The Importance of a Quality Teat Line
The Importance of a Quality Teat Line
TL;DR ~ A sow’s teat line determines how many piglets she can raise, how evenly they grow, and how long she stays productive. Teat number and quality are moderately heritable, so good teat lines produce better producers while poor teat lines can pass defects.
A superior quality line includes 12+ functional teats, 6×6 symmetry, good spacing, downward orientation, and no blind, pin, fused, or ectopic/off-line teats.
Extra teats behind (Caudal - toward the hind legs) the main 12 are normal biological variation and not faults.
Off-line teats above (dorsal, not cranial) the mammary ridge are faults.
Selecting for strong teat lines improves piglet survival, weaning weights, maternal performance, and sow longevity—especially under pasture-based, low-intervention systems. If you want predictable results in future generations, teat-line quality must be a core selection trait.
When we talk about breeding Red Wattles, conversations often drift toward meat quality, growth rate, temperament, conformation, or color genetics. Those matter — but nothing affects long-term herd improvement more quietly, or more powerfully, than a reliable teat line.
A sow’s teat line is her factory. It’s the foundation of every litter she’ll raise in her lifetime.
While we remain committed to judging the whole hog in balance — especially in a rare breed with limited genetics, where we can’t afford to let the perfect become the enemy of the good — teat line is still a key area to prioritize. A consistent, functional teat line produces pigs that reliably perform, even under pasture-based, low-intervention conditions.
Why Teat Count and Placement Matter: Piglets nurse non-stop in their first weeks of life. A sow with a clean, balanced teat line allows every piglet to nurse efficiently and consistently.
More functional teats = more piglets raised
- Functional teats directly influence:
- Litter survival
- Piglet uniformity
- Weaning weights
- Sow longevity and udder health, including:
- Less piglet competition
- Reduced mastitis risk
- Balanced gland use (reduced gland stress)
- Reduce stress hormones through calmer nursing
- Helps sow maintain body condition
- Improve maternal performance metrics
- Produce daughters who also last longer (generational longevity)
A sow with 12 or more, well-spaced, downward-facing teats can more easily raise a full litter without relying on pan feeding or piglet shuffling.
Teat lines are moderately heritable: This isn’t speculation — it’s some of the oldest documented facts in swine genetics. Total teat number, teat spacing, and teat defects such as blind or inverted teats all have moderate heritability.
This means:
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- Selecting for good teat lines produces measurable improvement.
- Defects such as blind or off-line teats absolutely travel through bloodlines.
- A boar’s teat line matters just as much as a gilt’s.
“Moderately heritable” means genetics play a strong role — but not the only role.
Developmental biology: Teats form along the mammary ridge very early in gestation. Like most polygenic developmental traits, mammary ridge development includes natural variation that is not strictly environmental and not strictly genetic.
Non-genetic influences include:
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- Uterine horn crowding
- Embryo position
- Placental blood flow differences
- Hormonal environment at the time the mammary ridge forms
(These factors explain why teat number and placement are not “highly heritable” — but still respond well to selection.)
What Makes a Teat Line ‘Quality’?
- A registrable breeding-quality teat line should show:
- Minimum of 12 strong, functional teats
- Symmetry: at least number on each side, 6+ x 6+
- This shows the mammary ridge developed correctly
- This predicts daughters will also have stable, symmetrical teat lines
- Spacing: teats far enough apart for piglets to latch comfortably
- Downward, not sideways or inverted orientation
- No double, blind, or pin teats
- A single weak teat isn’t the end of the world — but two or more is a red flag that should not be carried forward in breeding stock.
- You don’t need perfect mirror-image symmetry for a pig to raise a litter.
- You do need symmetry if you want predictability, heritable stability, and consistency in future generations
- Defining symmetry in teat lines:
- Symmetry matters for the core 12 teats
- Fully formed, extra teats, in the mammary line, that don’t disrupt the 12, are a positive because they increase the overall teat count.
- Posterior extras are generally harmless.
- These are a developmental timeline issue, not a defect
- Pig teats form along the mammary ridge which develops front to back.
- The ‘hind teats’ may continue to develop and ‘catch up’ over the first few weeks.
- This show potential for a longer teat line
- The mammary ridge has a fixed starting point, but a flexible ending point.
- Ectopic, dorsal, or off-line teats should be considered a fault.
- This is a teat outside the normal mammary ridge
- Teats that are not functional such as blind teats or pin teats should be considered a fault.
The Red Wattle Breed and Teat Line Expectations: Red Wattles—being a maternal, pasture-based breed—thrive when the sow can raise her litter with minimal human intervention. Because our breed is pasture-based and naturally hardy, self-sufficiency is part of the breed identity, and teat quality plays a major role in that.