Dr. Kerri Belsito, DVM

The fatal rabies virus that has been surrounding Colorado for years has finally made its way over the borders and become a threat to horses. In 2008, bat rabies as well as skunk rabies was identified in several counties in Colorado. No horses have been infected as of yet, but because of the proximity and certain fatality of the disease, as well as the risk to humans, Rabies vaccination is being recommended for all horses. The vaccine is a single vaccine (no booster required the first year of administration) and then boostered yearly. It is safe for pregnant mares, and if given with the pre-foaling vaccines, will transfer immunity to the foal for approximately six months. If a pregnant mare was not vaccinated for rabies, the mare and foal may be safely vaccinated any time after the foal is 3 weeks of age. Please consider this in your spring arsenal if you did not vaccinate in the fall.

Also, the Rabies vaccine may be required for your insurance policies so please check that closely. The vaccine must be given by a licensed veterinarian to be considered valid for the policies AND for the state if your horse is exposed. A veterinarian vaccinated horse that is exposed will be quarantined and observed for a designated period of time. An unvaccinated or owner vaccinated horse can be mandatorily euthanized as soon as exposure is confirmed, depending on the perceived threat to humans.

The clinic is excited to announce that the Aquapacer is here at the farm. This unit will allow Dr. Belsito and the team here to rehabilitate horses utilizing water therapy. The Aquapacer is an above ground unit to which water is added after the horse is loaded into the watertight chamber. The water is heated and filtered, much as a hot tub works. The horses can work at varying depths of water and speeds depending on how fit they are and what we are trying to accomplish/rehab. For example, normally after a joint arthroscopy, a horse is rested and not forcibly worked for 90 days. The Aquapacer allows these horses to go back to work as early as 3 weeks post surgery. At 90 days, you can have a horse ready for riding, not one you have to spend 8 weeks getting fit! Recovery times are reduced and often outcome is improved. We can also use this process to condition horses without the stress and trauma of land based exercise. The increased fitness level of horses enjoying this modality is proving to reduce performance related injuries! The farm and clinic are ecstatic to have been able to add this equipment to the armoire and can’t wait to show it to you. Please call Dr. Belsito if you would like to see the machine and watch a horse ‘swim’.

Also, if you do not wish to receive information from Dr. Belsito or Circle Back Farm any longer, please email at kbelsitodvm@gmail.com.

This is the same email you should use to update your contact information at any time.

I hope you enjoy the attached article on pasture management provided by Dr. Phil Dittberner.

Along the Colorado Front Range, most owners of small acreages (≤50-100 acres) face a very difficult task when balancing animal grazing with healthy pastures. Unpredictable and lower than average precipitation rates over the past decade and dwindling water available for irrigation as urban and suburban growth escalate human demand mean harsh growing conditions for the hardiest of forage species. Furthermore, this decline in available water has escalated the invasion of non-native, undesirable forage species such as cheat and medusa head grasses as land is continuously overgrazed.

Although this article will undoubtedly not answer all your grazing/pasture management questions, hopefully it will help you make more informed choices about how best to manage grazing to achieve land sustainability for both the short and long-term. One caveat before you begin reading: Although applicable, the information is generalized. Successfully managing land, particularly grazed land, depends on myriad factors, most of which are beyond our control. That said, I have seen several of these strategies implemented on small acreage with successful results.

How many horses can your pasture handle? Or, what is your pasture’s Stocking Rate?

Answering these questions is where you begin when determining how to graze your land. Essentially, the Stocking Rate is calculated by figuring the horse’s daily forage needs and subsequently comparing this amount to the amount of forage your pasture produces on a daily basis. Once you’ve determined your Stocking Rate, you will know how many horses your pasture can handle.

Horse daily forage needs are affected by many factors—the quality of the forage; the horse’s size, age and health condition; the topography of the land; and the horse’s breed—and vary among individual animals. Assuming the horse has reached maturity and is in good overall health, its average daily forage need is about 2.6% of its body weight. Using the 2.6% average of its body weight, a mature horse (~1,250 pounds) will consume the following amounts of dry forage:

Daily	Monthly	Yearly
32.5	988	11,862

The second part of the Stocking Rate is determining how much forage your pasture can supply. Per acre forage production varies significantly from site to site as a result of climate, soil, type of forage, available moisture, and the degree to which the land has been properly managed over time. Along the Colorado Front Range, forage production levels are between 200 to 2,000 pounds annually per acre in dryland pastures; and 2,000 to 10,000 pounds per acre on irrigated pastures. The following table illustrates the average annual useable pounds of forage per acre by type of forage grown:

*The annual useable yield as listed is based on the production level of typical rangeland found along the Colorado Front Range in fair to good ecological condition under normal annual precipitation. Also, the annual useable yield column lists 50% of the actual estimated forage production; this is in keeping with a “take half, leave half” theory that animal consumption of one-half the plant’s annual growth leaves the remaining one-half to collect the needed sunlight and nutrients to ensure healthy reproduction and growth.

Before reviewing an example of how to calculate your pasture’s Stocking Rate, let’s consider forage growth patterns. Forage will grow from approximately March through October, depending on the forage species, temperatures, and available moisture. (Forage growth patterns will be explained more precisely later in this article). Table 3 illustrates how to determine the Stocking Rate on 10 acres of dryland native pasture on loamy soils for two horses. In this example, the 10-acre pasture can support two mature horses only 58 days annually.

Using the Stocking Rate from the Table 3 example, we will explore grazing considerations. Yearlong grazing assumes that your horses will be left in one pasture for the entire year; however, in our example, this pasture does not produce enough forage to sustain the horses for a year. In this situation, the pasture should only be used for “turn-out” with little if any reliance on the existing forage to satisfy the horses’ forage needs. Additionally, in this “turn-out” example, you should assume that the horses would derive none of their nutritional needs. Checking with your equine veterinarian to determine an adequate diet including any supplements is advisable.

A much better option than yearlong grazing, particularly for smaller acreages, is rotational grazing. Using our 10-acre pasture example, we split the pasture into two equal (or as close to equal as possible) sections so that we are working with two approximately 5-acre pastures. In this arrangement, the horses can be grazed or turned out on one of the 5-acre pastures, leaving the other 5-acre pasture to rest. Resting your pasture is vital to its sustainability and weed reduction. Resting gives the forage an opportunity to grow its leaves and roots, recover from trampling, and reproduce unhindered.

Another benefit of resting is reduced soil compaction. When pasture areas are inundated with water either from irrigation or natural precipitation, animal traffic reduces or eliminates the soil structure that carries nutrients, water and air to the root systems of plants. Ideally, the top several inches of soil should be allowed to dry in irrigated or storm-drenched pastures before horses are allowed to graze.

When pastures are not given sufficient resting periods, overgrazing eventually occurs. Overgrazing happens when animals are left in one place too long, continually eating the plant regrowth thus weakening the plant. Weakened plants are highly susceptible to weed invasions that can ultimately take over the pastures by starving the more desirable forage.

How do I know when my pasture needs rest? How much rest do I need to give my pasture?

Accurately determining when and how much to rest your pasture is crucial for a successful, sustainable grazing and/or turn-out system. Much depends on the type of forage in the pasture, as well as general plant growth patterns. The following table shows the minimum stubble heights—what should be standing on the ground in the majority of pasture areas when animals leave—for some common types of grasses.

Forage Type	Minimum Stubble Height (Inches)
Crested wheatgrass on most soil types	2
Western wheatgrass on clay or loam soils	3
Tall wheatgrass, on wet meadow sites	6
Switchgrass on sandy soil	6
Little bluestem on loamy soil	4
Sideoats grama on loamy soil	3
Blue grama on loamy/clayey soil	2
Smooth brome on most soils	3

Once the horses have been moved off the pasture, the area should be rested until the plants have grown to at least double the amount of the minimum stubble. Depending on the time of year, precipitation, climate, and the type of forage, rest periods can be between 15 (with irrigation) and 90 days (in a drought year with no irrigation). If the forage plants are dormant, which usually occurs from October/November until March/April or during protracted drought, although the plants are not as vulnerable as during periods of higher growth—April/May through August/September—plants should not be grazed below the minimum listed in Table 4.

The importance of allowing pastures sufficient time for regrowth cannot be overstated. The most common type of small acreage mismanagement is allowing animals to graze pasture that does not have adequate regrowth. Along the Front Range, overgrazed pastures are all too prevalent, leaving once productive land barren and/or weed-filled.

Another grazing system worth considering is referred to as complex rotational. As the name implies, operating such systems are more complex than simple yearlong or rotational types. However, it can also mean greater forage productivity and harvest efficiency. In the previous example of splitting the 10-acre pasture into two 5-acre grazing areas, we gained some forage use efficiency. On these smaller areas, the horses turned out were forced to compete in smaller forage areas, thus pushing them beyond their areas of comfort such as the barn and water source to the edges of the pastures. Plants that previously may not have been used are thereby grazed. Complex rotational grazing systems operate on the same “competing for forage” principles, involving pastures that are subdivided into three or more areas. These systems take more time to manage and can appear daunting to the amateur land owner. However, if implemented and managed appropriately, complex rotational systems provide the best results.

How do I know that my horse’s nutritional needs are being met through grazing?

The simplest and most accurate answer to this question is that their nutritional needs will not be met through grazing alone. Even if you are among the fortunate who irrigate regularly, use an effective rotational grazing system, and have a Stocking Rate that says you can graze multiple horses yearlong, your horse will not receive the protein, vitamin and mineral levels necessary for optimal health. For one reason, forage does not provide the same nutrient values at all times. Typically, when forage is coming out of its spring growth cycle, it contains the highest levels of digestible protein and minerals. As summer progresses, forage nutritional values begin to decline, becoming very low toward fall and winter. Additionally, different types of forage contain varying nutritional values. As an example, blue grama, buffalo grass, smooth brome and wheat grasses provide higher nutritional values than some other grass species, but only during their growth cycles. In short, pasture grazing should not be considered an adequate way to supply your horses’ nutritional needs. Always confer with your equine veterinarian to ensure your horses are getting appropriate nutrition.

What are the most important considerations when determining appropriate grazing on small acreages?

First, you determine your land’s Stocking Rate defined as the ratio of daily horse forage needs to the daily forage produced on your land. Referring to Tables 1, 2 and 3 will assist you in calculating your Stocking Rate. If you do not know the type of forage growing in your pasture, contact your local extension office, your local agricultural resources or knowledgeable individuals. Many Front Range communities provide specialists in small-acreage management who will come inspect your land and offer management suggestions.

Next, commit to some type of rotational grazing system that you can realistically manage. Most small acreages will not tolerate continuous, year-long horse grazing even under ideal conditions; thus, dividing up available pastures into smaller segments and allocating time for rest periods are necessary.

Once you’ve settled on a rotational grazing system, monitor all the land segments, paying particular attention to the segment on which horses are currently grazing. If the grazing segment shows signs of reaching minimum stubble height, move the horses to a new segment provided the new segment has sufficient regrowth and does not need to dry out from recent irrigation or storm water. After rotating your horses to a different segment, allow ample time for regrowth in the previously grazed segments.

There will be times when none of your land is suitable for grazing and/or turnout. Although it might be tempting to turn your horses out despite substandard turn-out or grazing conditions, consider the consequences of following this path: overgrazing leading to loss of forage and weed invasion; soil compaction that keeps nutrients, water and air from nurturing plant regrowth; and, ultimately, little if any remaining area for horse turn-out or grazing.

Finally, remember that your horses will not receive adequate nutrition from grazing alone. It is essential to give them not only dry forage with ample protein levels, but also supplements to meet their vitamin, mineral and other necessary nutrients.

About the contributor: Phil Dittberner, Ph.D., is a range ecologist and small acreage management specialist. He can be reached at (970)686-5917.