Why We Recommend Checking Each Horse in the Pasture

By John Byrd, DVM

The best part of owning Horsemen’s Laboratory is getting to meet people who share my love of horses and have an interest in their health and welfare. Rene Stone, the Founder of Serenity Stables, is one of those people; she has been a loyal client for many years and has over 25 years of experience in owning and caring for horses.

In addition Rene Stone started the charitable organization, Serenity Stables, from Combat to Calm; it is the culmination of Rene’s dream to provide equine therapy for Veterans struggling with PTSD and TBI. She is an advocate of alternative therapies to help cope and overcome the real struggle associated with Post Traumatic Stress Disorder and Traumatic Brain Injury. Rene also supports the ASPCA and the American Veterans Organization.
Please visit her website to learn more: www.serenitystablesfcc.org
Recently I was studying the history of one of Rene’s horses, Tristan, and I decided to look at Rene’s other horse’s histories as well and discovered how representative of so many small herds of horses their results were. These horses’ results demonstrate just how variable fecal egg counts can be coming from horses all in the same pasture. Furthermore, it demonstrates how some horses in a pasture remain in the low shedder category year after year while other horses in the same pasture continue to be in the high shedder category no matter what you do as far as deworming is concerned.

Chart explanation:

Low shedders are horses with negative samples (no eggs found on counting chamber) plus horses with egg counts of less than 200 strongyle eggs/gm of stool.

Medium shedders are horses that are shedding 200-500 strongyle eggs/gm of stool.

High shedders are the horses that are shedding over 500-strongyle eggs/gm of stool

The chart below demonstrates how the old adage that only one horse in a pasture is all that is needed to be checked to determine if all the horses in the pasture need to be dewormed.

HORSE   #FEC   #Neg    #Pos    #Low       #Med     #High   # >1000    Yrs. Tested   Age

Tristan*   40        14         26        4 (*18)     5            17            6               2010-2017    28
Percent   100%   16%      65%     45%        12.5%    42.5%     15%

Ginger*   12         5          7          2 (*7)       3            2             0                2015-2017    25+
Percent   100%   42%     58%     58%         25%       17%        0%

Cruz*      11         6           5          5 (*11)    0            0             0                2014-2017     22
Percent   100%   55%      45%     100%      0%         0%         0%

Samson* 19        19         0          0 (*19)     0            0             0               2011-2017     13
Percent   100%   100%    0%       100%       0%        0%          0%

Total       82         44         38        11 (*55)   8            19           6
Percent   100%   54%      46%     67%        10%       23%        7%

#FEC (fecal egg count)
#Neg (number of samples where no eggs were found on counting chamber)
#Pos (number of samples where eggs were found on counting chamber)
#Low (number of samples indicating low shedder 50-200 eggs/gm)
#Med (number of samples indicating medium shedder 200-500eggs/gm)
#High (number of samples indicating high shedder 500 + eggs/gm)
#>1000 (number of times eggs found on counting chamber indicated count was more than 1000eggs/gm)
*Tristan, Ginger, Cruz, Samson are owned by Rene Stone (all of Cruz’s Pos. samples only contained 50eggs/gm)
*In all positive samples only strongyle eggs were found.
67% for low shedder includes the samples that were negative.
*All horses reside in New Jersey.

Ginger & Finn