Suppression of ovarian progesterone production in dairy cows using an implant of GnRH-agonist (deslorelin) for the purpose of evaluating progesterone metabolism

OBJECTIVE: To evaluate the potential of an implant of a GnRH-agonist (deslorelin) to create a progesterone free animal suitable for studying progesterone (P4) metabolism in intact cows by measuring blood P4 and faecal P4 metabolites. METHODS: Experiment 1: Eighteen non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to one of three groups to study plasma P4 concentrations preceding an intravaginal insert. These groups comprised: i) a deslorelin group (GnRH-agonist implanted); ii) a PGF group receiving two injections of prostaglandin (PGF2alpha) 12 days apart; and, iii) an ovariectomised (OVX) group. An intravaginal device (CIDR) was inserted into the vagina of each animal and left in place for 11 days. Plasma P4 concentrations were measured during the study period. Experiment 2: Twelve non-lactating cycling Holstein-Friesian cows, 4 to 7 years old, were allocated to two groups: i) a deslorelin group (GnRH-agonist implanted); and ii) an ovariectomised group. Plasma P4 and faecal P4 metabolites (20-oxo-pregnanes, 20alpha-OH and 20beta-OH) were monitored for a period of 5 weeks. RESULTS: Experiment 1: Average plasma P4 concentration did not differ between the three groups (1.28, 1.43 and 1.55 ng/mL for deslorelin, OVX and PGF cows, respectively, P = 0.8) during the period of supplementation. Experiment 2: There was no difference in plasma P4 (mean plasma P4 < 0.02 ng/mL, P = 0.9) and faecal P4 metabolites between deslorelin and OVX cows 2 weeks after the implantation (P = 0.7). CONCLUSIONS: These data showed that a GnRH-agonist (deslorelin) implant may be used as an alternative to ovariectomy to create a progesterone free animal suitable for studying the metabolism of administered P4.     

Comparative water relations of three successional hardwood species in central Wisconsin

Water relations of co-occurring understory saplings of Quercus ellipsoidalis E.J. Hill, an early successional, xeric species, Populus tremuloides Michx., an early successional, mesic species, and Acer rubrum L., a late successional species that occurs on both wet and dry sites, were evaluated on four dates during the 1986 growing season. The understory was characterized by high soil water content, low irradiance and low vapor pressure deficit throughout the growing season. Stomatal conductance and calculated transpiration flux were lowest for A. rubrum and highest for P. tremuloides and Q. ellipsoidalis. Except early in the growing season, leaf water potentials were lower in P. tremuloides than in the other species. Populus tremuloides had the highest bulk modulus of elasticity, Q. ellipsoidalis the lowest. Over the growing season, Populus tremuloides and Q. ellipsoidalis, but not A. rubrum, exhibited a decrease in osmotic potential at both full and zero turgor. Of the three species, Populus tremuloides exhibited the sharpest decrease in leaf water potential and turgor pressure with decreasing relative water content.     

Theileria orientalis: a review

Theileria orientalis (also known historically as T. sergenti and T. buffeli) is responsible for benign or non-transforming theileriosis, and exerts its major effect through erythrocyte destruction. The life cycle of T. orientalis is essentially similar to that of other Theileria species, except that the schizonts do not induce transformation and fatal lymphoproliferation. The pathogenesis of anaemia as a result of infection is not clearly established and may be multifaceted. Clinical signs of weakness, reluctance to walk and abortion are early but non-specific indications of disease, particularly if accompanied by a history of cattle being moved. Physical examination may reveal pallor (pale eyes, vaginal mucosa), pyrexia, and elevated heart and respiratory rates. T. orientalis is an economically important parasite of cattle in New Zealand, Australia and Japan, especially where naïve animals are introduced into an endemic area or in animals under stress. Increased awareness of the risks posed by the parasite is required to enable management practices to be implemented to minimise its impact.     

Risk factors influencing death prior to discharge in 302 dogs undergoing unilateral adrenalectomy for treatment of primary adrenal gland tumours

Adrenalectomies for canine adrenal tumours are associated with peri-operative morbidity and mortality. Objectives of this study included assessing the prognostic value of tumour- or surgery-related variables in predicting peri-operative mortality and overall survival in dogs undergoing adrenalectomies for primary adrenal tumours as well as pre-treatment with phenoxybenzamine on survival to discharge with pheochromocytomas specifically. A multi-institutional retrospective cohort study was performed across nine institutions. Electronic medical record searches identified 302 dogs which met the inclusion criteria. Data collected included dog-related, tumour-related, treatment-related, surgery-related, and outcome variables. Univariate and multivariable logistic regression and cox proportional hazards models were used to identify variables associated with death prior to discharge and tumour-related survival. Overall, 87% of dogs survived to discharge with a tumour-related survival time of 3.96 years. Post-operative complications were reported in 25%. Increased surgical time (p = 0.002) and pre-surgical medical treatment other than phenoxybenzamine (p = 0.024) were significantly associated with increased peri-operative mortality while ureteronephrectomy (p = 0.021), post-operative pancreatitis (p = 0.025), and post-operative aspiration pneumonia (p < 0.001) were significantly associated with decreased overall survival. Phenoxybenzamine pretreatment had no effect on peri-operative mortality. Thirty-seven of 45 (82%) dogs with pheochromocytomas not pretreated survived to discharge, and 50 of 59 (85%) dogs with pheochromocytomas pretreated with phenoxybenzamine survived to discharge (p = 0.730). This study provides information on risk factors for death prior to discharge and tumour-related survival that may help guide clinical management and owner expectations. In addition, the study findings challenge the previously reported benefit of phenoxybenzamine for pretreatment of dogs undergoing adrenalectomies for pheochromocytomas.     

Naphthalophos combinations with benzimidazoles or levamisole as effective anthelmintics for sheep

Objective: To investigate the relative efficacy and safety of the anthelmintic naphthalophos in sheep, either given alone or in combination with benzimidazole (fenbendazole and albendazole) or levamisole anthelmintics.
Design: A parasitological study using faecal egg count reduction tests, a validating slaughter trial and field safety trials.
Procedure: Faecal egg count reduction tests were carried out on 13 farms. Naphthalophos and combinations of naphthalophos with levamisole and fenbendazole were included in the drench tests. On one property a controlled efficacy study was carried out to validate faecal egg count reduction test findings. In this trial, sheep were slaughtered 10 days after treatment and the remaining parasites recovered from the gastro-intestinal tract. Safety trials were carried out on eight farms where approximately 50 000 sheep were treated with naphthalophos and albendazole that were tank mixed in the backpack.
Results: The efficacy of naphthalophos alone in faecal egg count reduction tests ranged from 59 to 98% with one test showing 95% reduction. The efficacy of naphthalophos and levamisole ranged from 74 to 100%, with 5 farms showing 95% reduction. The efficacy of naphthalophos and fenbendazole ranged between 88 and 100% with 95% reduction achieved on 10 farms. The controlled efficacy study showed a good correlation between the faecal egg count reduction tests and numbers of parasites recovered, except for Nematodirus where the faecal egg count reduction tests overestimated efficacy. The mortality rate in the safety trials was 0.05%, with most fatalities occurring on one farm.
Conclusion: The combination of naphthalophos and fenbendazole was more effective than a combination of naphthalophos and levamisole, and will provide a sufficiently safe drench rotation option.