‘Grass-related’ edemas appear quickly and generally should resolve quite easily.
Swellings called ‘Edemas’, are due to fluid becoming trapped within various tissues. Because gravity causes fluid to follow the path of least resistance, edemas usually occur in the lower limbs, under-belly and/or sheath. Sometimes they can be observed in odd places like the cheeks (‘chipmunk cheeks’).
Geldings will often get a swollen sheath and some horses and ponies will develop a ‘ventral edema’ as in the picture below.
They are frequently closely associated with either current or impending laminitic episodes. (It is very interesting that the digital cushion within the hoof capsule is made of similar tissue to the crest of the neck).
Note we are not talking here about swellings associated with injuries. Also be aware that some edemas are potentially life threatening, if they are not resolved within a few days, call the vet!
Grass Related Edemas can be multi-factorial but ultimately are a related to one or more of the following: Lack of sodium relative to water intake the high water content of wet, lush grass can cause a temporary low sodium: water ratio Low protein levels in the blood (particularly albumin) which precipitates the peripheral capillaries leaking fluid. This is a downstream effect of changes in the grass. Albumin is a protein made by your liver. Albumin helps keep fluid in your bloodstream so it doesn't leak into other tissues. It is also carries various substances throughout your body, including hormones, vitamins, and enzymes.
Other Micro-nutrient deficiencies
contribute to ‘vascular dysfunction’ (a condition in which normal blood flow is compromised leading to 'overperfusion or underperfusion').
‘Grass related’ edemas will be the same temperature as the non-swollen, surrounding tissues and are not painful to touch. Apart from the crest of the neck they will usually be ‘pitting’, meaning if you press your thumb on them the indentation will stay there after you remove it. They are not ‘inflammatory’ swellings which would be hot and painful.
LYMPHEDEMA is also characterized by swelling but is a more serious long-term condition where a blockage of the lymphatic system causes excess fluid to collect in tissues resulting in swelling of the limbs. It is EXTREMELY painful and requires urgent veterinary intervention.
STOCKING UP is another form of swelling which is obviously not a grass related issue as it is associated with inactivity as when the horse is confined to a small area such as a stable. Constant motion is an integral part of the circulatory system, ensuring that fluids are pumped back up the limbs. Horses stock up in hind limbs because these are furthest away from the heart.
WHAT TO DO: Usually these edema’s will resolve on their own once the grass ‘settles down’ but meantime if the condition persists make sure to:
• Feed lots of hay and add AlleviateGold which has proved very beneficial in resolving edema’s. AlleviateGold can be added to feeds but in order to get sufficient ingested it is easily dissolved and syringed. • Add salt to feeds and not just relying on a salt-lick. Wet, lush grass means increased water intake which will cause metabolic problems if salt isn’t present. • Make sure the horse gets plenty of exercise, movement will promote fluid resorption • Premium MVA (and/or ShapeUp) supply the amino acids which are the building blocks for the manufacture of albumin.