Unusual case of uterine stump pyometra in a cat

This report describes an unusual case of uterine stump pyometra in a cat whose main clinical sign at presentation was abdominal straining. At the time of ovariohysterectomy, the surgeon reported that the uterine body had a purulent content. Nearly a month after the surgery the cat showed abdominal straining. The enlarged uterine stump, filled with purulent fluid, had caused a compression of the rectum and secondary intestinal sub-occlusion. Surgical revision consisted of draining the purulent content of the remnant of the uterine body and ablating as much of it as possible; checking of the ovarian pedicles revealed the presence of a small fragment of whitish tissue on the right side, which was shown to contain, by means of histological observation and immunohistochemical staining, ovarian tissue. Four months after surgical revision the queen did not show any pathological signs and 1 year later she is still in good health.     

Clinical pharmacology of clemastine in healthy dogs

The pharmacokinetic properties of clemastine were investigated in six healthy dogs and compared with the effect of the drug recorded as inhibition of wheal formation induced by intradermal injections of histamine. Clemastine clearance was high (median: 2.1 L h(-1) kg(-1)) and the volume of distribution large (13.4 L kg(-1)). The half-life after intravenous administration was 3.8 h and the plasma protein binding level in vitro was 98%. After oral administration, the bioavailability was only 3%. Given intravenously, clemastine (0.1 mg kg(-1)) inhibited wheal formation completely for 7 h, whereas the effect after oral administration (0.5 mg kg(-1)) was minor. The data show that most dosage regimens suggested in the literature for the oral administration of clemastine to dogs are likely to give too low a systemic exposure of the drug to allow effective therapy.     

Compensatory load redistribution of horses with induced weightbearing hindlimb lameness trotting on a treadmill

REASONS FOR PERFORMING STUDY: The compensatory mechanisms of horses with weightbearing hindlimb lameness are still not fully understood. HYPOTHESIS: That weightbearing, unilateral hindlimb lameness would not only alter stride characteristics to diminish structural stress in the affected limb but also induce compensatory load adjustments in the other supporting limbs. OBJECTIVE: To document the load and time shifting mechanisms of horses with unilateral weightbearing hindlimb lameness. METHODS: Reversible lameness was induced in 8 clinically sound horses by applying a solar pressure model. Three degrees of lameness (subtle, mild and moderate) were induced and compared with the nonlame (sound) control measurement. Vertical ground reaction forces were recorded for all 4 limbs simultaneously on an instrumented treadmill. RESULTS: Compared to the sound situation, moderate hindlimb hoof lameness induced a decrease in stride duration (-3.3%) and stride impulse (-3.1%). Diagonal impulse decreased selectively in the lame diagonal stance (-7.7%). Within the diagonal limb pair, vertical impulse was shifted to the forelimb during the lame diagonal stance (+6.5%) and to the hindlimb during the sound diagonal stance (+3.2%). Peak vertical force and vertical impulse decreased in the lame limb (-15%), but only vertical impulse increased in the contralateral hindlimb (+5.7%). Stance duration was prolonged in both hindlimbs (+2.5%). Suspension duration was reduced to a greater extent after push-off of the lame diagonal limb pair (-21%) than after the sound diagonal limb pair (-9.2%). CONCLUSIONS: Four compensatory mechanisms could be identified that served to reduce structural stress, i.e. peak vertical force on the affected limb: 1) reduction of the total vertical impulse per stride; 2) diagonal impulse decreased selectively in the lame diagonal; 3) impulse was shifted within the lame diagonal to the forelimb and in the sound diagonal to the hindlimb; and 4) the rate of loading and peak forces were reduced by prolonging the stance duration. POTENTIAL RELEVANCE: Load shifting mechanisms are not only effective in diminishing peak forces in the affected limb, but also suppress compensatory overload in other limbs. Selected force and time parameters allow the unequivocal identification of the lame limb. Future studies have to examine how far these compensatory mechanisms may be generalised for other defined orthopaedic problems in the hindlimb.     

A critical evaluation of serum methylmalonic acid and vitamin B12 for the assessment of cobalt deficiency of growing lambs in New Zealand

AIM: To derive reference ranges for serum methylmalonic acid (MMA) for the diagnosis of cobalt/vitamin B12-responsiveness in lambs and critique existing serum vitamin B12 reference ranges. METHODS: Individual animal data from earlier supplementation trials, involving 225 ewes, 106 suckling lambs, 301 lambs during the suckling and post-weaning periods and 414 weaned lambs, for which weight gain to supplementation was observed, were used to derive relationships between serum vitamin B12 and MMA, and liveweight gain. RESULTS: Serum MMA concentrations were rarely elevated above the norm of <2 micromol/L when serum vitamin B12 concentrations were >375 pmol/L, and not elevated into the range where a liveweight response to supplementation occurred (>10 micromol/L) unless serum vitamin B12 concentrations were below 200 pmol/L. Suckling lambs were able to maintain high growth rates despite elevated serum MMA concentrations (>20 micromol/L). CONCLUSIONS: The current reference ranges used in New Zealand for serum vitamin B12 are set conservatively high. Serum MMA concentrations appear to allow better differentiation of a responsive condition than vitamin B12 concentrations. Serum MMA concentrations >13 micromol/L indicate responsiveness to supplementation whilst concentrations <7 micromol/L indicate unresponsiveness. In the range 7-13 micromol/L, variation in response was observed and predictability of response is less certain, but supplementation is advisable. CLINICAL RELEVANCE: The current reference ranges for vitamin B12 responsiveness are conservatively high and lead to over-diagnosis of vitamin B12 deficiency in ill-thriftiness of sheep.     

The effect of individual liveweight and condition scores of ewes at mating on reproductive and scanning performance

AIMS: To determine the effects of liveweight (LW) and condition score (CS) of ewes at mating on both mating performance and scanning percentage, and to determine if effects of CS were independent of LW. METHODS: Two groups of ewes, comprising 1,780 mixed-aged Romney (Rom MA) and 692 composite two-tooth (1/8 East Friesian 1/16 Finn 13/16 Romney, Comp TT) ewes were grazed separately with harnessed rams for two reproductive cycles. Romney rams were used for the first 17 days of mating and then replaced on the morning of Day 18 by Suffolk rams. Ewes were weighed and CS assessed on a scale of 0-5 before the introduction of the rams. Ewes were identified as having been mated during the first cycle only, during both cycles, during the second cycle only, or not mated. All mated ewes were scanned using ultrasound, 50 days after the end of mating, and identified as being either non pregnant, single-, twin- or triplet-bearing. RESULTS: Linear relationships (R2=0.99) between mean LW and CS at mating were evident for both Rom MA and Comp TT ewes and the mean increase in LW per unit increase in CS was greater in the Rom MA ewes (7.88 kg) than the Comp TT (4.78 kg) ewes (p<0.05). Ewes mated in the second cycle only were significantly (p<0.05) lighter than those mated in the first cycle only. In Rom MA ewes, a greater proportion were mated in the first cycle only if CS was >/=2.0 than if CS was <2.0, and the proportions of ewes mated in the first cycle only or in both cycles did not differ if CS was >/=2.5. In Comp TT ewes, there was no difference in the proportions mated in the first cycle or both cycles, if CS was >/=2.0. Triplet-bearing ewes were heavier than twin-bearing ewes, which were in turn heavier than both singleton-bearing and non pregnant ewes. Twin-bearing ewes had higher CS than both single-bearing and non pregnant ewes (p<0.05) but differences were not significant if LW was included as a covariate. In both Rom MA and Comp TT ewes, greater proportions were non pregnant and lower proportions had twins if CS was <2.0 than if CS was >/=2.0. In Rom MA ewes only, a greater proportion again had twins and a lower proportion had singletons if CS was >/=3.0 than if CS was <3.0. In Comp TT ewes, the proportion that were non pregnant or twin-bearing did not vary with CS if CS was >/=2.0. Reproductive performance was maximal for Rom MA and Comp TT ewes that had CS at mating >/=3.0 and >/=2.0, respectively, equating to LW of 62.6 and 48.5 kg, respectively. CONCLUSIONS: In both groups of ewes, CS and LW at mating positively affected reproductive performance measured at the time of mating and at scanning, however, no reproductive advantage was evident above a minimum CS of 3.0 and 2.0, equating to LW of 62.6 and 48.5 kg, for Rom MA and Comp TT ewes, respectively. Sheep farmers should direct management to ensure that no ewes are below these minimum targets rather than ensuring high average LW and/or CS of a mob.     

Treatment of shoulder instability caused by medial glenohumeral ligament rupture with thermal capsulorrhaphy

A three-year-old, male springer spaniel had chronic left forelimb lameness with a medial glenohumeral ligament tear and articular cartilage damage diagnosed on arthroscopy. The animal failed to respond to conservative therapy of rest and an intra-articular injection of methylprednisolone. The use of thermal capsulorrhaphy using bipolar radiofrequency bought about a return of joint stability and resolution of the lameness.     

Effects of intraovarian infusion of insulin-like growth factor-I on ovarian follicular function in cattle

The objective of this study was to determine if increased secretion of intraovarian insulin-like growth factor-I (IGF-I), experimentally induced via minipumps, affects follicular function in cattle. Fourteen cycling Holstein cows were divided equally into two groups: Control, osmotic minipumps (containing vehicle) surgically inserted into each ovary, or IGF-I treated, osmotic minipumps as in Controls but pumping 2.0 microg of recombinant human IGF-I per hr for 7 days. All cows were synchronized with prostaglandin F(2alpha) 0.10) between Control and IGF-I-treated cows during Days 2 to 6 of treatment. IGF-I treatment increased (P<0.05) estradiol concentrations in follicular fluid of small follicles, but had no effect (P<0.10) on estradiol concentrations in follicular fluid of large follicles, or on progesterone, androstenedione, or IGF binding protein concentrations in small or large follicles. We conclude that a 7-day infusion of IGF-I directly into the stroma of the ovary altered follicular growth and follicular fluid estradiol concentrations.     

Continuous infusion of gentamicin into the tarsocrural joint of horses

OBJECTIVE: To develop a method for continuous infusion of gentamicin into the tarsocrural joint of horses, to determine pharmacokinetics of gentamicin in synovial fluid of the tarsocrural joint during continuous infusion, and to evaluate effects of continuous infusion of gentamicin on characteristics of the synovial fluid. ANIMALS: 12 healthy adult horses. PROCEDURE: An infusion catheter consisting of flow control tubing connected to a balloon infuser was used. Gentamicin solution (100 mg/ml) was infused in the right tarsocrural joint and balanced electrolyte solution was infused in the left tarsocrural joint for 5 days. Synovial fluid and serum gentamicin concentrations were measured by use of a fluorescence polarization immunoassay. RESULTS: 17 of the 24 (71%) infusion catheters initially placed functioned without complications for the entire 5-day infusion period. Median gentamicin concentration in synovial fluid from treated joints during the 5-day infusion period ranged from 2875 to 982 microg/ml. Median serum gentamicin concentration during this period ranged from 2.31 to 2.59 microg/ml. Mean (+/- SD) elimination half-life and total clearance of gentamicin from the synovial fluid were 6.25+/-1.01 hours and 1.52+/-0.96 ml/min, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: An infusion catheter can be used for continuous infusion of gentamicin into the tarsocrural joints of horses for up to 5 days. At a gentamicin dosage of 0.17+/-0.02 mg/kg/h, continuous intra-articular infusion results in synovial fluid gentamicin concentrations greater than 100 times the minimal inhibitory concentration reported for common equine pathogens.