Here's how the typical conversation about grazing muzzles go...
Me: "A grazing muzzle would be a great tool in your nutrition toolbox for your high laminitis risk horse!"
Client: "Ugh"
Me: "Tell me why the "ugh"".
Client: "My connotations with them are negative. They are too clunky, too hot, too unnatural, too cruel, don't fit, don't stay on. I haven't had good luck with them... ect., ect., ect."
Me: "Well, your horse is obese and we decided that his/her risk for laminitis is high. In addition, one of your nutrition goals is to prevent gastric ulcers. There are actually a lot more styles and brands available than just the thick, black feed store grazing muzzles, and many people have great success with them including myself! Plus, the research results on their use are promising!"
If this conversation is relatable or you'd just like to know more about the research, advantages, and disadvantages behind grazing muzzles, then read on!
An Update on Wilma's Weight Loss Journey
It's been exactly a month since I brought Wilma home, and I couldn't be happier with her. She is everything that I hoped she would be. Her thrift and longevity is very important to me, so I'm working hard to decrease her body condition score, get her feet and teeth healthy, and make a progressive conditioning plan. I've made good progress on this list, but, according to the weight tape, she has yet to lose any pounds. However, I'm not discouraged for a couple reasons. First, there's a tremendous amount of trial and error involved in getting to know a new horse. I don't know quantity or quality of what she was eating before. Secondly, I just this week stocked the barn with lower calorie hay just for her. Third, she has NOT gained weight on the plentiful green grass pasture, so I'm considering that a win. In part 4, I will dive into rate of weight loss; what to expect and what rate is safe?
One of the very first things I did towards her health goals was to buy her a grazing muzzle. It arrived about a week after getting her home. Over the years, I've heard a lot of positive reviews about the GreenGuard Grazing Muzzles and subsequently put them on the top of my recommendations. However, I had never used them myself as I was lucky to have a uniform herd of young performance horses. Wilma changed that dynamic! I am very happy to report that my experience thus far has been overwhelmingly positive; from the quick delivery to the easy fitting guide and lack of sores or rubs! I even bought a second one for my easy-keeping youngster.
If you're new to grazing muzzles, I totally get your delay to deploy. There are some challenges and potential risks to consider and mitigate before purchasing and placing on your fat horse. I've purposefully kept the list of advantages and disadvantages the same length! However, the weight of each item will be different for each of you as we all prioritize different things and our horses have unique risk factors. Let's take a closer look at those lists and consider what the research tells us.
The Disadvantages of Grazing Muzzles
Yes, grazing muzzles can be expensive, time consuming, and common sense says they could cause problems. Let's address these concerns first.
Increased human anxiety from considering the list below
Initial risk of decreased water consumption
Something to get snagged on and cause accidents
Poor fit leading to rubs/sores
Time consuming to take on and off especially if your horse runs from you when in hand
Possible abnormal teeth wear
Prevent self-grooming and peer-grooming
Extra miles walking the pasture looking for lost muzzles
The Advantages of Grazing Muzzles
When they work, they REALLY work great!
Lowered risk of laminitis by controlling calories and water soluble carbohydrates (Longland et al., 2016)
Lowered risk of gastric ulcers from more hours eating forage
The opportunity to socialize with herd mates outdoors
Increases movement throughout the day which is good for cardiovascular health (Davis et al., 2020)
Greater nutrient availability from green grass compared to hay only diet
Greater flexibility in your schedule and farm management plan
Great for pasture management (more even grazing and manure dispersal)
Research indicates no physical signs of increased stress while using grazing muzzles (Davis et al., 2020)
What Does the Research Say?
There have been a handful of important studies in the last 10 years attempting to quantify and qualify the use of grazing muzzles. I'm going to discuss the results of four of them that I felt were significant and worth reading.
As a nutritionist who is constantly calculating calories and nutrients in a diet, one of the most important research results is "how much do grazing muzzles restrict intake"? The answer is, unfortunately, very unsatisfying for three reasons. First, results ranged between 30% (Glunk et al., 2014) and 80% (Cameron et al., 2021) decreased intake compared to unmuzzled horses. Secondly, we don't know the shape, style, or brand of grazing muzzles used across studies. If you've ever done an internet search for "grazing muzzles", you know that brands differ wildly in fit, size, number of holes, and accessibility of grass. The third reason that the results are unsatisfying is because other factors, such as length of grass stem and species of grass, influence intake with a grazing muzzle and there are many other potential factors that common sense would tell us change the equation.
Even though the research results are not as crystal clear as we'd like, we can still infer some really useful information. Let me summarize in bullet points.
The only way to assess the efficacy of your grazing muzzle is to monitor your horse's weight and body condition score regularly. What an important reminder! I have a notification on my phone to remind me to weight tape and body condition score once per month. Adjust as you learn more each month.
You must keep the grazing muzzle on for the entirety of your horse's time on pasture, because they will "compensate" by eating more per hour when they are left without the grazing muzzle (Davis et al., 2020).
Compared to other restricted grazing methods (i.e. strip grazing, limited time, tracks, ect), the grazing muzzles are the only method to allow MORE time out on pasture.
We know with quite a bit of certainty that grazing muzzles decrease the water soluble carbohydrate intake of your horse which is such a useful tool in your management of metabolic disease since tools are few and far between!
According to Davis and colleagues (2020), there were no signs of increased stress in miniature horses wearing grazing muzzles. Their salivary cortisol concentrations and heart rates did not increase with use. Isn't that great?
Wilma is doing great with her grazing muzzle which allows her to be out on my high quality pasture 10 hours per day. I think that my primary focus moving forward towards weight loss is going to be exercise! Now that her feet are in good shape, her boots arrive today, and I have a saddle fitting this week, we will both be more comfortable on the trails! Secondly, I'll start using that new hay that I got just for her and consider restricting it further now that her stress levels have decreased from adaptation to her new environment.
The GreenGuard website has some very helpful articles about problem solving your muzzles, so CHECK IT OUT HERE ON THIS LINK.
REFERENCES
Cameron, Amelia, P. Harris, A. Longland, S. Horseman, and J. Hockenhull. 2021. UK Horse Carers’ Experiences of Restricting Grazing When Aiming to Prevent Health Issues in Their Horses. Journal of Equine Veterinary Science. Volume 104,103685, ISSN 0737-0806. Retrieved September 23, 2024 from https://doi.org/10.1016/j.jevs.2021.103685.
Davis, K.M., M.E. Iwaniuk, R.L. Dennis, P.A. Harris, and A.O. Burk. 2020. Effects of grazing muzzles on behavior and physiological stress of individually housed grazing miniature horses. Applied Animal Behaviour Science. Volume 231, 105067, ISSN 0168-1591. Retrieved September 23, 2024 from https://doi.org/10.1016/j.applanim.2020.105067.
Glunk, E.C., C.C. Sheaffer, M.R. Hathaway, K.L. Martinson. 2014. Interaction of Grazing Muzzle Use and Grass Species on Forage Intake of Horses. Journal of Equine Veterinary Science. Volume 34:7(930-933). ISSN 0737-0806. Retrieved September 23, 2024 from https://doi.org/10.1016/j.jevs.2014.04.004.
Longland, A.C., C. Barfoot, and P.A. Harris. 2016. Effects of Grazing Muzzles on Intakes of Dry Matter and Water-Soluble Carbohydrates by Ponies Grazing Spring, Summer, and Autumn Swards, as well as Autumn Swards of Different Heights. Journal of Equine Veterinary Science. Volume 40(26-33). ISSN 0737-0806. Retrieved September 23, 2024 from https://doi.org/10.1016/j.jevs.2015.09.009.
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