Cross-lumber – Proper Prevention and Treatment

The weather is nice, and you’re out on a long ride with your horse. But right at the start of the first stretch of canter, your horse suddenly becomes very stiff and starts sweating unusually heavily. It barely wants to move and is arching its back downward. However, these signs seem too severe to be just simple muscle soreness, especially since you haven’t done anything with your horse in the last few days. Avoid any further movement of your horse and always contact your veterinarian immediately in such a case. The symptoms described are very painful and may be the first signs of a laminitis attack.

INHALT
Origin and Cause Symptoms and Diagnosis Therapy Forecast Prevention
Origin and Cause

Cross-lambing is a metabolic disorder. During prolonged periods of rest combined with a high-carbohydrate diet, the horse’s muscles build up an energy reserve known as glycogen. When you start exercising your horse again, this glycogen is broken down through muscle work with the help of oxygen. If there is too much glycogen, not enough oxygen can be supplied for its breakdown, and breakdown products such as lactate (=lactic acid) accumulate in the muscle. This accumulation is further exacerbated by reduced blood flow in cool outdoor temperatures, as less lactate can be removed. The muscles become acidic and cramp up. As the condition progresses, muscle cells may be destroyed and the muscle protein myoglobin may leak out.

Since this muscle disorder frequently occurs after horses have not been worked for one or more days while maintaining the same feed ration, it is also known as “holiday disease” or “Monday Morning Disease.” However, horses that are worked regularly can also develop the condition. Young horses of heavy breeds are particularly at risk. In the days when carriage and work horses were heavily labored, this disease was greatly feared. Today, it occurs only sporadically, mostly in horses that are light eaters and in good nutritional condition.

Symptoms and Diagnosis

In typical cases, the first symptoms appear within the first 15 minutes after the horse begins moving. The horse starts to tremble, sweat, and exhibits a stiff gait or stops moving altogether. The back is arched, the forelegs are extended forward, and the hind legs are thrust far back. This "sawhorse stance" is characteristic of cross-strike. If movement is not stopped immediately, the hindquarters may buckle and the horse may fall. If the heart muscle is affected, an elevated heart rate and cardiac arrhythmias may occur. The muscles of the back, croup, and thighs are severely hardened and painful. Another very noticeable symptom is the brownish discoloration of the urine, caused by the breakdown of myoglobin.

The condition is extremely painful for the horse and requires immediate veterinary treatment.

In addition to assessing the typical symptoms, a blood test is the best way for your veterinarian to confirm the diagnosis.

Diagram of a Horse's Muscles: Back, Croup, Thighs
1 Latissimus dorsi | 2 Lumbodorsal fascia | 3 Tensor fasciae latae | 4 Gluteus minimus | 5 Semitendinosus | 6 Biceps femoris | 7 Fascia lata
Therapy

The most important immediate action is to prevent the affected horse from moving at all in order to prevent its condition from worsening. Blood circulation can be stimulated by covering the horse and massaging in liniments. This helps improve oxygen supply and the removal of harmful substances.

Veterinary treatment aims to prevent further muscle damage. To this end, metabolism and kidney function are stabilized through fluid administration via intravenous infusion. Pain relievers and antispasmodics may also be used. Your veterinarian will determine the exact course of action on a case-by-case basis. Only once your horse is completely at rest again can it be carefully led back to the stable or transported.

Forecast

The likelihood of a full recovery depends heavily on the severity and extent of the condition, and in particular on whether the horse was immediately restricted from movement when the first symptoms appeared. In mild cases and with immediate treatment, a complete resolution of symptoms without any lasting damage can be expected within 12 to 24 hours. Even if the horse is lying down but is able to stand up on its own or with assistance on the second or third day after treatment, there is a good chance of recovery. If significant muscle damage has occurred, the healing phase can be significantly prolonged. In such cases, incomplete healing with long-term consequences in the form of muscle atrophy and permanent lameness is also possible. Affected horses are prone to relapse.

In extremely severe cases, if no attempts to stand are made even after three days, the prospects for recovery are very poor, as too large a portion of the musculature has already been irreparably damaged.

Prevention

The incidence of this condition has already decreased significantly thanks to improved housing and training conditions. Nevertheless, certain factors are known to contribute to the development of colic. So what can you, as a horse owner, do to eliminate these factors?

The foundation of good prevention is feeding your horse a diet tailored to its needs, with sufficient roughage, which should be adjusted daily based on the varying level of exertion. Ensure your horse gets a consistent amount of exercise every day. If this isn’t possible, reduce the concentrate ration. Don’t expect your horse to run a marathon if it has had a long break from training. Always ensure an adequate warm-up phase. Increase the workload only gradually so that you can enjoy your next ride with your equine partner without any worries!