Pregnancy and calving are essential for dairy cows in order for them to keep producing milk and provide the next generation of replacement heifers on dairy operations. Although calving is considered to be one of the most stressful and challenging times for dairy cows, its effects on cow health and performance are still being investigated. During the transition period, the period encompassed between 3 weeks before parturition to 3 weeks after parturition, dairy cows experience several physiological challenges that, if proper management is not in place (e.g., nutrition, cow comfort), can impair their health and performance during lactation. In this period, dairy cows experience a drop in dry matter intake (DMI), which forces them to mobilize body reserves, especially fat tissue (Grummer, 1993). If this drop is excessive, fat tissue metabolites increase metabolic stress and also cause inflammation (LeBlanc, 2014). In addition, high concentration of these metabolites can impair immune function, which in turn increases the risk of infectious diseases in dairy cattle during early lactation (LeBlanc, 2010; 2014).
This drop in DMI not only causes the mobilization of body reserves, but also can cause inadequate consumption of certain minerals, such as calcium, which coupled with the high calcium demands from the initiation of lactation, are risk factors for hypocalcemia, better known as milk fever (Goff and Horst, 1997). Milk fever is the clinical phase of hypocalcemia and can cause important losses in dairy operations (Reinhardt et al., 2011); however, its prevalence has been decreasing (national incidence = 2.8%; USDA, 2014), most likely due to the adoption of preventive management practices during the transition period. Subclinical hypocalcemia, characterized by low blood calcium without expression of clinical signs, is rarely diagnosed or treated; nonetheless, this condition can cause important economic losses since it is a major risk factor for several infectious and metabolic diseases (Reinhardt et al., 2011; Martinez et al., 2014). This is even more startling since more than 50% of the dairy cows in U.S. experience this condition (Reinhardt et al., 2011). During and after calving, cows also experience inflammation and stress that, in excess, can affect their health and performance. For instance, one study reported that cows that developed hypocalcemia experienced higher stress during calving compared to cows that did not (Goff and Horst, 1997). Similarly, another study showed that cows that had metritis in early lactation had greater inflammation around calving compared to cows that did not (Huzzey et al., 2006).
It is clear that calving and the initiation of lactation cause metabolic and physiological challenges in dairy cows. Now the question is: Do cows benefit from anti-inflammatory therapy after calving? The answer may be that with appropriate management during the dry and transition periods, starting from the day of dry-off, pain and inflammation treatment should not be necessary. However, on certain occasions, this approach may be beneficial. Before even talking about cow treatments, it is worth mentioning that every treatment protocol on your operation must be developed and regularly reviewed by your herd veterinarian, without exception. One of the challenges of managing pain in cattle is that currently, there is only one drug approved by the U.S. Food and Drug Administration (FDA) specifically for the treatment of pain, and it is not labeled for use in lactating dairy cattle. However, veterinarians can prescribe drugs that are not labeled for pain treatment in lactating cattle as an extralabel drug use (ELDU; AVMA, 2018), which means that all medications used for pain treatment are considered extra-label treatment and must be prescribed by a veterinarian (AVMA, 2018).
One of the most common classes of drugs used in this manner is non-steroidal anti-inflammatory drugs (NSAID). Flunixin meglumine is a common NSAID used for the treatment of inflammation in cattle. However, negative effects of flunixin meglumine treatment after parturition have been reported, including increased rates of retained placenta, stillbirths, and metritis, as well as decreased milk production (Waelchli et al., 1999; Newby et al., 2017). Therefore, its use for treatment of inflammation after calving is discouraged.