Electrocardiographic values in Spanish-bred horses of different ages

SUMMARY The duration of electrocardiograph wave forms and intervals were determined in 179 Spanish-bred (Andalusian) horses aged from 1 month to 17 years. The values were compared with those of other breeds, and the relationship between electrocardiographic data and age was examined. High correlation coefficients were found between PR, ST and QT intervals and the age of the horses, and an inverted relation between heart rate and age was found. A multiple range analysis was made and the results suggest that significant changes in duration values and heart rate ocurred at the age of 6 months and in the second year of life.     

Comparison of Diverse Differential Plating Methods to Enrich Bovine Spermatogonial Cells

Spermatogonial stem cells (SSC) have important applications in domestic animal reproduction and advanced biotechnologies. Because differential plating is one of the most common methods used for SSC enrichment, the goal of this study was to compare three differential plating methods for the enrichment of bovine SSC. To achieve this goal, testicular parenchyma from pre‐pubertal calves was minced and single cells were obtained after two enzymatic digestions. We compared three coating methods for differential plating: laminin (20 ng/ml), BSA (0.05 mg/ml) and PBS. Cells were incubated at 37°C, 5% CO₂ in air for 15 min onto laminin‐coated dishes or 2 h onto BSA‐ or PBS‐coated dishes. Cell viability was assessed by trypan blue exclusion method. Recovered cells were analysed for the expression of SSC molecular markers by quantitative RT‐PCR (GFRA1, CXCR4, ITGA6, THY1) and flow cytometry (GFRA1, CXCR4 and ITGA6). Cells at time 0, adherent cells on laminin and non‐adherent cells from BSA and PBS groups had the same cell viability (p = 0.0655). GFRA1, CXCR4 and THY1 relative gene expression was higher (p = 0.0402, p = 0.0007, p = 0.0117, respectively) for non‐adherent cells selected in PBS group. Flow cytometry analysis revealed that the presence of GFRA‐positive (GFRA+) cells was higher in non‐adherent cells from BSA and PBS groups (p < 0.001). However, laminin‐adherent cells had higher number of ITGA6+ cells (p < 0.001) and lower presence of CXCR4+ cells (p = 0.0012). In conclusion, differential plating is an effective method for the enrichment of bovine undifferentiated spermatogonia and higher expression of SSC markers is obtained without laminin or BSA coating.     

Does the Microbial Flora in the Ejaculate Affect the Freezeability of Stallion Sperm?

In an attempt to evaluate the possible relationship between the microbial flora in the stallion ejaculate and its ability to freeze, three ejaculates from five stallions were frozen using a standard protocol. Before freezing, an aliquot was removed for bacteriological analysis. Bacterial growth was observed in all the ejaculates studied. The isolated microorganisms were: Staphylococcus spp. and Micrococcus spp. (in all the stallions), β-haemolytic Streptococcus (in stallions 3 and 4), Corynebacterium spp. (in stallions 1, 3–5), Rhodococcus spp. (in stallion number 2), Pseudomonas spp. (in stallion number 1) and Klebsiella spp. (in stallions 1, 3 and 5). The presence and richness of Klebsiella and β-haemolytic Streptococcus in the ejaculate were related to two sperm variables post-thaw, namely the proportion of dead spermatozoa (ethidium+ cells; r = 0.55, p < 0.05) and the amplitude of lateral displacement of the sperm head (ALH, μm; r = −0.56, p < 0.05), respectively. The degree of growth of Corynebacterium spp. in the ejaculate was positively correlated with the percentage of spermatozoa showing high caspase activity post-thaw (r = 0.62, p < 0.05). The presence and number of colonies of β-haemolytic Streptococcus were negatively correlated (r = −0.55, p < 0.05) with low sperm caspase activity. It is concluded that the microbial flora of the equine ejaculate may be responsible for some of the sublethal damage experimented by the spermatozoa during cryopreservation.     

Epidemic of blindness in kangaroos - evidence of a viral aetiology

OBJECTIVE: To determine the cause of an epidemic of blindness in kangaroos. DESIGN AND PROCEDURES: Laboratory examinations were made of eyes and brains of a large number of kangaroos using serological, virological, histopathological, electron microscopical, immunohistochemical methods, and PCR with cDNA sequencing. In addition, potential insect viral vectors identified during the disease outbreak were examined for specific viral genomic sequences. SAMPLE POPULATION: For histopathological analysis, 55 apparently blind and 18 apparently normal wild kangaroos and wallabies were obtained from New South Wales, Victoria, South Australia, and Western Australia. A total of 437 wild kangaroos and wallabies (including 23 animals with apparent blindness) were examined serologically. RESULTS: Orbiviruses of the Wallal and Warrego serogroups were isolated from kangaroos affected with blindness in a major epidemic in south-eastern Australia in 1994 and 1995 and extending to Western Australia in 1995/96. Histopathological examinations showed severe degeneration and inflammation in the eyes, and mild inflammation in the brains. In affected retinas, Wallal virus antigen was detected by immunohistochemical analysis and orbiviruses were seen in electron microscopy. There was serological variation in the newly isolated Wallal virus from archival Wallal virus that had been isolated in northern Australia. There were also variations of up to 20% in genotype sequence from the reference archival virus. Polymerase chain reactions showed that Wallal virus was present during the epidemic in three species of midges, Culicoides austropalpalis, C dycei and C marksi. Wallal virus nucleic acid was also detected by PCR in a paraffin-embedded retina taken from a blind kangaroo in 1975. CONCLUSION: Wallal virus and perhaps also Warrego virus are the cause of the outbreak of blindness in kangaroos. Other viruses may also be involved, but the evidence in this paper indicates a variant of Wallal virus, an orbivirus transmitted by midges, has the strongest aetiological association, and immunohistochemical analysis implicates it as the most damaging factor in the affected eyes.     

Alpaca plant poisonings: nitrate–nitrite and possible cyanide

Nitrate–nitrite poisoning killed four adult alpacas and induced the abortion of a full-term fetus after access to oaten hay ( Avena sativa ) containing 3.2% KNO₃ equivalent in dry matter. Necropsy findings were cyanosis, dark-coloured blood, and pulmonary congestion and oedema. Aqueous humour from two adults contained 25 mg NO₃/L and that from the fetus contained 10 mg NO₃/L. Cyanide poisoning possibly killed two adult wether alpacas that ate a garden-cultivated variety of Osteospermum ecklonis (South African daisy, bietou) with a cyanide potential of 6800 mg HCN/kg dry matter.     

Peripartum Haemodynamic Status of Bitches with Normal Birth or Dystocia

There has been limited investigation of parturition in the bitch and there is little information published on clinical and obstetrical examination other than opinion and anecdote. While there are substantial data on haemodynamic and vascular changes during normal parturition in humans, little is known about the physiological events in the dog. This study was aimed at maternal haemodynamic changes occurring during normal parturition and to investigate how these were modified in bitches with dystocia (DYST) treated either medically or via assisted delivery and caesarean operation. Three groups of 10 bitches were investigated; those with normal parturition, those with DYST corrected by manipulative assistance or caesarean operation and those with uterine inertia treated by oxytocin administration. Heart rate, systolic and diastolic blood pressure, electrocardiogram and blood glucose concentration were measured pre-partum, intra-partum, immediately after parturition and 1 h later. Heart rate was high at all times throughout the study and the majority of bitches had normal sinus rhythm. Blood pressure was generally within the normal range, and although systolic and diastolic blood pressure was highest during the intra-partum period and sometimes during the immediate post-partum period, there were no significant differences between groups. All bitches had blood glucose concentrations within the normal range throughout the study although pre-partum concentrations were statistically lower than many of the other time periods. The study provides useful physiological data that will facilitate monitoring and clinical management of bitches throughout normal parturition and DYST.     

Caspase Activation,Hydrogen Peroxide Production and Akt Dephosphorylation Occur During Stallion Sperm Senescence

To investigate the mechanisms inducing sperm death after ejaculation, stallion ejaculates were incubated in BWW media during 6 h at 37°C. At the beginning of the incubation period and after 1, 2, 4 and 6 h sperm motility and kinematics (CASA), mitochondrial membrane potential and membrane permeability and integrity were evaluated (flow cytometry). Also, at the same time intervals, active caspase 3, hydrogen peroxide, superoxide anion (flow cytometry) and Akt phosphorylation (flow cytometry) were evaluated. Major decreases in sperm function occurred after 6 h of incubation, although after 1 h decrease in the percentages of motile and progressive motile sperm occurred. The decrease observed in sperm functionality after 6 h of incubation was accompanied by a significant increase in the production of hydrogen peroxide and the greatest increase in caspase 3 activity. Additionally, the percentage of phosphorylated Akt reached a minimum after 6 h of incubation. These results provide evidences that sperm death during in vitro incubation is largely an apoptotic phenomena, probably stimulated by endogenous production of hydrogen peroxide and the lack of prosurvival factors maintaining Akt in a phosphorylated status. Disclosing molecular mechanisms leading to sperm death may help to develop new strategies for stallion sperm conservation.