Udder edema is the swelling and visible accumulation of fluid in a cow’s udder at calving, or it may appear a couple of weeks ahead of time in the close-up pen. Fortunately, most distressed cows do not need any producer or vet intervention. That’s because most of these cases disappear on their own, usually after few days of cows being milked.
On the other hand, there are dairy farms that I have visited on my travels that seem to have every other cow come down with udder edema as they enter the milk line. In those situations, the underlying reasons for such problems should be investigated, so preventive action can be taken, particularly in those persistent and damaging cases.
The accompanying photo shows a cow with udder edema on day six of lactation. She is part of a 150-cow dairy herd. The extent of her edema encompasses the entire udder, as well as the excess fluid accumulation seen right in front. The cow could still be milked, but her milk letdown was understandably poor. The producer told me that it took a few days for her udder edema to disappear, but he said that on occasion there were other fresh cows in the herd, which had internal udder damage set in and he eventually culled them.
Where does it come from?
What exactly caused such mild or severe udder edema in this dairy or others is not known. However, there are lots of credible theories that make sense to me. Such notions are backed by dairy producers, veterinarians and sound scientific research which dictates that common udder edema is a combination of parity of cow, metabolic changes prior to calving, genetics as well as inadequate pre-calving and/or post-calving diets.
First-calf heifers with udder edema are good examples of underlying parity, pre-calving metabolism and even genetic reasons. They are often compared to mature cows in this manner, because they are more prone to udder fluid-retention problems since their mammary blood vessel network is still developing. So it is expected that blood circulation in their udders will be significantly limited in the first place. Furthermore, the transference of immunoglobulins from their blood to colostrum may increase vascular hydrostatic pressure, which naturally contributes to leakage of fluids from the bloodstream serum into the udder tissues’ interstitial spaces.
Such microscopic symptoms are eventually seen as visibly enlarged udders in either the close-up dry cows or post-calving pens. This means that a quick barn walk will reveal that edema-filled udders are doughy to the touch and pressing any quarter should result in an indention that will quickly fill itself in, once outside pressure is released.
Fortunately, most people don’t confuse them with udder quarters that are infected with mastitis, where quarters are hard and heat of inflammation is evident.
A change in feeding program
Aside from these helpful physiological reasons, it became obvious to me that inadequate nutrition played a much more substantial role in the udder edema problems that faced this 150-cow dairy. I traced the feeding program back to three major challenges: 1. poor-quality water, high total dissolved solids (TDS) and unacceptable high salinity (sodium); 2. unbalanced close-up dry cow and lactating dairy diets; and 3. high levels of dietary elements of “oxidative stress” — excessive levels of iron, which can lead to cell damage in the udder and increased fluid permeability.
There wasn’t much that I could do to solve the edema problems associated with this dairy farm’s salty and hard water. However, I did start by reformulating the feeding program of the close-up dry cows using the NRC recommendations for dietary energy, fibre, protein, no added salt, and a good dose of antioxidants such as vitamin E @ 3,000 IU, and organic-selenium @ 6 mg per head daily.
Similar dietary changes were also made to the herd’s lactation TMR, mainly in its mineral/vitamin profile where all sodium-laden ingredients were either reduced or removed such as common sodium chloride (table salt), sodium bicarbonate, and dietary potassium chloride (with an equivalent increase in dietary magnesium). Finally, zinc-methionine, 150,000 iu/hd/d of Vitamin A and 2,500 iu/hd/d of Vitamin E were added.
As a result, the high incidence of udder edema in this herd was almost immediately cut down by two-thirds. Those few remaining cases per month became the mild types that notably disappeared after a few days. In the end, this exercise was a good testimony that by investigating the problem and then applying the best nutrition and management tools at our disposal, we were able to take away much of the pressure that was underlying a high incidence of udder edema.