Replacement & Disease Risk: Higher turnover of breeding stock increases costs and the risk of introducing new diseases.
Breeding Schedule Disruptions: Unreliable pool of pigs affects animal flow throughout the growing-finishing areas.
Reproductive Failures: Lame sows often have lower numbers of pigs born alive, higher stillborn rates, and decreased subsequent litter sizes due to poor lactation feed intake.
Piglet Welfare: Increased preweaning mortality caused by clumsy or lame sows treading on or crushing piglets.
Salvage Value: Decreased value of culled sows due to excessive weight loss and higher mortality rates.
Metabolic Bone Disease: Osteomalacia and Osteoporosis:
Osteomalacia: Characterized by unmineralized or poorly mineralized bone during remodeling.
Osteoporosis: Loss of established bone minerals and mass through osteolysis; often occurs in first- or second-parity sows.
Pathogenesis: Driven by inadequate or unbalanced Calcium, Phosphorus, or Vitamin D; worsened by the high calcium demands of milk secretion during lactation.
Clinical Presentation: Acute lameness, paraplegia, or fractures (femur, humerus, lumbar vertebrae, ribs) during late gestation, lactation, or post-weaning.
Risk Factors: Limited exercise and short recovery times (less than 7 days) between breeding cycles.
Osteomyelitis and Spinal Abscesses:
Etiology: Often secondary to vertebral fractures or "showering" of organisms from superficial wounds or respiratory/GI tracts.
Primary Agent:Trueperella pyogenes is the most frequent cause of suppuration and abscesses.
Clinical Signs: Nonspecific lameness, ataxia, hypermetria, or bilateral flaccid paralysis of the pelvic limbs.
Prognosis: Recovery is highly unlikely; affected animals should be culled.
Osteochondrosis (OC) and Leg Weakness Syndrome (DJD):
Definition: The major cause of degenerative joint disease (DJD) and culling in swine.
Pathogenesis: A developmental defect in growth plate or articular cartilage; necrotic cartilage leads to clefting (osteochondritis dissecans), pain, and bone exposure.
Clinical Indicators (Specific Gaits):
"Knee walking": Indicates severe DJD in the elbows.
"Elephant on a ball" stance: Indicates DJD in the stifles, tarsi, or intervertebral joints.
Hopping/Collapse: Associated with separation of the ischial tuberosity.
Risk Factors: Genetic predisposition (certain boars); fastest-growing, most muscular, and heaviest pigs are at higher risk.
Foot Disorders:
Prevalence: High (20%–68% morbidity); significantly impacts productivity and longevity.
Common Lesions: Heel erosions, white line separation, toe/sole erosions, and vertical hoof wall cracks.
Infectious Agents: Mixed infections involving Trueperella pyogenes, Fusobacterium necrophorum, and various cocci.
Management Challenges: Effectiveness of systemic penicillin is unproven and decreases as the lesion becomes chronic.
Trauma and Environmental Risks:
Social Stressors: Fighting during mixing to establish social order; mounting by other sows in estrus.
Environmental Hazards: Entrapment in farrowing crate bars; slippery floors; tearing of dewclaws on concrete slats.
Handling: Anxiety in gilts during movement into farrowing facilities.
Prevention and Strategic Gilt Development:
Selection: Cull gilts with conformational abnormalities or abnormal ambulation.
Environment: Provide at least 1.1 square meters of space per animal; use nonslip, clean flooring; resurface abrasive areas.
Nutrition: Ensure adequately fortified rations; supplement with biotin and trace minerals to enhance hoof strength.
Strategy: Purchase gilts at < 75 kg; restrict feed intake to slow growth; wait until 8–10 months of age for first breeding.