Sites of Persistence of Lumpy Skin Disease Virus in the Genital Tract of Experimentally Infected Bulls

The objectives of this work were to determine the site of persistence of lumpy skin disease virus (LSDV) in bulls shedding the virus in semen for a period longer than 28 days, to determine if the virus is present in all fractions of semen and to study lesions that developed in the genital tract. Six serologically negative postpubertal bulls were experimentally infected with a virulent field isolate of LSDV. The polymerase chain reaction (PCR) was performed on sheath washes, vesicular fluid, supernatant and cell‐rich fractions of semen from day 10 to day 26 postinfection (p.i.). Bulls that were positive by PCR on the whole semen sample collected on day 28 p.i. were slaughtered and tissue samples from their genital tracts submitted for histopathological evaluation, immunoperoxidase staining, virus isolation and PCR. Two of the bulls developed severe lumpy skin disease (LSD) and were found to be shedding viral DNA in their semen on day 28 p.i. Viral DNA was identified in all semen fractions from all bulls, but mostly from the cell‐rich fraction and from the severely affected bulls. The PCR assay was positive on postmortem samples of testes and epididymides from the two severely affected bulls. Virus could be recovered from the testes of these two bulls and from the epididymis of one of them. Immunoperoxidase staining was positive for LSDV staining in sections of testes and epididymides exhibiting necrosis. This study suggests that the testis and epididymis are sites of persistence of LSDV in bulls shedding virus in semen for prolonged periods and revealed that viral DNA is present in all fractions of the ejaculate.     

Effect of Pregnancy and Foetal Number on Diameter of Corpus Luteum,Maternal Progesterone Concentration and Oxidant/Antioxidant Balance in Ewes

The aim of this study was to determine the changes in diameter of corpus luteum (CL), maternal progesterone (P) concentration, lipid peroxidation and non‐enzymatic antioxidant levels along with enzymatic antioxidant activities in pregnant ewes bearing single and twin foetuses. The ewes were selected from healthy animals that were brought to the abattoir for slaughtering. The ewes were divided into three groups: Group 1 (non‐pregnant, non‐oestrous, n = 30), Group 2 (pregnant bearing a single foetus, n = 30) and Group 3 (pregnant bearing twin foetuses, n = 12) after they were slaughtered. Pregnant ewes were in the first half of the pregnancy. The diameter of CL and P concentration of pregnant ewes bearing a single foetus or twin foetuses were found higher than that found in non‐pregnant ewes. Similarly, the P concentration of pregnant ewes bearing twin foetuses was higher than that found in pregnant ewes bearing a single foetus. Malondialdehyde (MDA) level in pregnant ewes bearing twin foetuses was higher than that found in both non‐pregnant and pregnant ewes bearing a single foetus. The serum glutathione (GSH) level and glutathione‐peroxidase (GSH‐Px) activity of pregnant ewes bearing twin foetuses were found lower than that found in non‐pregnant ewes. Additionally, the GSH‐Px activity of pregnant ewes bearing twin foetuses was found lower than that found in pregnant ewes bearing a single foetus. No significant difference was found between pregnant ewes bearing female and male foetus with respect to diameter of CL, P concentration and oxidative stress parameters. There were significant positive correlations between foetal number (0, 1, 2) and diameter of CL, P concentration, MDA level, and between P concentration and diameter of CL, MDA level. However, significant negative correlations were found between foetal number (0, 1, 2) and GSH level, GSH‐Px activity, and between P concentration and GSH‐Px activity. In conclusion, the diameter of CL enlarges, P production increases and oxidant/antioxidant balance impairs because of the gestation stress in ewes during pregnancy.     

Compatibility of rhenium in garnet during mantle melting and magma genesis

Measurements of the partitioning of rhenium (Re) between garnet and silicate liquid from 1.5 to 2.0 gigapascals and 1250 degrees to 1350 degreesC show that Re is compatible in garnet. Oceanic island basalts (OIBs) have lower Re contents than mid-ocean ridge basalt, because garnet-bearing residues of deeper OIB melting will retain Re. Deep-mantle garnetite or eclogite may harbor the missing Re identified in crust-mantle mass balance calculations. Oceanic crust recycled into the upper mantle at subduction zones will retain high Re/Os (osmium) ratios and become enriched in radiogenic 187Os. Recycled eclogite in a mantle source should be easily traced using Re abundances and Os isotopes.     

Effects of diazepam, ketamine, and their combination on intraocular pressure in normal dogs

Ketamine has been implicated as causing increases in intraocular pressure. The purpose of this study is to document the effects of ketamine, diazepam, and their combination on intraocular pressure (IOP) in normal, unpremedicated dogs. Random-source dogs were assigned to one of five groups of 10 dogs each: ketamine 5 mg kg^–1 (KET5), ketamine 10 mg kg^–1 (KET10), diazepam 0.5 mg kg^–1 (VAL), ketamine 10 mg kg^–1 with diazepam 0.5 mg kg^–1 (KETVAL), saline 0.1 mL kg^–1 (SAL), all given intravenously. A baseline IOP was measured before injection, immediately after injection, and at 5, 10, 15, and 20 minutes following injection. IOP was increased over baseline immediately after injection in the KET5, KET10, and KETVAL groups; at 5, 10, and 15 minutes in the KET5 group; and at 20 minutes in the KETVAL group. The mean IOP change compared to SAL increased immediately after injection and at 5 minutes in the KET5, KET10, and KETVAL groups; at 10 and 15 minutes in the KET5 group, and at 20 minutes in the KETVAL group. The mean IOP increased up to 5.7, 3.2, and 3.1 mm Hg over mean baseline in the KET5, KET10, and KETVAL groups, respectively. All dogs in the KET5 group and the majority in the KETVAL and KET10 groups had an increase in their IOP over baseline. Ketamine caused a clinically and statistically significant elevation in IOP over baseline and compared to SAL. The concurrent addition of diazepam did not blunt this increase. Ketamine should be avoided in dogs with corneal trauma, glaucoma, or in those undergoing intraocular surgery.     

Effect of Exogenous GnRH at the Time of Artificial Insemination on Reproductive Performance of Awassi Ewes Synchronized with Progestagen–PMSG–PGF2α Combination

This study was carried out to investigate the efficacy of PGF_2α for oestrus synchronization (ES) in Awassi ewes to which were administered the progestagen–PMSG combination, and to evaluate the effect of the exogenous GnRH administration immediately after the artificial insemination (AI) on their pregnancy rate and lambing performance during the breeding season. The ewes (n = 33) were treated with an intravaginal sponge impregnated with 30 mg fluorogestane acetate for 12 days and were injected with 500 IU PMSG at the time of removal of the sponge. The ewes were then divided into three equal groups of 11 ewes each. One millilitre of physiological saline (0.9% NaCl; placebo) was administered to each ewe in Group 1 at the time of second AI. Approximately 4 μg GnRH (busereline) was injected to each ewe in Group 2 immediately after second AI. A total of 150 μg PGF_2α (cloprostenole) was injected at the time of sponge removal on day 12 and 4 μg GnRH immediately after the second AI was also treated to each ewe in Group 3. Intracervical AI with diluted fresh semen was performed twice at 12 and 24 h following the onset of oestrus. The injection‐oestrus onset and injection‐oestrus‐end interval in Group 3 was significantly (p < 0.001) shorter than both Groups 1 and 2. Although the pregnancy rates of Groups 2 and 3 (81.8%; 9/11) were numerically higher than of Group 1 (63.6%; 7/11), the difference among the groups was statistically insignificant. The multiple birth rate of Group 3 was found higher than Groups 1 and 2. However, the number of single lambs of Group 1 was also higher than Groups 2 and 3 (p < 0.05). Despite the litter sizes of Groups 2 (1.27; 14/11) and 3 (1.55; 17/11) being numerically higher than Group 1 (0.73; 8/11), the differences among all the groups were statistically insignificant. In conclusion, the administration of PGF_2α at the time of removal of the sponge shortens the injection oestrus‐onset and oestrus‐end interval in Awassi ewes treated with progestagen–PMSG. Additionally, exogenous GnRH treatment immediately after the AI increases the multiple birth rate of Awassi ewes synchronized with progestagen–PMSG–PGF_2α combination.     

Principles for the use of macrocyclic lactones to minimise selection for resistance

OBJECTIVE: To provide principles for the appropriate use of avermectin/milbemycin or macrocyclic lactone (ML) anthelmintics in sheep, to ensure effective worm control and to minimise selection for ML resistance. STRATEGY: The principles were based on an assessment of the information currently available. The MLs were categorised into three groups (ivermectin [IVM], abamectin [ABA] and moxidectin [MOX]) based on structural differences, persistence and efficacy against ML resistant strains. The reported order of activity or efficacy against ML resistant worm strains was IVM相似文献   

Hazard Analysis and Critical Control Points System for a Bull Semen Production Centre

Bull semen production centres (SPC) generally present satisfactory quality control for sperm processing, but non‐standardized hygiene procedures. This study describes a Hazard Analysis and Critical Control Points (HACCP) system developed for bull SPC and subsequently implemented in a commercial SPC. After the identification of hazards at each step of semen processing and the determination of their risk and severity, monitoring and corrective procedures were designed to assess the system's efficiency. The HACCP system identified six microbiological hazards, 10 physical hazards, four chemical hazards and three critical control points. After the establishment of Good Processing Practices, Standard Operating Procedures and Standard Sanitizing Operating Procedures, the system was validated through an audit, to identify eventual failures and to define measures to correct them.