Research Note

Extreme Weight Cycling:

Body Condition, Parities, Immune Risk

Weight cycling — repeated loss and gain of body condition over multiple lactations — occurs in many species and can be extreme in high-producing dairy cows. New research suggests extreme weight cycling affects immune cell activity in adipose tissue and can impact health and fertility in later parities.

Can diet management reduce extreme weight cycling and its potential negative impacts?

Adipose tissue (AT) is the body’s primary rapidly available energy reserve, notes Michigan State’s Dr. Barry Bradford. Its mass fluctuates more dramatically than other tissues with shifts in energy balance. Most cows lose body weight in early lactation, which they regain in later lactation.

“The magnitude of these changes varies dramatically between cows, but can be as high as 30% loss in the first several weeks of lactation. Moreover, as they age, modern high-producing cows may experience increasingly extreme weight cycling.”

As parities add up, repeated cycles of lipolysis and repletion may result in persistent immune cell infiltration and altered adipose tissue (AT) function, which can drive altered immune responses to disease challenges. Adapted from Bradford and Contreras, 2024

“Research in other species shows that both rapid AT lipolysis and AT lipogenesis can promote accumulation of immune cells in AT that change the function of the tissue. So the cow’s AT is not simply an energy reserve, but an active reservoir of immune cells involved in endocrine signaling and immune regulation.”

Bradford points to studies showing that dramatic loss of body condition score (BCS) in early lactation has negative associations with health and reproductive success, although researchers find it “difficult to disentangle BCS from clinical and subclinical diseases that can drive BCS loss.”

Bradford cautions that while weight cycling itself contributes to immune cell accumulation in AT, subclinical disease especially during transition also can increase AT inflammation.

“Given the numerous AT-immune cell connections,” he says, “we can hypothesize that inflamed AT promotes excessive lipolysis and systemic inflammation in response to either metabolic or infectious disease challenges, which ultimately makes the cow less resilient to these disruptions and increasingly so with subsequent parities.”

What to do in terms of diet management?

• Reduce excessive mobilization of AT after calving, starting with BCS management in late lactation coupled with controlled energy diets in the dry period
• Consider adjusting fatty acid supplementation with more oleic acid to help limit lipolysis and enhance lipogenesis in early lactation, thereby limiting AT inflammation
• Look at high-oleic soybeans as a practical means to supply oleic acid to transition cows

For more, see the recently published Cornell paper.

Ultimately, for AT immune cell dynamics, abdominal fat is mostly where it’s at.

Questions?

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