Sow Health and Milk Production: 3 Health Problems That Reduce Milk Yield in Pigs

As the number of piglets born per sow increases, nutritional requirements and demands on housing and health care also increase. Sows carrying many piglets may experience a negative energy balance around farrowing. Even minor health problems can place additional demands on their energy, reduce feed intake and delay the start of milk production.

Identifying these problems early can help pig farmers investigate the causes of low milk production and improve sow health and performance.

Low milk production after farrowing is a familiar challenge in pig farming. A sow that is ill, recovering from an infection or affected by a chronic health problem may not perform optimally during this period.

Three health problems that can affect milk production in the farrowing pen are:

• Flu infections, including infections associated with PRRS.

• Urinary tract infections.

• Poor foot and hoof health.

Understanding these conditions can help farmers identify potential causes of reduced feed intake and delayed milk production.

Flu is an important potential cause of reduced performance in the farrowing pen. An infection can reduce a sow’s feed intake, affecting her condition and the start of milk production.

Flu is often associated with visible signs such as fever and, in some cases, abortions. However, infection can also occur without obvious symptoms. Blood analyses may reveal antibodies against flu even when sows show no unusual signs of illness.

On large pig farms, flu infections may remain present in the herd over time. Sows infected towards the end of gestation may enter the farrowing pen in poor condition, with reduced feed intake and lower initial milk production.

Diagnosing flu in practice can be difficult, particularly on farms where sows are vaccinated.

Two diagnostic approaches described for investigating flu infections are:

• Paired blood analysis: Take an initial blood sample from affected sows, followed by a second sample three to four weeks later.

• PCR virus testing: Analyse saliva for the presence of the flu virus. Saliva from weaned piglets can also be examined using a cotton cloth to collect the sample.

Testing weaned piglets may help determine whether the infection is also present in this group.

Urinary tract infections can affect sow health and milk production, even when the animals do not appear seriously ill.

Research conducted among sows in Flanders, Belgium, found urinary tract infections in 18% of younger sows and up to 38% of older sows. These figures relate to the research conducted in Flanders and should not be interpreted as prevalence rates for pig farms in Kenya.

Bladder infections are often chronic and may continuously consume a sow’s energy. This can make it more difficult for her to eat adequately in the farrowing pen, preventing milk production from reaching the desired level.

In some cases, the infection can spread to the kidneys, causing serious illness. Urinary tract infections are also associated with an increased likelihood of uterine infections.

Urine sampling can help investigate whether urinary tract infections are affecting sows.

The recommended approach described in the original research is to:

1. Collect urine samples from approximately 20–30 sows.

2. Take samples in the morning, when the sows get up and begin urinating.

3. Give particular attention to older sows around farrowing.

4. Use urine test strips as an initial screening method.

5. Consider laboratory urine cultures to investigate infections more reliably.

Urine test strips can detect nitrite, which is produced by certain bacterial infections, particularly those caused by E. coli. However, the research in Flanders showed that nitrite was present in only about half of the urine samples from sows with urinary tract infections.

This means that a negative nitrite test does not rule out an infection. Laboratory analysis and urine culture can provide further information.

Foot and hoof health is another important factor to consider when investigating low milk production after farrowing.

The condition of sows’ feet varies between farms. Sows with damaged or imperfect claws may suffer from chronic infections, which place additional demands on their energy.

Pain or discomfort associated with poor hoof condition can also make sows less likely to stand up and eat in the farrowing pen. This may continue after farrowing, delaying the start of milk production.

A hoof check can help farmers assess the condition of their sows’ feet and identify potential problems.

Research at the De Heus research farm has investigated the effects of administering minerals, including chelated zinc, on foot health. Research on another farm has examined the effects of foot baths in group housing.

These investigations focus on understanding how different approaches may affect sow foot health.

When a sow produces less milk after farrowing, it is important to investigate the possible underlying causes rather than focusing on milk production alone.

The following checks are based on the health problems discussed in this article:

• Check for flu: Investigate possible infections, including cases where obvious clinical signs are absent.

• Assess urinary tract health: Use urine sampling and consider laboratory analysis when an infection is suspected.

• Inspect feet and hooves: Check for poor hoof condition and possible chronic infections.

• Monitor feed intake: Pay attention to sows that eat less, particularly around farrowing.

• Assess sow condition: Consider whether the sow may be affected by an ongoing illness or recovering from an infection.

These checks can help farmers investigate why milk production is slow to start and identify health problems that may be affecting sow performance.

Why does a sow produce less milk after farrowing?

Reduced milk production may be associated with flu infections, urinary tract infections or poor foot health. These conditions can affect the sow’s energy balance and feed intake, delaying the start of milk production.

Can a sow have flu without showing obvious symptoms?

Yes. The original research describes cases in which blood analyses revealed antibodies against flu even though the sows showed no unusual signs of illness. Further diagnostic testing may be needed to investigate suspected infections.

How can urinary tract infections affect milk production?

Urinary tract infections can place continuous demands on a sow’s energy. Even when a bladder infection does not make the animal appear seriously ill, it may affect her ability to eat adequately in the farrowing pen and reduce milk production.

Why is hoof health important for milk production?

Sows with poor hoof condition may suffer from chronic infections and may be less willing to stand up to eat. Reduced feed intake around farrowing can contribute to a slower start to milk production.

How can farmers investigate urinary tract infections in sows?

Farmers can collect urine samples, particularly from older sows around farrowing. Urine test strips can be used for initial screening, but laboratory analysis and urine cultures may be needed because a negative nitrite test does not rule out an infection.

Identifying the health problems that affect feed intake and milk production is an important step in understanding sow performance.

If you want to learn more about improving the health of your pigs, contact a local De Heus specialist for further assistance.