Effects of two large doses of equine recombinant growth hormone on clinical, haematological and serum biochemical variables in adult horses

Objective To evaluate the clinical, haematological, and serum biochemical effects of two large doses of recombinant equine growth hormone.
Design Duplicated Latin square.
Sample population
Three Thoroughbred and three Standardbred mares aged between 12 and 17 years.
Procedure Two horses were randomly assigned into one of three groups. On each of three successive days, each horse pair received one of two dosages of growth hormone or a saline placebo so that by the end of the experiment all three horse pairs had received both dosages and the saline placebo. Dose rates selected were 50 μg/kg, and 100 μg/kg. A clinical examination was performed and a venous blood sample drawn for a complete blood count and serum biochemical analysis before administration of growth hormone and at 1, 2, 3, 4, 6, 8 and 24 h after injection. Data were analysed by a repeated measures analysis of variance assessing the effects of dose and time.
Results There was an effect of time on a number of clinical, haematological, and serum biochemical variables. There were significant effects of growth hormone on heart rate and serum glucose concentration but values for both variables remained within the reference range.
Conclusion The results of the present study suggest that equine recombinant growth hormone has a wide margin of safety and show that the single administration of up to five times the recommended dose rate has no significant effects on clinical, haematological, or serum biochemical variables.     

ABNORMAL BONE SCAN FINDINGS OF THE EQUINE ISCHIAL TUBEROSITY AND THIRD TROCHANTER

Obtaining high-quality radiographs of the proximal aspect of equine limbs is difficult because of the large muscles in these regions. The use of scintigraphy may provide further information. Abnormal bone scan findings of the ischial tuberosity or the third trochanter were found in 29 adult horses with obscure hind limb lameness between 1986 and 1996 at the Large Animal Clinic of the University of Bern. Each had abnormal radiopharmaceutical uptake but not all had radiographic changes. Radio-pharmaceutical uptake ratios between the ischial tuberosity and the greater trochanter were calculated. The uptake ratio in a control group of 11 clinically sound horses was lower than in 11 lame horses with subjectively enhanced radiopharmaceutical uptake.     

Ultrasonic shear wave velocities of MgSiO3 perovskite at 8 GPa and 800 K and lower mantle composition

Ultrasonic interferometric measurements of the shear elastic properties of MgSiO3 perovskite were conducted on three polycrystalline specimens at conditions up to pressures of 8 gigapascals and temperatures of 800 kelvin. The acoustic measurements produced the pressure (P) and temperature (T) derivatives of the shear modulus (G), namely ( partial differentialG/ partial differentialP)T = 1.8 +/- 0.4 and ( partial differentialG/ partial differentialT)P = -2.9 +/- 0.3 x 10(-2) gigapascals per kelvin. Combining these derivatives with the derivatives that were measured for the bulk modulus and thermal expansion of MgSiO3 perovskite provided data that suggest lower mantle compositions between pyrolite and C1 carbonaceous chondrite and a lower mantle potential temperature of 1500 +/- 200 kelvin.     

Mantle seismic structure beneath the MELT region of the east pacific rise from P and S wave tomography

Relative travel time delays of teleseismic P and S waves, recorded during the Mantle Electromagnetic and Tomography (MELT) Experiment, have been inverted tomographically for upper-mantle structure beneath the southern East Pacific Rise. A broad zone of low seismic velocities extends beneath the rise to depths of about 200 kilometers and is centered to the west of the spreading center. The magnitudes of the P and S wave anomalies require the presence of retained mantle melt; the melt fraction near the rise exceeds the fraction 300 kilometers off axis by as little as 1%. Seismic anisotropy, induced by mantle flow, is evident in the P wave delays at near-vertical incidence and is consistent with a half-width of mantle upwelling of about 100 km.     

SHORT CONTRIBUTION: The latest endangered species in Australia: A tobacco-smoking veterinarian

The results of a tobacco smoking survey conducted among veterinarians in Queensland, Australia, during 2007 are presented. Of the 567 participants only 3% reported being current smokers, 24% were ex-smokers and 73% had never smoked. The prevalence of smoking was similar among males and females, and the highest smoking rate was reported among veterinarians aged 31–40 years. However, the rate of never-smokers was strongly and negatively correlated with age, and the proportion of ex-smokers increased with age. Encouragingly, the results from this study suggest that tobacco use has all but disappeared from the Australian veterinary profession in recent years.     

Comparison of bone healing,as assessed by computed tomography,following tibial tuberosity advancement in dogs with and without autogenous cancellous bone grafts

Abstract

AIMS: To objectively compare measures of bone healing, using computed tomography (CT) in dogs following bilateral tibial tuberosity advancement (TTA), between tibiae treated with and without autogenous cancellous bone grafts.

METHODS: Ten dogs with bilateral cranial cruciate ligament disease requiring surgical stabilisation were prospectively recruited to undergo single-session bilateral TTA, with only one, randomly assigned, tibia receiving bone graft in the osteotomy deficit. Bone healing at the osteotomy site was assessed using CT performed 38–70 days post-operatively. CT images were evaluated using both objective measurements of osseous bridging and subjective evaluation by six radiologists. Repeated measures ANOVA was used to compare the objective outcomes between the grafted and non-grafted tibiae.

RESULTS: The mean percentage of the osteotomy deficit bridged at the lateral cortex was greater in grafted (77.6, SD 35.2%) compared to non-grafted (63.0, SD 36.5%) tibiae (p=0.001), but did not differ at the medial cortex (p=0.1). The mean minimum callus width was greater in grafted (7.2, SD 3.3 mm) compared to non-grafted (3.6, SD 2.9 mm) tibiae (p<0.001). There was no difference in mean attenuation (measured in Hounsfield units) of the callus between grafted and non-grafted tibiae (p=0.5). The grafted tibia was deemed to have superior bone healing in 50/60 subjective assessments made by radiologists.

CONCLUSIONS: Superior osseous bridging was detected by CT analysis following TTA using autogenous cancellous bone grafts compared with no graft. This was shown by greater bridging percentage at the lateral cortex and formation of a broader callus. Qualitative assessments made by six radiologists also supported the conclusion that bone healing was improved by use of autogenous cancellous bone graft. CT was a useful method for assessing evidence of bone healing following TTA.

CLINICAL RELEVANCE: These findings justify the application of autogenous cancellous bone graft to augment healing following TTA in dogs.     

Advances in pasture plant breeding for animal productivity and health

Plant breeding has had a substantial effect on the productivity and health of ruminant animals in New Zealand by improving the quantity, quality and reliability of grazed temperate pastures. Genetic changes have affected annual pasture productivity, seasonal growth, digestibility, protein/energy balance, level of rumen undegradable protein, leaf properties affecting intake, resistance to foliar diseases, and reductions in compounds that have an adverse impact on the health, welfare and reproductive fertility of ruminant animals. Most plant improvement programmes have achieved genetic gains in excess of 1% per year for a variety of target traits, and these gains are likely to continue given the high genetic variation available within forage plants. Significant heritable variation exists to improve forage quality, particularly for soluble carbohydrate and fibre fractions in grasses, and in the rate at which these change during the season. Deleterious animal health and welfare effects can be alleviated through the use of non-toxic endophytes in grasses, that do not produce lolitrem B and ergovaline. Use of improved cultivars, with the appropriate management, can add value to animal products.     

Variation in ptaquiloside content in bracken (Pteridium esculentum (Forst. f) Cockayne) in New Zealand

AIM: To examine stands of bracken fern (Pteridium esculentum) from throughout New Zealand for the presence and concentration of ptaquiloside (Pta), and to compare the presence and/or concentrations of Pta in areas where bovine enzootic haematuria (BEH) and/or acute haemorrhagic syndrome (AHS) has been known to occur with those where BEH/AHS has not been recorded.

METHODS: Stands of bracken fern were sampled from 275 sites throughout New Zealand. Sixty-two stands were from a regional survey predominantly from the Waikato and Coromandel regions, 27 were from a farm in the King Country where BEH/AHS had been investigated previously, and 186 were from a national survey of the North and South Islands. Sampling sites were from a mixture of grazed paddocks, roadsides, and forest and bush areas. Samples comprised whole young fronds, the tops of unfurling young fronds, or, for the Regional Survey, mature green fronds from the previous season. Pta was extracted from the samples, and measured using high-performance liquid chromatography. Information on the occurrence of BEH/AHS at specific locations was obtained from published information and records from animal health laboratories in New Zealand.

RESULTS: The 275 samples contained widely varying concentrations of Pta. In the Farm Survey, concentrations ranged from 280–13,300 (mean 3,800) µg/g (on a dry-weight basis) in the 63% of samples that contained Pta. A high proportion of samples from the Regional and National Surveys covering large areas of the country contained no detectable levels of Pta. The majority (61%) of samples from these two surveys which contained Pta were from areas where BEH/AHS was reported to occur. Combining data from all surveys, in areas with reported BEH/AHS, 42% of samples collected contained Pta, compared with 6% where BEH/AHS was not known to occur.

CONCLUSIONS: Concentrations of Pta in bracken in New Zealand vary greatly, and in a high proportion of stands Pta is not found. A higher incidence of Pta, and some very high concentrations, are found in areas where BEH/AHS was known to occur.