Using Veterinary Ultrasound to Monitor Sows After Farrowing

In modern pig production, the health and productivity of sows after farrowing (giving birth) play a crucial role in determining the survival and growth of piglets. The early postpartum period is a vulnerable time for sows, with complications such as postpartum paralysis and lactation failure posing serious risks to both the sow and her offspring. In recent years, siêu âm thú y—particularly B-mode ultrasonography—has emerged as a practical, non-invasive, and highly valuable tool in identifying and managing postpartum disorders in sows.

Trong bài viết này, we explore how veterinary ultrasound is used to monitor sows after farrowing, focusing on two major conditions: postpartum paralysis and postpartum lactation failure. We also explain how this tool is integrated into routine management practices on commercial pig farms, particularly in countries where precision livestock farming is on the rise.

Understanding Postpartum Paralysis in Sows

Postpartum paralysis, also known in some countries as “downer sow syndrome,” is a sudden-onset neurological disorder that typically occurs within 2–5 days after farrowing. It is characterized by loss of sensation, inability to stand, and eventual complete hind limb paralysis. While it can occur in sows of all ages and parities, older, high-parity sows are often at higher risk.

Causes and Risk Factors

The underlying causes of postpartum paralysis are multifactorial and often related to nutritional and metabolic imbalances. Key contributing factors include:

• Calcium and phosphorus deficiency: During lactation, sows excrete large amounts of calcium and phosphorus into their milk. If their diet is deficient or the calcium-to-phosphorus ratio is imbalanced, they may develop hypocalcemia and skeletal demineralization, which weakens bones and nerves.

• Vitamin D and glucose deficiency: Lack of essential nutrients like glucose or vitamin D may impair muscle and nerve function.

• Poor housing conditions: Cold, wet, or slippery farrowing pens can contribute to injuries or nerve compression.

• Genetic predisposition or previous farrowing difficulties.

Ultrasound Application in Diagnosis

Veterinary ultrasound can be used to rule out other conditions that may mimic paralysis, such as musculoskeletal injuries, abscesses, uterine infections, or retained placentas. A transabdominal scan can detect:

• Uterine distension or fluid accumulation, suggesting postpartum metritis.

• Abnormalities in the pelvic region that may compress nerves.

• Signs of mineral deposition or bone thinning in the spine and pelvis.

Additionally, by scanning muscle tone and movement response under the skin, veterinarians can assess the severity of nerve or muscle dysfunction.

Clinical Signs and Outcomes

Affected sows typically show:

• Extreme lethargy and refusal to eat.

• Dry feces and discolored urine due to dehydration or metabolic stress.

• Weak or wobbly gait, eventually leading to complete hindquarter paralysis.

• Reduced or ceased milk production, which endangers piglets.

Without intervention, the sow deteriorates over days or weeks, eventually dying from exhaustion or being culled. This highlights the need for early detection and intervention.

Treatment and Prevention

In Western pig farming systems, prevention through nutrition is key. Many farms implement the following strategies:

• Provide calcium and phosphorus supplements during late gestation and lactation.

• Maintain a balanced calcium-to-phosphorus ratio (usually around 1.5:1).

• Ensure sows receive high-energy feed rich in glucose and vitamins before and after farrowing.

• Keep farrowing areas clean, dry, and warm, especially in colder climates.

For sows already showing signs of paralysis, common treatment options include:

• Oral laxatives (e.g., magnesium sulfate) to treat constipation.

• Intravenous calcium gluconate injections to restore calcium levels.

• Combined glucose and calcium chloride drips to improve energy metabolism.

• Sodium phosphate injections for correcting hypophosphatemia.

The use of ultrasound during and after treatment helps track internal recovery, such as uterine involution and fluid clearance, ensuring that therapy is effective.

Monitoring Postpartum Lactation Failure

Lactation failure or agalactia is another significant postpartum issue. It often occurs within the first 1–3 days after farrowing and leads to insufficient or absent milk production. This is a critical concern, as piglets rely exclusively on colostrum and milk for nutrition and immunity during their first weeks of life.

Causes and Contributing Factors

Lactation failure is typically caused by:

• Poor nutrition: Diets lacking sufficient protein, energy, vitamins (especially vitamin A and E), or trace elements like zinc and selenium.

• Infectious diseases: Conditions like postpartum metritis or mastitis can impair mammary gland function.

• Poor mammary development: In gilts or young sows bred too early, mammary tissue may be underdeveloped.

• Stress or environmental discomfort: Overcrowding, high temperatures, or lack of water can suppress lactation hormones.

Using Ultrasound to Evaluate Mammary Glands

Veterinary ultrasound provides a clear image of mammary gland health and function. By scanning the udder, one can assess:

• Glandular tissue density and uniformity.

• Milk duct blockage or inflammation.

• Signs of mastitis such as hypoechoic areas or fluid-filled cavities.

• Blood flow to the udder using Doppler features (in advanced systems).

In cases of lactation failure, these ultrasound images help distinguish between primary agalactia (no milk production) and secondary causes such as mastitis or systemic infection.

Symptoms and Impact on Piglets

Sows with lactation failure may still exhibit normal nursing behavior, but piglets are often restless, constantly suckling without satisfaction. Symptoms in piglets include:

• Poor weight gain.

• Loud squealing or agitation.

• Visible ribcages and sunken bellies.

• Higher mortality within the first week.

Veterinarians can use ultrasound not just to confirm udder issues but also to examine the uterus for retained placenta or fluid, which may indirectly affect lactation.

Therapeutic Interventions

Treatment of lactation failure typically includes:

• Hormonal therapy: Oral or injectable galactagogues (e.g., domperidone or metoclopramide) stimulate milk let-down.

• Traditional remedies: In some regions, feeding sows with pig placenta broth or herbal mixtures (e.g., milk thistle, fennel, or traditional Chinese medicine formulations) is practiced.

• Antibiotics: For sows with suspected bacterial mastitis or uterine infection, broad-spectrum antibiotics like oxytetracycline or amoxicillin may be prescribed.

• Supportive care: Maintain optimal hydration, reduce stress, and ensure constant feed availability.

Ultrasound Monitoring Beyond Disease

Beyond disease management, veterinary ultrasound is being increasingly adopted as a routine postpartum monitoring tool in progressive swine operations, especially in North America and parts of Europe. Some of the regular assessments include:

• Uterine involution: Ensuring the uterus is returning to pre-pregnancy size.

• Retained placenta detection: Identifying any remaining fetal membranes that may cause infection.

• Fluid clearance: Monitoring any abnormal fluid retention.

• Early estrus signs: Detecting when sows are ready for the next breeding cycle.

The ability to perform these evaluations without sedation or invasive procedures makes ultrasound highly suited for sow barns, where minimal disruption is critical for lactation and piglet care.

Benefits of Ultrasound in Postpartum Sow Care

From international perspectives—whether in China, Đức, the U.S., or Denmark—veterinary ultrasound has become an important element in sow reproductive management. Key benefits include:

• Non-invasive and pain-free.

• Quick and real-time diagnosis.

• Cost-effective in preventing severe complications.

• Improves sow welfare and piglet survival rates.

• Reduces unnecessary culling and treatment costs.

Kết thúc

The postpartum period is one of the most challenging times in a sow’s life, with immense demands on her body and metabolism. By integrating veterinary ultrasound into routine post-farrowing checks, farmers and veterinarians can detect early warning signs of complications like paralysis and lactation failure, act promptly, and improve outcomes for both sows and their litters.

As precision livestock farming continues to evolve, the role of diagnostic tools such as B-mode ultrasound will become increasingly vital. Whether used in smallholder operations or large-scale commercial farms, ultrasound offers a reliable, accessible, and welfare-friendly method of postpartum monitoring—ensuring healthier sows, stronger piglets, and more profitable swine production.