New mutation within a common haplotype is associated with calf muscle weakness in Holsteins.

A recessive haplotype resulting in elevated calf mortality but with apparent incomplete penetrance was previously linked to the end of chromosome 16 (78.7-80.7 Mbp). Genotype analysis of 5.6 million Holsteins indicated that the haplotype was common and traced back to 1952, with a key ancestor born in 1984 (HOUSA1964484, Southwind) identified from chip genotypes as homozygous for the suspect haplotype. Sequence data from Southwind (an affected calf) and the sire of the affected calf were scanned for candidate mutations. A missense mutation with a deleterious projected impact at 79,613,592 bp was homozygous in the affected calf and heterozygous in the calf's sire and Southwind. Sequence data available from the Cooperative Dairy DNA Repository for 299 other Holsteins indicated a 97% concordance with the haplotype and an 89% call rate. The exon amino acid sequence appears to be broadly conserved in the CACNA1S gene, and mutations in humans and mice can cause phenotypes of temporary or permanent paralysis analogous to those in calves with the haplotype causing muscle weakness (HMW). Improved methods for using pedigree to track new mutations within existing haplotypes were developed and applied to the haplotypes for both muscle weakness and Holstein cholesterol deficiency (HCD). For HCD, concordance of the gene test with its haplotype status was greatly improved. For both defects, haplotype status was matched to heifer livability records for 558,000 calves. For HMW, only 46 heifers with livability records were homozygous and traced only to Southwind on both sides. Of those, 52% died before 18 mo at an average age of 1.7 ± 1.6 mo, but that death rate may be underestimated if only healthier calves were genotyped. The death rate was 2.4% for noncarriers. Different reporting methods or dominance effects may be needed to include HMW and other partially lethal effects in selection and mating. Direct tests are needed for new mutations within existing common haplotypes because tracking can be difficult even with accurate pedigrees when the original haplotype has a high frequency.

Nemaline myopathy in a six-month-old Pomeranian dog.

ABSTRACT: Nemaline myopathy - a clinically and genetically complex heterogenous group of disorders - is described uncommonly in humans and rarely in animals, and is characterised by progressive muscle weakness. The diagnosis is confirmed by histological and/or ultrastructural identification of subsarcolemmal, thread-like, rod-shaped structures called nemaline rod bodies within more than 40% of skeletal muscle fibres. These rods contain the Z-line protein, α-actinin, that can be effectively stained in skeletal muscles using Gomori or Masson trichrome and negatively stained with periodic acid-Schiff. Similar rod-like bodies have been found in smaller numbers in dogs with endocrine disorders and occasionally in other conditions in humans. This report is of a six-monthold Pomeranian dog which had progressive exercise intolerance over a two-month period associated with severe disuse muscle atrophy of the thoracic limbs, as well as gradual pelvic limb weakness and regurgitation of food. Baseline diagnostics ruled out endocrinopathies and after histological and ultrastructural evaluation of thoracic limb muscles and nerve biopsies confirmed nemaline myopathy. The clinical course, diagnostic test results, ultrastructure of skeletal muscle and peripheral nerve, gross necropsy findings and histopathology using various stains are described and illustrated.

Experimental oral transmission of chronic wasting disease to red deer (Cervus elaphus elaphus): early detection and late stage distribution of protease-resistant prion protein.

Chronic wasting disease (CWD), an important emerging prion disease of cervids, is readily transmitted by intracerebral or oral inoculation from deer-to-deer and elk-to-elk, suggesting the latter is a natural route of exposure. Studies of host range susceptibility to oral infection, particularly of those species found in habitats where CWD currently exists are imperative. This report describes the experimental transmission of CWD to red deer following oral inoculation with infectious CWD material of elk origin. At 18 to 20 months post-inoculation, mild to moderate neurological signs and weight loss were observed and animals were euthanized and tested using 3 conventional immunological assays. The data indicate that red deer are susceptible to oral challenge and that tissues currently used for CWD diagnosis show strong abnormal prion (PrP(CWD)) accumulation. Widespread peripheral PrP(CWD) deposition involves lymphoreticular tissues, endocrine tissues, and cardiac muscle and suggests a potential source of prion infectivity, a means of horizontal transmission and carrier state.

Acupuncture for Anaemia and Large Intestine Impaction Associated with Hind Limb Weakness in a Horse: A Case Report.

A 24-year-old horse was presented with a clinical history of anaemia, large intestine impaction and hind limb weakness. Loss of body weight was also reported. Hematocrit and hemoglobin levels were low and piroplasmosis test was negative. Nasogastric intubation with laxative agents was performed and 50 ml of a red blood-cell-supplement was given daily during a month. An assessment following Traditional Chinese Veterinary Medicine (TCVM) principles was performed after the last episode of large intestine impaction. A swollen, pale and wet tongue was observed. A superficial, weak pulse combined punctually with a slippery pulse was detected on the right side. The pulse on the left side was very thin. BL18, BL20 and BL23 were the most sensitive acupoints on the right side. BL18 and BL23 were the most sensitive on the left. TCVM diagnosis was Qi/Yang Kidney Deficiency, Spleen Qi Deficiency with Stagnation and Blood Deficiency. It received acupuncture at Bai-Hui, KI3, KI7, KI10, BL23, GB39, ST36, BL17 and acupressure at SP10. The client reported a significant improvement after treatment and hematocrit and hemoglobin levels were normal. KI3, ST36, BL39 acupoints were treated 14 days later. The outcome was favourable and one acupuncture session per month was recommended. No previous case reports in equines have been documented with a combination of blood, gastrointestinal and musculoskeletal problems in the same episode. This case is an example of an integrative approach to investigate the origin and the interdependent relation between body systems.

Identification of genetic markers associated with fatness and leg weakness traits in the pig.

Pigs have undergone long-term selection in commercial conditions for improved rate and efficiency of lean gain. Interestingly, it has been observed in both experimental and field conditions that leg weakness has increased over time, concurrent with the selection for improved rate of lean gain, while fatter animals tend to have better leg action, and foot and leg (FL) structure. The exact molecular mechanisms or individual genes responsible for this apparent genetic correlation between fatness and leg weakness and other physical adaptability traits have been less well reported. Based on our recent studies involving candidate genes and leg weakness traits, the present investigation has identified 30 SNPs from 26 genes that were found to be associated with 10th rib backfat in a sow population consisting of 2066 animals. The specific alleles associated with increased backfat tended to be associated with better overall leg action, as shown for the genes including MTHFR, WNT2, APOE, BMP8, GNRHR and OXTR, while inconsistent associations with the single FL structure trait and backfat were observed for other genes. This study suggests that in some cases there may be a common genetic mechanism or linked genes regulating fatness and leg weakness. Such relationships are clearly complex, and the utilization of genetic markers associated with both traits should be treated cautiously.

A possible new inherited myopathy in a young Labrador retriever.

A 5-month-old, male, Labrador retriever was evaluated for progressive weakness and muscle atrophy. Histologic evaluation of fresh frozen muscle revealed distinct cytoarchitectural changes and central mitochondrial accumulations indistinguishable from those found in the inherited myopathy described in Great Danes. Multiple male littermates and half-siblings were similarly affected.

Myopathy in horses with pituitary pars intermedia dysfunction (Cushing's disease).

Fifteen horses with pituitary pars intermedia dysfunction were studied. The horses were of various breeds and between 15 and 28 years of age. Control horses matched for breed and age were studied for comparison. Evaluations included complete blood cell count and serum biochemical analysis, electromyography, and gluteus medius muscle biopsies for histochemical, morphometric, and ultrastructural analysis. No differences were found between groups of horses on routine laboratory analysis or electromyography. We demonstrated that muscle wasting in diseased horses was the result of atrophy of types 2A and 2B muscle fibers and loss of type 2B myofibers. Mild non-specific non-inflammatory myopathic alterations such as myofiber size variation, internal nuclei, perimysial, endomysial and sarcoplasmic fat accumulation were observed. At the ultrastructural level, subsarcolemmal mitochondrial accumulation and increased lipid droplets were evident. Similar to other species, this study confirmed atrophy of type 2 fibers as the cause of muscle mass loss in horses with Cushing's disease.

Effect of transforming growth factor-beta on decorin and beta1 integrin expression during muscle development in chickens.

Myoblast-extracellular matrix interactions play a pivotal role in skeletal muscle development. Transforming growth factor-beta (TGF-beta) is a key regulator of muscle cell proliferation and differentiation. The level of TGF-beta expressed will affect the concentration of the extracellular matrix proteoglycan decorin and the cell surface beta1 integrin subunit. The decorin proteoglycan is a regulator of cell growth as well as the organization of the extracellular matrix. The beta1 integrin plays a role in muscle cell attachment, migration, and the formation of multinucleated myotubes. In the current study, chicken myogenic satellite cells isolated from the pectoralis major muscle from the chicken genetic muscle weakness, low score normal (LSN), and normal pectoralis major muscle were used to investigate TGF-beta expression as it relates to decorin and beta1 integrin mRNA expression. The LSN muscle defect is characterized by altered myotube formation and sarcomere structure, and the satellite cells have reduced proliferation and differentiation. The mRNA expression was measured by real-time quantitative reverse transcription PCR. The LSN condition has elevated expression of TGF-beta2 and TGF-beta4 with increased expression of decorin and decreased beta1 integrin during myogenic satellite cell proliferation and differentiation. Normal satellite cell cultures were treated with the addition of exogenous TGF-beta during differentiation to determine if the altered expression of LSN decorin and beta1 integrin was associated with TGF-beta expression. The addition of exogenous TGF-beta decreased decorin expression during differentiation and reduced beta1 integrin expression at 24 and 48 h of differentiation. These results suggested that alteration of decorin expression in the LSN myogenic satellite cells may occur by a mechanism involving factors in addition to TGF-beta, but the addition of exogenous TGF-beta did affect both decorin and beta1 integrin expression. These data, therefore, suggested that TGF-beta might play a pivotal role in chicken skeletal muscle formation through modulation of the expression of both extracellular matrix molecules and cellular receptors important in the control of cell migration and growth regulation.

Investigation of stillbirths, perinatal mortality and weakness in beef calves with low-selenium whole blood concentrations.

In this on-farm investigation, we report on stillbirths, weakness and perinatal mortality seen in calves on a commercial beef farm in the Roossenekal area, Mpumalanga province, South Africa. Post-mortem examination of these calves and histopathological examination of organ and tissue samples did not indicate an infectious aetiology. Affected calves had marginal to deficient whole blood selenium concentrations. Whole blood samples collected from adult cattle on this farm and five neighbouring farms were deficient in selenium. The potential contributions of other minerals to the symptoms seen are a subject of ongoing investigation, but selenium deficiency was marked in this herd and required urgent correction. Methods to correct the deficiency included the use of injectable products, and an oral selenium supplement chelated to methionine. Selenium availability to plants is primarily determined by the selenium content of the parent bedrock, the presence of other minerals and the pH of the soil. The apparent sudden onset of this problem implicates a soil factor as being responsible for reducing selenium's bioavailability in this area. Selenium deficiency can have a significant impact on human health. HIV and/or AIDS, various forms of cancer and several specific clinical syndromes are associated with selenium deficiency in humans, and the impact on human health in this area also requires further investigation.

Molybdenum deprivation, purine ingestion and an astrocyte-associated motor neurone syndrome in sheep: assumed clinical effects of inosine.

BACKGROUND: An astrocyte-associated motor neurone syndrome was produced in molybdenum-deprived sheep fed xanthosine. Mo-deprived sheep fed inosine, adenosine or guanosine would be also expected to develop astrocyte-associated motor neurone syndromes, because all these purine nucleosides can act as neuromodulators and all depend on the Mo-associated enzyme xanthine oxidase-dehydrogenase for their catabolism. DESIGN: To investigate the relationship between inosine ingestion and low Mo concentration, eight sheep were fed lucerne chaff with a Mo value <0.10 ppm and the Mo antagonist, sodium tungstate, for 21 weeks, with inosine (35 mg/kg/day) fed for the last 18 of these weeks. This clinical study was uncontrolled. RESULTS: An astrocyte-associated motor neurone syndrome was produced in three sheep 18-27 months later. It was characterised by diaphragmatic, laryngeal, lingual and pharyngeal muscle weakness. The diaphragmatic muscle weakness was the most severe and potentially lethal. CONCLUSION: These findings suggest that purinergic neuromodulation of respiration, vocalisation and swallowing is different to that of limb movement. The syndrome produced, and assumed to be caused by the treatment given, has not been reported in livestock. A similar syndrome is seen in human motor neurone disease, but not in equine motor neurone disease, and this is consistent with it being an upper, not a lower, motor neurone effect.

Polimiopatia hipocalêmica e hipertensão secundária a hiperaldosteronismo primário felino / Hypokalemic polymyopathy and secondary hypertension to feline primary hyperaldosteronism

O hiperaldosteronismo se define pela hipersecreção de aldosterona pelas suprarrenais, resultando em excesso de sódio e redução de potássio sanguíneo. Esta hipersecreção deve-se à síntese autônoma de aldosterona por células adrenais hiperplásicas ou neoplásicas, que agem independentemente da estimulação pelo sistema renina-angiotensina. A doença acomete felinos de adultos maduros a idosos. O excesso de aldosterona culmina em hipertensão sistêmica e/ou hipocalemia, que levam à fraqueza muscular e alterações oculares. O diagnóstico é baseado em exames laboratoriais e de imagem, e o tratamento pode ser clínico ou cirúrgico. O prognóstico é considerado favorável quando as medicações são capazes de melhorar as manifestações clínicas ou quando é possível realizar o procedimento cirúrgico. O presente trabalho visa relatar o caso de um felino macho de 13 anos, castrado, sem raça definida, com hipocalemia persistente secundária a um presuntivo tumor adrenal.

Hyperaldosteronism is defined by the hypersecretion of aldosterone by the adrenal glands resulting in excess sodium and reduced blood potassium. This hypersecretion is due to the autonomous synthesis of aldosterone by hyperplastic or neoplastic adrenal cells, which act independently of stimulation by the renin-angiotensin system. The disease affects felines in the age group from mature adults to the elderly. The excess of aldosterone culminates in systemic hypertension and/or hypokalemia, which leads to muscle weakness and ocular changes. The diagnosis is based on laboratory and imaging tests and treatment can be clinical or surgical. The prognosis is considered favorable when the medications are able to improve the clinical manifestations or when it is possible to perform the surgical procedure. The present paper aims to report the case of a 13-year-old male cat, castrated, crossbred, with persistent hypokalemia secondary to a presumptive adrenal tumor.

A familial degenerative neuromuscular disease of Gelbvieh cattle.

A degenerative skeletal muscle disease with vascular, neurologic, and renal lesions and a probable familial distribution was identified in 4-20-month-old purebred Gelbvieh cattle. Thirteen affected animals were confirmed from 6 separate beef herds, with a mortality rate of 100%. Clinical signs in affected animals consisted of ataxia, weakness, and terminal recumbency. Gross and histologic muscle lesions were indicative of nutritional myopathy of ruminants, with a lack of myocardial lesions in most cases and only rare myocardial changes in a few animals. Acute to chronic lesions in most large skeletal muscle groups consisted of degeneration, necrosis, regeneration, fibrosis, and atrophy. Fibrinoid necrosis of arterioles was a common feature in multiple tissues. Lesions in the spinal cord white matter and peripheral nerves consisted of degeneration of the dorsal columns and axons, respectively. Changes in the kidneys consisted of chronic interstitial nephritis with fibrosis, hyaline droplet change and tubular epithelial vacuolar change and were most severe in the older calves. Intracytoplasmic myoglobin and iron were demonstrated within the hyaline droplets in degenerate renal cortical tubular epithelial cells. Vitamin E levels were deficient in most (6/7) of the animals tested. Investigation of the pedigree of affected animals revealed a common ancestry for all but 1 of the animals whose parentage could be traced. This investigation suggests that a hereditary metabolic defect, possibly involving antioxidant metabolism, could be responsible for this condition. Renal disease, possibly secondary to myoglobinuria, may be unique to this bovine condition.

Mode of inheritance of the low score normal condition in chickens.

The abnormal muscle condition termed low score normal (LSN) was first detected in an outcross of chickens with hereditary muscular dystrophy (MD) to a commercial White Leghorn stock. At 2 to 3 mo of age, normal birds can right themselves between 15 and 20 times (exhaustion score) when placed on their back on a flat surface, whereas birds with MD cannot right themselves under similar conditions. Birds classified as LSN are intermediate to these extremes. The inheritance of the LSN abnormality has not been established. In order to determine if the LSN condition was controlled by a single gene, the LSN line was reciprocally crossed with a White Leghorn line to produce two F1 populations. Two F2 populations were produced by randomly mating individuals within each F1 population. Each F1 population was backcrossed to the White Leghorn line. When birds with an exhaustion score of 6 or less were considered LSN, ratios obtained in the F1 population were 3 normal and 134 LSN individuals for the cross of the LSN line males and White Leghorn line females, and 8 normal and 118 LSN for the reciprocal cross, suggesting that the LSN condition was influenced by a dominant gene with incomplete penetrance. The frequencies did not differ between sexes in either F1 cross, suggesting autosomal inheritance. In general, ratios of normal to LSN individuals in the two F2 populations and in the two backcross populations supported the hypothesis that the LSN trait was controlled by a dominant autosomal gene. However, there was an excess of normal females relative to that expected in the cross of the White Leghorn line males and LSN line females. Heritability (h2) of the LSN trait was estimated by regression of F2 offspring on F1 parents. The h2 estimates based on regressions were higher (range = 0.520 to 1.107) in the LSN line male x White Leghorn line female cross than in the reciprocal cross (range = 0.161 to 0.621). The h2 estimates based on regression of offspring on dams were higher for male offspring than for female offspring, suggesting the presence of sex-linked effects. It was concluded that the LSN trait was influenced primarily by an autosomal dominant gene but was also influenced by other genes, some of which were on the sex chromosome.

Effects of dietary potassium supplementation for growing turkeys on leg weakness, plasma potassium concentration, and selected blood variables.

The objectives of this research were to observe the effects of increased K in the diets of growing tom turkeys from 6 to 18 wk of age on body weight, feed-to-gain ratio, and leg weakness; to study the effects of time and temperature of blood storage after sampling and before centrifugation on plasma K concentration; and to evaluate plasma creatine kinase activity as an indicator of leg weakness. Male Nicholas White turkeys were fed corn-soybean meal based starter and grower diets from 1 d to 6 wk of age. At this time, each of three dietary treatments was assigned randomly to three pens of toms, 30 toms per pen. The dietary treatments consisted of 1) corn-soybean meal control (control) diets, 2) corn-soybean meal diets supplemented with 25% more K than the control diets contained (Mod K), and 3) corn-soybean meal diets supplemented with 50% more K than the control diets (High K). Potassium carbonate was used as the source of supplemental K for the Mod K and High K diets. Calculated K concentrations of the control diets fed from 6 to 9, 9 to 12, 12 to 15, and 15 to 18 wk were 0.84, 0.74, 0.57, and 0.54%, respectively. Results of laboratory analysis of the diets agreed closely with the calculated values. By 12 wk, toms fed the High K diets weighed less (P = 0.018) than toms fed the control diets, and this difference was still evident at 18 wk (P = 0.013), even though the High K groups were changed to the control diets at 12 wk. Toms fed the Mod K diets also tended to weigh less at 16 and 18 wk than those fed the control diets, however, the diet effect at the latter time was not significant (P > 0.05). There were no consistent effects of dietary K on feed efficiency. Total incidence of leg weakness at 12 wk was greater (P = 0.015) among toms fed Mod K and High K diets than for those toms fed the control diets. These results show that dietary K concentrations greater than those usually present in corn-soybean meal based diets for growing turkeys should be avoided. Increases in dietary K concentrations were associated with increases in plasma K concentration. Storage of blood after sampling and before centrifugation decreases the plasma concentration of K. The decrease is minimized when ambient temperature of storage is decreased. Accordingly, blood should be centrifuged immediately after sampling for accurate measurement of plasma K concentration. Plasma creatine kinase activity is not a good indicator of associated leg weakness unless physical activity and stress can be controlled before blood sampling.

Meal feeding is more effective than early feed restriction at reducing the prevalence of leg weakness in broiler chickens.

Two trials were conducted to investigate whether manipulation of feeding pattern or early feed intake affected the prevalence of leg weakness in broiler chickens. In Trial 1, the birds were offered two, three, or four meals per day or consumed feed ad libitum. In Trial 2, a multifactorial design was used with age at start, duration of restriction, and severity of restriction as factors. The start of restrictions were at 5, 7, or 9 d, duration of restriction was 5 or 7 d, and feed was restricted to achieve 25, 50, and 75% of predicted growth during the restriction period. Ad libitum birds served as controls. Leg weakness was assessed by gait scoring (GS) and tibial dyschondroplasia (TD) by radiography. Foot burn, hock burn, angulation of the hock joint, feed consumption, and body weight gain were also assessed. The response of the birds to meal feeding was clear. Fewer meals per day was associated with less TD, less hock burn, better walking ability, lower body weight, and better feed conversion. The response of the birds to feed restriction was also clear. Earlier restriction, longer duration, and more severe level of restriction were all associated with lower prevalence of TD, better walking ability, lower body weight, and better relative growth rates and feed efficiency. However, adjusting the observations for differences in body weight removed many of the significant differences; only birds that started feed restriction earlier had less TD. From these trials, it was concluded that meal feeding can beneficially affect the prevalence of leg weakness, and that the major part of this effect is independent of changes in body weight. It was also concluded that early feed restriction reduced many aspects of leg weakness, but that these effects were mainly a result of reduced body weight. Meal feeding and early feed restriction improved feed efficiency.

Hypokalemia, muscle weakness, and recumbency in dairy cattle.

Seventeen cases of severe hypokalemia (serum or plasma potassium < or = 2.1 mEq/L) in association with profound muscle weakness and recumbency in lactating dairy cattle were included in a retrospective study. The cattle were from 15 different farms. Eleven of the 17 animals were recumbent at presentation while the remaining six became recumbent within 6 hours of admission. Both multiparous cows (n = 11) and first calf heifers (n = 6) were included. The median days in milk was 21 (range: 5 to 110), and chronic, recurrent ketosis (15 of the 17 cases) was the most common preexistent condition. Potential musculoskeletal and neurologic causes of recumbency were ruled out on the basis of physical examination and ancillary diagnostics. Ten of the 17 animals were euthanized and underwent full necropsy examination that demonstrated ischemic muscle damage and varying degrees of hepatic lipidosis. Aggressive potassium supplementation was instituted in all 17 cases either orally, intravenously, or by a combination of both routes. In the seven individuals that survived, potassium supplementation was administered orally and intravenously in five, orally only in one, and intravenously only in one.

Hypokalaemia as a cause of recumbency in an adult dairy cow.

A 3-year-old Holstein cow was presented for evaluation of recumbency. Physical examination and laboratory evaluations resulted in a diagnosis of hypokalaemia causing extreme skeletal muscle weakness. Treatment involved intravenous and oral potassium supplementation, antimicrobial and anti-inflammatory therapy, and management of recumbency using a flotation tank (the Aquacow Rise System). The cow recovered and returned to the milking herd. Multifactorial elements were identified as the cause of hypokalaemia including inappetance, treatments for ketosis and administration of dexamethasone.

Chiari 1/syringomyelia complex in a King Charles Spaniel.

A 9-year-old King Charles Spaniel presented with a history of progressive forelimb weakness and paroxysmal involuntary flank scratching over a 2-year period. Neurological examination suggested a myelopathy of C1 to C4 spinal cord segments. Advanced imaging studies revealed hydrocephalus, caudal herniation of part of the caudal lobe of the cerebellum through the foramen magnum and marked syrinx formation to the level of the caudal thoracic spine, resembling Arnold-Chiari malformation with secondary hydromyelia in humans. Mechanical obstruction at the craniocervical junction, altering CSF flow dynamics, may lead to syrinx formation. Response to diuretic therapy was moderate but surgical decompression may offer better long term prognosis.

[Periodic muscle weakness and cervical ventroflexion caused by hypokalemia in a Burmese cat]. / Periodieke spierzwakte en cervicale ventroflexie ten gevolge van hypokaliëmie bij een Burmese kat.

A 2-year-old female Burmese cat was referred to the University Hospital of Companion Animals of Utrecht University because of periodic muscle weakness and cervical ventroflexion. Laboratory examinations revealed hypokalemia. The combination of breed, clinical signs and hypokalemia warranted the diagnosis of 'periodic hypokalemic myopathy', a homozygote recessive hereditary disease in Burmese cats. Potassium supplementation resulted in complete disappearance of the signs. Possible causes of hypokalemia in the cat are discussed.