Effects of magnesium with or without boron on headshaking behavior in horses with trigeminal-mediated headshaking.

BACKGROUND: Oral administration of magnesium and boron might have a beneficial effect on headshaking behavior in horses. OBJECTIVE: Evaluate the effects of oral magnesium alone or in combination with boron on headshaking behavior in affected horses. ANIMALS: Twelve geldings (6 healthy controls and 6 affected). METHODS: Prospective randomized controlled dietary trial over 42 days in 12 horses (6 horses diagnosed with trigeminal-mediated headshaking and 6 unaffected healthy controls). All horses received a hay diet and were randomized into 3 treatment groups: pelleted feed combination (PF), pelleted feed combination with magnesium (M), and pelleted feed combination with magnesium-boron (MB) with a week washout of hay only between treatments. Headshaking behavior and biochemical blood variables were assessed at baseline (hay only) and then after each week of supplementation. RESULTS: All 3 diet interventions increased blood ionized and total magnesium. Groups M and MB further increased Mg2+ when compared to PF. Horses receiving treatments had a significant reduction in headshaking behavior, as measured by incidence rate ratio (IRR), when compared to unsupplemented hay diet (44% for PF, IRR, 0.558; CI, 0.44, 0.72; P < .001; 52% for M, IRR, 0.476; CI, 0.37, 0.62; P < .001; and 64% for MB, IRR, 0.358; CI, 0.27, 0.48; P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Magnesium in combination with boron had the greatest decrease in headshaking. Oral supplementation with magnesium or magnesium in combination with boron should be considered in horses affected with headshaking.

Specific bioactive collagen peptides (PETAGILE® ) as supplement for horses with osteoarthritis: A two-centred study.

The aim of the study was to evaluate the clinical efficacy of specific bioactive collagen peptides (BCP), here administered orally as PETAGILE® , on horses with mild to moderate, naturally occurring osteoarthritis. Data from a two-centred pilot study were used for the meta-analysis. Thirty-eight privately owned horses of various breeds were available. In one centre, 18 of these patients (6 ± 3 years; 519 ± 100 kg BW) received either 25 g (n = 6) or 50 g (n = 12) BCP/day orally for 12 weeks. In the second centre, 20 horses (18 ± 4 years; 413 ± 94 kg BW) received either a placebo (control; n = 10) or 25 g BCP/day. The attending veterinarians performed an orthopaedic examination including flexion tests and evaluated the degree of lameness, rotation pain, step length and arc of foot flight during trot (8 parameters) at the beginning and after 6 and 12 weeks. The horse owners answered a weekly questionnaire about their perception of lameness, mobility and the horses' willingness to run. In the 50 g BCP group, in six of eight parameters, a strong effect (Cohen's r > .5) was detected with two parameters (lameness and flexion pain) significantly improved already after 6 weeks. In the 25 g BCP group, a moderate effect (Cohen's r = .3-0.5) was seen in six parameters, with three parameters improved already after 6 weeks. The owners reported a strong effect for mobility and willingness to run (Cohen's r = .69 and .62, respectively) and a moderate effect (Cohen's r = .49 and 0.41) for the development of lameness in the 50 g and 25 g BCP group in comparison with the placebo treatment. This study revealed promising effects of the safe oral-specific BCP supplementation on symptoms of osteoarthritis in horses already after 3 months. The higher dosage of 50 g BCP/day had superior impact. Further long-term investigations on specific BCP efficacy in horses with osteoarthritis, preferably in blinded and placebo-controlled studies, should be performed to confirm these first positive results.

Effects of two alfalfa preparations with different particle sizes on the gastric mucosa in weanlings: alfalfa chaff versus alfalfa pellets.

BACKGROUND: Feeding alfalfa hay is often recommended for its buffering components, like protein and calcium, to prevent lesions of the gastric mucosa in horses. Until now, there has been no information regarding the influence of alfalfa particle size on the gastric mucosa. The aim of this study was to investigate the effects of feeding two alfalfa preparations with different particle sizes (alfalfa chaff vs alfalfa pellets) in comparison with grass hay on the gastric mucosa in weanling horses. We hypothesized that feeding a high proportion of fine alfalfa particles would negatively impact gastric mucosa and that feeding long alfalfa chaff would improve gastric mucosal health in weanlings. RESULTS: Before weaning, the prevalence of gastric mucosa lesions (one or more lesions considering all locations in the stomach) was 84.3 %; at 14 days after weaning, it was almost 100 %. Before and after weaning, most of the lesions were found at the greater curvature of the squamous mucosa and at the lesser curvature. After weaning, gastric mucosal lesions at the pylorus were significantly more severe in the group fed alfalfa chaff (p = 0.002). In the other regions, no differences related to the feeding regimes were observed. CONCLUSIONS: Feeding alfalfa failed to improve gastric mucosal lesion scores in weanlings. Furthermore, foals fed alfalfa chaff had higher lesion scores at the pylorus. Alfalfa leaves contain a superior protein source and high amounts of calcium and magnesium, providing extra nutritional advantages in growing horses. At this time, either traditional grass hay rations or grass hay with alfalfa pellets can be recommended.

Influence of an n-3 long-chain polyunsaturated fatty acid-enriched diet on experimentally induced synovitis in horses.

Dietary n-3 long-chain polyunsaturated fatty acid (LCPUFA) supplementation has previously been shown to modify joint-related inflammation in several species, although information in the horse is lacking. We investigated whether dietary supplementation with n-3 LCPUFA would modify experimentally induced synovitis in horses. Twelve, skeletally mature, non-pregnant mares were randomly assigned to either a control diet (CONT) or an n-3 long-chain fatty acid-enriched treatment diet (N3FA) containing 40 g/day of n-3 LCPUFA for 91 days. Blood samples taken on days 0, 30, 60 and 90, and synovial fluid collected on days 0 and 90 were processed for lipid composition. On day 91, joint inflammation was stimulated using an intra-articular (IA) injection of 100 ng of recombinant equine IL-1beta (reIL-1ß). Synovial fluid samples taken at post-injection hours (PIH) 0, 4, 8 and 24 were analysed for prostaglandin E2 (PGE2 ), matrix metalloproteinase (MMP) activity and routine cytology. Synovium and articular cartilage samples collected at PIH 8 were analysed for gene expression of MMP 1 and MMP 13, interleukin-1beta (IL-1ß), cyclooxygenase 2 (COX-2), tumour necrosis factor-alpha and the aggrecanases, a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5. A 90-day feeding period of n-3 LCPUFA increased serum phospholipid and synovial fluid lipid compositions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) compared to CONT horses. The reIL-1ß injection caused an inflammatory response; however, there was no effect of dietary treatment on synovial fluid PGE2 content and MMP activity. Synovial tissue collected from N3FA horses exhibited lower expression of ADAMTS-4 compared to CONT horses. Despite the presence of EPA and DHA in the synovial fluid of N3FA horses, dietary n-3 LCPUFA supplementation did not modify synovial fluid biomarkers compared to CONT horses; however, the lower ADAMTS-4 mRNA expression in N3FA synovium warrants further investigation of n-3 LCPUFA as a joint therapy.

Effects of a docosahexaenoic acid-rich microalgae nutritional product on insulin sensitivity after prolonged dexamethasone treatment in healthy mature horses.

OBJECTIVE: To determine effects of a microalgae nutritional product on insulin sensitivity in horses. ANIMALS: 8 healthy mature horses. PROCEDURES :Horses (n = 4/group) received a basal diet without (control diet) or with docosahexaenoic acid-rich microalgae meal (150 g/d) for 49 days (day 0 = first day of diet). On day 28, an isoglycemic hyperinsulinemic clamp procedure was performed. Horses then received dexamethasone (0.04 mg/kg/d) for 21 days. On day 49, the clamp procedure was repeated. After a 60-day washout, horses received the alternate diet, and procedures were repeated. Plasma fatty acid, glucose, and insulin concentrations and glucose and insulin dynamics during the clamp procedure were measured on days 28 and 49. Two estimates of insulin sensitivity (reciprocal of the square root of the insulin concentration and the modified insulin-to-glucose ratio for ponies) were calculated. RESULTS: Baseline glucose and insulin concentrations or measures of insulin sensitivity on day 28 did not differ between horses when fed the control diet or the basal diet plus microalgae meal. On day 49 (ie, after dexamethasone administration), the microalgae meal was associated with lower baseline insulin and glucose concentrations and an improved modified insulin-to-glucose ratio for ponies, compared with results for the control diet. CONCLUSIONS AND CLINICAL RELEVANCE: Although the microalgae meal had no effect on clamp variables following dexamethasone treatment, it was associated with improved plasma glucose and insulin concentrations and insulin sensitivity estimates. A role for microalgae in the nutritional management of insulin-resistant horses warrants investigation.

Dietary restriction in combination with a nutraceutical supplement for the management of equine metabolic syndrome in horses.

Few studies have examined the effect of dietary restriction in horses with equine metabolic syndrome (EMS). This study aimed to determine improvements in insulin sensitivity following dietary restriction for 6 weeks, and to determine if the improvement would be greater in horses receiving short-chain fructo-oligosaccharides (sc-FOS). Dietary management involved feeding grass hay, restricted to 1.25% of body mass (BM) as daily dry matter intake and soaked in cold water prior to feeding, with the addition of a vitamin and mineral nutraceutical supplement with or without the addition of sc-FOS (10 g/100 kg). Soaking the hay resulted in a significant reduction in non-structural carbohydrates (38%, P = 0.01), digestible energy (6.78%, P = 0.01) and water soluble minerals. Following 6 weeks of dietary restriction with soaked grass hay and nutraceutical supplement, horses lost an average of 6.8% BM and showed reductions in body condition score (BCS) and belly circumference. Sensitivity to insulin improved overall, as determined by the total insulin response during the combined glucose insulin test. The magnitude of improvement in insulin sensitivity was associated with the degree of insulin resistance recorded at outset, and the extent of overall losses in BM and BCS, but was independent of the addition of sc-FOS. The nutraceutical supplement was highly palatable and no adverse effects were noted. From the findings of this study a strict dietary program in combination with a specifically designed vitamin and mineral nutraceutical supplement can be recommended to obtain rapid improvements in BM, BCS and insulin sensitivity of animals presenting with EMS.

Systematic review of efficacy of nutraceuticals to alleviate clinical signs of osteoarthritis.

BACKGROUND: Various treatments of osteoarthritis (OA) have been described, including use of nutraceuticals. OBJECTIVES: To review systematically the literature about the effects of nutraceuticals on clinical signs of pain or abnormal locomotion in horses, dogs, and cats, and to discuss methodological aspects of trials and systematic reviews. METHODS: A systematic search of controlled trials evaluating the impact of nutraceuticals on OA in horses, dogs, and cats was performed, using Medline, CAB Abstracts, and Google Scholar. Scientific evidence was evaluated by means of criteria proposed by the Food and Drug Administration (FDA), and a scoring system adapted from both the CONsolidated Standards of Reporting Trials (CONSORT) statement and recommendations for assessing trials by the Center of Evidence Based Medicine of Oxford. RESULTS: Twenty-two papers were selected and reviewed, with 5 studies performed in horses, 16 in dogs, and 1 in cats. The strength of evidence was low for all nutraceuticals except for omega-3 fatty acid in dogs. There were limited numbers of rigorous randomized controlled trials and of participants in clinical trials. CONCLUSIONS AND CLINICAL IMPORTANCE: The evidence of efficacy of nutraceuticals is poor, with the exception of diets supplemented with omega-3 fatty acids in dogs. Greater access to systematic reviews must be part of the objectives of the veterinary science in the future. Their reporting would be improved by internationally agreed-upon criteria for standards and guidelines.

Effects of a supplement containing chromium and magnesium on morphometric measurements, resting glucose, insulin concentrations and insulin sensitivity in laminitic obese horses.

REASONS FOR PERFORMING STUDY: Obesity and insulin resistance are risk factors for laminitis in equids and supplements containing chromium and magnesium might improve insulin sensitivity. HYPOTHESIS: A supplement containing chromium, magnesium and other nutraceuticals would alter morphometric measurements, blood variables, and insulin sensitivity in laminitic obese horses. METHODS: Twelve previously laminitic obese (body condition score ≥ 7/9) horses were randomly allocated to treatment (n = 6) and control (n = 6) groups and 2 obese horses with clinical laminitis were included in the treatment group. Treated animals received 56 g supplement with 0.25 kg oats once daily for 16 weeks. The supplement contained chromium (5 mg/day as yeast), magnesium (8.8 g/day as oxide/proteinate), and other nutraceuticals. Insulin-modified frequently sampled i.v. glucose tolerance tests were performed with hay provided at 0, 8 and 16 weeks, and insulin sensitivity was estimated by minimal model analysis. Physical measurements were collected at the same points. Horses were not exercised. RESULTS: Hyperinsulinaemia (>30 µu/ml) was detected in 12 of 14 horses prior to treatment. Glucose and insulin data from one mare with clinical laminitis were excluded because of persistent pain. Mean ± s.d. insulin sensitivity was 0.64 ± 0.62 × 10(-4) l/min/mu prior to treatment for the remaining 13 horses. Time and treatment × time effects were not significant for any of the variables examined, with the exception of resting insulin concentrations, which significantly increased over time (P = 0.018). Health status remained the same. CONCLUSIONS: The supplement containing chromium and magnesium evaluated in this study did not alter morphometric measurements, blood variables, resting insulin concentrations or insulin sensitivity in laminitic obese horses. POTENTIAL RELEVANCE: Additional research is required to determine the appropriate use of chromium and magnesium supplements in horses.

Evidence-based equine nutrition.

One of the most difficult problems in equine nutrition research is often the lack of objective and clinically relevant end points. Nevertheless, this article attempts to present the best evidence (or lack thereof) for some of the most common clinical questions pertaining to such topics as the evaluation of glucose and insulin tolerance and factors that may confound results, dietary management of horses prone to laminitis and rhabdomyolysis, nutritional prevention of gastric ulcers and developmental orthopedic disease, the efficacy of commonly used herbal products, and feeding geriatric horses.

Modulation of leptin, insulin, and growth hormone in obese pony mares under chronic nutritional restriction and supplementation with ractopamine hydrochloride.

Horses fed beyond their nutritional requirement and that are physically inactive will develop obesity, which is often accompanied by insulin resistance and heightened risk of laminitis. The use of pharmacologic agents in combination with nutritional restriction may promote weight loss in obese horses unable to exercise because of laminitic pain. This study shows that reducing feed intake of brome grass hay to 75% of ad libitum intake in obese pony mares reduces body weight without induced exercise. Additional supplementation of ractopamine hydrochloride for 6 weeks resulted in a tendency for increased weight loss. Subsequent modulation of obesity-associated hormones, leptin and insulin, as a result of caloric restriction was observed.

Pharmacologic and alternative therapies for the horse with chronic laminitis.

This article deals with treatment of the chronically foundered horse. The first section of this article is focused on aspects of the traditional pharmacologic approaches to management of digital pain and sepsis, dietary management, and thyroid supplementation. A second section introduces the concepts, principles, and agents that are used in homeopathic treatments for laminitis. Lastly, a third section of this article reviews the use of acupuncture and traditional Chinese medicine approaches to treatment of chronic laminitis.

Effect of copper supplementation on the evidence of developmental orthopaedic disease in pasture-fed New Zealand Thoroughbreds.

The effect of copper status on the evidence of bone and cartilage lesions was investigated in 21 Thoroughbred foals. The foals and their dams were grazed on pasture containing 4.4-8.6 mg Cu/kg dry matter (DM). Four treatment groups were created by randomly allocating mares and their foals to either copper supplemented (0.5 mg Cu/kg liveweight (LW)/day), or control (pasture only) groups. This experimental design allowed the effect of copper supplementation of mare and foal to be examined independently. Parameters of bone and cartilage development were assessed in the foals both in vivo, and at post mortem at approximately age 150 days. Mare copper supplementation significantly (P<0.01) decreased radiographic indices of physitis in the distal third metatarsal bone of the foals at 150 days, and the prevalence of articular cartilage lesions (P<0.05). Articular cartilage lesions were minor in all foals, with no evidence of clinical developmental orthopaedic disease (DOD) in vivo, with the exception of minor radiographic changes assessed at post mortem. Copper supplementation of the foal had no effect on any of the bone and cartilage parameters. Copper supplementation of the mares did not abolish DOD in the growing foals, emphasising the probable multifactorial nature of this condition. However, mare supplementation may be a useful treatment regime on a farm where the incidence and severity of DOD are of concern.

Dietary control of exertional rhabdomyolysis in horses.

OBJECTIVE: To determine whether feeding a low-carbohydrate, high-fat diet would decrease severity of exercise-induced muscle injury in horses with exertional rhabdomyolysis. ANIMALS: 19 horses with a history of exertional rhabdomyolysis. DESIGN: Case series. PROCEDURE: Specimens of the semitendinosus or semimembranosus muscle were obtained for histologic examination, and serum creatine kinase (CK) and aspartate transaminase (AST) activities 4 hours after exercise were determined. Horses were then fed a low-carbohydrate, high-fat diet, and serum CK and AST activities 4 hours after exercise were reevaluated at approximately monthly intervals for 3 to 6 months. RESULTS: Serum CK and AST activities 4 hours after exercise were high before any change in diet. All 19 horses had evidence of chronic myopathic change and abnormal glycogen accumulation in muscle biopsy specimens; 11 horses also had evidence of complex polysaccharide accumulation. Adaptation to diet change required approximately 3 to 6 months. Sixteen horses did not have any episodes of exertional rhabdomyolysis after 3 to 6 months of diet change, and 3 horses had mild episodes of exertional rhabdomyolysis following either a reduction in dietary fat intake or restriction in exercise. Postexercise serum CK and AST activities 3 to 6 months after the change in diet were significantly less than initial values. CLINICAL IMPLICATIONS: Results indicated that exertional rhabdomyolysis may be a result of abnormal carbohydrate metabolism in some horses. Feeding a diet with low carbohydrate and high fat content may reduce severity of exercise-induced injury in some horses with exertional rhabdomyolysis.

Effects of dietary supplementation with butylated hydroxyanisole, cysteine, and vitamins B on tansy ragwort (Senecio jacobaea) toxicosis in ponies.

Dried tansy ragwort, which contains pyrrolizidine alkaloids, was fed as 10% of a complete diet to ponies, with and without a mixture of additives. The additives provided a dietary supplement equivalent to 1% cysteine, 0.75% butylated hydroxyanisole, 200 micrograms of vitamin B12/kg of feed, and 5 mg of folic acid/kg of feed. The additives did not alter tansy ragwort toxicity, as assessed by survival time, liver changes, sulfobromophthalein (BSP) clearance rate, serum gamma-glutamyl transpeptidase activity, and plasma amino acid patterns. In ponies fed tansy ragwort, BSP clearance rate was a sensitive indicator of liver damage, and decreased to about 20% of control values. gamma-Glutamyl transpeptidase activities showed considerable variability, but generally were elevated in animals fed tansy ragwort. Liver iron and copper concentrations increased, and liver zinc concentrations decreased in tansy ragwort-fed ponies. Plasma amino acid patterns in tansy ragwort-fed ponies showed changes typical of those observed in liver disease.