Happy Lines: A Window to Cow Health

Happy Lines: A Window to Cow Health

Happy Lines: A Window to Cow Health
Guest blog by Jim Vanderlinde, Dairyhack

What is the undeniable sign of a person in excellent shape?

That one thing that we can unanimously agree that if you have one you are in excellent health. It’s the one visual marker that is never contested. You don’t need to take their blood pressure, have them list off their family history, and submit a urine sample for confirmation.

Certainly you could make a long list, but the hardest parts to achieve and first area to let go are six pack abs.

I bet you can even remember a time when you had a nice stomach and how now it’s harder and harder to maintain, isn’t it? At first you tried to keep it, and gradually, you started to settle for bigger shirts. It’s scary to admit these things but every time you pass the mirror you can tell. You don’t need anyone else’s confirmation. You certainly don’t need to see a doctor just so they can tell you to exercise more and eat some lettuce.

I bet you can even remember a time when you had a nice stomach

We have all experienced some version of that. The fact that we know what a really healthy person looks like yet we make excuses for our own selves. Your cows are no different. You already work with a nutritionist and a vet for your cattle. You already prescribe when they eat, what they eat, when they go to work, and what they sleep on. So what is your report card? How can you tell if it is all going right without seeing any stats like milk production and reproduction performance?

Even if you are on a farm for the very first time there is one cardinal sign, that without a shadow of a doubt, will clue you into how the herd is fed and cared for. An instant report card from the past several months of nutrition and husbandry that you can spot at the blink of an eye.

Happy lines.

Happy lines are not a myth. They do exist. Not everyone can agree on exactly what they do or how they are formed, but the general consensus is if you see happy lines you have happy cows.

What are happy lines?

For hundreds of years, before pedigrees, before milk testing, before genomics, cattle have been selected based on hair coat condition. You are well aware that healthy, shiny, clean hair coats are only on the healthiest cows. Happy lines are the horizontal folds across the ribs typically on the middle to lower third of the rib cage. Chances are you have seen them and just passed them off as a fat cow, but they have a story to tell

Happy lines on a bull.jpg
Can you see at least four happy lines on this bull?

Are happy lines muscle or fat?

There is some belief that these lines are a conglomerate of skin muscles and are only visible when the cow has a full rumen and a shiny haircoat. Steve Campbell, a bovine linear measurement consultant, believes these lines are a glandular expression of peak nutrition and health. In Mr. Campbell’s line of work, he predicts future performance based on reading adrenal swirls in hair coats and linear measurements of key performance indicators, like relation of length of top line to heart girth.

From all appearances happy lines are hard ridges in the skin. The bigger ones you can easily grip and the smaller ones feel like running your hand over a pencil lodged in the skin.

Glandular expression wasn’t enough of an answer for me so I went further. I came across this statement from Dr. Paul Dettloff. Dr. Detloff is the consulting staff veterinarian for the CROPP Cooperative

Happy lines are not a myth. They do exist.

According to Dr. Dettloff-

“Lines may appear in the mid-thoracic region. These are known as happy lines and are the sign of a healthy animal on a high-forage diet. What these lines are, he said, are deposits of volatile fatty acids, high in acetic and propionic acid, with little butyric acid.”

Now, pay attention here, because that is a potentially very powerful statement on what is going on inside the cow that you can physically see on the outside of the cow.

I contacted Dr. Dettloff directly to confirm this statement. He still stands by it. He is not sure of the exact ratios of volatile fatty acids that make up the happy lines but he does figure they play a large role. For myself, I don’t quite understand how volatile fatty acids escape the rumen and lodge themselves in the skin. Let’s set that aside for a moment, and focus on what we do know about rumen function. We know a healthy rumen would be higher in volatile fatty acids as rumen pH comes closer to 7.

happy lines pH.jpg
This graph from the Australian Veterinary Association shows the levels of Volatile Fatty Acids at different rumen pH levels.

If Dr. Dettloff’s comments are correct that happy lines are made up of volatile fatty acids, high in acetic and propionic acid, with little butyric acid then happy lines should be a direct correlation to rumen pH.

We know that rumen pH needs to be between 6 and 7 for optimal forage digestion. Once you add silages and grains to the mix the buffering capacity of the saliva and volatile fatty acids the cow produces herself can be compromised.

As more grain and silage is fed it is possible to drive rumen pH low enough that lactic acid starts to be produced by the rumen. Now- get this- lactic acid is known to be ten times stronger than the three main volatile fatty acids that are present in normal rumen fermentation. This is why sudden feed changes can wipe out the good rumen bacteria in a hurry.

As lactic acid production increases from a low rumen pH, the cow can no longer balance the rumen herself. This is when you see her go for the free choice sodium bicarb. This is where you start to head down the road of acidosis.

Butterfat production.

We can all agree that breed can influence butterfat, but feeding also is a large player. This explains why we can see a wide variety in fat test between farms that milk the same breed. With those assumptions in mind that a cow with happy lines has an ideal rumen environment, and she is producing plenty of acetic acid to aid in forage digestion. We should also be able to draw the conclusion that cows with happy lines should be above average for butterfat test.

Acetic acid is used to produce over half of the butterfat the cow makes. This is why long stem dry hay is always thought of to improve butterfat tests. In order to have a high butterfat test you need a balanced rumen pH. With a balanced rumen pH you get lots of acetic acid production and the cow can convert to a higher fat test.

happy lined grass fed beef Florida.JPG
Grass fed Florida beef - photo by Mace Bauer

Happy lines are almost always thought of as only being found in grazing herds. It makes perfect sense that well managed grazing herds should exhibit more signs of happy lines than their confined counterparts. They simply eat less stored grains and silage that could potentially drive rumen pH away from the ideal 6-7 range.

So happy lines could be an indicator of rumen pH. That’s nice, but that doesn’t explain why we see more prominent happy lines in well managed grazed cattle than we do in well managed, confined, TMR fed cattle.

happy lines dry cow.png
This is a dry cow housed in a bedded pack system with no outside access. Can you see her happy lines?

The truth is they can be found in all herds, not just cows on grass based diets. When asked to explain happy lines, Dr. Hue Karreman admits that “they are also known as “health stripes” on the healthy, shiny cow. They are related to essential fatty acids of the cows. They can be seen in totally [confined] as well as organic grazed herds and are based on good nutrition.”

Ok, so we have our first disagreement.

Vets are like that.

Dr. Dettloff is citing volatile fatty acids and Dr. Karreman is calling them essential fatty acids. Volatile fatty acids are produced in the rumen. Essential fatty acids are not. Essential fatty acids are your Omega-3 and Omega-6 fatty acids. Essential fatty acids are not naturally produced by the cow. These are altered by what she eats. Typically, essential fatty acids come from your vegetable oil products like soybeans and cottonseed. Rumen microbes turn these into saturated fats. For essential fatty acids to escape the rumen microbes some must be bypassing the rumen. We know that diet affects the ratios of Omega-3 and Omega-6 but we don’t know if they directly correlate to happy lines.

happy lines in free stall environment.jpg
Happy lines on a cow in a free stall environment

Well managed confined cattle do show signs of happy lines. They are just not as distinct. You have to look close. Once you train your eye to spot them you will have no trouble finding them in well managed herds of all types. The cow above doesn’t graze at all, but you can tell by her coat condition and obvious happy lines that she is in good health and on a high plane of nutrition.

Other thoughts on happy lines

There are plenty of myths around happy lines. All of them have a valid belief and they all tie directly to cow health.

Ok, so we have our first disagreement. Vets are like that.

  • Sometimes referred to as protein lines
  • Only extreme fat cows show them
  • More lines are better
  • They demonstrate the ideal ratio of protein to starch in the diet
  • Only see in cows with ideal glandular function
  • Milk of superior taste

I don’t believe any of these are really myths. They can all be related back to a cow in optimum health. A cow doesn’t have to be extremely fat to show happy lines but she does have to be in positive energy balance and gaining condition. Cows with happy lines have felt good for a long time to form those lines.

Happy lines can go away and come back. At least it appears that way. One organic grass-fed producer I interviewed, Rob Moore of NY, USA. Claims his herd has the lowest numbers of happy lines in early spring when the grass is lush and low in energy, but they rebound and become quite noticeable as the season wears on. Dr. Detloff echoed these same sentiments that and organic grass-fed herds will have more pronounced happy lines.

Some of the very earliest methods of selecting cattle are strictly from hair coat and condition. Smooth, shiny hair coats have been the norm well before computers and genomics. Happy lines takes judging a cow by her haircoat a step further. As you have noticed, no one can quite agree how they are formed. It seems unanimous and unquestioned that if you find a herd of cows with these pronounced stripes that extend across the middle of a broadside cow, then she is a happy cow with very astute caretakers.

We can all agree that happy lines gives us a glimpse of what is going on inside the cow’s rumen and a quick guide to her previous nutrition level. This is very similar to how you feel when you can spot someone that works out and eats right to someone who has let themselves go and just opted for a bigger shirt.

For more articles like these and other powerful techniques for Dairy Herd Managers visit Dairyhack.com

Comments (1)


Very interesting article!
I see these Happy lines quite often on (well managed) dry cows. It seems to be a good indicator of rumen health and the farmers I visit in my practice like this new way of looking their cows.
Jean-Luc (french vet)

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