
  • Penrose drain, IV tourniquet, or a rubber tie frequently used for endotracheal tube tie-ins 
  • Sterile, self-adhesive bandage (alternatively)
• Sterile marker pen to outline the incision and flaps (optional)
• Sterile, self-adhesive bandaging if a wound or necrotic area needs to be covered (optional)
• Purse-string suture to avoid contamination in a high tail amputation (optional)
• Rongeurs to remove cartilage (optional)

Clip the dorsal pelvic/lumbar area, tail, and perineum. Cover the most distal portion of the tail with a glove only, a glove covered with a second layer of self-adhering bandaging, or self-adhering bandaging only, as this part of the tail will be fully removed during surgery and does not need to be fully clipped. Place an anal purse-string suture. Position the patient in ventral recumbency and at the edge of the table, with the pelvic limbs hanging freely over the edge of the table (with an appropriate amount of padding underneath), or pull the patient forward with the pelvic limbs partially supported on the table. Suspend the tail to allow a hanging limb preparation and draping technique. Depending on the impermeability of the primary bandage, place a sterile self-adhering bandage (shown in Step 2) or an impermeable drape followed by a sterile self-adhering bandage to cover the distal portion of the tail and prepare for coverage.

Choose the area of amputation and corresponding joint space. If desired, use a hypodermic needle to help identify the location of the intervertebral space. Place a tourniquet around the proximal aspect of the tail to decrease bleeding.

Plan to make the incision in 2 U-shaped flaps (ie, dorsal and ventral), with the tip of the U positioned toward the tip of the tail and the end of the “leg” of the U on the lateral side of the tail at the level of the planned disarticulation to allow for tension-free closure.

Make an incision at the preplanned site, and dissect the subcutaneous tissue to the level of the desired disarticulation site (A). Reinsert the hypodermic needle at the desired intervertebral space after completing the subcutaneous dissection (B).

Sharply transect the muscles of the tail, and dissect away from the intervertebral space. Maintain hemostasis of the arteries via targeted cautery or suture ligation of the arteries.

Locate and disarticulate the joint space with a blade or heavy scissors. Remove the remaining cartilage at the proximal vertebra with rongeurs. Release the tourniquet prior to closure to check for hemostasis. Move and manipulate the skin to assess tension on the closure line before closing the wound.

Start closure by approximating sutures in the deeper tissues using a simple interrupted pattern (A), followed by routine closure of the subcutaneous tissues and skin (B). Trim the flaps if excess skin is present. After the incision is fully closed, remove the purse string (either in the operating room or in the preparation or recovery area).

• Mechanical trauma from malpositioned dental hard tissue (dental malocclusion) 
• Mechanical trauma from foreign body
• Hyperimmune mucositis reaction to adjacent plaque
• Mucocutaneous pyoderma 
• Mechanical injury or trauma (eg, chewing on an electric cord)
• Thermal injury
• Chemical injury
• Drug reaction (eg, methotrexate [shown to cause oral ulceration in humans])
• Breed predisposition (eg, Cavalier King Charles spaniel) 
• Viral infection (canine distemper virus)
• Erythema multiforme 
• Malignancy (eg, amelanotic melanoma, squamous cell carcinoma, fibrosarcoma, epitheliotropic lymphoma, melanoma, osteosarcoma) 
• Uremia
• Eosinophilic granuloma
• Lupus erythematosus (discoid, mucocutaneous) 
• Pemphigus vulgaris or pemphigus foliaceus
• Bullous pemphigoid or mucous membrane pemphigoid
• Candidiasis 
• Leptospira spp infection
• Chemotherapy or radiation therapy

It would seem to make sense that ectoparasites such as fleas, ticks, and mosquitoes would become less active or disappear in harsh winter weather; however, more data continue to describe that the risk for ectoparasites is not absent in the winter months.^4,5,7

Many tick species can survive in colder temperatures, and some even thrive in temperatures near freezing.⁷ In a survey, veterinarians across the United States collected ticks from pets entering their clinic.⁴ Ticks were recovered from dogs and cats every month of the year. Of the ticks submitted from October through March, ≈61% collected from dogs and 72% collected from cats were Ixodes scapularis.⁴ The second most common tick collected from dogs during those winter months was Rhipicephalus sanguineus, at ≈19% of the total ticks.⁴

Similar data regarding fleas exist. In one collaborative global flea-monitoring study, veterinarians collected flea eggs from infested pets entering their practice year-round.⁵ The months with the fewest flea eggs collected and submitted were January through March, with peak months running August through October.⁵

When infecting pets, internal parasites are being housed at ≈101.5°F (38.6°C), with plenty of surrounding nutrients to support their existence. Furthermore, parasites with life stages that are hardy in adverse climatic conditions (eg, roundworms, whipworms, tapeworms) are primed for transmission year-round.

For internal parasites, stages within animals that do not receive treatment are fully protected against the outside world, although their offspring (typically eggs) may enter an environment that could be incompatible with life, especially in the winter. However, the eggs of some parasites are incredibly resilient and can withstand freezing temperatures and other climate adversities. ^8-10

In addition, some internal parasites utilize intermediate or paratenic hosts for transmission, through which the immature parasite stages may survive for extended periods while safely contained within that host. Using the data available through the Companion Animal Parasite Council, a recent study detailed the seasonality of fecal-based diagnoses for select internal parasites of dogs.⁶ Year after year, detection of both roundworm and whipworm infections peaked during the cooler months as compared with hookworms, which were identified more frequently in the warmer months. Survivability of environmental stages, seasonal use of preventive products, and canine breeding season were hypothesized as contributing to the seasonal nature of internal parasite detection.⁶

How can compliance with recommendations for year-round parasite prevention and protocols, including the use of broad-spectrum products, be increased? As with so many preventive care challenges, the answer lies in improving client education and communication.

More information regarding the threat of parasitism in the “off season” is available now than ever before. Through utilization of the published literature, interactive websites with county-level data, and one’s own clinical experiences and findings, pet owners can be educated on the risks that exist to their pets during the different times of year and that the best way to prevent parasite-related problems is to stay ahead of them by using safe and effective year-round prevention strategies. These can include in- or on-pet approaches (eg, broad-spectrum preventive products), as well as environmental strategies such as fecal stewardship, limiting roaming and scavenging behaviors, and vector mitigation in and around the home.

Communication is also key to the implementation and continuation of a new or updated strategy regarding parasite control. The entire veterinary team must be on-board so that clients receive a cohesive and consistent message on year-round parasite prevention and its importance. The team must also continue to communicate the importance after the visit, whether that be with directed, timely reminders for re-dosing or monthly social media updates highlighting local parasite data. These follow-up conversations can serve as opportunities for encouragement and positive reinforcement with clients.

Lastly, but most importantly, parasite prevention should make it easy for the pet owner to succeed. That means finding the products that best fit the lifestyle of the pet and preferences of the pet owner. Would using something long-lasting that only needs to be administered every few months increase the owner’s ability to comply with recommendations? Does the owner want to give a “treat,” or would they prefer to apply something topically? Are there skin or food allergies to consider? Offering too many product choices can make it harder for pet owners to make a decision; limiting product recommendations to a few options allows for consistent messaging and inventory control but still permits owners to choose preventives that best suit their needs. It is imperative that the veterinary team actively include the client in the decisionmaking process, combining the owner’s knowledge of their capabilities and their pet with the team’s knowledge of risks and products that will result in the most comprehensive and effective strategy for parasite prevention.

The data that continue to be gathered and published highlight year-round parasite risk for pets, regardless of lifestyle or geography. Even though not all parasites may pose the same risk during all months of the year in all locations, year-round implementation of a parasite prevention program, including the use of broad-spectrum parasite preventive products, is still recommended. Compliant use of the right product or combination of products by pet owners will be beneficial for controlling and preventing parasitic diseases in pets.