A survey of neurological diseases in horses

SUMMARY: Case records of 450 horses with signs of neurological disease are reviewed. One hundred and nineteen horses with neurological disease due to trauma were examined, of which 60 were due to spinal cord trauma, 47 to brain or cranial nerve trauma and 12 to peripheral nerve trauma. Cervical vertebral fractures/trauma were the most common injury. Basisphenold/basloccipital bone fractures were the most common form of cranial trauma and facial nerve paralysis the most common cranial nerve injury. Eighty-nine horses with neurological disease due to malformation were examined. Cervical vertebral malformation occurred in 83 horses and congenital defects in 6 foals. Neurological disease due to inflammation or infection occurred in 30 horses. The most common disease of this type was meningitis, which occurred in 11 horses and foals. Neoplasms in the CNS caused neurological disease in 8 horses. The final category was miscellaneous neurological disease, which was diagnosed in 204 horses. Diseases in this category included neonatal (28 cases), toxic/metabolic (27 cases), idiopathic (133 cases), degenerative (3 cases) and other neurological diseases (13 cases). The most common condition was idiopathic laryngeal hemiplegia (116 cases).
Where possible, diagnosis relied on a thorough neurological examination with use of ancillary tests in selected cases including rhinolaryngoscopy, radiography, myelography, ophthalmoscopy and cerebrospinal fluid analysis when indicated. In many cases necropsy and histopathological confirmation or diagnosis was necessary.     

Report on the first detection of pectenotoxin-2, spirolide-a and their derivatives in French shellfish

In the context of the French Phytoplankton and Phycotoxins Monitoring Network (REPHY) programme, shellfish samples were harvested from different locations where harmful algae blooms were known to have occurred. For all shellfish samples found positive by the mouse bioassay for diarrhetic shellfish poisoning (DSP) toxins, liquid chromatography (LC) coupled with mass spectrometry (MS) was used to search for the following lipophilic toxins: okadaic acid (OA), dinophysistoxins (DTXs), pectenotoxins (PTXs), azaspiracids (AZAs), yessotoxins (YTXs), spirolides (SPXs) and gymnodimines (GYMs). In order to investigate the presence of acyl-OAs and/or acyl-DTX-1,-2 (DTX-3), alkaline hydrolysis was performed on all samples, and LC/MS analyses were carried out on the samples before and after hydrolysis. The results revealed different lipophilic toxin profiles as a function of the shellfish sampling location. The primary finding was that all of the samples contained OA and acyl-OA. In addition, other lipophilic toxins were found in shellfish samples: DTX-2, acyl-DTX-2 and SPXs (SPX-A, SPX-desMeC) on the Atlantic coast (Southern Brittany, Arcachon), and pectenotoxins (PTX-2, PTX-2-seco-acid and 7-epi-PTX-2-seco-acid) on the Mediterranean coast (Thau lagoon, the island of Corsica). This paper reports on the first detection of PTX-2, SPX-A and their derivatives in French shellfish.     

Assessment of Progesterone Concentration Using Enzymeimmunoassay, for Early Pregnancy Diagnosis in Sheep and Goats

The objective of this study was to determine a value of serum progesterone (P₄) concentration, assessed using an enzymeimmunoassay (EIA), for the early distinction between pregnant and non‐pregnant ewes and goats. Adult, non‐lactating ewes of Chios (n=53), Berrichon (n=30) and Sfakia (n=45) breeds were synchronized during the breeding season with progestagens and gonadotrophins and mated to fertile rams (Experiment I). Adult, lactating goats of Swiss breeds (Alpine and Saanen, n=104) and indigenous Greek breed (n=45) were synchronized during the transitional season with progestagens, PGF₂α and gonadotrophins. Cervical artificial insemination (AI) with fresh semen was applied once, 42–44 h after sponge removal (Experiment II). Jugular blood samples were collected on day 19 after sponge removal (ewes) or on day 21 after AI (goats) and serum P₄ concentration was determined by EIA. Progesterone concentrations ≥1.0, ≥1.5, ≥2.5 and ≥4.0 ng/ml were tested as indicative of pregnancy. Pregnancy diagnosis was verified on birth. In the case of sheep, using a discriminatory level of 2.5 ng/ml, overall accuracy of pregnancy diagnosis was 91.4% and predictive value of negative and positive diagnoses were 98.3 and 85.3%, respectively. In the case of goats, predictive value of negative diagnosis was 95.8 and 94.0% and predictive value of positive diagnosis 71.3 and 71.7%, for 1.5 and 2.5 ng/ml, respectively; overall accuracy was 79.2% using either level. The other discriminatory levels tested did not improve these results. A significant positive correlation was observed between P₄ concentration and the number of lambs or kids born, and further analysis indicated that this relationship is not a simple linear function. Based on the results of this study, P₄ concentrations of 2.5 ng/ml in the case of ewes and 1.5–2.5 ng/ml in the case of goats, determined with EIA, are proposed as discriminatory levels between pregnant and non‐pregnant animals, at an interval of one oestrous cycle after service.     

Gametogenetic cycle and reproductive effort assessed by two methods in 3 age classes of Pacific oysters, Crassostrea gigas, reared in Normandy

Two methods were used to estimate the reproductive output of female Pacific oysters reared in Normandy: histology with image analysis and ELISA (Enzyme-Linked ImmunoSorbent Assay) which allowed the quantification of egg protein. Condition indices, gonad area and gametogenetic stages of the oysters were determined in the entire population (males and females) between May and October 2005. All investigations were performed in 3 age classes: oysters in their first, second or third years (corresponding to spat, half-grown and market-sized oysters, respectively). Both quantitative histology and ELISA provided similar results in terms of reproductive effort (illustrated by the gonado-somatic index, GSI) except during the GSI drop, corresponding to spawning, which was less marked with the ELISA method. Growth depended on oyster age, the sex ratio was well balanced and the reproductive cycle was synchronized in all age classes. In the 3 age classes, most of the oysters were ripe and ready to spawn on August 8, and ten days after the post-spawning stage was observed in 40% of spat oysters and 70% of half-grown and market-sized bivalves. The major difference between age classes was observed in the reproductive investment, with spat having a lower reproductive output. For example, in males and females, the gonad area reached 78–79% in the median animal section at full maturity (August 8) in half-grown and marketable oysters while it attained only 59% in spat. At the same time, GSI in females was, respectively in spat and the 2 oldest age classes, 33% (quantitative histology)–36% (ELISA) and 55% (quantitative histology)–60% (ELISA). The mean assessed gonad weight and fecundities increased with the age of the oysters: 1.3 g and 12 million eggs, 7.8 g and 135 million eggs, and 11.5 g and 146 million eggs in spat, half-grown and market-sized oysters, respectively. Marked differences thus appear between 2 and 3-year-old oysters and spat. As early as their first reproductive cycle, the young oysters not only showed the reproductive features of the species in Normandy, but also a pronounced lower reproductive effort. This lower energy demand could explain their higher survival rate.     

Factors affecting the relationship between arterial and end-tidal carbon dioxide pressures in the anaesthetised horse

Objective To assess the effects of the duration of anaesthesia, position of recumbency, mode of ventilation, anaesthetic drug protocol, patient age and type of surgical procedure on the usefulness of capnometry as a measure of the partial pressure of arterial carbon dioxide (P_aco ₂) during general anaesthesia in horses. Design A prospective study compared the P_aco ₂ values with those of partial pressure of end-tidal carbon dioxide (ETco ₂) in horses anaesthetised for elective or emergency surgical procedures. The difference between P_aco ₂ and ETco ₂ (P_aco ₂− ETco ₂) and the physiological dead space to tidal volume ratio (V_D/V_T) were calculated. The effects of the study parameters on these variables was determined. Results The agreement between P_aco ₂ and ETco ₂ was poor. P_aco ₂− ETco ₂ and V_D/V_T during the first 60 min of anaesthesia was significantly less than after 60 min of anaesthesia. Mode of ventilation, position of recumbency, anaesthetic drug protocol, patient age and type of procedure did not have a significant affect on either value. Conclusions P_aco ₂− ETco ₂ in anaesthetised horses can be large, making ETco ₂ unreliable as a predictor of P_aco ₂ and for assessment of pulmonary ventilation. For anaesthesia lasting less than 60 min at least one blood gas analysis of an arterial blood sample is required to assess P_aco ₂− ETco ₂. Arterial blood gas analysis should be repeated after 60 min of general anaesthesia.     

Glycerol,Methyl‐Formamide and Dimethyl‐Formamide in Canine Semen Cryopreservation

The aim of the present work was to compare the efficiency of methyl‐formamide (MF), dimethyl‐formamide (DF) and glycerol (GL) as cryoprotectants in canine semen cryopreservation. For the experiment, pooled semen was submitted to one of the three cryoprotectants, with a final concentration of 3% in egg yolk–TRIS extender. Semen was subjectively evaluated for total and progressive motility, vigour and morphology. Sperm membrane functional integrity was assessed by hypo‐osmotic swelling test (HOST), and longevity was assessed using the thermoresistance test (TRT). Fresh semen showed normal physical and morphological characteristics. After thawing, differences were observed between semen frozen using GL and DF, regarding total and progressive motility and vigour (p < 0.05), but not between MF and GL or MF and DF. Means for total motility, progressive motility, vigour and morphologically normal spermatozoa were, respectively, 69.0 ± 5.4%, 61.0 ± 7.4%, 2.9 ± 0.5 and 57.1 ± 5.0% for GL; 59.0 ± 8.9%, 50.0 ± 10.0%, 2.5 ± 0.7 and 66.9 ± 7.7% for MF; and 44.0 ± 21.0%, 37.0 ± 19.8%, 2.1 ± 0.6 and 61.1 ± 5.5% for DF. On HOST, GL was superior (p < 0.05) to MF and DF (57.8 ± 12.4%, 35.8 ± 18.4% and 34.4 ± 9.4%, respectively). During the TRT, both GL and MF were superior to DF, with no differences between GL and MF. In conclusion, the use of MF as cryoprotectant showed results similar to GL, and can be considered as an alternative in canine semen cryopreservation. Further studies testing different concentrations of MF may improve its effects on cryopreservation of canine semen.