Grazing News

With the warm temperatures this summer, it is very important to understand heat stress and heat stroke so you can avoid it. During exercise heat is produced internally from normal reactions that produce energy. In fact only about 25% of the energy used in the working muscles is used to produce movement. The remaining 75% is represented by waste heat. To alleviate the heat horses sweat. Heat stress can result from prolonged fluid and electrolyte loss during exhaustive or long distance exercise. Heat stress can lead to Heat Stroke which is failure of the body to regulate its core temperature and can occur in a short period of time. It is seen more often in unfit horses worked hard or horses confined in trailers in high ambient temperatures.

What Symptoms to Look for Possibly Indicating Heat Stroke

• Poor sweating response
• Hot, dry skin signals the early onset of heat stroke
• Abnormally fast heart beat
• Rapid breathing
• Elevated rectal temperature (106° to 110° F)
• Prolonged capillary refill time
• Depression
• Weakness
• Decreased appetite
• Refusal to work

What to Do for Heat Stroke

• Decrease the body temperature- The more rapid the cooling and the earlier treatment is provided, the better the prognosis.
• Move the horse to a shaded, well-ventilated area. If fans are available use them to help cool the horse.
• Apply cold or ice-water hydrotherapy to the entire body and repeat as needed.
• Use alcohol baths over the neck, thorax, and abdomen if cold water is not available.
• Allow the horse to drink restricted amounts of water by giving them sips of water. Unrestricted water consumption can lead to colic.
• A veterinarian may administer an antipyretic if the horse's internal temperature is very high and try to restore blood volume by administering fluids.

What Not to Do for Heat Stroke

• Do not use wet towels or any fabric cover (blanket) because these prevent heat loss .

When Does The Climate Become Unsafe To Compete?

The Heat Index is the sum of Temperature (oF) + Humidity (%). If the   

Techniques to Decrease the Incidence of Heat Stroke

• Provide supplemental cooling techniques which include fans, natural air movements, cold water baths, and placing the horse under shade.
• Avoid the most thermally stressful time of day or 12 to 3 PM.
• Reduce the distance and/or effort of the horse.
• Provide cooling stops and water drinking stops if the horses are to work all day.
• Monitor the horse's vital signs throughout the day.
• Provide electrolyte-rich, high quality hay and fortified grain, free-choice trace mineralized salt and water for a few days after the intense or exhaustive exercise. This should replace both the loss of fluid and the electrolyte loss.

1. Lindinger, M. 2008. Sweating, dehydration and electrolyte supplementation: Challenges for the performance horse. Proceedings of the 4th European Equine Nutrition & Health Congress. The Netherlands.
2. Wood, C. and A. Griffin. 2009. Equine Thermoregulation. http://www.extension.org/pages/11557/equine-thermoregulation 

Schedule

Monday, August 6 

3:00 pm            Horses May Arrive

                          Barn Party (see July Grazing News) 

Tuesday, August 7

8:00 - 10:30 am  Horses May Check-In

10:30 am            Horses Must Be In

1:00 pm              Exhibitor Meeting - Jacobson Exhibition Center  

2:00 pm              Jacobson Exhibition Center - Ranch Horse  

                           Pleasure, Poles, Barrels 

                           Livestock Pavilion - Pony Showmanship, Miniature Horse  

                           Showmanship, Pony Pleasure, Hunter Under Saddle, Hunt Seat Equitation, Saddleseat  

                           Pleasure, Saddleseat Equitation, Miniature Horse Driving 

Wednesday, August 8

8:00 am            Livestock Pavilion - 5-8 Showmanship, 5-8 Horsemanship, Trail,  

                         Miniature Horse In-Hand Trail 

                         Outdoor Arena - 9-12 Showmanship, 9-12 Horsemanship, Reining 

Thursday, August 9

8:00 am               Jacobson Exhibition Center - 2 & 3 yr old Western Pleasure,  

                            Western Pleasure starting with 5th grade

 __________________________________________________________________________________

The following championship classes are still needing sponsors. Are you interested? Contact Dr. Peggy M. Auwerda  

• Light Horse Showmanship Junior Exhibitor
• Saddle Seat Equitation  
• Reining

• Two farm/ranch visits from an ISU specialist 
• Soil analysis
• Fertility recommendations
• Forage quality analysis (if possible) and species identification
• Poisonous plant identification and weed control recommendations
• Feeding program analysis
• Overall facilities assessment
• Manure management recommendations
• Phone and e-mail support
• Supporting fact sheets and supplemental information
• Customized pasture and grazing management plans
• Cost is $650 and is limited to 25 Iowa horse farms

Colic is a common term in the horse industry and something many horse owner's fear, as it can be life-threatening. Colic is the leading cause of premature death in domestic horses and has a 10-11% annual incidence rate (White and Shehan, 2009). Not every horse needs colic surgery but when it is indicated it can be a life-saving procedure. There have been many studies done on determining the survivability of colic surgeries in horses but none have looked at survival, horse performance level following surgery, and owner satisfaction in one combined study.

A retrospective study, done by M.T. Christophersen, et al, and published in the Equine Veterinary Journal in 2011, reviewed cases that underwent exploratory colic surgery between January 2005 and August of 2010. Any owners whose horses were discharged following the colic surgery were included in a telephone questionnaire, to gather the information for the study. The horse medical records were also used to collect some specific data on the horse and the colic surgery. The study had three objectives; 1) determine the survival rate at 6, 12, 24, 36, 48, and 60 months following colic surgery 2) determine the prevalence of horses that returned to or started sporting activities after surgery 3) assess the owners satisfaction with the surgery. Before the study began it was hypothesized that a high percentage of discharged horses would return to or begin sporting activities, with a high amount at the performance level they were at before the surgery. It was also hypothesized that most horse owners would be satisfied with the colic surgery.

Of the 88 horses that were discharged following surgery, 79 horse owners completed the questionnaire and were included in the study. Only data on horses that survived at least 6 months past the surgery were included in the sporting activity portion of the study. In the study there were 42 geldings, 26 mares, and 11 stallions with many different breeds including warm-blood, Icelandic, and Thoroughbreds. The horses in the study varied in age from 1 day to 21 years with the mean age being 7 years old. The horses were grouped into 3 different sporting activity disciplines; 65 sport horses, 12 pleasure/pasture horses, and 2 racing horses. The information that was collected from the horses medical records included; age, breed, gender, disease location, surgical treatment, and whether or not an enterotomy or enterectomy was necessary. Questions the horse owners were asked via telephone questionnaire included: is the horse currently alive or was it euthanized (date and reason), any post operative complications, pre and post surgical use of the horse, length of time before the horse returned to or started a sporting activity and at what performance level, any behavioral changes in the horse, management changes made by owners after surgery, and finally whether or not the owner would recommend colic surgery.

There are some common signs that help veterinarians decide whether or not a colic surgery is indicated. When a veterinarian makes the decision for colic surgery it is usually an emergency and is best based on diagnosis, however that is not always possible so clinical signs are used to make the decision when a diagnosis is not attainable. There are no strict guidelines or parameters vets follow to decide the need for surgery. This is because there are varying degrees of severity and a range of clinical signs, and every horse responds differently, so each case should be judged individually. The following table is a generalization of signs that either indicate or contraindicate colic surgery. (White and Shehan, 2009)   

The survival rates found during this study were as follows: 6 months- 95.3%, 12 months- 86.6%, 24 months- 80.9%, 36 months- 76.9%, 48 months- 62.1% and 60 months- 57.6%. This study wanted to look at long term survival, and 6 months was considered long term. A previous study (Launois, et al. 2006) looking at the outcomes of 100 colic surgeries had similar results with a 91% survival rate up to 1 year in the 43 horse owners that responded to their questionnaire. Another study reported a survival rate of 91.2% at 11 months after colic surgery (Mezerova and Zert, 2008). All three of these studies indicated that complications following the surgery were the biggest predictors in the length of survival following the surgery. The most common complication following surgery is that the horse may colic again, and usually within the first 100 days following the surgery. The incidence of colic is 2.8 - 7.6 times higher in horses that have undergone colic surgery. (Proudman et al. 2002) It is important to note that the study found that there was no decrease in survivability with increasing age of the horse undergoing surgery.

The study found that 86.1% of horses surviving beyond 6 months returned to or started a sporting activity following colic surgery. Of those, 83.5% of owners believed the horse was back to it pre-operative performance level or better. The study by Launoies, et al (2006) also had similar results and found 90.32% of surviving horses returned to sporting activities following colic surgery, with the majority of the horses in that study being show-jumpers and dressage horses. Wound complication and hernia formation were found to be the only significant predictors of worse performance following the procedure. This study also noted horses usually need 5 to 6 months to recover from colic surgery before returning to or beginning a sporting activity. However, it can take a horse more than 1 year to recover in some cases.

Owner satisfaction was the last objective of the study and was hypothesized to be high. The study found that the majority of owners 89.9% would recommend the colic surgery for their horses. Post-surgical performance was the only thing statistically associated with the owners' decision to recommend the surgery, as all owners whose horses had increased performance levels would recommend the surgery. Launois, et al (2006) also found that the majority of owners would recommend colic surgery. That study found; 79.1% would recommend surgery, 9,3% would not recommend surgery, and 9,3% would request colic surgery depending on the case. Their study also found that 60% of owners would not recommend the surgery if their horse died. Colic surgery in most clinics is the second most expensive surgery and the costs vary depending of the wealth of the clientele and value of the horses in the practicing area. In general the cost of colic surgery in the United States starts at $4,000 and can vary from there depending on the severity of the colic and any complications associated with the surgery (Freeman, 2003).

In conclusion the hypotheses made before the beginning of the study held true in that there was a high long term survival rate in horses following colic surgery, a high level of those horses undergoing the surgery returned to or started a sporting activity with many achieving or exceeding their pre-operative performance level, and finally the majority of owners were satisfied and would recommend colic surgery. It is encouraging to see the high survival rates along with the high performance levels in sporting activities following the surgery especially in many different disciplines. In appropriate circumstances the colic surgery is a high-quality option for horse owners today and one that should be seriously considered.

References

• Christophersen M.T, Tnibar A, Phil T.H, Andersen P.H, Ekstrom C. T. (2011). Sporting activity following colic surgery in horses: A retrospective study. Equine Veterinary J 43 (suppl. 40):3-6.
• Freeman D. E. (2003). Abdominal Surgery: Complications and Costs. 8th Congress on Equine Medicine and Surgery. Publisher: International Veterinary Information Service, Ithaca, New York, USA. Accessed Feb 13, 2012. www.ivis.org.
• Launois, T, Heiles, PH, Desbrosse F, Perrin R, Rossignol F, Scicluna C. (2006). Sports activity after colic surgery: Post-operative outcome of 100 procedures. Proceedings of the 9th International Congress of World Equine Veterinary Association, Marrakech, Morocco. Publisher: International Veterinary Information Service. Accessed February 13, 2012. www..ivis.org.
• Mezerova, J. and Zent, Z. (2008) Long-term survival and complications of colic surgery in horses: analysis of 331 cases. Vet Med. (Praha). 53, 43-52.  
• Proudman, C.J., Smith, J.E., Edwards, G.B. and French, N.P. (2002) Long term survival of equine surgical colic cases. Part 1: patterns of mortality and morbidity. Equine vet J. 34, 432-437.
• White N.A., Shehan J.E. (2009) Diagnosis of Colic: Decision for Surgery. Proceedings of the 11th International Congress of World Equine Veterinary Association, Guaruja, SP, Brazil. Publisher: International Veterinary Information Service. 

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