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Biomedical subjects

L B Jeffcott

Publications and source records attributed to L B Jeffcott.

At least 91 records · Page 5Linked to original sources
PubMed1984

Mammary secretions in normal spontaneous and induced premature parturition in the mare.

Total calcium, total protein, albumin and globulin content were determined in 49 samples of mammary secretions from 37 crossbred and Thoroughbred mares. The mares were divided into three categories: Group 1--post partum samples from spontaneous full term Thoroughbred deliveries (n = 20); Group 2--pre- and post partum samples from spontaneous full term Thoroughbred deliveries (n = 6); Group 3--pre- and post partum samples from induced premature deliveries in crossbred mares (n = 11). Calcium concentrations of the mammary secretions proved useful in predicting full term and also in assessment of the chances of foal survival in prematurely induced parturition. Mean (+/- se) calcium levels in full term mares that foaled spontaneously (Group 1) were 10.6 +/- 2.7 mmol/litre on the day of parturition. However lower values than this did not necessarily mean parturition would not take place. In Group 2 mares, calcium levels were 4.1 +/- 0.8 mmol/litre just before foaling and rose to 9.2 +/- 1.5 mmol/litre within 20 mins of parturition; an increase of 124 per cent. Group 3 mares, induced prematurely, showed poor foal survival if pre-partum calcium levels were less than 3 mmol/litre. Total protein, albumin and globulin concentrations showed a similar trend but the increase just before or during parturition was much less marked.

Albumins↗
PubMed1984

Studies on equine prematurity 1: Methodology.

This paper describes the general management of mares and foals during the perinatal period and the methodology used in a collaborative research project on equine prematurity. Sixteen mares with dated pregnancies delivered 45 foals over three breeding seasons (1981 to 1983). In the majority, parturition was induced with oxytocin and/or fluprostenol; the remainder were allowed to foal spontaneously. Pre-colostral milk analysis provided a means of assessing the pre-foaling status of the mare. All were observed and monitored before, during and after parturition and the sampling protocol for both mare and newborn foal is discussed in detail. The foals were assessed for their degree of maturity at birth using behavioural, haematological, acid-base status and other criteria; they were then assigned to groups for further study and tests.

Animals↗
PubMed1984

Intracranial haemorrhage in pre-viable, premature and full term foals.

A neuropathological examination was carried out on the brains of 58 foals. Forty-two were pony foals induced at various periods of gestation from 200 days onwards. Two were pre-viable pony foals delivered by caesarean section and 14 were Thoroughbred foals (one set of twins, two stillborn, five premature, two dysmature, two convulsive and one induced). The only significant pathological change involved intracranial haemorrhage. Subarachnoid haemorrhage occurred in all of 10 pony foals induced before 301 days of gestation and in two pony foals born by caesarean section at 270 and 280 days gestation. Subarachnoid haemorrhage was also present in some pony and Thoroughbred foals born after 301 days gestation; the incidence usually appeared greater in those pony foals which survived for the shortest periods. Haemorrhage also occurred elsewhere in the brains, including the cerebral white matter, the molecular layer of the cerebellum and the medulla, but the intensity could not be related to either length of gestation or duration of survival. No other neuropathological changes were found that could account for the functional state of the animals, whether they were pre-viable, premature, dysmature or convulsive.

Animals↗
PubMed1983

Aspects of the pathology of stifle bone cysts in the horse.

The gross and histological appearance of subchondral bone cysts in six Thoroughbred or partbred horses is described. The lesions were all situated in the centre of the medial femoral condyle and were not associated with any other damage to the articular surface of the femorotibial or femoropatellar joints. In three cases the cysts were unilateral but had an early non-cystic lesion present in the opposite stifle. All the cysts had a narrow channel at their distal extremity which communicated with the femorotibial joint. The more recently developed ones were fluid filled and contained fibrous strands, while those in the older horses contained dense fibrotic detritus. No signs of significant ossification of the cysts were detected. The likely pathogenesis of these lesions is discussed in the light of the pathological findings.

Animals↗
PubMed1982

Radiographic examination of the equine stifle.

A radiographic technique is described for the equine stifle joint with the horse in the standing position or under general anaesthesia. The method with the animal anaesthetised in the dorsal recumbency and the leg extended was preferred because it gave greater flexibility with a better range of views and greatly reduced the safety hazards. In the standing position a useful practical tip for the lateral view was to raise and extent the limb caudally. This provides some flexion and ventral movement of the stifle allowing improved access for the cassette, a more accurate lateral view of the joint and a reduction in exposure. Some of the features of radiographic anatomy, from birth to adulthood, of this rather complex joint are described to form a basis for radiological interpretation in cases of suspected stifle lameness.

Anesthesia↗
PubMed1982

Stifle lameness in the horse: a survey of 86 referred cases.

The clinical and radiological characteristics of stifle lameness in 86 horses are described. The majority of these cases had been lame for some weeks before referral. The most frequent diagnoses made were osteochondrosis dissecans (13 per cent) and subchondral bone cyst (38 per cent). Both of these conditions were seen principally in Thoroughbreds at or before the onset of training. The other bone lesions encountered were osteoarthritis (3 per cent), fractures (4 per cent) and "epiphysitis" (1 per cent). The commonest soft tissue condition was an atypical or partial upward fixation of the patella (15 per cent), ligamentous/meniscal damage comprised 12 per cent of the cases and the remaining 13 per cent were attributed to non-specific strain of the stifle joint. Treatment in most of these chronic stifle injuries consisted of a period of rest followed by a gradual return to exercise; in some cases this was combined with a short course of a non-steroidal anti-inflammatory drug. The prognosis in most cases of osteochondrosis dissecans was grave to hopeless, while the majority of the horses with a subchondral bone cyst improved clinically after an extended period of rest (ie, 6 months). Ligamentous/meniscal damage usually responded satisfactorily to rest, provided there was no gross tearing or rupture of the structures involved. The outcome in cases of chronic osteoarthritis was always poor and these cases did not respond satisfactorily to analgesic and anti-inflammatory medication.

Animals↗
PubMed1982

Clinical and radiological aspects of stifle bone cysts in the horse.

Thirty-three cases with subchondral bone cysts in the stifle are reported. The condition was most commonly seen in young Thoroughbreds and produced intermittent lameness of varying degree. Radiographically distinct areas of radiolucency were found in the distal femur or proximal tibia adjacent to the femorotibial joint. Lesions were usually unilateral but 5 horses had cysts in both stifles. The cases could be divided into 2 distinct groups. Horses in Group A (28 cases) had a large circular or dome-shaped cyst in the medial femoral condyle with a distinct communication with the femorotibial joint. In Group B (5 cases) the cysts were much more variable in shape, size and location. The common sites were the distal femur adjacent to the intercondyloid fossa or the proximal tibia just beneath the tibial spine. No evidence of radiological signs typical of osteochondrosis dissecans were seen in any of the cases. All the horses were treated conservatively with a 6 month rest period out at grass, followed by a gradual return to full training. Fourteen horses were re-examined 4 to 33 months after the initial examination and none of them showed disappearance of the cysts. There was a tendency to increased radiodensity of the cyst in some cases but this was only to a minor degree. The outcome of the 2 groups was different. In Group A just over half (14) made a complete recovery while a further 5 returned to full work although some persistence of mild lameness was still present. In Group B only one case was reported to have made a successful return to full work.

Animals↗
PubMed1982

Effect of induced back pain on gait and performance of trotting horses.

Back pain was induced in Standardbred horses by multiple intramuscular injections of a concentrated lactic acid solution into the left longissimus dorsi muscle. The investigation was divided into 2 parts. In Stage 1, 2 trotters were exercised on a treadmill and filmed by high speed cinematography before and after the induction of back pain. No signs of hindlimb lameness were evident and no quantitative changes in the components of the gait resulted, but a noticeable reduction was seen in performance capacity. Stage 2 involved a more intensive clinical and cinematic analysis of 3 horses. In these animals some changes were detected in the stride pattern, but no obvious gait disturbance was produced. The principal effect was stiffness in the thoracolumbar spine and an inability to perform at fast paces.

Animals↗
PubMed1982

Biochemical constituents of cerebrospinal fluid in premature and full term foals.

Total protein content and a variety of enzyme activities and electrolyte values were determined in 73 cerebrospinal fluid (CSF) samples from 66 horses and ponies. The foals (48) were divided into 3 categories-spontaneously delivered normal foals (Group A), full term induced normal foals (Group B) and premature induced non-surviving foals (Group C). CSF samples from a group of 18 normal adults (Group D) were included for comparison. Paired serum and CSF samples were collected on 32 occasions and subjected to similar analyses. CSF sodium and chloride were always higher than serum sodium and chloride; the reverse occurred with potassium. The CSF protein and enzyme levels were always lower than corresponding serum values. The foals had higher total protein and creatine kinase in CSF than the adults, except for Group C (non-survivors) which had significantly lower creatine kinase than either of the other 2 foal groups. Creatine kinase values tended to fall towards adult levels over 40 h post partum. It was also noted that foals with both high total protein and creatine kinase in CSF, compared with adult values, had a better chance of survival than those with high total protein but low creatine kinase.

Animals↗
PubMed1982

A comparison of agents for inducing parturition in mares in the pre-viable and premature periods of gestation.

Various regimens of prostaglandins, alone or followed by oxytocin, were given to induce parturition in mares during the pre-viable and premature periods of gestation and in near-term mares. The most successful method of induction was found to be 2 i.m. injections of 500 micrograms fluprostenol (Equimate: I.C.I.) at a 2-h interval followed (if necessary) by 10-20 i.u. oxytocin injected i.v. in 5 i.u. serial increments every 15-20 min. Peak concentrations of the prostaglandin metabolite (PGFM) in response to the inducing agents were shown to be associated with delivery at, but not before, 320 days of gestation. A radiolabelled study of [14C]fluprostenol distribution showed that fluprostenol was present in placenta, amnion, allantoic and amniotic fluid, and in foal plasma and liver.

Animals↗
PubMed1980

Natural rigaidity of the horse's backbone.

The functional anatomy of the thoracolumbar (TL) spine is considered in relation to the horse's ability to perform at speed and to jump. The morphological features quite clearly show the relative inflexibility of the equine back and this was confirmed by some experimental studies. Fresh post mortem specimens from 5 Thoroughbreds were used to estimate the limits of dorsoventral movement of the TL spine from mid-thoracic to the cranial lumbar (T10-L2). The individual spinous processes could be moved a mean 1.1-6.0 mm on maximum ventroflexion and 0.8-3.8 mm on dorsiflexion. The overall flexibility of the back was found to be 53.1 mm. Caudal to the mid-point of the back (T13) there was virtually no lateral or rotatory movement of the spine possible. The pathogenesis of some of the common causes of back trouble are discussed including the so-called vertebral subluxation and its treatment by chiropractic manipulation. From an anatomical viewpoint, this condition appears to be a misnomer and may simply be attributable to muscular imbalance leading to aspastic scoliosis.

Animals↗
PubMed1980

The slap test for laryngeal adductory function in horses with suspected cervical spinal cord damage.

The paper describes the assessment and practical implications of a laryngeal adductory reflex in a series of 30 ataxic and 64 non-ataxic horses. The reflex was evoked by slapping the saddle region just caudal to the withers. In normal horses this produced a flickering adductory movement of the contralateral arytenoid cartilage which was observed endoscopically. Abolition of the laryngeal response was encountered in in 3 situations:--(1) Disruption of the afferent impulse occurred in those horses in which there was significant spinal cord pathology affecting the pathway from the cranial thoracic region to the medulla. (2) Disruption of the efferent impulse was manifest when damage to the adductory component of the recurrrent laryngeal nerve prevented normal adduction. (3) The reflex was abolished in tense or frightened horses, possibly due to interference from higher centres. The laryngeal adductory reflex was considered to be a useful diagnostic and prognostic aid in the assessment of ataxia and spinal cord lesions in the horse.

Animals↗
PubMed1980

Disorders of the thoracolumbar spine of the horse--a survey of 443 cases.

The survey comprised 443 horses, referred to the clinical department of the Equine Research Station, with a history of a thoracolumbar (TL) complaint. A wide range of lesions were capable of producing back problems and more than one condition or site of injury was found in 75 animals (17 per cent). There were 103 horses (19.7 per cent) with no evidence of damage to the TL spine or its associated structures. In 66 of these cases, clinical signs were attributed to a variety of hindlimb lamenesses and, in 37, no specific diagnosis could be made. Soft tissue injury was diagnosed in 203 cases (38.8 per cent), the most frequent sites being the longissimus dorsi muscles and/or the supraspinous ligament in the caudal withers and cranial lumber regions. Chronic sacroiliac strain or mild sacroiliac instability was also a frequent cause of low back trouble in competitive horses. Other conditions included tying-up, subluxation of a lumbar vertebra and neuritis of the cauda equina. Fifteen cases (2.9 per cent) of vertebral malformations were found including scoliosis, lordosis and kyphosis. Vertebral lesions accounted for 202 (38.6 per cent) of the diagnoses. The most common condition was associated with crowding and overriding of the dorsal spinous processes in the caudal thoracic and cranial lumbar regions. This was most often diagnosed in competitive jumping horses (173 cases) and caused a loss of suppleness and spinal flexibility resulting in lowered performance and bouts of back pain. There was a comparatively low incidence of fractures (13 cases) and degenerative spondylosis (14 cases).

Animals↗
PubMed1979

Radiographic evidence of impaired pulmonary function in laterally recumbent anaesthetised horses.

Studies in conscious and anaesthetised ponies demonstrated that starvation, anaesthesia and changes in body position influence the radiographic appearance of the lungs in the lateral and dorsoventral views. Radiographic appearances could not be closely correlated with blood gas values, but they suggested that the volume of the lowermost lung of the laterally recumbent animal is greatly reduced.

Anesthesia↗