Is Calving Stressful In Dairy Cows.

 By Adrian A Barragan, DVM, MS, PH.D. - Assistant Clinical Professor.

 Pain, inflammation, and stress during the transition period can negatively affect the well-being and performance of dairy cows during early lactation.

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.

An NSAID that has been increasingly used in cattle over the last few years is meloxicam. One study reported that treatment with meloxicam increased milk production and decreased somatic cell counts (Carpenter et al., 2016); while another study reported no effects in milk production or diseases (Newby et al., 2013). Although meloxicam may have some promising features, findings from current studies are conflicting and further research is needed to elucidate its benefits on cow health and performance.

Acetylsalicylic acid, better known as aspirin, is perhaps the most commonly used NSAID in general medicine worldwide (Vane and Botting, 2003). Unfortunately, aspirin products cannot be used in cattle under ELDU rules (Smith et al., 2008). Subsequently, the use of aspirin products in dairy operations is controversial. Nevertheless, aspirin products are an attractive alternative due to their easy administration, short milk and meat withhold, and low cost. Several studies have shown consistent results regarding the benefits of aspirin treatment after calving in dairy cows. For instance, my recent research work has shown that cows treated with aspirin had decreased inflammation and pain, produced more milk (4.4 lbs/d) during the first 30 DIM, and had lower somatic cell counts during the first five DHIA tests compared to cows treated with a placebo (Barragan et al., 2017a, b). Although these results are encouraging, before considering the use of any of these treatments in your operation, you must consult with your veterinarian, who will develop the proper treatment protocol based on drug withdrawal times and the specific condition to be treated.

Pain, inflammation, and stress during the transition period can negatively affect the well-being and performance of dairy cows during early lactation if cows are not well managed. Treatment with certain NSAID may decrease pain and inflammation during this period, improving animal welfare and productivity. However, this approach should be utilized as a temporary strategy, and always with the intervention of your herd veterinarian, while focusing on finding the root issues in transition cow management. Efforts should be aimed at maximizing cow comfort (e.g., heat abatement, low stocking density, optimal nutrition, feed and water availability), while diminishing negative energy balance, stress, and inflammation in the transition cow group.