Milk Production and Suckling Pattern


Anatomy of the Udder

Mammary milk teat openings 2

Mammary gland section

The two glands are illustrated by the two drops of milk above and the two colours side picture

Hormonal Control of Lactation

The two major hormones of lactation are Prolactin (production) and Oxytocin (release), both can be stopped by stressors and toxins from bacteria such as E. coli.

Normal suckling pattern

Once an hour for 20 seconds.  In outdoor sows by day 18 suckling has reduced to every 2 hours, this is not seen in crated sows.


Produced for 5 days.

Absorption through piglets stomach only within the first 12 hours (ideally 6)


Modern sows can produce 12 litres of milk at peak lactation.

Problems with milk let down

Factors than can affect colostrum and milk intake


No milk let down

Nervous or stressed sow.  Defect of the udder

Blind or inverted teat



Chilling reduces colostrum intake.  Chilling reduces swallowed colostrum uptake by the stomach


Teat design

Teat too large for piglet’s mouth.  Blind teats

Non functioning teats


Too many piglets

Inadequate cross-fostering


Weak piglets

Disease i.e. PRRSv,  Parvo etc. Cold, wet piglets


Number of teats

Inadequate for the number of piglets


Birth order

A 10% difference in colostrum availability can occur between the first and last piglet, particularly if farrowing takes a long time


Disease of the sow

Mastitis  Constipation  Metritis  Mycotoxins


Gestation overfeeding

Udder oedema


Crate design

Udder and nipple access restricted by crate design.


Sow feeding curve

No adherence to a feeding curve results in inadequate milk production. 

Inadequate water supply restricts milk production.


Chronic mastitis

Associated with flies, rough surfaces in the farrowing house or damage of the teat and udder by the sow's feet.


Diseases of the mammary gland


Acute Mastitis

Acute mastitis is primarily associated with E. coli but also staphylococcus and/or streptococci.  Accurate diagnosis of the causal agent is complicated by the difficulty in obtaining a suitable sample to investigate.  Note only one mammae within the gland may be diseased.

Clinical signs:

Sow is obviously ill and probably toxic.  She may have discoloured ears.  The udder is hard and reddened particularly in the area infected.  She has a temperature of 40-42C


1 Inject the sow with oxytocin 10 IU

2 Inject antibiotics as prescribed by the vet

3 If the sow is toxic the veterinarian may inject Flunixin intravenously

4 Ensure excellent hygiene of the udder line

5 Provide artificial milk replacement for the piglets.  However, initially leave the piglets on the sow to help remove the infected milk and to give her a will to live

6 Provide the sow with excellent water supplies and consider providing some fresh food

Mastitis acute


  1. Review farrowing house hygiene practices especially the water supply
  2. Review teeth clipping
  3. Review fly controls
  4. Cull infected sows if a herd problem exists

Chronic mastitis

Chronic mastitis is associated with a range of bacteria such as Staphylococcus, Streptococcus, Arcanobacterium pyogenes and Actinobacillus suis. The sow presents with large often multiple lumps in the mammary gland, classically first seen at the end of lactation or in the newly weaned sow.  The sow will generally show no other clinical signs.  The infected gland will be non functional. Once observed, there is no effective treatment.   Review the number of remaining functional teats and programme the sow to enter the cull pool

Mastitis chronic

Udder oedema

Udder oedema is seen in sows and gilts.  This may even be recognised in the dry/gestating sow 20 days prior to farrowing.

Clinical signs:

There is a build up of fluids in the mammary gland with little or no milk let down

The sow shows some discomfort with the glands, which may be large enough to interfere with locomotion

Piglets attempting to use the affected teats will not thrive and may require fostering

Palpation of the gland will reveal that when a thumb is pressed into the udder the depression will take a long time to disappear.

Mammary oedema kr

Predisposing factors:

Majority of udder oedema cases are associated with overweight sows that receive too high a feed plane while pregnant. This is particularly so at the end of pregnancy. 


Individual: Can be difficult.  Inject with oxytocin 5iu every 4 to 6 hours  Provide milk replacer for the piglets


Review feeding practices in the later stages of pregnancy and condition score the sows.

Ensure the water supplies are excellent.  Avoid constipation by providing more fibre before farrowing


Mycotoxicosis – Ergot poisoning

Ergot (Claviceps purpurea) poisoning results in an immature udder – of about 110 days of gestation.  Ergotamine interferes with prolactin production.  Sows present with a flaccid udder and milk production is sparse and non responsive to oxytocin.  Ergot tends to occur on small grains – wheat for example.  Circulation problems and end arterial thrombi occur in finishing pigs

Ergot in wheat

Teat injuries

Teat damage

Teats can be damaged by piglet teeth.  However, teeth clipping is not required to stop damage to the mammary glands.  Ensuring the sow produces plenty of milk will reduce or eliminate the damage.


Teats damage

Particularly the hind teats can be damaged by the hind legs and slats.



Teat necrosis

All new born piglets are born with swollen naturally enlarged teats (and vulvas) associated with maternal oestrogen production during the later stages of parturition.   If the piglets rub their teats on rough flooring, teat necrosis occurs.  This damage can result in poor mammary development.






Supernumerary teats

These can occur sporadically.  They should be avoided in replacement breeding stock.

Mammary teat damage


Teat lesion 02  sw


Mammary teat necrosis


Teats Supernummary