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1.
The pre- and post-natal development of the feline claw was studied in 22 feline fetuses with a crown-rump length (CRL) ranging from 40 to 160 mm, in six kittens up to an age of 22 days, and in four adult cats. In fetuses up to a CRL of 75 mm, the characteristic shape of the feline claw was developed. Segment-specific dermal modifications in the various segments, especially the dorsal ridge, started to develop in fetuses with a CRL between 75 and 105 mm. Modifications of the papillary body in the different claw segments took place in the last third of prenatal development and were continued postnatally. At first, the basal lamina became wavy, followed by the formation of small dermal microridges, which would be enlarged to dermal ridges and lamellae. In the claw of adult cats, the papillary body was very small. The dermal tissue of the proximal part of the coronet formed low microridges with short papillae originating on and between these low ridges. In the wall segment, dermal microridges were formed which were arranged in a parallel fashion, and in the distal part of the wall, short dermal micropapillae arose on the crest of each microridge. In the sole segment, thin dermal lamellae were developed. The sequence of papillary body development and the varying conformations of the papillary body in the different segments of the feline claw are compared to those in the nail, the canine claw and hooves. 相似文献
2.
Evidence for the non-involvement of the uterus in the lifespan of the corpus luteum in the cyclic dog 总被引：1，自引：0，他引：1
Progesterone levels in peripheral blood of dogs were analysed during the cycle in which hysterectomy (n = 5) or sham surgery (n = 3) was performed as well as during the cycle of dogs (n = 5) hysterectomized at least one year prior to this study; the data were compared with the findings in control dogs (n = 3). The averages of the duration of the luteal period observed in the three experimental groups were not significantly different from those of control dogs. Immediately after surgery, the progesterone level decreased from 25 to 50% of the presurgical level, but returned to presurgical level in about four days. Prolactin levels were elevated for about 30 h after surgery. Nevertheless, the averages of the mean prolactin levels for each animal during the luteal period of the experimental groups were not significantly different from those of control dogs. It is concluded that in the dog, the uterus is not involved in the lifespan of the cyclic corpus luteum. 相似文献
3.
M. Masko M. Domino K. Skierbiszewska Ł. Zdrojkowski T. Jasinski Z. Gajewski 《Equine Veterinary Education》2020,32(12):654-663
Complications in late gestation are challenging problems for the equine clinician and are causes of considerable distress to owners. Health problems in a pregnant mare in each stage of gestation can adversely affect the pregnancy. It is important to obtain a thorough history and perform a detailed and systematic examination of the pregnant mare so that the mare may be classified as normal or high-risk. However, even after a thorough examination, practitioners may face problems with the interpretation and assessment of risk. Normal mares should foal in the stable or pasture. Mares classified as having a high-risk pregnancy need to be monitored precisely for signs of oncoming foaling with attendance of trained personnel when labour begins. A valuable method for monitoring of the high-risk mare is assessing fetoplacental well-being. Fetoplacental well-being is most accurately assessed with ultrasonography as well as several available hormone profiles. We are proposing our scoring system of the mare's health, which may be useful in the assessment of risk during pregnancy and help clinicians to decide whether sending the mare to the clinic is reasonable or unnecessary. 相似文献
4.
Webbon P 《Equine veterinary journal》2012,44(1):8-12
The understanding and application of genetics have grown extremely quickly since it has become possible to sequence the whole genome of an organism. The human genome sequence was completed in 2001 and that of the horse in 2007. The significance of this is that it makes it more feasible to explain how both genetically simple and complex traits are transmitted from one generation to the next and, therefore, to make informed breeding decisions, modify how horses are managed and trained to minimise the risk of disease and injury, and improve methods of prevention, diagnosis and treatment of many conditions. The science of genetics/genomics will continue to grow internationally, limited only by the funds available. The application of the science to man, horses and other species raises very complex moral and commercial issues. Thoroughbred breeders are perceived by some as resistant to change, but their apparent intransigence is often based on a genuine concern for the integrity of the breed. By taking control of the application of the advances in genetics, the Thoroughbred industry potentially has the opportunity to improve both the health and performance of Thoroughbreds. If, however, the science is applied in an uncoordinated manner, driven by commercial interests with no underlying concern for the horses themselves, there is a very real risk that breeders, the Thoroughbred breed and individual horses will all suffer as a consequence. 相似文献
5.
由于主线教学法具备明晰、易于串联知识点、帮助学生识记理解等多方面的特性,所以在中学的生物教学中已经被广泛研究和应用。而在高校生命科学各课程的教学中,却乏人问津。本文从昆虫学教学的分类、生理生化等多个方面入手,初步探索了主线教学法在高校昆虫学课程中的应用,在实际的教学运用中发挥了良好的作用。 相似文献
6.
The aim of this work was to investigate the postnatal development of the feline spinal cord. Our study showed that the main period of growth leading to the cervical and lumbar enlargements begins after birth and is completed at the age of 5–6 months. Comparing the relationship between the length of the spinal cord and the vertebral column, we found that in contrast to the adult cat, in the newborn cat, length, area and volume of segments show similar values along the spinal cord. This also applied to the length of the vertebrae. Due to a heterogeneous growth, not all segments of the spinal cord end up situated cranial to their corresponding vertebrae. As a consequence, the end of the conus medullaris is still located within the sacral canal in animals older than 2 months. These findings strongly propose that injections into the vertebral canal of the cat have to be performed caudal to the sacral vertebrae. 相似文献
7.
The thyroids of 117 bovine foetuses were studied by some histochemical and selective staining methods with respect to the occurrence of parafollicular cells. Furthermore, 7 foetuses were studied by electron microscopy. The length of the foetuses varied from 6 to 72 cm corresponding to an estimated age of about 2 to 9 months. Parafollicular cells were observed in the thyroids of all foetuses examined. The ultrastructure of the parafollicular cells in the foetuses differed very little from that described in adult animals. Histochemically, Luxol fast blue positive phospholipids and α-glycerophosphate dehydrogenase activity could be observed in the cells. The Solcia-Sampietro method gave positive results in most of the foetuses examined. The reactions observed at light microscopic level were rather faint in the youngest foetuses. The functional aspects of the results are discussed. 相似文献
8.
No explicit relations to the milk yield on the day of sampling were found when studying the content of calcium, phosphorus, magnesium, potassium and sodium in the arterial and venous blood of cows before and after milking in the peak lactation period. However, there is a tendency of higher milk yields at higher phosphorus levels in the milk of the Black-Pied and higher-yielding cows. Some relations to milk fat content were found to be significant: a positive effect of phosphorus content in the blood of Slovak Spotted cows, a positive effect of calcium and magnesium content in the blood of more productive cows and a negative effect of magnesium content in the blood of less productive cows. 相似文献
9.
As it is for mammalian species, growth hormone (GH) is indispensable for normal growth and development of avian species. In contrast to mammals, exogenous GH administration has little, if any, potential for improving the growth rate and feed efficiency of rapidly growing broilers; it is more likely to do so in older birds. This is at least partly because of age-related changes in tissue GH-binding activity and GH-receptor mRNA expression. The effects of GH on lipid deposition depends on the age of the bird and pattern of GH administration. Pulsatile, but not continuous, GH administration to older broilers seems to reduce fat deposition. As in rats, the bioactivity of GH might also depend on the pulse-induced cyclicity in GH receptors and GH-binding proteins. In chickens, GH is also a very potent lipolytic hormone, but seems to have no diabetogenic effect, which is reported in mammalian species. Both insulin-like growth factors have apparently no growth-promoting effects in normal growing broilers, but seem to have opposite effects on fat deposition. In contrast to GH, both insulin-like growth factors have a marked hypoglycemic effect. Whether all these effects are direct effects, or are mediated by secondary mechanisms, awaits further investigations. 相似文献
10.
Middleton G Hillmann DJ Trichel J Bragulla HH Gaschen L 《Veterinary radiology & ultrasound》2012,53(5):545-551
Our objectives were to establish a magnetic resonance (MR) protocol for the examination of, and then describe, the normal ligaments and the supporting structures of the occipitoatlantoaxial region. This was done in 10 cadaver dogs. In addition, MR images of three patients with cervical pain localized to the occipitoatlantoaxial region are included to provide examples of ligamentous abnormalities. All ligaments were hypointense in all pulse sequences. The apical, dorsal atlantoaxial, and dorsal longitudinal vertebral ligaments were seen best in the sagittal T1W and PD-weighted images. The transverse ligament was best visualized in the transverse plane in all pulse sequences and appeared to be confluent with the dorsal longitudinal vertebral ligament dorsal to the dens in the sagittal plane. A 20° dorsal plane reconstructed image in 0.6-mm slice thickness was necessary to visualize the alar ligaments, which were visible in 9/10 dogs. The dorsal longitudinal vertebral ligament appeared continuous with the apical ligament and tectorial membrane. Abnormalities in clinically affected dogs included thickening of the alar ligaments, absence of transverse ligament and elongation, and irregularity of the apical ligament. 相似文献
11.
K. S. Deshpande D. Krishnamurthy J. M. Nigam D. N. Sharma 《The Canadian veterinary journal. La revue veterinaire canadienne》1981,22(7):234-236
Dissection of embalmed and untreated water buffalo carcasses (n=10) revealed that hernias had occurred at the musculotendinous junction of the diaphragm, ventral to the foramen venae cavae and slightly lateral to the median plane. The diameter of the hernial ring varied from 7 cm to 20 cm. Herniation was more common in the right thoracic cavity with the reticulum firmly adherent to the hernia ring. Adhesions between the herniated portion of the reticulum and pleura, lung, pericardium or thoracic wall were present, while in a few cases thick fibrous tracts concealing metallic bodies were found. In two cases, involvement of esophageal groove with malalignment of cardia and reticulo-omasal opening was observed. Displacement and compression of the heart was observed in four animals. 相似文献
12.
Polarised light biomicroscopy was used to examine the normal pre-corneal tear film in 21 eyes of 12 pekingese dogs. The purpose of the study was to examine the influence of excessive exophthalmos on the pre-corneal tear film in the dog. The majority of the animals were found to have high levels of ocular surface contamination by particulate material and plaques of viscous mucus. Other abnormalities included surface lipid with an abnormal granular (three dogs) or 'curdled' (two dogs) appearance; excessive thinning of the lipid layer of the tear film; and the presence of dark globular structures in two dogs, which were presumed to be abnormal meibomian lipid. Break up of the tear film was observed in one dog. Grossly, a thread of viscous mucus was frequently observed along the margin of the lower eyelid. It is postulated that this thread forms because of the excessively exophthalmic conformation of the breed, which prevents the normal access of effete mucus and entrapped debris to the lower conjunctival fornix. The combination of the above factors in the pekingese is suggested as the mechanism whereby the tear film has a reduced stability, thus enhancing the risk from factors more usually considered to initiate corneal ulceration in the breed. The possible adverse effects of lid splitting for the mass removal of distichiae in exophthalmic dogs is discussed. 相似文献
13.
青藏高原多年冻土地区公路建设对植被类型的影响 总被引：3，自引：3，他引：0
在查阅相关资料的基础上,采用常规草地调查的方法进行了实地调查.结果显示:随着生态因子发生变化和人类活动的加剧,该区公路沿线高寒草甸类草地群落结构表现出了较强的稳定性,中旱生耐旱的根茎型禾草比重有所增加;高寒草原植物群落稳定性相对较差,草地群落为适应新的生境而发生了自然演替;沼泽化草甸亚类草地植物群落中群落伴生种的种类增加,优势种嵩草属植物在群落中的比重有所下降. 相似文献
14.
W. F. van Tijen 《British poultry science》1968,9(1):31-36
Calculations from data of egg quality obtained at four Regional Experimental Farms for Poultry Husbandry and at the Central Institute for Poultry Research “Het Spelderholt” at Beekbergen, the Netherlands, support the conclusions advanced in recent American investigations that the uniform regression of Haugh (1937), which is used for the correction of the height of the thick albumen in relation to the egg weight (0.05 mm. per g. difference in weight), has no general validity. Only for fresh eggs at the beginning of the laying period was an average regression found which did not deviate significantly from the Haugh regression. Significant differences between farms and strain crosses were not established as long as exceptionally deviating circumstances were not considered. It was also found that as the laying period proceeded the Haugh correction factor for the height of the thick albumen in relation to the egg weight could have an adverse effect. The same conclusion is valid for stored eggs produced at the end, and probably at the beginning, of the laying period. 相似文献
15.
In vitro studies of lens formation in chick embryo have suggested the action of two factors leading the lens induction in the cephalic ectoderm in the absence of optic vesicle: preliminary instructive specific stimulus (homotypic endo-mesoderm) and permissive unspecific stimulus (heterotypic mesenchymes). In order to detect the true capacities of tissues that exert this influence in the cultural condition, series of in vitro experiments were planned. Exclusion experiments: explants including presumptive lens ectoderm were cultured previous to a progressive exclusion of adjacent tissues to trigger lens formation (endoderm, mesoderm and neural tissue), from stage 1 to 7 of HAMBURGER/HAMILTON. Recombinant experiments: Recombinations of caudal epiblast with cephalic hypoblast from blastoderms stages 3, 4 and 5; and recombinations of cardiac mesoderm stage 7 with trunk ectoderm stage 11, were cultured in close association. Lens and lentoids were formed in the presumptive lens ectoderm, even when endoderm, neural tissue and optic vesicle were excluded, but always in presence of subjacent mesoderm. Observation of cephalic epiblast after to be separated mechanically from the underlying tissues showed that the presumptive cardiac mesoderm remains in contact with the epiblast. Beside the cardiac area was capable of forming lens bodies in contact with the trunk ectoderm. It was concluded that the cardiac mesoderm is able to exert a instructive specific stimulus and a permissive unspecific stimulus during in vitro lens formation. 相似文献
16.
17.
Rashed R Imagawa T Uehara M 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(12):1261-1263
A single olivocerebellar fiber branches off several climbing fibers. One Purkinje cell receives input from only one climbing fiber. A single inferior olivary neuron, therefore, synapses with several Purkinje cells, so that there are more Purkinje cells than the inferior olivary neurons. We aimed to elucidate the numerical ratio of the inferior olivary neurons to Purkinje cells in the chicken. The total numbers were 353,834 +/- 5,274 in the Purkinje cells per the cerebellum and 21,553 +/- 904 in the inferior olivary neurons of both sides. The numerical ratio of inferior olivary neurons to Purkinje cells was 1:16. The ratio of those neurons in mammals is about 1:4-17, so that the ratio in the chicken is within the range of mammals. 相似文献
18.
Behrens BA Nolte I Bouguecha A Helms G Gerkhardt E Meyer-Lindenberg A 《DTW. Deutsche tier?rztliche Wochenschrift》2006,113(1):24-27
Total hip endoprotheses are a good possibility for treatment degenerative wear and pathologic damage of the hip joint in man as well as in dogs. However, aseptic loosening of the protheses, especially in the area of the shaft, is still a problem in conventional total hip endoprotheses. The purpose of the present study was to use the finite-element-analysis (FEA), to enhance endoprothetic design and to prevent loosening of protheses. In order to simulate the femur of the dog for numerical analysis, a material law for the compacta in the femur of the dog was developed. The elastic properties of the compacta were experimentally determined by using compression tests of bone samples of euthanised dogs. The results show constant denseness and a constant axial elastic modul in the compacta. 相似文献
19.
Behrens BA Nolte I Bouguecha A Kammler M Halbritter U Besdo S Meyer-Lindenberg A 《Berliner und Münchener tier?rztliche Wochenschrift》2005,118(3-4):160-163
The degenerative wear and pathologic damage of the joints are reasons for total endoprotheses in man as well as in dogs. The main problem is the aseptic loosening of the protheses. By usig the finite-element-method, the total endoprothesis is designed with new features, with the purpose of preventing loosening and being better adapted to load transmission. In order to simulate the femur of the dog for the numerical analysis, a material law is developed. By taking into account the anisotropy and the local density of the cancellous bone in the femoral head, the young's modules are experimentally determined. The measurements are performed by ultrasonic methods on femoral heads of euthanised dogs. The results show planar isotropic cancellous bone. 相似文献
20.
Neurophysiologic maps of the cutaneous innervation of the external genitalia of the ewe 总被引：1，自引：0，他引：1
The area of skin supplied by the afferent fibers in a peripheral nerve is called the cutaneous area (CA) of that nerve. The CA responsive to movement of wool or hair in the genital regions were mapped in 17 ewes, with the identifications of the peripheral nerves and of the spinal nerves contributing to the pudendal plexus being checked at necropsy. Differences were found in the origins and extent of CA of the cutaneous branches from the sacral plexus. The CA of the caudal rectal nerves and of a nerve that passed caudally between the caudal vertebrae and the ventral sacrococcygeus muscle lay lateral to the anus and in the adjacent skin of the tail. The CA of the proximal cutaneous branch and of the distal cutaneous branch from the pudendal nerve (or plexus) overlapped craniocaudally (by approx one-half) the CA of the distal cutaneous branch extending ventrally and ending just caudal to the ipsilateral mammary gland. The deep perineal nerve innervated the skin immediately lateral to the anus and vulva. The dorsal nerve of the clitoris innervated hairs on the ipsilateral half of the vulva. Other fibers in the pudendal nerve were presumed to pass into the mammary branch of the nerve. They innervated the skin ventral to the vulva, the ipsilateral mammary gland, and (in some ewes) areas of the skin cranial to the mammary gland. The CA of the genitofemoral nerve included the ipsilateral teat and the inguinal fossa.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献