While many horse owners are ready to cut back on their hay and feed bills and enjoy the bounty that spring has to offer, for some it means grazing muzzles and metabolic issues are on the horizon. What is the big deal with spring grass? Who has to be careful and why? Let’s look at the components of the spring time conundrum: equine dietary changes and forage growth cycle.

Equine Dietary Changes & Forage Growth Cycle

The equine digestive tract is created from start to finish for small, frequent meals, made of primarily forage, throughout the course of the horse’s day. As horse owners, we have adapted the horse to tolerate and even perform well under different conditions, but that does not change the horse’s biology and digestive function. From a relatively small stomach to a hind-gut fermentation vat called the cecum, horses rely heavily on consistent forage for overall health. When they undergo sudden changes in the diet, bad things can happen to an otherwise healthy horse.

Most owners know how to safely transition from one feed type to another or one hay to a new option, but not every manager thinks about the changes happening in the pasture. Though a “natural change,” it still can cause digestive upset in the horse to rapidly move from hay and concentrate to spring pastures. Simply stated, the microbial population in the horse’s cecum cannot adapt to the change in time to utilize the forage properly if not given enough prep time.

Why is the spring pasture so different? Much like moving to winter hay feeding schedules over the course of a few weeks, horses need to be transitioned back to fresh forage in much the same way. There are a few differences to note though, since most spring pastures have the ability to be an overall higher quality than a lot of winter hays. When our warm-season grasses begin spring green-up, they are proportionally higher in non-structural carbohydrates than later in their growth cycle. While we see tender, green grasses, horses taste fresh, juicy sugars without all those pesky structural carbohydrates that later help grasses extend into the sky as they mature. This can lead to problems. Horses tend to overeat these delicious delicacies since it’s like being released to an all you can eat candy buffet after eating health-conscious meals all winter. On top of the potential of eating too much of a good thing, this high proportion of sugars can be a shock to the horse’s system, specifically the microbial population in the cecum. When the cecum microbiome is disrupted, bad things can happen such as: colic, laminitis, founder, etc. To help prevent a sugar overload, pasture management strategies should be employed.

Managing the Spring Transition

When choosing the proper management strategy for spring grazing, consider both the horses on the system and the pasture itself. Most pastures benefit from reduced stress, limited grazing and traffic, during green-up. This helps a healthy stand of grass to become established for the duration of the growing season. Knowing that it’s also good for the pasture, consider the types of horses in your herd. If you have otherwise healthy horses, some general feed transition strategies should serve as a sound basis for the spring transition management. If some horses or ponies have metabolic conditions or are prone to laminitis, spring might call for some larger safety measures. Once green-up is well underway and the grasses have been established, start by grazing for short periods on the new forage, approximately 30 minutes per day for the first couple of days. Increase grazing time by 30 minutes each day until you reach a 3–4-hour daily turnout time. Stick with this maximum for a week or two before reaching the final desired total turnout time.

Some additional strategies to ensure horses do not gorge on their new sugary feast is to make sure they have had a meal or access to hay prior to turnout so they are not as hungry and limiting the size of the pasture during turnout. When body condition scores, cresty neck scores, and histories of laminitis are high, slowly transitioning through timing may not be enough to ensure the horse’s health during spring grazing. Additional measures such as grazing muzzles may be needed. If using a grazing muzzle to slow down spring pasture consumption, be sure to ensure the safety of the fit and check on these horses routinely. Muzzles should be secure enough to limit forage but not rubbing or at risk for getting caught up on something in the pasture. Be sure to not leave these on 24/7 as it will need cleaning and inspecting. Your horse’s mental health will also thank you for these grazing muzzle breaks. If you have concerns about metabolic conditions that might be negatively affected by spring pastures, be sure to speak with a veterinarian prior to spring turnout.

Spring can be a great time to own horses from temperature for riding to picturesque views in the pastures. Be sure you are prepared for all that spring has to offer before it is pawing at the pasture gate. Have a plan in place to make spring a pleasant and safe grazing transition.

Brooklyne Wassel, Pike County Extension Coordinator & Agriculture and Natural Resources Agent