Vertical distribution, size and composition of the weed seedbank under various tillage and herbicide treatments in a sequence of industrial crops

Investigations were conducted during the 2003, 2004 and 2005 growing seasons in northern Greece to evaluate effects of tillage regime (mouldboard plough, chisel plough and rotary tiller), cropping sequence (continuous cotton, cotton–sugar beet rotation and continuous tobacco) and herbicide treatment on weed seedbank dynamics. Amaranthus spp. and Portulaca oleracea were the most abundant species, ranging from 76% to 89% of total weed seeds found in 0–15 and 15–30 cm soil depths during the 3 years. With the mouldboard plough, 48% and 52% of the weed seedbank was found in the 0–15 and 15–30 cm soil horizons, while approximately 60% was concentrated in the upper 15 cm soil horizon for chisel plough and rotary tillage. Mouldboard ploughing significantly buried more Echinochloa crus‐galli seeds in the 15–30 cm soil horizon compared with the other tillage regimes. Total seedbank (0–30 cm) of P. oleracea was significantly reduced in cotton–sugar beet rotation compared with cotton and tobacco monocultures, while the opposite occurred for E. crus‐galli. Total seed densities of most annual broad‐leaved weed species (Amaranthus spp., P. oleracea, Solanum nigrum) and E. crus‐galli were lower in herbicide treated than in untreated plots. The results suggest that in light textured soils, conventional tillage with herbicide use gradually reduces seed density of small seeded weed species in the top 15 cm over several years. In contrast, crop rotation with the early established sugar beet favours spring‐germinating grass weed species, but also prevents establishment of summer‐germinating weed species by the early developing crop canopy.     

MENINGEAL HAEMORRHAGE AND CONGESTION ASSOCIATED WITH THE PERINATAL MORTALITY OF BEEF CALVES

Thirty Angus, Hereford and Shorthorn term calves dying before, during or within 7 days of birth in a large beef herd were autopsied. Selected specimens were examined histologically. Two carcasses were classified in the category of ante-parturient death, 24 as parturient, and 4 were classified in the post-parturient death category. Three of the latter showed evidence of starvation. Eight of the calves in the parturient death category were assisted during delivery, and 16 were not assisted. The incidence of nulliparous dams among assisted parturient deaths was significantly higher than among the unassisted group. A high incidence of meningeal haemorrhages and congestion were observed at single or multiple sites, within and around the cranial and spinal meninges. The lesions comprised subdural and epidural haemorrhages, bloodstained cerebrospinal fluid and leptomeningeal haemorrhage and congestion. They were seen in calves in both parturient and post-parturient death categories but not in the ante-parturient group. All calves classified in the parturient death category which were assisted during delivery showed haemorrhages involving the cranial and/or spinal meninges. Additional birth injuries, including separation of the costo-chondral junctions, fractured ribs, haemorrhage into the hip joints, inter-vertebral fibrocartilages and axillae, and rupture of the liver, were frequently present. Ten of the calves in the parturient death category which were unassisted during delivery showed meningeal haemorrhage and congestion. Two of the 4 calves in the post-parturient death category showed similar lesions and both showed evidence of starvation. The meningeal haemorrhages and congestion were similar to those observed in perinatal lamb mortality. They are considered manifestations of injury to the CNS arising from trauma and/or hypoxia during birth. Gross or microscopic evidence of infection was present in 2 calves in the post-parturient death category. Calves which had starved showed subcutaneous oedema of the distal limbs, congestion and focal haemorrhage of the adrenal cortex and red-brown fat depots. It is suggested that these changes are evidence of cold injury, and that fat in newborn calves responds to cold and starvation in a manner similar to the brown fat of newborn lambs.     

EPIDEMIOLOGY OF HELMINTH INFESTATION OF BEEF CATTLE IN CENTRAL QUEENSLAND

The results of epidemiological studies of helminths in young beef cattle in Central Queensland over a 2½-year period commencing in January 1964 are reported. Studies were made on ten beef cattle properties, which have a total annual calf crop of approximately 2500 calves. Twenty-five faecal samples were collected monthly at random from 30 to 40 permanently identified calves on each property, to determine the types and intensity of helminth infections. Although rainfall was well below average, infections with most of the helminth species commonly found in Queensland were detected. Increases in infection levels occurred, after rainfall of two inches or more, in animals up to 21 months of age. Only on a property where pastures were irrigated and the stocking rate was higher than normal for the area did a high percentage of calves show clinical symptoms of parasitic gastroenteritis. Haemonchus placet and Oesophagostomum radiatum were the predominant species. An immunity developed to O. radiatum during the first 12 to 15 months of the calf's life. The immunity to H. placet was variable with some animals susceptible to re-infection up to 21 months of age. Recommendations for the control of helminths in beef cattle in this area are given.     

Evaluation of Methods to Determine Sperm Density for the European eel,Anguilla anguilla

European eel, Anguilla anguilla, is a target species for future captive breeding, yet best methodology to estimate sperm density for application in in vitro fertilization is not established. Thus, our objectives were to evaluate methods to estimate European eel sperm density including spermatocrit, computer‐assisted sperm analysis (CASA) and flow cytometry (FCM), using Neubauer Improved haemocytometer as benchmark. Initially, relationships between spermatocrit, haemocytometer counts and sperm motility were analysed, as well as the effect of sperm dilution on haemocytometer counts. Furthermore, accuracy and precision of spermatocrit, applying a range of G‐forces, were tested and the best G‐force used in method comparisons. We found no effect of dilution on haemocytometer sperm density estimates, whereas motility associated positively with haemocytometer counts, but not with spermatocrit. Results from all techniques, spermatocrit, CASA and FCM, showed significant positive correlations with haemocytometer counts. The best correlation between spermatocrit and haemocytometer counts was obtained at 6000 ×  g (r = 0.68). Of two CASA variants, one or three photographic fields (CASA‐1 and CASA‐2), CASA‐2 showed a very high accuracy to haemocytometer counts (r  =  0.93), but low precision (CV: CASA‐2 = 28.4%). FCM was tested with and without microfluorospheres (FCM‐1 and FCM‐2), and relationships to haemocytometer counts were highly accurate (FCM‐1: r  =  0.94; FCM‐2: r  =  0.88) and precise (CV: FCM‐1 = 2.5; FCM‐2 = 2.7%). Overall, CASA‐2 and FCM‐1 feature reliable methods for quantification of European eel sperm, but FCM‐1 has a clear advantage featuring highest precision and accuracy. Together, these results provide a useful basis for gamete management in fertilization protocols.     

Endometrial Adenocarcinoma and Mucometra in a 6-year-old Alaska Malamute Dog

A 6-year-old female Alaska Malamute dog was presented for evaluation of abdominal enlargement referred by a local veterinarian. On the history, the owner complained of chronic abdominal enlargement initiated more than 4 months ago, reduced appetite, occasional vomiting and general dullness. He also complained of greenish mucous intermittent vaginal discharge starting 10 days ago. The bitch was chronically treated with medroxiprogesterone acetate. A laparatomy was performed and fluid in the abdomen was found and aspirated during the surgery. Also a very fluid-filled distended uterus and a mass in the distal part of the left uterine horn were found. The mass was encapsulated by the omentum, but areas of necrosis and calcification were identified. Histopathological diagnosis was endometrial adenocarcinoma.     

Ribotyping of Indian Isolates of <Emphasis Type="Italic">Pasteurella multocida</Emphasis> Based on 16S and 23S rRNA Genes

The applicability of ribotyping based on 16S and 23S rRNA was evaluated for molecular epidemiological studies. Forty-eight isolates of Pasteurella multocida isolated from different hosts and geographical locations and one reference isolate were ribotyped. Only four ribotypes were found. All the isolates including reference isolate from wild carnivores had the same ribotype, though they had different serotypes. The isolate from a tiger had one band in addition to the bands present in the major ribotype. The isolates from lions represented two ribotypes; of these ribotypes, one (r2) had an additional band of 3.6 kbp, which was absent in all other ribotypes. The second ribotype (r4) from a lion had one band missing (6 kbp) that was present in the other ribotypes. These isolates were further typed using ERIC-PCR and REP-PCR. With ERIC-PCR and REP-PCR, higher D values of 0.83 and 0.89 were obtained. The current study revealed that ribotyping is not a very efficient typing tool for use in molecular epidemiology for differentiation of isolates.     

Effects of preanesthetic administration of morphine on gastroesophageal reflux and regurgitation during anesthesia in dogs

OBJECTIVE: To determine the effect of morphine administered prior to anesthesia on the incidence of gastroesophageal reflux (GER) in dogs during the subsequent anesthetic episode. ANIMALS: 90 dogs (30 dogs/group). PROCEDURE: The randomized prospective clinical study included healthy dogs with no history of vomiting. Dogs were scheduled to undergo elective orthopedic surgery. Food was withheld for (mean+/-SD) 17.8+/-4.1 hours prior to induction of anesthesia. The anesthetic protocol included acepromazine maleate, thiopental, and isoflurane. Dogs were randomly selected to receive morphine at various dosages (0, 0.22, or 1.10 mg/kg, IM) concurrent with acepromazine administration prior to induction of anesthesia. A sensor-tipped catheter was used to measure esophageal pH, and GER was defined as a decrease in pH to < 4 or an increase to > 7.5. RESULTS: 40 dogs had acidic reflux, and 1 had biliary reflux. Proportions of dogs with GER were 8 of 30 (27%), 15 of 30 (50%), and 18 of 30 (60%) for morphine dosages of 0, 0.22, and 1.10 mg/kg, respectively. Mean duration of GER was 91.4+/-56.8 minutes. There was no significant association between GER and age, weight, vomiting after preanesthetic medication, administration of antimicrobials, or start of surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Most healthy dogs vomit after a large dose of morphine, but vomiting does not increase the likelihood of GER during the subsequent anesthetic episode. Administration of morphine prior to anesthesia substantially increases the incidence of GER during the subsequent anesthetic episode.