Prevalence of hereditary diseases in three-year-old horses of the Freiberger breed

The objective of this study was to investigate clinical signs indicating diseases with known or suspected hereditary components like equine sarcoid, insect bite hypersensitivity, osteochondrosis, allergic airway diseases, podotrochleosis, prognatism and wind-sucking in the franches-montagnes horse.We performed a clinical examination on 702 three-year-old, privately owned franches-montagnes horses, which were shown at the Swiss-Field-Tests in 2004.With the help of the owners a questionnaire on health, environment and feeding habits of the animals was completed. In 11.9% of the horses, sarcoids were detected, 6.2% carried one tumor and 5.7% had several. The prevalence was higher in chestnuts (16.6%) than in bays (10.1%). The prevalence of sarcoids in offspring from sires with known sarcoids (data from Station-Tests 1994-2005) was not significantly higher than in descendants from stallions without a known history of sarcoids. Clinical signs of insect bite hypersensitivity were only found in six horses (0.9%). In 12.0% hoof abnormalities like brittle horn, ring hoofs or hoof cracks of different degrees were recorded. The angle between hoof base and hoof wall was 56.7 +/- 0.1 degrees, the average hoof width was 13.7 +/- 0.3 cm in the front feet. For both of these measures we found no significant difference between left and right feet. With the exception of a high sarcoid prevalence, our results indicate that the franches-montagnes horse is a healthy breed overall.     

Effects of genetic and environmental factors on chronic lower airway disease in horses

Background : Environment and genetics influence the manifestation of recurrent airway obstruction (RAO), but the associations of specific factors with mild, moderate, and severe clinical signs are unknown.
Hypothesis : We hypothesized that sire, feed, bedding, time outdoors, sex, and age are associated with clinical manifestations of mild, moderate, and severe lower airway disease.
Animals : Direct offspring of 2 RAO-affected Warmblood stallions (F1S1, n = 172; F1S2, n = 135); maternal half-siblings of F1S1 (mHSS1, n = 66); and an age-matched, randomly chosen control group (CG, n = 33).
Methods : A standardized questionnaire was used to assess potential risk factors and to establish a horse owner assessed respiratory signs index (HOARSI 1–4, from healthy to severe) according to clinical signs of lower airway disease.
Results : More F1S1 and F1S2 horses showed moderate to severe clinical signs (HOARSI 3 and HOARSI 4 combined, 29.6 and 27.3%, respectively) compared with CG and mHSS1 horses (9.1 and 6.2%, respectively; contingency table overall test, P < .001). Sire, hay feeding, and age (in decreasing order of strength) were associated with more severe clinical signs (higher HOARSI), more frequent coughing, and nasal discharge.
Conclusions and Clinical Relevance : There is a genetic predisposition and lesser but also marked effects of hay feeding and age on the manifestation of moderate to severe clinical signs, most markedly on coughing frequency. In contrast, mild clinical signs were not associated with sire or hay feeding in our populations.     

Influence of nonhost plant diversity and natural enemies on the potato leafhopper, Empoasca fabae, and pea aphid, Acyrthosiphon pisum, in alfalfa

We examined the effects of nonhost plant diversity and predators on the potato leafhopper, Empoasca fabae (Harris), the pea aphid, Acyrthosiphon pisum (Harris), and their primary host plant, alfalfa, Medicago sativa L. Potato leafhopper intensity (i.e., leafhoppers/alfalfa stem density) and plant damage (i.e., hopperburn) were significantly greater in alfalfa mono- than in polycultures of alfalfa mixed with nonhost plant species. There was no significant effect of nonhost plant diversity on pea aphid intensity or on predator abundance. Predator:prey ratios were higher in poly- than in monoculture. One predator, Nabis sp., was selected for further study. A microcosm experiment indicated that Nabis is an effective predator of both herbivores, and suggested that nonhost plant diversity may enhance the predation of leafhoppers by Nabis. These results suggest that nonhost plant diversity and Nabis limit leafhopper populations and protect alfalfa from herbivory. The potential for nonhost plants to increase herbivore movement and vulnerability to predation is discussed.     

Combined moxidectin and environmental therapy do not eliminate Chorioptes bovis infestation in heavily feathered horses

Chorioptes bovis infestation is a common cause of pastern dermatitis in the horse, with a predilection in draft horses and other horses with thick hair ‘feathers’ on the distal limbs. The treatment of this superficial mite is challenging; treatment failure and relapse are common. Furthermore, C. bovis infestation may affect the progression of chronic pastern dermatitis (also known as chronic proliferative pastern dermatitis, chronic progressive lymphoedema and dermatitis verrucosa) in draft horses, manifesting with oedema, lichenification and excessive skin folds that can progress to verruciform lesions. An effective cure for C. bovis infestation would therefore be of great clinical value. In a prospective, double‐blind, placebo‐controlled study, the efficacy of oral moxidectin (0.4 mg/kg body weight) given twice with a 3 week interval in combination with environmental treatment with 4‐chloro‐3‐methylphenol and propoxur was tested in 19 heavily feathered horses with clinical pastern dermatitis and C. bovis infestation. Follow‐up examinations over a period of 180 days revealed significantly more skin crusting in the placebo group than in the treatment group. However, no other differences in clinical signs or the numbers of mites detected were found between the two groups. The results of this study suggest that moxidectin in combination with environmental insecticide treatment as used in this study is ineffective in the treatment of C. bovis in feathered horses.     

Earth's energy imbalance: confirmation and implications

Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols, among other forcings, calculates that Earth is now absorbing 0.85 +/- 0.15 watts per square meter more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years. Implications include (i) the expectation of additional global warming of about 0.6 degrees C without further change of atmospheric composition; (ii) the confirmation of the climate system's lag in responding to forcings, implying the need for anticipatory actions to avoid any specified level of climate change; and (iii) the likelihood of acceleration of ice sheet disintegration and sea level rise.     

Maximising lucerne (Medicago sativa L.) production with fixed‐length recovery intervals after defoliation in mild winter environments

Lucerne (Medicago sativa L.) is an important temperate legume for livestock production systems. Lucerne requires a recovery period after a defoliation event so that taproot energy and nutrient stores can be replenished. A field experiment examined the effects of recovery period management following defoliation, on lucerne herbage production and nutritive value at two contrasting sites in Victoria, Australia. Sites were established at Rutherglen and Hamilton, using established SARDI Seven lucerne stands. Treatments were short recovery (SR; plots cut at 21‐day intervals), long recovery (LR; plots cut at 42‐day intervals), new shoots (NS; plots cut when new shoots from the crown were at least 2 cm long) and new shoots + flowering (NSF; as for NS but plots were left to grow to reach late flowering from late summer to mid‐autumn). At each defoliation, measurements were made of phenology, dry matter production and herbage nutrient concentrations (neutral detergent fibre, crude protein, metabolisable energy and water‐soluble carbohydrate %). Persistence was measured at approximately 6‐month intervals. At both sites, lucerne persisted equally well in all treatments although SR showed some decline at Hamilton at the final measurement. LR led to a more productive pasture (in terms of cumulative dry matter, neutral detergent fibre, crude protein, metabolisable energy and water‐soluble carbohydrate %) than the three other treatments. The results indicate that phenological management systems that allow lucerne to replenish reserves through late summer and autumn are unnecessary in mild winter environments.