Genetic parameters of juvenile osteochondral conditions (JOCC) in French Trotters.

Juvenile osteochondral conditions (JOCC) have been defined as lesions resulting from biomechanical influences (compressive, tensional or shear forces) on the developing and growing musculoskeletal system. They include different types of osteochondrosis, osteochondral fragmentation of the articular surface or of the periarticular margins, juvenile subchondral bone cysts, osteochondral collapse, avulsion fractures of epiphyseal (or metaphyseal) ossifying bone and 'physitis'. The aim of this study was to estimate heritability of JOCC in a sample of 2106 French Trotters from four different sources, comprising representative samples of the Trotter population, as well as material from auctions. Horses were aged 6-24months and were either not yet in training or just beginning training. Radiographs were taken of fore and hind feet, including proximal interphalangeal (pastern) joints, metacarpophalangeal and metatarsophalangeal (fetlock) joints, tarsocrural (hock) joints, carpi and femoropatellar (stifle) joints. The threshold model used included sex, age, region and month of birth, sampling group and sire (n=159) with all inter-sire relationships. The main results were a moderate heritability for findings in the hind fetlock (0.29) and the hock (0.19). There was a weak genetic correlation between findings in fetlocks and hocks (0.26). Higher heritability was found for findings in the hock (0.37 for findings in the distal row and 0.49 for the proximal row of tarsal bones) in that part of the data (699 horses) in which it was possible to integrate the grade, bilateral occurrence or not, and distal or proximal location of the lesions. It is possible to use these genetic parameters in breeding selection with more efficiency when detailed phenotypes are considered.

Analysis of several factors of variation of gestation loss in breeding mares.

The files for ultrasound diagnosis of gestating mares belonging to the French equine herd recorded for 3 consecutive years were joined with the files for foal birth of these same mares, allowing the statistical analysis of factors of pregnancy loss. For 28 872 positive diagnoses of gestation, 2898 losses were recorded, that is, a global rate of gestation interruption of 9.12%. The etiology of these interruptions is mainly extrinsic: the year and month of insemination, as well as region for climatic reasons. The intrinsic causes that are implicated are breed of the father (heavy breeds except the hypermetric ones lose fewer pregnancies than warm-blooded breeds), age of the mother (losses are lower in mares of 7 to 10 years of age) and status (mares with foals have fewer pregnancy losses than mares not having foaled the previous year), as well as fetuses with consanguinity (when this increases, the pregnancy losses increase as well). However, the additive genetic effect is extremely low; it corresponds to heritability below 5% and few effects of the environment, common to the offspring of the same mare, were identified. This therefore gives little hope of being able to select against the 'gestation loss' trait.

Muscular microRNA expressions in healthy and myopathic horses suffering from polysaccharide storage myopathy or recurrent exertional rhabdomyolysis.

REASONS FOR PERFORMING STUDY: MicroRNAs (miRNA) are small endogenous noncoding interfering RNA molecules (18-25 nucleotides) regarded as major regulators in eukaryotic gene expression. They play a role in developmental timing, cellular differentiation, signalling and apoptosis pathways. Because of the central function of miRNAs in the proliferation and differentiation of the myoblasts demonstrated in mouse and man, it is assumed that they could be present in equine muscles and their expression profile may be related to the muscle status. OBJECTIVE: To identify miRNA candidates in the muscles of control and affected horses suffering from polysaccharide storage myopathy (PSSM) and recurrent exertional rhabdomyolysis (RER). METHODS: Muscle biopsies were collected in the gluteus medius of horses allocated into 4 groups: French Trotters (3 control-TF vs. 3 RER-TF) and Norman Cob (5 control-Cob vs. 9 PSSM-Cob). Blood samples were collected for miRNA analysis. Total RNA were extracted and real time quantitative RT-QPCR analysis were conducted using 10 miRNA assays (mir-1-23-30-133-181-188-195-206-339-375). RESULTS: All the miRNA candidates were significantly detected in the muscles and some in blood samples. Variance analysis revealed highly significant (P < 0.0001) effects of the miRNA type, breed and pathology on the miRNA expression. A specific miRNA profile was related to each myopathy: a higher expression of mir-1, 133, 23a, 30b, 195 and 339 in RER-TF vs. control-TF (P < 0.05); a higher expression of mir-195 in PSSM-Cob vs. control-Cob (P < 0.05). The miRNA profile was different between breeds for mir-181, 188 and 206 (P < 0.05). The mir-1, 133, 181, 195 and 206 were detected in blood of control-Cob and PSSM-Cob horses. CONCLUSIONS: This first study about muscular miRNA profile in equine myopathies indicated that it is possible to discriminate pathological from control horses according to their miRNA profile. The RER miRNA profile was more specific and contrasted than the PSSM profile.

A GYS1 gene mutation is highly associated with polysaccharide storage myopathy in Cob Normand draught horses.

Glycogen storage diseases or glycogenoses are inherited diseases caused by abnormalities of enzymes that regulate the synthesis or degradation of glycogen. Deleterious mutations in many genes of the glyco(geno)lytic or the glycogenesis pathways can potentially cause a glycogenosis, and currently mutations in fourteen different genes are known to cause animal or human glycogenoses, resulting in myopathies and/or hepatic disorders. The genetic bases of two forms of glycogenosis are currently known in horses. A fatal neonatal polysystemic type IV glycogenosis, inherited recessively in affected Quarter Horse foals, is due to a mutation in the glycogen branching enzyme gene (GBE1). A second type of glycogenosis, termed polysaccharide storage myopathy (PSSM), is observed in adult Quarter Horses and other breeds. A severe form of PSSM also occurs in draught horses. A mutation in the skeletal muscle glycogen synthase gene (GYS1) was recently reported to be highly associated with PSSM in Quarter Horses and Belgian draught horses. This GYS1 point mutation appears to cause a gain-of-function of the enzyme and to result in the accumulation of a glycogen-like, less-branched polysaccharide in skeletal muscle. It is inherited as a dominant trait. The aim of this work was to test for possible associations between genetic polymorphisms in four candidate genes of the glycogen pathway or the GYS1 mutation in Cob Normand draught horses diagnosed with PSSM by muscle biopsy.

Polysaccharide storage myopathy in Cob Normand draft horses.

Gluteus medius muscle was sampled from 53 Cob Normand horses for histologic evaluation. Twenty horses (38%) exhibited amylase-resistant material in myocytes consistent with polysaccharide storage myopathy. Diameter of affected type II fibers was increased (67.7 +/- 21.4 microm) compared with normal ones (57.3 +/- 19.7 microm). Two groups were distinguished by quantitative study. The first group (n = 14; 26%) was characterized by a low percentage of fibers (m = 0.98%) containing aggregates occurring singly or in perifascicular clusters without myopathic changes. The second group (n = 6; 11%) was characterized by a high percentage (m = 18.1%) of fibers containing aggregates scattered in biopsy with chronic myopathic changes. Re-biopsy of 4 horses showed an increase with time in the number of aggregate-containing fibers for horses of the first group only. In 1 necropsied horse, aggregates were observed in a wide range of muscles including smooth muscles. Ultrastructurally, granular material was found interspersed among arrays of filamentous material.

A 11.7-kb deletion triggers intersexuality and polledness in goats.

Mammalian sex determination is governed by the presence of the sex determining region Y gene (SRY) on the Y chromosome. Familial cases of SRY-negative XX sex reversal are rare in humans, often hampering the discovery of new sex-determining genes. The mouse model is also insufficient to correctly apprehend the sex-determination cascade, as the human pathway is much more sensitive to gene dosage. Other species might therefore be considered in this respect. In goats, the polled intersex syndrome (PIS) mutation associates polledness and intersexuality. The sex reversal affects exclusively the XX individuals in a recessive manner, whereas the absence of horns is dominant in both sexes. The syndrome is caused by an autosomal gene located at chromosome band 1q43 (ref. 9), shown to be homologous to human chromosome band 3q23 (ref. 10). Through a positional cloning approach, we demonstrate that the mutation underlying PIS is the deletion of a critical 11.7-kb DNA element containing mainly repetitive sequences. This deletion affects the transcription of at least two genes: PISRT1, encoding a 1.5-kb mRNA devoid of open reading frame (ORF), and FOXL2, recently shown to be responsible for blepharophimosis ptosis epicanthus inversus syndrome (BPES) in humans. These two genes are located 20 and 200 kb telomeric from the deletion, respectively.

Reproductive management of silver foxes (Vulpes vulpes) in captivity.

Specific protocols need to be developed that take into consideration the requirements of silver foxes. This study was designed to investigate the reproduction of 26 pairs of silver foxes (Vulpes vulpes). Reproduction parameters (breeding season, age at puberty, fecundity and fertility) of the foxes were examined under experimental conditions, and new techniques to optimize fox breeding were assessed. Staining of the vaginal smears with the double Harris-Schorr stain allowed for the precise detection of estrus and proved to be more reliable than simply measuring vaginal resistance. Ultrasonography was demonstrated to be useful for pregnancy diagnosis and prediction of parturition. Results demonstrate that the methods reported in this paper are easily applicable to similar studies carried out on small groups of animals within the framework of fox animal experimentation.

Molecular analysis of 60,XX pseudohermaphrodite polled goats for the presence of SRY and ZFY genes.

The polled mutation is characterized by a recessive, incompletely penetrant, hermaphroditic effect associated with the dominant genetic factor responsible for polledness in breeds of goat. The present study describes the external morphology, anatomy of the reproductive tract, histology, chromosomal constitution and Y chromosome screening of three intersex polled goats. The animals were tested for different Y-specific sequences, including SRY and ZFY. Using Southern blot and PCR amplification, no Y-derived sequences were detected in DNA from three 60,XX pseudohermaphrodite goats. This, therefore, excludes Y chromosome translocation and XX/XY chimaerism and mosaicism. This recessive mutation leading to sex reversal might be used to map and ultimately clone the autosomal genes implicated in the sex-determining pathway.

[Intersexuality in domestic mammals]. / L'intersexualité chez les mammifères domestiques.

With the exception of bovine freemartinism, intersexuality is rarely reported in domestic animals. The few cases of intersexuality reported here in dogs, cattle, goats, sheep and horses were classified according to the karyotype. The XX intersexes described here included goats which were either polled male pseudohermaphrodites or true hermaphrodites and dogs which were female pseudohermaphrodites. Among the XY intersexes studied, one dog was a true hermaphrodite, whereas the others were male pseudohermaphrodites, all mares showed gonadal dysgenesis and one cow was a female pseudohermaphrodite. XX/XY intersexes were detected in ovine cases of freemartinism.

Progesterone therapy in mares with abnormal oestrous cycles.

In two studies in Holland and France a total of 41 mares found either to be in anoestrus or showing continuous oestrous behaviour during the early part of the covering season were treated with a progesterone releasing intravaginal device. Of the 32 mares in the first study, 24 ovulated after treatment and 11 became pregnant to a covering at the induced oestrus. In the second study all but one of the nine mares showed oestrus, seven ovulated and six became pregnant at the post treatment oestrus. By the end of the covering season 15 of the 21 mares treated for anoestrus and seven of the 11 mares treated for persistent oestrus were found to be in foal.

Placental products induce suppressor cells of graft versus host reaction.

Cells from mice alloimmunized in the presence of placental extract were coinjected with cells from mice conventionally alloimmunized in the footpad of virgin female recipients. The contralateral footpad received a control twice the dose of cells from alloimmunized mice. Cells from the popliteal lymph nodes were harvested on day 3, and pulsed in vitro for measurement of proliferative capacity with 3H thymidine. The response of lymph nodes was compared (homo- vs contralateral). The cells from mice alloimmunized with placental extract in conjunction with alloantigens displayed a marked suppressive capacity of the local graft versus host (GVH) potential of cells from mice conventionally alloimmunized. It is suggested that this local GVH assay represents a quick, objective assay for suppressor-cell induction by placental products.

Regulatory mechanisms of cell-mediated immunity in allogeneic pregnancy.

The transfer of cells from allopregnant animals to syngeneic receivers allografted with paternal strain tumor leads to mild but significant enhancement. The effect can be defined as T cell mediated. Cells from allopregnant animals can suppress a mixed lymphocyte reaction (MLR) of maternal responders against paternal stimulators. The effect relies upon a THY 1+, Ly 2+, Ia+ cell. Cell-mediated lympholysis (CML) assay could also be suppressed by cells from allopregnant animals. Placental products are capable of interfering with allograft rejection in vivo. They can block MLR in vitro, and seem to act in part via the induction of suppressor cells. The respective roles of these depressive components, together with enhancing antibodies, is discussed.

[Comparative study of the 3 beta-hydroxy-delta 5-steroid dehydrogenase activity of the mitochondrial and microsomal fractions of human and cat placentas]. / Etude comparée de l'activité delta 5, 3 beta hydroxystéroïde deshydrogénase des fractions mitochondriales et microsomales de placentas humains et de chatte.

Delta 5, 3 beta hydroxysteroid dehydrogenase activity was studied on mitochondrial and microsomal fractions of human and cat placentas. This activity was assessed by measuring the rate of [3H] progesterone formation from [3H] pregnenolone and of [3H] delta 4-androstenedione from [3H] dehydroepiandrosterone (DHA), by a double isotope dilution method. Specific activities measured under initial velocity conditions were similar in both human and cat placentas. However, the kinetics of the reaction with DHA as substrate exhibit a zoological specificity.

Peripheral plasma concentrations of progesterone in the bitch with pyometra.

In the present study, 35 bitches (various breeds and ages) with pyometra were involved. Blood sampling (jugular vein) took place every day between examination and hysterectomy. All the bitches examined after 60 days post-oestrus had a low progesterone concentration (about 1 ng/ml). Along the 27 bitches observed before that time, 22 had a high mean level (about 8 ng/ml). By contrast 5 of them had low levels. As a whole these results suggest that: 1) There is no evidence of an essentially high or prolonged progesterone secretion in pyometra. 2) Luteolysis occuring normally about 60 days post ovulation is not postponed by this affection and 3) In some animals, early luteolysis seems to occur. Therefore it cannot be concluded that progesterone has an indispensalbe role in polymetra.

[Peritoneal exudate, with mononucleated cells, during normal pregnancy in different species]. / Exsudat péritonéal avec mononucléaires au cours de la gestation normale de différentes espèces.

A peritoneal cell rich fluid, containing mononucleated leukocytes, macrophages, monocytes, mast cells and lymphocytes, was observed during normal pregnancy in animals belonging to various species. These cells might be concerned in a homograft-like, mother-foetus, relationship.