Experimental acute yellow-wood (Terminalia oblongata) intoxication in sheep

SUMMARY An aqueous suspension of air-dried, hammer-milled leaf of Terminalla oblongata (yellow-wood) was administered to sheep by gavage, as a single dose of 5 to 20 g (dry weight)/kg body weight. Doses of 15 g/kg, or more, caused depression, Inappetence, abdominal pain and reduced ruminal movements within 24 to 48 h and some sheep also showed dyspnoea, oplsthotonus and champing of the Jaws. Haematology and blood gas and acid-base measurements were unaffected. In sheep given a dose of 12.5 g/kg, or more, plasma osmolality, aspartate aminotransferase activity and potassium and bilirubin concentrations Increased while plasma total protein markedly decreased and plasma sodium concentration and alkaline phosphatase activity remained normal. Most sheep were necropsled 48 h after dosing. The liver showed zonal hepatocellular necrosis, the pattern of which varied with the dose given. No renal lesions were observed, although one sheep given a very high dose became azotaemic and hyperkalaemic. Hydrothorax, hydroperlcardlum and ascltes developed In sheep given doses of 15 or 20 g/kg.     

Effect of nutrition during calfhood and peripubertal period on serum metabolic hormones, gonadotropins and testosterone concentrations, and on sexual development in bulls

The objective of the present study was to characterize the effects of nutrition on circulating concentrations of metabolic hormones, gonadotropins, and testosterone during sexual development in bulls. Nutrition regulated the hypothalamus-pituitary-testes axis through effects on the GnRH pulse generator in the hypothalamus and through direct effects on the testes. Pituitary function (gonadotropin secretion after GnRH challenge) was not affected by nutrition. However, nutrition affected LH pulse frequency and basal LH concentration during the early gonadotropin rise (10-26 weeks of age). There were close temporal associations between changes in insulin-like growth factor-I (IGF-I) concentrations and changes in LH pulse frequency, suggesting a role for IGF-I in regulating the early gonadotropin rise in bulls. The peripubertal increase in testosterone concentration was delayed in bulls with lesser serum IGF-I concentrations (low nutrition), suggesting a role for IGF-I in regulating Leydig cell function. Serum IGF-I concentrations accounted for 72 and 67% of the variation in scrotal circumference and paired-testes volume, respectively (at any given age), indicating that IGF-I may regulate testicular growth. Bulls with a more sustained elevated LH pulse frequency during the early gonadotropin rise (high nutrition) had greater testicular mass at 70 weeks of age relative to the control group (medium nutrition), despite no differences in metabolic hormone concentrations after 26 weeks of age. Therefore, gonadotropin-independent mechanism regulating testicular growth might be dependent on previous gonadotropin milieu.     

Radio Frequency Signals in Jupiter's Atmosphere

During the Galileo probe's descent through Jupiter's atmosphere, under the ionosphere, the lightning and radio emission detector measured radio frequency signals at levels significantly above the probe's electromagnetic noise. The signal strengths at 3 and 15 kilohertz were relatively large at the beginning of the descent, decreased with depth to a pressure level of about 5 bars, and then increased slowly until the end of the mission. The 15-kilohertz signals show arrival direction anisotropies. Measurements of radio frequency wave forms show that the probe passed through an atmospheric region that did not support lightning within at least 100 kilometers and more likely a few thousand kilometers of the descent trajectory. The apparent opacity of the jovian atmosphere increases sharply at pressures greater than about 4 bars.     

Weaning,yearling, and preharvest ultrasound measures of fat and muscle area in steers,bulls, and heifers

Longissimus muscle area and fat thickness were measured following weaning, at yearling, and prior to harvest using real-time ultrasound, and corresponding carcass measurements were recorded 3 to 7 d following the preharvest scan in composite steers (n = 116, 447 +/- 19 d), bulls (n = 224, 521 +/- 11 d), and heifers (n = 257,532 +/- 12 d). Although fat deposition was limited in bulls and heifers from weaning to yearling, coefficients of variation ranged from 8.46 to 13.46% for muscle area, and from 27.55 to 38.95% for fat thickness, indicating that significant phenotypic variance exists across genders. Residual correlations, adjusted for the effects of year of birth, gender, and age at measurement, were high and ranged from 0.79 to 0.87 among ultrasound and carcass measures of muscle area. Residual correlations among ultrasound and carcass measures of fat thickness were also high, ranging from 0.64 to 0.86. Weaning and/or yearling ultrasound muscle area yielded similarly accurate predictions of carcass muscle area. Yearling ultrasound fat thickness accounted for 13% more of the observed variance in carcass fat thickness than the weaning ultrasound measure in single-trait prediction models. When both weaning and yearling ultrasound measures were used to predict carcass fat thickness, partial R2 values were 0.15 and 0.61 for weaning and yearling ultrasound fat thickness, respectively. The difference between predicted and carcass measures with respect to muscle area (fat thickness) was less than 6.45 cm2 (2.5 mm) for 80.2 to 88.9% (90.3 to 95%) of animals. Preharvest ultrasound measures yielded standard errors of prediction of less than 4.95 cm2 for muscle area and 1.51 mm or less for fat thickness. These results indicate that ultrasound measures taken between weaning and yearling provide accurate predictors of corresponding carcass traits in steers, bulls, and heifers.     

Clinical and anatomical features of lymphosarcoma in 118 cats

Objective To determine patients' characteristics and anatomical distribution of lesions in cats with lymphosarcoma. Design Prospective multi-institutional study of naturally occurring feline lymphosarcoma. Methods Veterinarians in Sydney were provided with free diagnostic laboratory services for suspect cases of feline lym-phosarcoma. Lymphosarcoma was diagnosed based on physical findings, radiographic and/or ultrasonographic images and results of cytological or histopathological examination. When owners were not interested in pursuing an antemortem diagnosis, suspect cases were collected for necropsy. Patients' characteristics and physical findings were recorded. A modified scheme for anatomical classification of lesions was devised including a ‘mixed’ category for cases which involved two or more anatomical forms. Results One hundred and eighteen cases were accrued over an 18 month period. The median age was 120 months and range 5 to 212 months. Age distribution was bimodal, with a small peak for cats less than 24 months, and a normal distribution centred on 97 to 120 months. Eighty cats were domestic crossbreds, 22 were Siamese or Oriental cats (including crosses), 6 were Burmese, 5 were purebred longhairs and the remaining 5 were one of a number of purebred shorthaired breeds. In comparison to 1017 consecutive cases admitted to our hospital for conditions other than lymphosarcoma, Siamese/Oriental cats were over-represented amongst lymphosarcoma cases (P = 0.0006). Male cats were also over-represented, accounting for 72 of 118 cases (P = 0.05). Abdominal lymphosarcoma was the most common anatomical form (43 cats), followed by mixed (39), nodal (20), mediastinal (9) and atypical (involving non-lymphoid organs, 7) forms. When analysed for specific organ involvement, 29 (25%) had mediastinal involvement, 71 (60%) had abdominal involvement including 60 (51%) with involvement of the intestinal tract and/or mesenteric lymph nodes and 36 (31%) with bilateral renal involvement, and 47 (40%) had peripheral lymph node involvement. No case of primary lymphoid leukaemia was identified. A noticeable subgroup of cats younger than 24 months had involvement of the anterior mediastinum with or without concurrent enlargement of cervical or axillary lymph nodes; Siamese/Oriental cats were over-represented in this subgroup. Among cases with nodal involvement, lymph nodes of the head and neck were frequently involved, mandibular nodes most commonly, followed by superficial cervical nodes. In seven cases a solitary node was affected. Conclusions Compared with similar surveys overseas, our cats were older and male cats were over-represented. There was a notable subgroup of young cats with mediastinal involvement. Siamese/Oriental cats were over-represented in this subgroup as well as in the larger population of cats with lymphosarcoma. Compared with overseas surveys, renal involvement, mixed cases and atypical cases (including nasal lymphosarcoma) were more common. A new subcategory of nodal lymphosarcoma, with involvement restricted to node(s) of head and neck, was identified.     

Prevalence of megabacteria in budgerigar colonies

Objective To measure the prevalence of megabacteria in budgerigar-breeding colonies and to evaluate possible methods to reduce the prevalence.
Design A monitoring study over several years.
Sample population Two budgerigar ( Melopsittacus undulatus ) colonies with over 300 birds each.
Procedure The prevalence of megabacteria in the faeces in two budgerigar breeding colonies, colony 1 and 2, was determined by faecal examination of each bird. Following an initial survey (1990), most of the birds that were scored 2+ or more were culled and a management practice was implemented to discriminate against positive birds. Consecutive yearly surveys (1991, 1992) were conducted on the young birds bred in these colonies. The prevalence of megabacteria in colony 2 was also evaluated in 1994 and 1996 after all the birds were treated with amphotericin B administered in drinking water.
Results The prevalence of megabacteria in the two colonies was significantly (P < 0.001) different. Overall the prevalence of megabacteria adjusted for colony differences was significantly higher (P < 0.025) in males compared to females. Age was not an influencing factor. After the initial survey, the prevalence in the offspring did not significantly (P > 0.05) decrease in the following two annual breeding seasons but by inference it did significantly decrease after amphotericin B treatment.
Conclusion The practice of culling most birds with more megabacteria in faeces and discriminating against positive birds when selecting birds for breeding or culling birds on show quality does not decrease megabacteria prevalence in the offspring. However, a reduction in prevalence does occur with administration of amphotericin B. Birds may have amphotericin B-resistant organisms and these birds need to be identified and culled.     

Cochlosoma infections in finches

Objective To survey finches in pet shops for Cochlosoma infection and evaluate the efficacy of antiprotozoal therapy with metronidazole or ronidazole.
Design A survey of pet shop finches and drug efficacy trials.
Procedure Finches in pet shops were randomly selected and their faeces examined microscopically for motile Cochlosoma sp trophozoites. Drug trials were carried out on 60 adult finches with naturally occurring infections. Body weight was measured and the faeces of each bird was examined for trophozoites at the beginning and 7 days after the end of treatment. In some birds, additional daily faecal examinations were done until three consecutive negative results were obtained. Metronidazole was administered at various dose rates by crop gavage or in drinking water to eight groups of five to ten finches each. Ronidazole was given in water for 7 days to ten finches. In addition, six finches whose faeces tested positive were necropsied and their tissues collected for histological examination.
Results Motile flagellates in the faeces were identified as C anatis -like protozoa. Red-headed parrot-finches, Bengalese and Lady Gould finches were found to be most commonly infected. Cochlosoma sp was also found in the blue-faced parrot-finch, zebra finch, painted finch, nutmeg mannikin and double-barred finch. Metronidazole and ronidazole were found to be effective against Cochlosoma sp. Histological findings on infected adult finches were normal, except for the presence of numerous flagellates between the colorectal villi and cloacal mucosal folds.
Conclusions Cochlosoma anatis -like organisms can infect several species of finches and in adult finches are confined to the colorectum and cloaca. Infection in adult finches was mostly subclinical and could be treated effectively with metronidazole or ronidazole.     

Genetic parameters for ultrasound and carcass measures of yield and quality among replacement and slaughter beef cattle.

Real time ultrasound (RTU) measures of longissimus muscle area and fat depth were taken at 12 and 14 mo of age on composite bulls (n = 404) and heifers (n = 514). Carcass longissimus muscle area and fat depth, hot carcass weight, estimated percentage lean yield, marbling score, Warner-Bratzler shear force, and 7-rib dissectable seam fat and lean percentages were measured on steers (n = 235). Additive genetic variances for longissimus muscle area were 76 and 77% larger in bulls at 12 and 14 mo than the corresponding estimates for heifers. Heritability estimates for longissimus muscle area were 0.61 and 0.52 in bulls and 0.49 and 0.47 in heifers at 12 and 14 mo, respectively. The genetic correlations of longissimus muscle area of bulls vs heifers were 0.61 and 0.84 at 12 and 14 mo, respectively. Genetic correlations of longissimus muscle area measured in steer carcasses were 0.71 and 0.67 with the longissimus muscle areas in bulls and heifers at 12 mo and 0.73 and 0.79 at 14 mo. Heritability estimates for fat depth were 0.50 and 0.35 in bulls and 0.44 and 0.49 in heifers at 12 and 14 mo, respectively. The genetic correlation of fat depth in bulls vs heifers at 12 mo was 0.65 and was 0.49 at 14 mo. Genetic correlations of fat depth measured in bulls at 12 and 14 mo with fat depth measured in steers at slaughter were 0.23 and 0.21, and the corresponding correlations of between heifers and steers were 0.66 and 0.86, respectively. Live weights at 12 and 14 mo were genetically equivalent (r(g) = 0.98). Genetic correlations between live weights of bulls and heifers with hot carcass weight of the steers were also high (r(g) > 0.80). Longissimus muscle area measured using RTU was positively correlated with carcass measures of longissimus muscle area, estimated percentage lean yield, and percentage lean in a 7-rib section from steers. Measures of backfat obtained using RTU were positively correlated with fat depth and dissectable seam fat from the 7-rib section of steer carcasses. Genetic correlations between measures of backfat obtained using RTU and marbling were negative but low. These results indicate that longissimus muscle area and backfat may be under sufficiently different genetic control in bulls vs heifers to warrant being treated as separate traits in genetic evaluation models. Further, traits measured using RTU in potential replacement bulls and heifers at 12 and 14 mo of age may be considered different from the corresponding carcass traits of steers.