Morphology of the non-sensory tissue components in rat aging vomeronasal organ

With 30 figures, 3 histograms and 3 tables SUMMARY: The vomeronasal organ (VNO) is a chemosensory organ that detects environmental pheromones. The morphology of the 'non-sensory' epithelium (NSE) of the VNO and its lamina propria, as well as how it relates to ageing has received little attention. Histological, histochemical, morphometric and ultrastructural techniques were used to study the morphological structure of the rat NSE in five adult (3 months old) and five aged (2-2.5 years old) male albino rats. In adult rats, the NSE contained dark and light columnar cells with predominance of the latter. The surface of the epithelial cells was covered with microvilli and/or cilia. The lamina propria contained serous vomeronasal glands (VNGs), smooth muscles with numerous variable-sized mitochondria, vessels including lymphatic capillaries and nerve bundles. The following changes were detected in aged rats. The NSE exhibited an increase in number of dark columnar cells. Some cells revealed a prominent cell coat, dense aggregation of filaments in the luminal cytoplasm and appearance of multinucleated cells. Their surface revealed malformed configuration. Large mitochondria (2 μm), formed by fusion, were frequently observed in the smooth muscle cells of the lamina propria. Lipid droplets were frequently detected both in the VNGs acini and in the lymphatic endothelium. Ageing affected both the cells of the tissues and the extracellular matrix.     

Light and scanning electron microscopic studies of the nasal turbinates of the horse

The nasal turbinates of 5 young horses were studied by light and scanning electron-microscopy. Stratified cuboidal epithelium lined the rostral part of the dorsal and ventral nasal turbinates of the vestibular region. The polyangular microvillus cells of this region were separated by linear depressions. The mid and caudal parts of the dorsal and ventral nasal turbinates and the rostral part of the ethmoturbinates were lined by pseudostratified columnar ciliated respiratory epithelium. Numerous cilia with dilated blebs on the ciliated cells concealed adjacent non-ciliated supporting cells and goblet cells. The olfactory zone consisting of the olfactory vesicle and a dense network of olfactory cilia localized to the caudal part of the ethmoturbinates. The three regions were delineated from each other by transitional zones.     

Histological Characteristics of the Tracheobronchial Tree of the Least Shrew (Cryptotis Parva)

The least shrew (Cryptotis parva) is a small vomit‐competent insectivorous species which has recently been introduced as an emesis animal model in the laboratory. In this study, the respiratory system of the least shrew was examined and compared with the well‐established larger species routinely used in the laboratory. Five least shrews (4–5 g body weight, 45–60 days old) were used. Standard histological procedures were followed for light microscopic examination. The lining epithelium of the trachea was found to be pseudostratified ciliated columnar (PSCC). Three types of cells were easily identified, basal and ciliated as well as few goblet cells interspersed among the ciliated cells and they were not clearly recognizable. A few tracheal seromucous glands were located at the free end of the C‐shaped cartilaginous rings. The cartilaginous rings are replaced by smooth muscle cells before the bronchi enter into the lung. The lining epithelium of tracheobronchial tree gradually changes into simple cuboidal epithelium that lacks goblet cells. However, the division of the tracheobronchial tree is similar to other mammalian species. On the other hand, the principal bronchus lacks cartilaginous plaques as it becomes intrapulmonary bronchus. The wall of the bronchi is supported by thick layers of spirally arranged smooth muscles. Two types of cells were readily recognizable: basal and ciliated cells, with rarely observed goblet cells. In addition, the PSCC epithelium changes into simple cuboidal much earlier in the bronchial division relative to other species.     

Apoptosis‐Related Protein Expression During Pre‐ and Post‐Natal Testicular Development After Administration of Glucocorticoid in utero in the Sheep

Pre‐natal glucocorticoids are used in women at risk of preterm delivery to induce foetal lung maturation. However, glucocorticoids can produce negative outcomes for other tissues such as the reproductive system. We therefore tested the effects of pre‐natal betamethasone on testicular morphology and apoptotic protein immune expression during pre‐ and post‐natal development. Pregnant ewes (n = 42) bearing singleton male foetuses were randomly allocated to receive intramuscular injections of saline or betamethasone (0. 5 mg/kg) at 104, 111 and 118 days of gestation (DG). Testes were collected at 121 and 132 DG, and at 45 and 90 post‐natal days (PD) and subjected to morphometric analysis (volume densities of sex cords and interstitial tissues; sex cord diameter). Immunohistochemistry (% stained area) was used to assess active caspase‐3, Bax, Bcl‐2 and cell‐cycle proteins (PCNA). Compared with control values, betamethasone treatment decreased sex cord diameter at 121 DG, 45 and 90 PD, and sex cord volume at 90 PD. Active caspase‐3 was decreased by betamethasone at 121 DG and 90 PD, but Bax was increased in all betamethasone groups. Bcl‐2 and PCNA decreased in the betamethasone groups at 121 DG and 45 PD, but increased at 132 DG and 90 PD. We conclude that high levels of pre‐natally administered glucocorticoid reduce foetal testicular development, perhaps via changes in the balance between pro‐ and anti‐apoptotic proteins and cell‐cycle proteins. These outcomes could compromise the future spermatogenic potential of male offspring.     

鸡中脑导水管及视叶脑室壁的扫描电镜观察

鸡中脑导水管及视叶脑室的底壁主要由多纤毛细胞构成.表面满布草丛状纤毛和微绒毛,无区域性差异;其顶壁的表面结构呈非均一性,主要由少纤毛细胞、无纤毛细胞及伸张细胞交错排列形成的嵌合体构成.在中脑导水管顶壁,除见有神经元样细胞、神经胶质样细胞和类组织细胞外,还发现了神经元样复合体.     

Scanning electron and light microscopic studies of the surface epithelium of the rete testis and epididymis of the boar. I. Rete testis and efferent ducts

The use of the scanning electron microscope gave a three dimensional representation of the epithelial surface. Additionally, light microscopy revealed the representative structure of the epithelium. The rete testis showed a single layer of cubic epithelial cells. Short and dense microvilli were found on the surface. Sporadically a single, cilia-like structure was recognized. An extratesticular rete testis was identified. The flowing transition of the epithelium between the rete testis and the efferent ductuli occurred at different levels, so that both kinds of epithelial structures were recognized in the same area. The efferent ductuli were composed of a single columnar epithelium consisting of two cell types, principal cells and ciliated cells. The ciliated cells were recognized by their cilia protruding into the lumen. The principal cells showed microvilli on their surface and bleblike apical protrusions which erupt into the lumen.     

An intrauterine catch‐up growth regimen increases food intake and post‐natal growth in rats

Nutritional conditions during the intrauterine stage are an important developmental programming factor that can affect the growth and metabolic status during foetal development and permanently alter the phenotypes of newborn offspring and adults. This study was performed to examine the effects of intrauterine catch‐up growth (IUCG) on food intake, post‐natal body growth and the metabolic status of offspring and growing rats. Control pregnant rats were fed ad libitum during the entire gestation period. For the IUCG regimen, pregnant rats were fed 50% of the food of the controls from pregnancy days 4 through 11 (8 days), followed by ad libitum feeding from pregnancy days 12 through parturition. The birth weight of offspring was not affected by the IUCG regimen. At weaning, offspring from each treatment group were assigned to two groups and given either a normal diet or high‐fat diet (HFD) for 12 weeks until 103 days of age. In the normal diet group, the IUCG offspring showed a 9.0% increase (P < 0.05) in total food intake, were 11.2% heavier (p < 0.05) at 103 days of age and had an 11.0% greater (p < 0.05) daily weight gain compared with control offspring. The IUCG regimen did not affect body glucose and lipid metabolism. After exposure to the HFD, the IUCG regimen has not exacerbated metabolic disorders. In conclusion, our findings suggest that the IUCG nutritional regimen during pregnancy can increase the food intake and post‐natal body growth of offspring without inducing metabolic disorders such as obesity and insulin resistance. The IUCG nutritional regimen might be used to improve the food intake and post‐natal body growth of domestic animals.     

Morphological Studies on the Development of the Bronchial Epithelium of the Fetal Camel Lung

Light microscopic observations revealed that in camel foetuses of 25 mm crown‐to‐rump length (CRL) the primordial tubular system of the prospective lung was formed of several tubules lined by undifferentiated columnar epithelium. Intra‐epithelial neuroendocrine cells were the first elements to be differentiated in the lining epithelium of the primordial tubular system of the prospective lung as early as 25 mm CRL. On reaching 50–67 mm CRL, the primordial tubular system started to differentiate into two systems of primordial tubules, the prospective bronchial or light tubules and the future respiratory or dark tubules. The lining epithelium of the prospective bronchial tubules revealed a clear evidence of ciliogenesis as early as 80 mm CRL. From 800 mm CRL onwards, the bronchial epithelium demonstrated ciliated and non‐ciliated secretory cells. The non‐ciliated secretory cells of the bronchial epithelium of fetal camel lung showed moderate reaction to AB/PAS technique, for the first time, in fetuses reaching 600 mm CRL.     

Dominant follicles development and estradiol‐17β concentrations in non‐ovulating and ovulating post‐partum Bulgarian Murrah buffaloes

This study was designed to evaluate the dominant follicles development and the estradiol‐17β concentrations in non‐ovulating and ovulating post‐partum buffaloes. Sixteen Bulgarian Murrah buffaloes were submitted to transrectal ultrasonographic examination from the 1st post‐partum day until day 50, 3 days apart. The follicular diameter of the different categories of follicles and the ovulations was recorded. The animals were allocated into two groups: I (n = 6) non‐ovulating and II (n = 10) ovulating buffaloes. Serum estradiol‐17β concentrations on the days for dominant follicle registration were measured by enzyme‐linked immunosorbent assay. The results were statistically processed by analysis of variance, non‐parametric and correlation analysis. The mean intervals between calving and first dominant follicle detection differed significantly (p < .05) among the groups (19.5 ± 6.2 vs. 13.8 ± 5.1 days), while the mean intervals between registered dominant follicles from two successive waves were comparable. The mean follicular diameters for the same category follicles in both groups were similar. Different estradiol‐17β concentrations (p < .05) for the first dominant follicle between non‐ovulating (23.5 ± 7.0 pg/ml) and ovulating (33.3 ± 8.4 pg/ml) buffaloes were determined. The cumulative percentages of buffaloes with firstly detected dominant follicle and ovulating animals correlated positively (r ≥ .84; p < .05) to post‐partum days. In conclusion, non‐ovulating and ovulating post‐partum Bulgarian Murrah buffaloes showed differences in the development of the first dominant follicle and estradiol‐17β concentrations during the time of dominant follicles detection.     

Ultrastructural Features of the Bovine Cecal Mucosa

The cecal surface epithelium of cattle was lined entirely by columnar cells except near the openings of the glands where a few partially depleted goblet cells were encountered. Surface columnar cells with pale cytoplasm, indented (sometimes dome-shaped) apical border and irregular microvilli, were also found near the gland orifices. Surface columnar cells -near the openings of the glands contained large cytoplasmic vacuoles and lysosomal-like bodies. Near the extrusion zone, however, the columnar cells contained highly indented and apically displaced nuclei. The glands were usually long and straight and lined by an epithelium concisting mainly of undifferentiated and goblet cells. There were few entero-endocrine and non-epithelial cells (intra-epithelial lymphocytes and globule leukocytes). Paneth cells were absent. The undifferentiated cells contained many free ribosomes and apical secretory granules. Some of these cells were undergoing mitotic division. Goblet cells exhibited a typical brandy-glass appearance and showed dark and light mucigenous granules. Endocrine cells with polymorphic secretory granules and cells with more uniform secretory granules were identified in the basal part of the epithelium. Globule leukocytes and intra-epithelial lymphocytes were usually encountered near the basal part of the epithelium. The lamina propria was highly cellular. It contained many plasma cells, mast cells and small lymphocytes, and few eosinophils, neutrophils and globule leukocytes. Some of the plasma cells contained large, dense Russell bodies within the cisternae of the rough-surfaced endoplasmic reticulum. The neutrophils displayed distinct populations of small and large cytoplasmic granules. Some of the eosinophilic granules showed narrow crystalline cores. Large lymphocytes were found in the lamina propria, but occurred less frequently than small lymphocytes.     

Light and electron microscope studies on the nasopharynx and nasopharyngeal tonsil of the horse

Light and electron microscope studies were conducted on the nasopharynx and the nasopharyngeal tonsil of 15 young horses. The nasopharynx and nasopharyngeal tonsil was lined with pseudostratified columnar ciliated epithelium and goblet cells. The lymphoepithelium of the nasopharyngeal tonsil was folded forming crypts, the mucosa of which was modified into follicle associated epithelium characterized by stratified cuboidal epithelium, loss of cilia, absence of goblet cells and infiltration of lymphocytes. The lamina propria mucosae of the nasopharyngeal tonsil contained well-developed lymphoid tissue and clusters of seromucus acini. Scanning electron-microscopy revealed a dense mat of cilia covering the nasopharynx and nasopharyngeal tonsil. The follicle-associated epithelium consisted of different populations of microvillus cells in addition to M cells with very short microvilli and a few squamous and intermediate cells. Microvillus cells in the deeper part of the FAE had larger microvilli and their cytoplasm contained a dense population of mitochondria, smooth and rough endoplasmic reticulum, Golgi complexes and lysosomes. The flat surfaced M cell had a more electron-dense cytoplasm and contained small supranuclear vacuoles in addition to the organelles seen in microvillus cells.     

The Effect of Lactation on Post‐Partum Uterine Involution in Holstein Dairy Cows

The objective was to examine the effect of lactation on uterine involution in post‐partum dairy cows. Holstein primiparous cows were used (n = 19, mean age: 3.9 ± 0.1 years). At calving, cows were randomly assigned to one of two treatment groups, lactating (n = 11) or non‐lactating (i.e. dried off at calving, n = 8). Examination of the reproductive tract was carried out by ultrasonography twice weekly until week 7 post‐partum. Blood samples were collected twice weekly for the analysis of progesterone to indicate the resumption of cyclicity and metabolites indicative of energy status. Uterine involution was assessed in terms of size of the uterine horns, uterine body diameter and uterine fluid volume as assessed by the amount of non‐echogenic material measured by ultrasound and position of the uterus. Vaginal mucous score was taken on day 28 post‐partum for the assessment of uterine inflammation. Resumption of cyclicity (serum progesterone > 1 ng/ml) had occurred in both groups on average by day 21 post‐partum. Concentrations of non‐esterified fatty acids and beta‐hydroxybutyrate were higher, whereas concentrations of glucose, insulin and IGF‐1 were lower (p < 0.05) in lactating compared to non‐lactating cows. Lactating cows had a smaller mean uterine body diameter (p < 0.05) than non‐lactating cows from days 28 to 42 post‐partum (day 28: 20.2 ± 1.3 vs 24.9 ± 1.5 mm, respectively) and had a lower mean uterine fluid volume up to day 49 (p < 0.05). By day 49, there was no difference in uterine diameter (15.2 ± 1.8 vs 15.2 ± 1.6 mm) or uterine fluid volume (0.11 ± 0.38 vs 0.18 ± 0.46) between lactating and non‐lactating cows, respectively. Vaginal mucous score revealed no evidence of uterine inflammation in either group. In conclusion, while lactation induced significant alterations in metabolic status, it did not have a major effect on the rate of uterine involution as defined in this study.     

Blood Metabolite Profiles in Cycling and Non‐cycling Friesian–Sanga Cross‐bred Cows Grazing Natural Pasture During the Post‐partum Period

An experiment was conducted to investigate the effect of plasma concentrations of the metabolic hormones [Growth hormone (GH), insulin and insulin‐like growth factor –I (IGF‐I)] and nutritional metabolites (Glucose, cholesterol, total protein, albumin, globulin, urea and creatinine) on the resumption of post‐partum ovarian activity in sixteen Friesian–Sanga cows grazing extensively on native grassland. Blood samples were taken from cows from week 1 to 16 post‐partum. Cows were classified as having resumed ovarian activity when a plasma progesterone concentration of ≥ 1.0 ng/ml was recorded for two consecutive weekly samples. Based on the resumption of ovarian activity, cows were classified as early‐cycling, late‐cycling or non‐cycling. The concentrations of the metabolic hormones were measured from week 1 to 10, while those of the nutritional metabolites were measured during week 1, 3, 5, 7 and 9 during the study period. The concentrations of the metabolic hormones, GH and insulin were similar (p > 0.05) in the three ovarian activity groups, likewise the concentrations of the nutritional metabolites, glucose, total protein, globulin, urea and creatinine. Plasma IGF‐I concentration was higher (p < 0.001) in early‐cycling (18.7 ± 0.74 ng/ml) than in late‐cycling (12.4 ± 0.75 ng/ml) and non‐cycling (10.4 ± 0.91 ng/ml) cows. Plasma cholesterol concentrations were significantly lower (p < 0.05) in early‐cycling (1.94 ± 0.15 mmol/l) compared with late‐cycling (2.48 ± 0.12 mmol/l) and non‐cycling (2.61 ± 0.11 mmol/l) cows. For plasma albumin concentrations, the levels recorded for early‐cycling cows were higher (40.7 ± 2.85 g/l) than in late‐cycling (34.4 ± 1.97 g/l) and non‐cycling (33.6 ± 2.66) cows. The results suggest that cows with lower plasma concentrations of IGF‐I and albumin, but higher plasma cholesterol concentrations were at risk of delayed resumption of post‐partum ovarian activity.     

Birth of Kids After Artificial Insemination with Sex‐Sorted,Frozen‐Thawed Goat Spermatozoa

Successful sex‐sorting of goat spermatozoa and subsequent birth of pre‐sexed kids have yet to be reported. As such, a series of experiments were conducted to develop protocols for sperm‐sorting (using a modified flow cytometer, MoFlo SX^®) and cryopreservation of goat spermatozoa. Saanen goat spermatozoa (n = 2 males) were (i) collected into Salamon's or Tris catch media post‐sorting and (ii) frozen in Tris–citrate–glucose media supplemented with 5, 10 or 20% egg yolk in (iii) 0.25 ml pellets on dry ice or 0.25 ml straws in a controlled‐rate freezer. Post‐sort and post‐thaw sperm quality were assessed by motility (CASA), viability and acrosome integrity (PI/FITC‐PNA). Sex‐sorted goat spermatozoa frozen in pellets displayed significantly higher post‐thaw motility and viability than spermatozoa frozen in straws. Catch media and differing egg yolk concentration had no effect on the sperm parameters tested. The in vitro and in vivo fertility of sex‐sorted goat spermatozoa produced with this optimum protocol were then tested by means of a heterologous ova binding assay and intrauterine artificial insemination of Saanen goat does, respectively. Sex‐sorted goat spermatozoa bound to sheep ova zona pellucidae in similar numbers (p > 0.05) to non‐sorted goat spermatozoa, non‐sorted ram spermatozoa and sex‐sorted ram spermatozoa. Following intrauterine artificial insemination with sex‐sorted spermatozoa, 38% (5/13) of does kidded with 83% (3/5) of kids being of the expected sex. Does inseminated with non‐sorted spermatozoa achieved a 50% (3/6) kidding rate and a sex ratio of 3 : 1 (F : M). This study demonstrates for the first time that goat spermatozoa can be sex‐sorted by flow cytometry, successfully frozen and used to produce pre‐sexed kids.     

Gonadotropin‐Releasing Hormone Administration to Dairy Cows without a Corpus Luteum 4 Weeks after Calving Increases Reproductive Performance

This field study investigated whether the administration of a single dose of gonadotropin‐releasing hormone (GnRH) to dairy cows without a corpus luteum (CL) 4 weeks after calving can improve reproductive performance. Holstein dairy cows underwent ultrasonography to assess the presence of ovarian structures at 29.2 ± 5.2 days post‐partum, and cows were divided into two main groups based on the presence (CL group, n = 230) or absence (non‐CL group, n = 460) of a CL. The non‐CL group was further randomly divided into two subgroups based on the administration of GnRH (non‐CL GnRH group, n = 230) or no GnRH (non‐CL control group, n = 230). Subsets of cows from non‐CL control (n = 166) and non‐CL GnRH (n = 175) groups received a second ultrasonography at 44.5 ± 5.4 days post‐partum to assess CL formation. The percentage of cows with CL at the second ultrasonography was greater in the non‐CL GnRH group (70.9%) than in the non‐CL control group (53.0%, p = 0.0006). The hazard of the first post‐partum insemination by 150 days in milk (DIM) was higher in the CL group than in the non‐CL control group (hazard ratio [HR]: 1.36, p = 0.001). The probability of a pregnancy to the first insemination was higher in non‐CL GnRH (odds ratio [OR]: 1.50, p = 0.04) and CL groups (OR: 1.55, p = 0.03) compared to the non‐CL control group. Furthermore, the hazard of pregnancy by 210 DIM was higher in non‐CL GnRH (HR: 1.30, p = 0.01) and CL (HR: 1.51, p = 0.0001) groups than in the non‐CL control group. In conclusion, administration of GnRH to dairy cows without a CL 4 weeks after calving was associated with an increase in ovulation and improved reproductive performance.     

Post‐natal changes in MCT1 expression in the forestomach of calves

The monocarboxylate transporter 1 (MCT1) has been demonstrated to be involved in the transfer of short‐chain fatty acids (SCFA) and/or their intraepithelial metabolites from the rumen to the blood. As MCT1 plays a role in SCFA transfer, it is assumed that SCFA are the main substrates influencing its expression. However, there are hints that MCT1 may also be expressed during the early life of the animal when SCFA are not released in the forestomach. To figure out whether MCT1 expression in the forestomach is influenced independently of SCFA during that period, we studied post‐natal MCT1 expression immunohistochemically in the epithelia of omasum, atrium ruminis, saccus dorsalis ruminis, saccus ventralis ruminis and reticulum of calves born preterm and at term. The calves were nourished by colostrum or by milk‐based formula diet. MCT1 could be found in all the forestomach compartments tested, even in preterm calves. The protein was mainly oriented to the luminal side in the immature epithelium 24 h after birth. Orientation to the blood side of the cells developed during the first 4 days after birth. In the rumen epithelia (but not in the other forestomach compartments tested), orientation of MCT1 to the blood side of the cells was paralleled by an increase in the overall expression rate during the first 4 days after birth. As lactate levels were very high directly after birth, a lactate‐dependent substrate induction may have been the underlying mechanism. However, non‐specific changes due to general differential processes might also be the cause. Both early upregulation of MCT1 and high blood lactate levels may provide the epithelia with lactate as energy source.     

Ultrastructural pathology of Bordetella avium infection in turkeys

One-day-old turkeys were infected intranasally with Bordetella avium, and tracheas were examined by scanning and transmission electron microscopy at 1 to 5 weeks post-inoculation (PI). The predominant ultrastructural lesions were progressive loss of ciliated epithelium with replacement by nonciliated cells, bacterial colonization of ciliated cells, membrane-bound crystalline inclusions in cytoplasma of epithelial cells, depletion of mucous granules, and distortion of tracheal rings and the mucosal surface. Tracheal surface exudates consisted of mucus, necrotic cells, heterophils, and fibrin. Ciliated cells were replaced by immature cuboidal cells characterized by abundant rough endoplasmic reticulum with small numbers of electron-dense mucous granules in the apical cytoplasm. Bacterial surfaces were rough and contained numerous pleomorphic, knob-like structures, 20-50 nm in diameter. Other changes included enlarged mucosal gland openings, cell extrusion marks, pleomorphic microvilli, and cells with small numbers of short cilia.     

The surface features of the epithelial lining of the ducts of the epididymis of the ostrich (Struthio camelus)

The luminal appearance of the various ducts of the epididymis of the ostrich was studied by scanning electron microscopy in tissues fixed by immersion in glutaraldehyde. The ductal types were similar to those previously described for some other species of birds. Numerous short microvilli, as well as a single cilium, projected from the apical surface of the rete testis cell. The ciliated cells of the efferent ductules projected tufts of cilia into the ductal lumen, while the non-ciliated cells bore short microvilli. The connecting and epididymal ducts were lined by a columnar cell type whose apical surface bore uniformly distributed microvilli and a single, centrally situated cilium. The spermatozoa found in all ducts of the epididymis bore a distal cytoplasmic droplet. This observation has implications for the maturational process in the ostrich spermatozoon in the epididymis. The surface features of the ducts, except for a few noteworthy differences, were generally similar to those previously described for the male domestic fowl, turkey and duck.     

Haematological and biochemical analysis of healthy neonatal puppies during the immediate foetal‐to‐neonatal transition

For the neonatal patient, precocity of diagnosis is crucial for effectiveness of medical approach. However, the newborn has its own physiological peculiarities due to ongoing adaptive mechanism for extrauterine life and deserves special attention in order to underline a specific management or clinical approach. The objective of this work was to verify clinical adaptations and biochemical balance of neonates during immediate period, with special reference to haematological, renal and metabolic functions. Neonatal puppies (n = 51) were physically examined for vitality and rectal temperature at birth, 5 and 60 min post‐birth. Blood was collected at birth and 60 min post‐birth for analysis of glucose, sodium, potassium, chlorine, blood urea nitrogen (BUN), haematocrit and haemoglobin. Neonatal vitality was lower at birth compared with 5 min and 60 min post‐birth. Progressive decline in rectal temperature (36.5 ± 0.3°C, 34.2 ± 0.2°C, 32.3 ± 0.5°C) was observed at birth, 5 min and 60 min post‐birth, respectively. Puppies presented slight hyponatremia (140.7 ± 0.5 mmol/L) at birth and hypopotassemia (3.5 ± 0.1 mmol/L) and blood urea nitrogen (13.1 ± 0.7 mg/dl) during the first hour, and high haematocrit (45.1 ± 1.0%) and haemoglobin (15.3 ± 0.3 g/dl) concentration. In conclusion, puppies had rapid evolution of vitality. Marked decrease in rectal temperature occurred at 5 min post‐birth. Haematological values of neonates immediately after birth reflected mainly the dam's blood status, not being useful for a blood panel at this time point. The peculiar pattern of BUN, sodium and potassium observed during transition period, suggested that specific reference range should be considered for neonatal puppies.