Early and Systematic Observations to Improve the Welfare of the Sick or Compromised Pig
*Disclaimer: The views expressed in this article do not necessarily represent the views of the Animal & Plant Health Inspection Service, the US Department of Agriculture of the United States.
A “compromised animal” has been broadly defined as an animal which is unable to function optimally. Deficiencies in an animal’s well-being may result from changes in their physical, environmental, nutritional, behavioral, or social needs that are not adequately met and these effects may range from a medically treatable condition to one from which recovery is not likely which might require humane euthanasia (1). Early and systematic observation by the stockperson or caretaker will help identify the sick or compromised pig and encourage a timely and appropriate response by following the farm’s treatment protocols and consulting with a veterinarian.
The objectives of this fact sheet include:
- Offer practical ways to evaluate the state of well-being of an individual or groups of pigs.
- Empower the swine worker with useful skills to distinguish between healthy and compromised pigs across life stages from birth to market.
- Provide illustrations and a systematic tool for assessing the well-being of pigs through assessment of the body, eyes/ears/nose, skin/hair, and temperament which can easily be remembered by the acronym B.E.S.T.
B-body, E-eyes/ears/nose, S-skin/hair, T-temperament
To identify sick pigs, it is important to know what a normal, healthy group of pigs should look like. To train yourself to recognize compromised pigs, learn normal health, movement and behavior response for your herd. When walking the pens to check feeders and drinkers, observe normal behavior and contrast that with abnormal or compromised pigs (2,3).
Managing the compromised pig requires not only individual pig attention, but also an awareness of the group’s behavior (4). Initially, try to assess a group of pigs from a distance, before disturbing them (Figure 1), so that they are unaware of your presence and maintain their current behavior patterns. This may involve opening the door slightly, listening for coughing, sneezing or signs of restlessness.
After having made this initial assessment of the animals, enter the building/room quietly with slow smooth motions and scan the pens for (5,6):
- Down or lame animals
- Increased activity or inactivity at waterers (Figure 2a)
- Increased activity or inactivity at feeders (Figure 2b)
- Inactivity, as seen with downer animals
- Ventilation concerns such as cold air drafts or lack of air flow (condensation, fogging).
It is advised that you follow a consistent daily B.E.S.T pattern of observation, thereby setting a reference point from which you can make accurate comparisons in the future.
The B.E.S.T. Approach
A consistent, systematic observation of body condition and conformation should be made from head to tail (Figure 3). When evaluating the head or neck, they should be free from swellings/abscesses or neurological signs, which may include a tilting or frequent shaking of the head. Pigs should be in good body condition and not lame with a representative body condition score of at least a 3/5 (7). A pig with sunken flanks or with the spine, hip bones and ribs showing are experiencing malnutrition due to lack of access to feed or inability to reduced absorption of nutrients which could be caused by parasites or intestinal disease (Figure 4). The only bones that should be somewhat apparent are the shoulder blades. The top-line should be level and not arched (5) (Figure 4).
Animals often communicate pain through their posture. For example, sows due to farrow may exhibit dog-sitting, a greater time spent standing, or an increased number of positional changes due to the discomfort or pain associated with farrowing. An arched back may be a sign of abdominal pain due to diarrhea or a result of efforts to shift weight from a painful foot or lame leg (8). The rump should be free of damage or wounds and relatively clean without signs of discharge which may be associated with infectious disease, parasites, or malnutrition. Pigs should have well-formed feces and be free of diarrhea (9). Rectal prolapses are prone to damage, hemorrhage or cannibalism and may be life-threatening (10). The belly should appear well fed and the underline should be free of unusual swellings (11). Both inguinal and umbilical hernias are also a relatively common condition in pigs in the grower stage. Breeding stock may experience injured genitalia, teats or suffer from udder inflammation called mastitis (12,13).
While watching the body we can observe for normal breathing. Fast respiration or a “thumping” (heavy, abdominal breathing) pattern is correlated to heat stress, poor air quality, or a respiratory disease. Pigs that mouth-breathe, show signs of labored breathing, dog-sitting, sneezing, coughing (including thumping) or wheezing are potentially compromised (14). Joint alignment in the feet and legs is important considering that conformation can affect the function and structure of the pig. Joints and feet should be free of inflammation (redness, heat or swelling) or wounds and appear taut and slender (Figure 4). Observe the hairline at the top of the hoof- wall for any signs of blisters or ulcerations (15). Open sores, cracks, or sole and hoof lesions are painful and can lead to infection and more complicated health problems. These injuries often contribute to an abnormal gait, unwillingness to move or reluctance to stand (16).
Lameness, due to pain, may be observed as favoring a limb or simply the inability to rise and move around (8,17). Lameness may be attributed to injury, environmental problems such as a very slick floor, dietary insufficiencies, disease, or genetics (8,12,13,18-20). Signs of lameness may include a stiff or shortened stride, reduced weight bearing on affected limbs, unwillingness to rise or walk, or trembling (21). Consequently, these problems are a common reason for early culling of grower pigs and sows and may have a negative economic consequence for the producer (8,22,23).
Eyes, ears and nose
Both eyes should be first examined from a distance assessing the conformation, size and position of the globe. Healthy pigs should have bright, open eyes with pink eyelids. Pigs with dull, sunken, cloudy, twitching or irritated eyes are not normal. Excessive redness, inflammation, white or yellow (purulent) discharge, loss of hair, or lack of color around the eye may indicate a sick animal (Figure 5). Purulent discharge (pus) in the tear ducts is commonly seen in cases of respiratory disease resulting in a dark stain generated from the tear duct. Pig’s ears are normally alert and pointed (Figure 5) except in certain breeds such as Landrace. Ears should be devoid of any swellings, parasites or injuries, head shaking from parasite irritation, or injury due to the environment such as abrasive penning materials. Swollen ears may be due to a hematoma resulting from fighting or head shaking (24). The nose should be straight without deviation left or right, cool, and moist without lesions, blisters, bleeding or discharge.
Since pigs don’t talk to caretakers, the ability to assess the animal’s welfare using non-verbal methods an important area of research (8,25,26). Di Giminiani (et al. 2016) assessed changes in facial expressions of piglets undergoing known painful procedures such tail-docking and castration and developed a piglet grimace scale for assessing pain (27). Because pigs will often isolate themselves when in pain, the grimace scale, with training, could provide more rapid pain detection and more prompt treatment response (28).
Skin and hair
van Staaveren et al. (2017) state that skin and tail lesions are among the most frequently cited animal-based indicators of pig welfare and could possibly function as “iceberg indicators”, a small view of a larger problem (29,30). A pig’s skin and hair should be smooth, clean, flat and uniform (Figure 4). Fuzzy hair coat, lumps, bumps, sores, necrosis, pustules/papules, vesicles (clear blisters), scaly skin, bald patches, rough/dull/uneven coat, and reddened or yellow skin may have developed from parasites, infection, fighting, environment, or nutritional deficiencies. Pale or anemic pigs are fairly common due to failure to provide injectable iron at processing or blood loss. Blood loss can occur due to gastric ulcers from off feed events. Additionally, pale skin can often be seen following an Influenza break. Raised skin lesions, a greasy appearance, or bruising are also abnormal. Skin irritation and scratching may eventually lead to either raised areas of skin or cracks, which may become susceptible to bacterial infection.
It may be useful to note the life-stage of the animal, morbidity/mortality in the herd, distribution of lesions, appearance and progression of lesions, and any other clinical signs that exist while making observations (31). In sows, shoulder rubbing and poor body condition has been associated with shoulder sores (32). In sows, excessive wear on the skin can occur near the joint surfaces while in piglets it is primarily seen where there is competition within the litter for functional sow teats. Typically fight or aggression-related lesions, will show parallel lines at the head and neck or near the rump, while lesions from flank biting are generally round and located around the flank. Aggression-behavior due to mixing of animals may cause injuries to gilts and sows including skin lesions, ear, tail and vulva biting and even lameness (33).
Pigs by nature are naturally inquisitive, even when startled or excited. The tail, should be upright without damage, indicating a positive well-being. They should be responsive to their environment with nose in the air and curious. Healthy pigs should not be dull, depressed, apathetic or off-feed. When approached, they may respond to your presence with a vocalized “woof” and then move away as you enter their flight-zone. However, due to their inquisitive nature, they should return shortly to investigate or to observe you from a distance (Figure 6). If they are not observing you or interested in you, try to determine the reason.
Variations in behavior include avoiding social contact, isolation, flank rubbing, and decreased feed intake to name a few examples (34-36). Escape and avoidance behavior have also been used as a measure of pain recorded during a pre- and post-procedural handling period (37). During and immediately after the weaning period, nursery aged piglets may develop several maladaptive behavior patterns such as belly nosing, sucking or chewing on the ears or tails of other pigs. This behavior may result in injury of other pigs and may indicate an early weaning, lack of environmental enrichment, crowding or poor air quality (38,39).
Pigs that are lying on their side and paddling, shaking, or show lack of balance (ataxia) often require immediate care. Trembling, leg shaking, sliding, tail-jerking, vomiting and extensive standing are commonly witnessed in piglets in response to the pain of castration (8,34,40). The process of giving birth is also a source of pain in the sow, which may be observed as trembling, tail flicking, and kicking/pawing at their sides (8).
Environmental temperature is critical in raising pigs (41). Extremes in temperature, such as heat stress, can reach a point where increased respiration or panting does not cool the animal and if prolonged can result in death. Pigs that experience an environment that is too hot will spread out, avoid touching other pigs within the same pen and lay near the waterer. Using a combination of cooling equipment such as sprinklers and fans will relieve heat stress and can improve pig comfort. Pigs exposed to cold air drafts and lower room temperatures will display huddling and piling behavior. Exposure to their lower critical body temperatures increases susceptibility to disease and poor growth performance.
Once compromised animals are identified, it is suggested that the stockperson respond immediately following the farm-specific treatment protocols and veterinarian recommendations to increase the chance of recovery, reduce pig suffering and improve welfare. (7).
While not always pleasant, or easy, responsible care of pigs requires appropriate, timely decisions to be made about treatment, culling, and euthanasia of compromised animals (1). Stockpersons should work with their herd veterinarian to create and implement specific on-farm plans and protocols.
We hope that, in making early and systematic observations of pigs in the production setting, that the B.E.S.T. assessment tool will enable the stockperson to make better decisions when observing either an individual or group of animals (Table 1). These observations will not only improve the welfare of the sick or compromised pig but also help in preventing animal loss.
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