Fat and Obese Cows: Common Causes and Treatment

Both dairy cattle and beef cattle can suffer from being too fat, also known as over-conditioning. Common causes include high milk production, pregnancy and an unbalanced diet. Treatment requires changing feeds and managing specific cattle.

It is critical to diagnose and treat over-conditioning in cows and to practice preventative methods to keep your cows fit and in an optimal body condition score (BCS) range.

Fat cows will cost you at calving time. Just as having thin cows can be problematic for conception, fat cows and especially young heifers will have trouble conceiving and will likely experience problems while calving.

Beef cows sent to slaughter may have heavier hanging weights, but all that excess fat cover can cost you at the packer who gives discounts on overweight cattle.

There are many reasons for bovines to be overweight. This article will discuss the common causes of obesity in cows, the ramifications of allowing cows to remain in an over-conditioned state, and how to treat and prevent these health issues.


There are many culprits, both genetic and environmental that can lead to obesity in cows.

Milk Production

The modern dairy cow of today has an average milk production of 20 thousand pounds each lactation period. This increased milk production places a large strain on the cow’s body as increased blood flow to the liver is required to dilute hormones in her blood, which causes estrus to occur.

Delayed estrus and poor reproductive performance are common in cows that are obese.

To combat the constant drain of energy required to cycle blood properly for lactation purposes, cows will eat more in an attempt to create a positive energy balance. When lactation slows, cows continue to eat the same amount of feed as they were at the height of their lactation, which causes weight gain and can lead to obesity.

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Breeding and Calf Size

Cows at the time of breeding will pass on genetic material to their calves as they are being formed. The cow’s condition at this critical time will determine the size of the calf more than her size and feed intake during the last month of her pregnancy.

If a cow is in an obese state at the time of mating, and she continues to gain weight during her pregnancy, fat will build up within her pelvis. This extra fat narrows the already small birth canal, which greatly increases the likelihood of tears occurring and increases the risk of infections and calving complications.

It is also more likely for a cow with excess body weight to produce offspring with metabolic disorders and excess body fat. This is why it is critical to treat obesity prior to mating.

Fat Cow Syndrome

Fat Cow Syndrome occurs when there are reproductive conditions, metabolic and digestive processes, and infectious diseases affecting obese periparturient cows.

an obese cow standing on grass

This syndrome stems from an unbalanced diet allowing excessive consumption and poor feeding programs, especially when supplementation of excess energy sources such as corn silage and concentrates are given during the dry period, close to calving time.

Cows will gain excess weight as a result and be susceptible to a large number of health problems including ketosis, milk fever, placenta retention, mastitis and metritis. It even increases the chance of dying.


There is no perfect treatment for obese cows, but there are management methods that can greatly reduce the chances of having obese cows, and help overweight cows in your herd to reduce body fat percentage.

BCS Management

Managing BCS is incredibly important, particularly in the dry period. Cows with higher BCS in the weeks leading up to calving eat 50% less feed in comparison with the typical 30% drop with their more fit peers.

This is not good because in early lactation and during calving, obese cows must draw out more energy from their bodies to function, and some of them aren’t able to have proper mobilization of their resources in this critical time which endangers both cow and calf.

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According to this study on fat cows and fertility, “Cows classified as fat showed weaker relationships with contemporary fertility compared with BCS”.

This is why BCS management is essential and must be managed during both the wet and the dry period.

It is recommended to try and achieve a BCS score of 3.5 at dry-off, retaining this score throughout the drying-off period to lessen the chance of fat cow syndrome. Lactating cows at the height of milk production should not have their BCS drop to less than 2.5 because of weight loss.

In order to manage BCS, the following steps should be taken:

  • Don’t allow cows to enter the dry period over-conditioned – manage late-lactation cows by having an early dry-off or offer them a diet of low-energy dry cow feed.
  • Change feed to a higher energy, high-quality feed 3 weeks before calving in cows that have been dried off early
  • Ensure plenty of space is given inside dry pens, with bunk space, fresh water, and comfortable beds for laying down
  • If it is feasible to do so, separate the older cows from the first-time heifers
  • Immediately after calving, maximize feed intake to return cows to positive energy balance, which will help them regulate their hormones and cycle quickly

Feeding Strategy

Having an energy intake strategy that is closely in tune with the biological processes of cows is important in managing weight.

According to research on metabolic diseases, “Feeding strategy is recommended to restore lost body condition during late lactation. Not only will this practice help avoid severely overweight cows, but feed conversion into body tissue is more efficient during late lactation, compared to the dry period.”

It is important to balance nutrients as a cow’s intake needs will vary significantly throughout the year according to estrus cycle, pregnancy status, and age. Working with a knowledgeable veterinarian will help producers strategize and adapt to these changes effectively while keeping cows healthy.

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Offering supplemental vitamins and minerals can help balance the nutritional needs of fat cows. These supplements should have balanced protein and energy and include the following:

  • Calcium
  • Phosphorus
  • Selenium

Ramifications of Not Treating Obesity in Cows

Treating obesity in cows is incredibly important, not only for their health but for the sustainability of the herd and the profitability of the producer.

If obese cows aren’t treated, and preventative measures are not taken, the following conditions are likely to occur.

  • Cows are more likely to have mastitis and retained placentas during calving
  • Fatter cows with a BCS of 4 or more are 75% more likely to lose condition in the drying-off period
  • Prone to breeding season delays, lengthier gestation, and delays in lactation
  • Excess fat leads to narrow birth canals which are prone to vaginal tears and infection
  • The incidence of infectious disease occurrence is increased when metabolic diseases are left untreated
  • Stress stemming from metabolic issues can reduce immune system functioning, leading to less milk production and fertility issues
  • Untreated obesity complications can cause death in up to 25 percent of a herd over the course of a single year
  • The postpartum (calving interval) will be extended in obese cows, causing late estrus and is directly related to body fat percentage
  • Cows that are obese produce excess carcass waste which means lower yields and less lean, high-priced cuts to sell
  • Fat cows are more likely to experience heat stress
  • Obesity in cows leads to founder (laminitis) which can cause walking and gait issues

How Common Are Obese Cows?

Obese cows can occur in both dairy herds and beef herds though it is more likely to occur in feedlots than in grass-fed cattle. The incidence of fat cow syndrome is higher now than ever before because cattle are being selected for large size, and higher milk production, which makes them more likely to be over-conditioned.

If cows are being fed properly, and their BCS is being monitored regularly, it is unlikely for obesity and obesity complications to occur.

If more than 5% of a herd is obese or dying from obesity-related illness or disease, a veterinarian should be consulted and feed management practices should be adjusted accordingly.

Christina Pichler

A longtime resident of Southern California, Christina spent her childhood summers on a farm, raising and caring for cows owned by her grandparents, which prompted a lifelong love of cows, and other farm animals. Christina is passionate about writing, having written hundreds of articles for well-known websites, and uses her English degree in service of her love for animal welfare, most recently taking on a writing position at Cow Care Taker in 2022.

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