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.