Many things have to go right — or rather, few things can go wrong — for a cow to successfully transition into a healthy lactation after calving. One area that balancing act applies to is how a cow’s body deals with inflammation in the transition period.
At any point of lactation, inflammation is a natural, protective process to help the body maintain homeostasis, or a stable internal environment. During the end of the dry period, calving, and early lactation, there is not a lot of stability in a cow’s world. First off, parturition is an inflammatory process in itself, said Purdue University’s Rafael Neves, D.V.M., during the Dairy Cattle Reproduction Council Annual Meeting.
On top of that physical trauma, inflammation may result from the social stress, oxidative stress, uterine involution, mastitis, or heat stress that can also occur around calving. While it is hard to pinpoint exactly where or why inflammation occurs in a cow’s body, we know it is happening to some degree. Neves highlighted one study that observed significantly more stillbirths when cows were given a nonsteroidal anti-inflammatory drug (NSAID) when they were moved from the close-up pen to the maternity pen with the intention of helping reduce inflammation. This result illustrates that some level of inflammation is normal and necessary. Problems occur when it becomes more widespread or lasts too long.
Reduce stressors
To be sure, healthy cows will have some level of inflammation after calving. But sometimes, the body’s inflammatory response may not work as intended and the inflammation may become chronic, continued Neves. Cows may experience widespread inflammation for months or even years.
In research settings, the assistant professor said inflammation can be assessed by monitoring inflammatory cytokines and proteins like haptoglobin and fibrinogen. For example, Neves cited research done at Cornell University that measured haptoglobin from more than 1,400 cows on 72 farms during the first 17 days in milk (DIM). Cows with higher levels experienced more metritis, produced less milk, had a lower pregnancy rate, and were more likely to be culled in the first 30 DIM.
It is not currently practical for farms to measure haptoglobin levels or even fibrinogen levels, which Neves said is less expensive in a laboratory setting and still provides an accurate picture of cows that are high or low. Yet, it is useful to know how inflammation occurs so we can take measures that reduce stress and hopefully limit the inflammatory process. Neves’ group is measuring both haptoglobin and fibrinogen in more than 500 cows at 1, 3, 5, and 7 DIM. They have found that both indicators peak at 3 DIM and are higher in first lactation cows compared to older animals.
The costs of excess inflammation can add up quickly in terms of reduced animal performance. If we narrow in on just the reproductive effects, it’s been estimated that a case of metritis costs $513 on average due to lost milk and greater culling. Then there are the fertility effects — even if a herd employs synchronization, research has shown that transition health matters in how quickly those cows become pregnant.
Though much is still unknown about inflammation, we do know that reducing stress can help keep it in check. Neves said cows retain more inflammation when they experience more prepartum pen moves and spend more than 8 hours in the calving pen. Along with other efforts to support cow comfort, avoiding those challenges can help animals move into lactation more smoothly.
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