Aspirin After Calving: What About Udder Heath?

By Adrian A Barragan

It is well-known that around calving dairy cows are challenged by different physiological events. One of these main challenges is the systemic inflammatory process, that although normal, when exacerbated can have severe negative effects in a cow's health and performance. Treatment with anti-inflammatory drugs, such as aspirin, after calving has shown to have positive effects in cow production, uterine health, and fertility; but what about udder health?

During the production cycle, there are specific practices that challenge udder health in dairy cows; one of these practices is drying cows off. It is well known that this practice is necessary for udder tissue remodeling and preparing the mammary gland for the following lactation. Dairy cows that have a short dry period (<35 days) or no dry period at all have lower milk production, 4.5% or 19% respectively, compared to cows that have a standard dry period length (40-60 days). Similarly, having an extended dry period (>80 days) also negatively affects milk, and milk production and components, and can also cause over conditioning of cows.   

Although necessary, as mentioned above, drying cows off is a risk factor for subclinical and clinical mastitis as it increases the internal pressure in the udder cistern causing milk leakage, opening a direct path to the udder for pathogens. Recently, it was reported that cows with a higher milk production at dry-off (>33 lb./d) are more likely to have milk leakage, delayed formation of the keratin plug in the teat canal, and higher systemic inflammation. To address these issues, practices to decrease milk yield at dry-off, such as gradual milk cessation and diet changes, have been proposed. A few management practices, such as switching milking frequency from 3x to 1x the week before dry-off or a combination of decreasing daily milk frequency and intermittent milking days, have been studied and have shown to significantly decrease cow milk yield at dry off. However, the effects of these practices on cow metabolism are not yet fully understood, and therefore, caution should be exercise when implementing. 

Another practice that may help cows cope with these challenges is the use of anti-inflammatory therapy. Although there is a lack of studies assessing the effects of anti-inflammatory treatment of cows at dry-off, post-partum anti-inflammatory treatment has shown to have positive effects on udder health. In a research study where cows were treated with aspirin (daily drenches) or meloxicam (oral capsules) for three days after calving, authors reported that treated cows had significantly lower somatic cell scores during several months after calving compared to placebo cows (Carpenter et al., 2016). Similarly, aspirin trials conducted in collaboration with Penn State, where cows were treated with aspirin boluses (every 12 h) for 2 days after calving, we found that treated cows had around 43,000 cells/mL less somatic cell counts during the first 5 DHIA tests when compared to placebo cows (Barragan et al., 2020).

Well-established and necessary farm practices, such as drying off cows, can challenge udder health. Recent research has shown that cows with higher milk yield at dry off (>33 lb./d) are at a higher risk for having mastitis and have higher systemic inflammation compared to cows with lower milk yield. Managing cows to decrease their milk production during the week before dry-off may aid at preventing udder diseases. After calving, modulation of inflammation with anti-inflammatory drugs, such as aspirin, may also be beneficial at improving udder health during the early lactation period when udder health is challenged the most.