ASSESSMENT OF OVARIAN CHANGES AROUND OVULATION IN BITCHES BY ULTRASONOGRAPHY, LAPAROSCOPY AND HORMONAL ASSAYS

To identify the time characteristics of ovulation, 5 bitches were evaluated during heat by ultrasonography, laparoscopy and hormonal assay. Blood collections for progesterone and oestradiol 17-β assys and ultrasonography were performed every day and laparoscopy every other day. At ultrasonography, ovaries appeared as anechoic structures about 5 days before the estimated LH peak and gradually increased in size. The greatest changes were observed between days 2 and 4 post-LH peak: echogenicity varied greatly from one animal to another and from one day to the following going from totally anechoic to mixed hypo and hyperechogenicity. Then from day 6, ovaries always appeared as hypoechoic structures assimilated to corpora lutea. At laproscopy, small follicies were seen as early as day 10 before the LH peak. Their size slowly increased to become large protubering follicies around the day of LH peak (day 0). At day 1, corpra luta were observed for the first time and were present in all animals by day 5. During that period preceeding day 5, some ovaries had both corpora lutea and follicies clearly visible on their surface. In one animal, haemorrhagic foci were observed at day 3. Neither ultrasonography, nor laparoscopy allowed precise determination of the time of ovulation. Indeed, follicle collapses was never observed, but changes in echogenicity and in the appearance of the ovaries observed by laparoscopy, suggested that ovulation occurred between days 2 and 4 when progestrone concentrations were 12.6 ± 6.2 and 32.1 ± 10.9 nmol/L, respectively.     

Prevention of Toxoplasma gondii abortion in goats by vaccination with oocysts of Hammondia hammondi

Nineteen does (female goats) were dosed with 500,000 oocytes of Hammondia hammondi prior to breeding. At about 90 days of gestation these, and 18 uninoculated does were challenged with 25,000 Toxoplasma gondii oocysts. The 19 H. hammondi--inoculated does produced 26 live and one dead kid (newborn goat). The 18 does not given H. hammondi produced 12 live and 19 dead kids. However, examination of all of the kids by isolation of T. gondii in mice, serology and histology revealed that they were all infected with T. gondii. Thus, while H. hammondi "vaccination" is protective against the deleterious effects of T. gondii on pregnant does, perhaps by reducing the severity of placental lesions, it does not prevent foetal infection.     

Interactive effects of dietary crude protein and fermentable carbohydrate levels on odour from pig manure

The objective of this study was to determine the effects of dietary levels of crude protein (CP) and levels of fermentable carbohydrates (FC) and their interaction on odour emission, odour intensity, odour hedonic tone, and ammonia emission from pig manure, and manure characteristics. An experiment was conducted with finishing pigs (n = 36) in a 2 × 3 factorial randomized complete block arrangement with 6 treatment combinations in 6 blocks. There were 2 dietary CP levels (low 12%; high 18%) and 3 digestible FC levels: (low 95.5; medium 145.5; and high 195.5 g/kg feed, as-fed basis). Pigs with an initial body weight (BW) of 57.7 ± 2.5 kg were penned individually in partly slatted floor pens. Faeces and urine of each pig accumulated in separate manure pits under the slatted floor. In the 6th week of the collection period air samples were collected directly above the manure in each pit. Manure samples were taken for manure characteristics. Air samples were analyzed for odour concentration and for hedonic tone and odour intensity. Manure samples were analyzed for volatile fatty acids (VFA), indoles, phenoles, sulphurous compounds, ammonium, and total N concentrations. Dietary CP level and FC level did not affect odour emission, odour intensity and hedonic tone but their interaction affected odour emission at P = 0.06. At a high dietary CP level, increased FC level decreased odour emission, while at a low CP level, increased FC level increased odour emission from pig manure. Total N and ammonium concentrations, and ammonia emission from pig manure were reduced at low dietary CP level (P < 0.001). High FC level led to low ammonia emission from pig manure (P = 0.01). Manure pH increased at high dietary CP level (P < 0.001) and decreased when FC level increased (P < 0.05). Total VFA concentration increased at high dietary CP level (P < 0.001) and when FC level increased (P < 0.001). Enhanced dietary CP increased the manure concentrations of phenol (P < 0.001), cresols (P = 0.01), indole (P < 0.001), 4-ethylphenol (P < 0.001) and carbon disulfide (P < 0.001), but FC did not affect concentrations of these compounds (P > 0.05) in the manure. We conclude that the interaction between dietary CP and FC plays a role in odour production and emission. Ammonia emission from pig manure can be reduced substantially by decreasing dietary CP and by increasing FC.     

Pathology of experimentally-induced, acute toxoplasmosis in macropods

SUMMARY Thirteen Tammar wallabies (Macropus eugenii) were dosed orally with 500, 1000 or 10 000 oocysts of Toxoplasma gondii, as part of a vaccination trial. Eleven animals died of acute toxoplasmosis 9 to 15 days after challenge. The lesions were similar in all animals, consisting of foci of necrosis and inflammation in the intestines, lymphoid tissue, adrenal cortex, heart, skeletal muscle and brain, and severe generalised pulmonary congestion and oedema. Free and intracellular tachyzoites of Toxoplasma were associated with the lesions. The remaining 2 animals had shown no signs of disease when euthanased four months after challenge. Small, focal, non-suppurative inflammatory lesions were seen in brain, heart and skeletal muscle of these animals and chronic Toxoplasma infection was confirmed by mouse inoculation.     

Off-axis crustal thickness across and along the east pacific rise within the MELT area

Wide-angle seismic data along the Mantle Electromagnetic and Tomography (MELT) arrays show that the thickness of 0.5- to 1. 5-million-year-old crust of the Nazca Plate is not resolvably different from that of the Pacific Plate, despite an asymmetry in depth and gravity across this portion of the East Pacific Rise. Crustal thickness on similarly aged crust on the Nazca plate near a magmatically robust part of the East Pacific Rise at 17 degrees15'S is slightly thinner (5.1 to 5.7 kilometers) than at the 15 degrees55'S overlapping spreading center (5.8 to 6.3 kilometers). This small north-south off-axis crustal thickness difference may reflect along-axis temporal variations in magma supply, whereas the across-axis asymmetry in depth and gravity must be caused by density variations in the underlying mantle.     

Post-weaning feed intake level modulates gut morphology but not gut permeability in weaned piglets

Piglets with a high voluntary feed intake were compared with piglets fed restrictedly. Weaning induced changes in gut morphology and permeability. The intake level of dry pelleted feed affected intestinal villous architecture but did not affect permeability to small or large molecules from d0 to d7 post-weaning. A restricted feed intake level negatively affected gut morphology at d4 post-weaning. This effect could be alleviated but not completely prevented by a high voluntary intake of dry pelleted feed directly after weaning.     

Effects of a medetomidine-midazolam-butorphanol combination on renal cortical, intestinal and muscle microvascular blood flow in isoflurane anaesthetized dogs: a laser Doppler study

Objective To obtain renal cortical, ileal, colonic and skeletal muscle microvascular blood flow measurements in dogs using the laser Doppler technique and to characterize the effects of medetomidine‐midazolam‐butorphanol combination on these flows. Study Design Prospective randomized experimental study. Animals Fourteen clinically normal beagles (two groups of seven), aged 1–4 years and weighing 13.2 ± 1.8 kg. Methods All dogs were anaesthetized with 1.7% end‐tidal isoflurane in oxygen. In the treatment group, after instrumentation and when anaesthesia was considered stable, medetomidine (1 mg m^?2 body surface area (BSA)) was administered intramuscularly (time 0). Midazolam (1 mg kg^?1) and butorphanol (0.1 mg kg^?1) were administered intravenously 20 minutes later. Atipamezole (2.5 mg m^?2 BSA) was administered intramuscularly 60 minutes after medetomidine. In the control group, saline (0.5, 2.5 and 0.25 mL) was administered at the corresponding times. Heart rate, systolic, diastolic and mean arterial pressures, body temperature, renal cortical, ileal, colonic and skeletal muscle microvascular blood flows were measured before time 0, and 5, 15, 25, 40, 60, 65, 70 and 90 minutes thereafter. Results Heart rate, ileal and skeletal muscle blood flows decreased in the treatment group, while no changes were observed in the control group. Conclusions Laser Doppler flowmetry allowed the measurement of microvascular blood flow in different organs. The medetomidine‐midazolam‐butorphanol combination decreases intestinal and skeletal muscle microvascular blood flows, while renal cortical blood flow is maintained. Clinical relevance Medetomidine‐midazolam‐butorphanol combination can be used to induce a short duration anaesthesia in dogs, but it will induce cardiovascular depression. This depression appears to be accompanied by a redistribution of blood flow.     

Antagonistic activities of atipamezole, 4-aminopyridine and yohimbine against medetomidine/ketamine-induced anaesthesia in cats

The objectives of this trial were to determine the ability of atipamezole, 4-aminopyridine and yohimbine to reverse the anaesthetic effects of a combination of medetomidine and ketamine in cats. Forty healthy cats were anaesthetised with 80 micrograms/kg medetomidine combined with 5 mg/kg ketamine. Thirty minutes later atipamezole (200 or 500 micrograms/kg), 4-aminopyridine (500 or 1000 micrograms/kg) or yohimbine (250 or 500 micrograms/kg) were injected intramuscularly. The doses of antagonists were randomised, so that each dose was administered to five cats, and 10 cats were injected only with physiological saline. Atipamezole clearly reversed the anaesthesia and bradycardia induced by medetomidine and ketamine. The mean (+/- sd) arousal times were 28 (+/- 4.7), 5.8 (+/- 1.8) and 7 (+/- 2.1) minutes in the placebo group, and the groups receiving 200 and 500 micrograms/kg atipamezole, respectively. The heart rates of the cats receiving 200 micrograms/kg atipamezole rapidly returned to values close to the initial ones, but 15 minutes after the injection of 500 micrograms/kg atipamezole a significant tachycardia was observed. All the cats showed moderate signs of ataxia during the recovery period. A dose of 500 micrograms/kg yohimbine also clearly reversed the anaesthetic effects of medetomidine/ketamine but 250 micrograms/kg was not effective. The dose of 500 micrograms/kg allowed a smooth recovery with no particular side effects except for some signs of incomplete antagonism of the ketamine effects, ie, ataxia and muscular incoordination. With 4-aminopyridine there were no statistically significant effects on the recovery, or the heart and respiratory rates of the cats anaesthetised with medetomidine/ketamine.     

Influence of the estrous cycle on urodynamic and morphometric measurements of the lower portion of the urogenital tract in dogs

OBJECTIVES: To compare the values of the urodynamic parameters of the lower portion of the urinary tract and vaginourethral measurements obtained during the phases of the estrous cycle in dogs and determine possible functional or anatomic modifications of the lower portion of the urinary tract associated with those phases. ANIMALS: 7 adult female Beagles. PROCEDURE: Urethral pressure profilometry, diuresis cystometry, and vaginourethrography were performed in each dog during proestrus; estrus; early, mid, and late diestrus; and early and late anestrus. The maximum urethral pressure (MUP), maximum urethral closure pressure (MUCP), urethral functional and anatomic profile lengths (UFPL and UAPL, respectively), integrated pressure, threshold pressure, threshold volume, compliance, urethral length, and vaginal length and width were measured. RESULTS: For all measurements, significant interindividual variation was detected. Integrated and threshold pressures, APL, and each morphometric value significantly increased from late anestrus to proestrus. Compared with other phases, MUP, MUCP, and integrated pressure values were significantly lower in estrus and early diestrus; UAPL and UFPL values were significantly lower in late diestrus. At each cycle phase in old dogs, MUP, MUCP, threshold pressure, and vaginal length and width were significantly lower (except in proestrus for vaginal measurements) and threshold volume and compliance values were significantly higher, compared with middle-aged dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Urodynamic and morphometric measurements of the lower portion of the urogenital tract are affected by the changes in hormonal balance that occur during the estrous cycle. In sexually intact female dogs, estrous phase determination is important for the interpretation of urodynamic data.