If long enough, the tails of adult cows should be tied—usually to one hind leg—for standing procedures. Large disposable laparotomy cloths or disposable drapes are available.^* They may be fenestrated, or an appropriate-sized hole can be made by the surgeon. They are usually used alone and secured in place with penetrating towel clamps. Although they are relatively expensive, they are a great help in allowing the surgeon to focus on the procedure without worrying about contamination from dirt, fecal material, or body fluids.

Prevention of Peritonitis and Surgical Infection

The surgeon must always be aware of their potential to promote or prevent peritonitis or other infections of the surgical site development during surgery in the cow. It is often possible is to reduce the risk of infection before contamination ever occurs or to intervene between the time contaminants are first introduced into the abdomen and the development of infection.

PRECONTAMINATION

The optimum time to intervene in the development of a surgical infection is before a known or anticipated episode of contamination. Careful planning of the procedure will minimize the period of contamination, ensure adequate restraint, and minimize the use of potential adjuvants to reduce the risk of infection. Prophylactic antibiotics should be considered in planning any clean-contaminated or contaminated procedure and clean procedures in patients with identified risk factors. Common patient risk factors include preexisting nonbacterial inflammatory peritonitis, malnutrition, circulatory shock, and remote or systemic infection. In the latter case, elective procedures should be delayed until the preexisting infection can be treated and resolved. Similar steps should be considered when facilities, the animal’s behavior, or its condition increase the risk of contamination (see Section 4.7). Field conditions often involve less than optimal restraint facilities, fractious animals, limited control of external sources of contamination, and conditions that might predispose to unexpected recumbency during standing procedures (hypocalcemia, exhaustion, extreme peritoneal tension), all of which increase morbidity.

Antibiotics should be administered just far enough before surgery to maintain high serum levels throughout the period of contamination. Intravenous (IV) administration of a single dose 15 minutes before surgery or intramuscular (IM) administration 60 minutes before surgery achieves this goal for most antibiotics. Parenteral, subcutaneous, and intraperitoneal routes are not recommended for prophylaxis because the time to peak levels is longer and less predictable and because peak levels are lower in comparison to IV and IM routes of administration. If intraoperative sample collection for culture is planned, some prophylactic effect can still be obtained by intravenously administering an appropriate antibiotic immediately after sample collection.

Prophylactic antibiotics should be selected with as specific a spectrum as possible, based on probable contaminants. This can be based on knowledge of common contaminants from planned surgical sites (e.g., anaerobes for rumenotomy), culture results from potential sites of leakage or preexisting infection (e.g., culture results from an umbilical abscess), or by predicting other common infectious agents. The ability of antibiotics to penetrate fibrin or function in the presence of necrotic debris or altered pH should not be a major concern in antibiotic selection during the precontamination or contamination stages. Antibiotic options are provided in Appendix 1.

CONTAMINATION

Preventive measures are similar to those described for the precontamination stage, with a few additions. Prophylactic antibiotics can still be of some benefit, but they should be given intravenously to achieve high serum and tissue levels as soon as possible. If a source of contamination first develops intraoperatively, rapid steps to minimize the amount and distribution of contamination are indicated. For example, in gastrointestinal surgery, gross contamination should be localized whenever possible by exteriorizing the site of leakage or isolating it with laparotomy sponges; physically removing all accessible contaminants; and avoiding palpation unless absolutely necessary so that contaminants are not physically transported from the site of leakage to other sites in the abdomen. If the site can be adequately exteriorized to allow external drainage, localized lavage with a sterile isotonic fluid can help remove contaminants. However, generalized lavage is more likely to distribute high concentrations of organisms to potentially clean areas and is only recommended if the site cannot be exteriorized or dissemination has already occurred. Adding antibiotics to the lavage fluid may be indicated even if appropriate systemic antibiotics have been administered.

Other important considerations in the after care of the surgical farm animal are supplying adequate hydration (see Chapter 5), keeping neonates warm, and providing adequate nutrition and oral electrolytes.

Down cattle need excellent footing that keeps them from slipping. They need to be supported by having food and water where it can be reached. Good padding in a heavily bedded stall or on soft dirt is ideal. If cattle remain down for prolonged periods of time it may be necessary to try to get them up with well-padded hip lifts. Alternatively, cattle can be “floated” in a commercial tub (“Aqua cow”)^* (Figure 4.1-3). This apparatus requires a fair amount of time, patience, and manpower. Regardless it has been successful in the right hands for recumbent cows that are amenable to therapy.

Figure 4.1-3 Cow in flotation tank.

NONANTAGONISTIC	ANTAGONISTIC
Penicillin and aminoglycoside	Penicillin and tetracycline
Ampicillin and aminoglycoside
Amoxicillin and aminoglycoside
Cephalosporin and aminoglycoside
Erythromycin and rifampin^*
Trimethoprim and sulfonamide (TMP/S)^*
TMP/S^* and rifampin^*
Sulfonamide and tetracycline
Lincomycin and spectinomycin
Enrofloxacin^†

Perioperative Analgesics

Perioperative analgesics are indicated in most surgical procedures to temper the initial inflammatory response and decrease swelling as well as to improve the appetite and general well-being of the patient. In cattle with routine, relatively nontraumatic surgery (e.g., omentopexy), perioperative analgesics commonly are not used simply because of cost and loss of product value as a result of milk withholding. This is particularly true if cattle are being treated perioperatively with ceftiofur, which has no withholding time. The most commonly used antiinflammatory drug is flunixin meglumine (1.1 mg/kg IV or IM). Flunixin is a cyclooxygenase inhibitor that provides excellent analgesia, including visceral analgesia, and is the only FDA-approved nonsteroidal antiinflammatory drug for cattle—albeit only for beef cattle and only IV. It may be indicated during the time of routine (one or more dosages) bovine surgery and in the immediate postoperative period when withholding times for milk and meat are not a major issue (when used only preoperatively at label dose, it incurs 10 days of meat withholding and 3 days of milk withholding).

Phenylbutazone (PBZ) and aspirin are other anti-inflammatory analgesics that historically have been used in food animals. Given that detection of PBZ at any level in food animals is considered illegal (milk and meat withdrawal are recommended at 10 and 45 days, respectively) and given the potential adverse reactions in human consumers, the Food Animal Residue Avoidance Databank (FARAD) strongly discourages PBZ use in any food animal. FARAD further discourages aspirin use in food animals for the following reasons: 1) no FDA approval for use in food animals; 2) flunixin is an available alternative; and 3) it has questionable efficacy (administered orally, the drug reaches baseline serum concentrations in 12 to 24 hours).

Additional analgesics that may be used are lidocaine, alpha-agonists, and butorphanol. Lidocaine is mostly used either for epidural administration to provide analgesia to the pelvic area during and after perineal or rectal surgery or as intravenous anesthesia (with a tourniquet) during surgery on a distal limb (15 to 30 ml lidocaine). Lidocaine is most commonly used as a local analgesic for cutting skin to prevent an animal from becoming fractious.

Xylazine epidurals (0.05 mg/kg) or Medetomidine 5 to 15 μg/kg may provide slightly better analgesic effects than lidocaine. Xylazine 0.03 mg/kg can be combined with lidocaine (0.2 mg/kg) for both fast-acting and long-lasting (4 to 5 hours) analgesia. Butorphanol may also be used intramuscularly or intravenously (0.1 mg/kg) for severe pain that cannot be adequately diminished with NSAID therapy. For information regarding the use of nonapproved antibiotics and analgesics, the reader is encouraged to consult Food Animal Residue Avoidance Data Bank at www.farad.org.

Introduction

When working with livestock, one faces inherent risks to the safety of the animal and handler. Livestock, by their sheer size, are a threat to human safety. Fearful or aggressive animals with horns are exponentially more dangerous and can inflict significant injury—or even death. Bulls are always dangerous and unpredictable and should never be trusted. Dairy bulls, because of their extensive human contact, lack a natural fear of humans and may be overtly aggressive. Beef bulls generally react out of fear toward humans. The protective, maternal instinct of a cow with a calf makes them significantly more dangerous then a single cow. Because beef cows usually are not intensively handled, they are more dangerous than dairy cows. It has been suggested that the position of the hair whorl between a cow’s eyes correlates with the degree of agitation the cow demonstrates under restraint. Animals with whorls located high on the forehead, above the level of the eyes, were found to be more aggressive under restraint (high whorls, hot-headed) (Grandin, 1995).

Although small ruminants (sheep, goats, and calves) can inflict injury to their handlers, they are more likely to injure themselves when struggling against restraining devices or overly aggressive handlers. Sheep and goats have a strong herd instinct and become stressed when separated from herd mates. Stress adversely effects wound healing as well as general health, growth, and production. In pigs, stress has been associated with sudden death.

Animal Behavior

Consideration of the animals’ natural instincts will enable a handler to humanely and safely move and restrain livestock. Livestock are prey animals whose primary defense mechanism is sight and flight. They have evolved wide-set eyes that afford them extensive peripheral vision in surveillance of predators. With an angle of vision approaching 300 degrees, their only blind spot is directly behind them. To avoid startling an animal when approaching it, the handler should remain within its line of sight. Startling an animal could elicit struggling, provoke the animal to kick, or incite a stampede.

Panoramic vision provides prey animals a wide angle of vision but sacrifices depth perception. This is why cattle commonly balk at shadows, are reluctant to step across different colored floors, and closely inspect objects in their paths. Handlers should be patient. They should allow the animal to assess the danger of a situation or novel object before forcing it to enter a foreign environment or head gate.

Animals naturally maintain a safe distance between themselves and potential predators. This distance is the flight zone. If the flight zone is invaded, the animal will move away from the invader to reestablish an adequate safe distance. In relation to people, this distance is influenced by the amount of contact the animal has had with humans. Dairy cattle, which are handled daily, may have practically no flight zone and can be readily approached. Alternatively, beef cattle, which often have greater fear because of limited human contact, may require several meters of space. Sheep and goats commonly move as a herd, and the comfort level of the first animal establishes the flight zone for the herd.

Knots

Ropes are invaluable assets in animal restraint. However, a rope is only as good as the knot that is tied. There is a unique knot, with a particular advantage, for practically any situation imaginable. However, every animal handler should be proficient with the three knots covered in the following discussion.

SQUARE KNOT

The square knot joins two rope ends. Joining the ends of a single rope forms a loop that allows the rope to be tied to a fixed object. Alternatively, the ends of two separate ropes can be joined to form one long rope. Once tightened, a properly tied square knot will not slip under tension. A common error is to tie a “granny knot” that slips when tension is applied (Figure 4.3-1).

Figure 4.3-1 Square knot.

(Adapted from Leahy JR, Barrow P: Restraint of animals, ed 2, Ithaca, 1953, self-published.)

QUICK-RELEASE SLIP KNOT

The quick-release slip knot and its modifications (see Tail Ties) secure the rope but allow it to be easily untied. For example, the free end of a halter may be tied to a post to restrain an animal’s head. When properly tied, the bow end of the knot is entirely surrounded by rope; if the bow lies against the object to which it is tied, it is not secure and will loosen as the animal struggles. Because it is a slipknot, there will always be a little play in the rope as it slips down to its anchor; tying the knot as close to the anchor as possible is important (Figure 4.3-2).

Figure 4.3-2 Quick-release knot.

(Adapted from Leahy JR, Barrow P: Restraint of animals, ed 2, Ithaca, 1953, self-published.)

BOWLINE KNOT

The bowline knot creates a permanent loop that will not tighten. It is useful to place around an animal’s body, neck, or limb because it will not cinch down and compromise respiration or circulation (Figure 4.3-3).

Figure 4.3-3 Bowline knot.

(Adapted from Leahy JR, Barrow P: Restraint of animals, ed 2, Ithaca, 1953, self-published.)

Restraint of Cattle

MOVING CATTLE

One should take advantage of ruminants’ flight instinct when moving a single animal or a herd. The flight zone is entered slowly, steadily, and silently so the animal is not spooked. The rate at which the animal moves depends on how deeply and rapidly the flight zone is penetrated. If an animal gets too anxious or moves too quickly, the handler should back away and allow the animal to relax. Excited cattle are impossible to control and are more likely to be injured or injure a person. Cattle should be moved no faster than a walk.

The spatial relationship between the handler and the animal’s body dictates the direction the animal will move when approached. The animal’s shoulder is the point of balance. If approached caudal to the shoulder, the animal will move forward; if approached cranial to the shoulder, the animal will generally move backward.

HEAD RESTRAINT

Halters

Properly used halters provide excellent control of an animal’s head. The halter should be placed with the nosepiece over the top of the animal’s nose half way between the eyes and nostrils to prevent airway obstruction or trauma to the eyes. The lead rope should run below the jaw. Putting the halter on upside down with the lead rope running behind the ears or over the nose is a common mistake. An improperly fitted halter severely compromises control of the animal’s head and is prone to slip off.

Nose Tongs

A nose tong is a pincer-type device with blunt bulbous ends that are inserted into each nostril to apply pressure to the nasal septum. The discomfort deters movement. Nose tongs should only be used in conjunction with another form of head restraint such as a halter or head gate. Tension must be maintained on the nose tongs, but they should never be tied to a fixed object. If nose tongs are not available, the nasal septum can be grasped between the thumb and middle finger.

A nose ring is a variation of the nose tong that is used on bulls. It is permanently inserted through the nasal septum. Again, excessive pressure can rip through the cartilage, so a halter should always be used in addition to the bull’s nose ring.

Head Gates

Head gates are a necessity in working with large animals. Even the smallest cattle operation should be equipped with some type of head gate to provide ease in handling, restraint, and safety. Assorted head gates—ranging from homemade vertical wooden plank devices, dairy stanchions, and self-locking feeders to custom-made head gates—exist. Head gates constructed with curved bars reduce vertical head and neck movement but may increase asphyxiation potential from a blocked trachea or the carotid arteries if the animal lies down. Straight bars are less likely to result in asphyxiation, but they do not restrict vertical head movement.

Single file chutes provide an advantage in directing cattle into head gates while restricting sideways movement of the animal. Squeeze chutes are commercially manufactured with compressible side walls that apply pressure against the animal, creating a calming effect and supporting the animal if it attempts to lie down. Chutes are invaluable assets for controlling livestock, but they limit access to the animal and create a potential for operator injuries between the animal and chute. Also, spring-loaded levers and moving parts can cause severe injury to handlers.

KICKING

A major consideration for personal safety is the animal’s ability to kick. Cows are very deft kickers and are notorious for kicking to the side—“cow kicking.” They also kick forward surprisingly well, and can extend the leg as far cranial and dorsal as the shoulder. Cows are also very proficient at kicking straight backward. They may even “mule kick” with both hind feet at the same time. The safest place to stand when working at the hind end of a cow is immediately adjacent to the animal’s body, so that the cow pushes the handler away rather then delivering a harmful blow at the snap of the kick. When working cranial to the hind legs, the operator should stay out of reach of a forward kick by standing level with the animal’s shoulder at arm’s length.

Hobbles

Hobbles may be used to tie the hind feet together to deter cattle from kicking. Commercial hobbles are available, but effective restraints can easily be fashioned out of rope.

Flanking

A manual method to deter an animal from kicking is called “flanking.” The fold of skin in the flank is lifted, and the handler places a thigh against the animal’s stifle. This provides mechanical resistance that interferes with the animal’s ability to kick. A mechanical device working under the same premises lifts against the flank and attaches over the back beneath the lumbar vertebral processes.

Tailing

Tailing discourages kicking by causing discomfort and distracting the animal’s attention. To tail an animal, the tail’s base is grasped and lifted directly over the animal’s back. Coccygeal vertebrae may fracture if too much force is exerted.

TAIL TIES

A swishing tail can be a source of frustration and potential for injury. It may contaminate a previously cleaned site, catch the handler in the eye, or otherwise be an annoyance. Tying the animal’s tail out of the way is imperative for many surgical techniques and handler safety when he or she works near the back of the animal.

A secure tail-tie can be made using baling twine, rolled gauze, bandaging tape, or a light rope. One end of the rope is placed over the animal’s tail below the last coccygeal vertebra. The switch (long hair at the end of the tail) is folded over the rope. The short end of the rope is run completely around the tail, made into a bow, and tucked underneath the loop that encircles the tail. This modified quick-release knot is tightened by pulling on the long end of the rope, which is then tied to a leg or around the neck. The tail should not be tied to a fixed object in case the animal escapes or falls down.

A proper tail tie will not loosen as the tail moves. Incorporating the switch into the tie prevents the rope from sliding off the end of the tail. If the tail has been docked or the switch cut short, the tail tie must be modified. A modified quick-release knot is tied at the tail’s base with two or three half hitches made distally, creating an effective “Chinese finger trap” that prevents the rope from slipping off the bobbed tail. The free end of the rope is secured to the leg or neck as previously described.

SURGICAL POSITION

Surgical Tables

Surgical or tilt tables are convenient and effective for positioning animals for surgery or other procedures that require maximal restraint. Numerous variations are available, but the common theme uses belly bands or squeeze panels and leg wraps to secure the animal to the table. The table is then mechanically or hydraulically tilted until the animal is in lateral or dorsal recumbency. Tilt tables are convenient and offer excellent restraint but may be financially unfeasible unless a large number of surgeries are done to compensate the expense.

Casting

An animal may very effectively be maintained in lateral or dorsal recumbency by casting and rope restraint if no surgery table is available. The major disadvantage is that surgical procedures must be done at or near ground level, which may be inconvenient, uncomfortable, and exhausting, plus make it harder to maintain aseptic technique.

Casting is a technique used to force an animal to lie down (Figure 4.3-4). A loop of rope is placed around the animal’s neck with a bowline knot or a quick-release honda. Some people prefer to run the loop over the neck and between the front legs to prevent undue pressure on the trachea. Two half hitches are placed over the back so that the knots lie against the animal’s spine when tightened. The first half hitch is behind the shoulder, and the second is in the flank, cranial to the udder or caudal to the penis. With the head secured, the rope is pulled with steady pressure until the animal lies down. The rope is tied with a quick-release knot cranial to the second half hitch to maintain rope pressure and keep the animal recumbent. The front and hind legs are bound together with hobbles or ropes. The legs are extended and tied to sturdy supports to secure the animal. Alternatively, for a quick procedure, the hind legs can be tucked under the second half hitch. The animal can be balanced against a wall, between bales of straw, or supported manually if dorsal recumbency is required.