Inhibitory Effects of Pergolide and Cabergoline Formulations on Daily Plasma Prolactin Concentrations in Geldings and on the Daily Prolactin Responses to a Small Dose of Sulpiride in Mares

Two experiments were conducted to assess the efficacy and duration of action of two dopaminergic compounds, pergolide and cabergoline, on daily prolactin secretion in geldings and on prolactin responses to a small dose of sulpiride over 10 days. In the first experiment, oral administration of 2 mg of pergolide was compared to a single injection of 2 mg of pergolide in a slow-release vehicle and a single injection of 5 mg of cabergoline in slow-release vehicle. Controls received vehicle only. All drug treatments reduced (P < .05) prolactin concentrations relative to that in controls but differed substantially in duration of action (oral pergolide approximately 6 hours or less, injected pergolide 6 to 24 hours, and injected cabergoline at least 6 days). In the second experiment, repeated small doses of sulpiride (2 μg/kg of body weight intravenously) were used to stimulate prolactin release in mares, and the ability of seven daily injections of pergolide (2 mg each) and a single injection of cabergoline (5 mg) in slow-release vehicle to suppress this release were compared. Control mares receiving vehicle injections had robust prolactin responses to the sulpiride injections on all days of injection (days 1, 0, 1, 2, 3, 4, 6, 8, and 10 relative to treatment). Prolactin responses were muted (P < .05) by pergolide and cabergoline treatments on the first day of injection (day 0, 30 min after treatment) and were basically absent on days 1 to 8. The single injection of cabergoline continued to be suppressive through day 10, whereas mares previously treated with pergolide (through day 6) had begun to recover a prolactin response by day 10. We conclude that either daily 2-mg pergolide injections in slow-release vehicle or a single injection of 5 mg of cabergoline in slow-release vehicle is an effective way to apply dopaminergic activity to horses for approximately 7 to 10 days and may have application in the treatment of pituitary pars intermedia dysfunction in affected horses.     

Repeatability of Prolactin Responses to a Small Dose of Sulpiride in Estrogen-Primed Geldings in Spring and in Mares During the Estrous Cycle in Summer

Two experiments were conducted to assess the repeatability of prolactin responses to a small dose of sulpiride in estrogen-primed geldings in spring and in mares during the estrous cycle in summer. Six long-term geldings each received a single intramuscular injection of 100 mg of estradiol cypionate on March 31, 2011, and were then challenged with an intravenous injection of dl-sulpiride (5 μg/kg of body weight of the racemic mixture) every other day for a total of 8 days. Jugular blood was collected at 0, 10, 20, 40, and 60 minutes after the injection of sulpiride for prolactin measurement. The experiment was repeated with six mares during the summer (July), except that the number of challenges was extended to 15 over 30 days so that any effect of estrous cycle stage could be assessed. Prolactin responses in geldings during April were robust and were varied in a quadratic manner (P < .003) over the eight sulpiride injections, increasing linearly to a plateau by the fourth injection. Mares also displayed robust prolactin responses to sulpiride injections in July, and there was no effect (P > .1) of day of injection and no effect of stage of estrous cycle (follicular phase, early diestrus, or late diestrus). We concluded that prolactin responses to this dose of sulpiride were sufficiently robust and repeatable for use as a paradigm for studies of the relative competitive efficacy and duration of action of various dopaminergic compounds and their vehicular formulations.     

Prolactin and Gonadotropin Responses in Geldings to Injections of Estradiol Benzoate in Oil, Estradiol Benzoate in Biodegradable Microspheres, and Estradiol Cypionate

We previously reported success in inducing early ovulation in seasonally anovulatory mares with a combination of estradiol pretreatment followed by daily administration of a dopamine antagonist (sulpiride). Although every-other-day injections of estradiol benzoate (EB) were effective in that experiment, practical application of this technology would require simplification of the treatment regimen. The current experiment was designed to compare, in a gelding model, the biologic responses of two alternative, one-injection regimens for estradiol delivery to the established EB treatment used previously. Fifteen long-term geldings were sampled via jugular venipuncture from November 5 to 7, 2006, and were then administered intramuscular injections of vegetable oil (n = 4); EB, 11 mg in oil (n = 4; controls); EB in biodegradable microspheres (300 mg; n = 3); or estradiol cypionate, 100 mg in oil (n = 4). Injections of EB in oil were repeated every other day for a total of 10 injections, as was done in our previous experiment. Jugular blood samples were drawn from all geldings at 3, 6, 12, 24, 36, and 48 hours relative to injections, and then on the mornings of days 3, 4, 6, 8, 10 to 18, 22, 26, and 30. On days 10 through 13, all geldings received subcutaneous injections of 125 mg sulpiride, a dopamine receptor antagonist, to stimulate prolactin secretion. On day 12, each gelding received an intravenous injection of 30 μg gonadotropin-releasing hormone (GnRH) analog and 3 mg thyrotropin-releasing hormone (TRH); frequent blood samples were drawn to characterize the luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin responses. Relative to geldings receiving oil, all geldings receiving estradiol injections had a rise (P < .05) in estradiol concentrations lasting at least 12 days. Daily LH concentrations increased (P < 0.01) in all treated groups, but the response was delayed approximately 14 days in the geldings receiving EB in microspheres. Daily FSH concentrations decreased (P < .01) in all treated groups, with the greatest response in the geldings receiving EB in microspheres. Prolactin in daily samples increased (P < .01) similarly in all estradiol-treated groups after injection of sulpiride. The LH response to GnRH analog was greatest (P < .05) in geldings receiving EB in oil and estradiol cypionate; the FSH response was not altered by treatment. The prolactin response to TRH was greater (P < .01) in estradiol-treated geldings relative to controls, but did not differ among groups. Compared with the responses to every-other-day EB injections in oil, as we used previously, a single injection of 100 mg estradiol cypionate gave the most similar and consistent responses. Because of these similar responses in this gelding model, it is likely that a single injection of 100 mg estradiol cypionate can be used in lieu of every-other-day injections of EB in oil in the treatment regimen we reported previously for stimulating ovarian activity in seasonally anovulatory mares.     

Stimulation of Ovulation in Seasonally Anovulatory and Vernal Transitional Mares with Estradiol and Domperidone: Dose and Combination Studies

Three experiments were conducted to test the efficacy of different doses of estradiol cypionate (ECP) and domperidone for inducing ovulation in seasonally anovulatory (January; Experiments 1 and 2) and transitional period (March; Experiment 3) mares. In the first two experiments, mares in Kentucky and Louisiana were administered domperidone (3 g in biodegradable particles) alone or after pretreatment with 100 or 150 mg of ECP; another group received ECP, domperidone, and progesterone, and a fifth group received ECP and progesterone only (the latter two in Kentucky). Control mares in both states received no treatment. The proportion of mares ovulating within 35 days (for mares treated in January) was greater (P = .0002) for those receiving any combination of ECP plus domperidone relative to mares not receiving the combined treatment. Addition of progesterone to ECP plus domperidone did not enhance (P = .7) the response relative to the combination alone; domperidone by itself, or ECP plus progesterone, did not alter the response relative to controls (P > .24). Experiment 3 was conducted in Louisiana as a 2 × 3 factorial, with two doses of domperidone (1.5 or 3 g) and three doses of ECP (0, 75, or 150 mg). There was no main effect of domperidone or ECP dose; a greater proportion (P = .055) of mares receiving any combination of ECP plus domperidone ovulated in 21 days compared with those receiving no ECP. In conclusion, pretreatment with ECP before injection of domperidone 10 days later can be used to increase the proportion of mares ovulating early in the year; within the limits of the present experiments, there appears to be no difference in doses of ECP of 75, 100, or 150 mg, and no difference in doses of domperidone of 1.5 or 3 g.     

Responses of Adenohypophyseal Hormones to Substance P Administration in Geldings: Comparison to Responses After Brief Exercise and Sulpiride Administration

Nine adult geldings were used in three experiments to study the possible role of substance P in the prolactin responses to nondopaminergic stimuli. Experiment 1 was performed as an incomplete Latin square design to determine the secretory responses of prolactin, growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) to IV administration of substance P. Doses tested and compared to no peptide (0 dose, control) were 62, 125, 250, and 500 μg of substance P. The three highest doses of peptide caused an immediate rise in heart rate, sweating, salivation, rhinorrhea, stretching of hind legs, and defecation. The lowest dose (62 μg) caused minor sweating, some rhinorrhea, and a rise in heart rate. Recovery from these physical responses was complete in approximately 30 minutes. All doses of substance P caused an immediate rise (P < .01) in plasma prolactin concentrations, with the three highest doses producing similar responses, and the 62 μg dose producing a minimal response (P < .05). Concentrations of ACTH (P < .01) and GH (P = .05) also increased after substance P administration; concentrations of LH, FSH, and TSH were unaffected. Experiment 2 compared the effects of brief exercise on hormonal characteristics. Two minutes of trotting increased (P < .01) plasma concentrations of GH, ACTH, and prolactin, as well as LH (P = .055). Experiment 3 determined the relative responses of prolactin to a fixed dose of sulpiride (0.1 mg/kg of body weight). In general, the prolactin responses to substance P were similar to those after exercise, which were both generally less than after sulpiride. These data are consistent with a possible role of substance P in the prolactin response to stressful stimuli.     

蒙古利亚矮种母马垂体促性腺激素的血清含量与妊娠状态和年龄的相关性

选用 10匹 4～ 16岁怀孕和 2 2匹 0 5～ 17岁非怀孕的蒙古利亚矮种母马 ,采用放射免疫法分别测定了其血清中FSH和LH的浓度。其结果显示 ,妊娠母马的血清FSH和LH含量分别为 0 3 0 83mIU /ml± 0 1611mIU/ml和 0 65 67mIU /ml± 0 40 61mIU/ml,显著低于非妊娠母马的 2 40 5 9mIU/ml± 0 64 46mIU /ml和 2 3 85 5mIU /ml± 0 3 5 2 9mIU/ml(P <0 0 5 ) ;此外 ,3～ 8岁组、10～ 14岁组和 15岁以上组非妊娠母马血清FSH和LH含量分别为 2 44 0 0mIU /ml±0 780 0mIU /ml、2 40 0 0mIU/ml± 1 3 0 78mIU /ml、5 3 75 0mIU/ml± 0 885 0mIU /ml和 1 840 0mIU/ml± 0 80 0 0mIU /ml、2 5 92 9mIU/ml± 0 5 93 0mIU/ml、3 975 0mIU /ml± 0 485 0mIU/ml。以上结果表明 ,在妊娠阶段 ,母马血清中的FSH和LH显著降低 ,而繁殖季节的非妊娠母马血清FSH和LH的浓度却随着母马的老年化而呈现增加的趋势。     

Factors Affecting the Glucose Response to Insulin Injection in Mares: Epinephrine, Short- and Long-Term Prior Feed Intake, Cinnamon Extract, and Omega-3 Fatty Acid Supplementation

Five experiments were conducted with mares to better define factors that might affect the assessment of insulin sensitivity via direct insulin injection, and to then apply this method of assessing insulin sensitivity to trials which tested two potential supplements for improving poor insulin sensitivity in horses. The experiments assessed the effects of the following: (1) previous administration of epinephrine, (2) overnight feed deprivation versus hay or pasture consumption, (3) 10-day acclimatization to hay in a dry lot versus pasture grazing, (4) cinnamon extract supplementation, and (5) fish oil supplementation on insulin sensitivity. Mares of known high and low insulin sensitivities were used in the first three experiments, whereas mares with low insulin sensitivities were used in the supplement trials. Epinephrine administration increased blood glucose concentrations (P < .05) and prevented the insulin-induced decrease in blood glucose concentrations in both sensitive and insensitive mares. Overnight feed deprivation decreased (P < .06) insulin sensitivity relative to overnight ad libitum access to hay, and both regimens resulted in reduced insulin sensitivity relative to overnight pasture availability; sensitive and insensitive mares responded similarly except when kept on pasture (P = .0854). Ten days of hay consumption in a dry lot reduced (P < .05) insulin sensitivity in insensitive mares, but not in sensitive mares, relative to pasture grazing. Supplementation with cinnamon extract or fish oil had no effect on insulin sensitivity of mares with known low insulin sensitivity under the conditions of these experiments.     

Insulin Sensitivity in Thoroughbred Geldings: Effect of Weight Gain,Diet, and Exercise on Insulin Sensitivity in Thoroughbred Geldings

The effects of dietary energy source, controlled weight gain, and exercise restriction on insulin sensitivity (SI) were studied in mature Thoroughbred geldings with body condition scores (BCS) of 4.3 ± 0.1. Two dietary energy sources were used, one high in starch and sugar (HS; n = 9) and one high in fat and fiber (HF; n = 7), and horses were fed 20 Mcal digestible energy (DE)/day above maintenance requirements to encourage weight gain. Using the minimal model of glucose and insulin dynamics, no differences in SI between groups were noted before initiation of treatment concentrate feeding. After dietary acclimation, SI was decreased in HS (P < 0.01) as compared with HF. After 32 weeks of controlled weight gain (90.8 kg; final BCS, 7.0 ± 0.1), SI remained lower in HS (P = 0.07) but did not change from the preweight gain value. SI in HF did not change between the start and end of weight gain. After completion of weight gain, exercise was restricted for 2 weeks, resulting in a reduction in SI in HF (P = 0.03) but no change in HS. It was concluded that dietary energy source may be more influential than weight gain on SI in the mature Thoroughbred gelding between BCS 4 and 7. The higher SI found in horses consuming the HF diet appeared to be partially dependent on some level of physical activity.     

The Effect of Sulpiride Treatment During the Periovulatory Period on Prolactin Concentration and Ovulation in the Mare

Sixteen estrous cycles from 10 cyclic mares were randomly assigned to a control or sulpiride group (n = 8 each). All mares received 1,500 IU of human chorionic gonadotropin (hCG) (hour 0) during estrus with a follicular diameter ≥32 mm. Mares were scanned every 12 hours until ovulation. In the treatment group, beginning at hour 0, each mare received 1.5 mg/kg of sulpiride every 12 hours intra-muscularly until ovulation or formation of a luteinized unruptured follicle (LUF). Concentrations of luteinizing hormone (LH) and prolactin (PRL) were measured by radioimmunoassay. In each group, there were 10 preovulatory follicles for the eight cycles. The ovulation rate (9/10, 90%) was similar in the control and sulpiride groups. Two mares formed an LUF, which was first detected at hours 48 and 72 for the sulpiride and control mares, respectively. The interval from hCG to ovulation was 49.5 ± 11.1 and 43.5 ± 5.8 hours, for the control and sulpiride groups, respectively (P > .5). LH followed the typical preovulatory surge pattern, with no difference between groups (P > .5). Sulpiride administration increased PRL concentration in treated mares at 24 (P < .1), 36, and 48 hours (P < .05) after treatment. In conclusion, sulpiride administration every 12 hours increased PRL concentration in treated mares after 24 hours of the beginning of treatment. However, at this time window and concentration, PRL did not have any effect on ovulation. The control mare that developed an LUF had a PRL concentration similar to other ovulatory control mares (always ≤10 ng/mL).     

大白猪、长白猪和杜洛克猪催乳素受体基因多态性及其与繁殖性能的关系

本试验通过PCR-RFLP技术对大白猪、长白猪和杜洛克猪的催乳素受体(prolactin receptor,PRLR)基因第10外显子AluⅠ酶切位点进行多态性分析,并对各基因型母猪的第1至第3胎次产仔数、产活仔数、断奶仔猪数、初生窝重、21日龄窝重及断奶成活率进行测定,进而分析PRLR基因多态性与繁殖性能的关系。结果表明,PRLR基因在3个品种中均存在多态位点,且AA基因型都是其优势基因型。关联分析结果表明,大白猪AA基因型个体第1、2和3胎各繁殖性状均呈现出高于AB和BB基因型的趋势。在繁殖性能已经稳定的第3胎次AA基因型个体产仔数、产活仔数、断奶仔猪数、初生窝重及断奶成活率比BB基因型个体平均分别高出0.31头、0.63头、0.02头、0.65 kg和0.43%,但差异均不显著(P>0.05)。     

Effect of Parity,Season and FSH Treatment on the Calving Interval of Ayrshire Cows in the Tropics

A total of 607 calving intervals on 99 Ayrshire cows with parities from 1 to 10 and belonging to one dairy herd at Iringa in the southern highlands of Tanzania were analysed to study the effect of parity and season or month of calving on the subsequent calving interval. In addition, 22 calving intervals incorporating a superovulatory cycle were compared with those of 52 controls that had calved around the same period.The average (mean±SEM) age at first calving was 985±16 days. The effect of parity on calving interval was highly significant (p<0.001). Cows that calved in December, at the beginning of the rainy season, exhibited the shortest calving interval (404±13), while those that calved in September/October, in the dry season, exhibited the longest average calving interval (466±20 days), although this difference was not significant. Prior treatment with follicle-stimulating hormone to induce superovulation, significantly lengthened the average calving interval (579±28 vs 457±15 days; p<0.001).It was concluded that both parity and FSH treatment affected the calving interval. However, season (rainy vs dry) or month of calving did not influence this interval.     

Subjective Gait Assessment of 57 Sports Horses in Normal Work: A Comparison of the Response to Flexion Tests,Movement in Hand,on the Lunge,and Ridden

Historically, lameness has been evaluated in hand or on the lunge, but some lamenesses may only be apparent ridden. The objectives were to compare the response to flexion tests, movement in hand, on the lunge, and ridden in sports horses in regular work, assumed to be sound by the owners. It was hypothesized that lameness may be apparent in ridden horses that was not detectable in hand or on the lunge. Fifty-seven sports horses in regular work and assumed to be sound were assessed prospectively in hand, on the lunge on both soft and firm surfaces, and ridden. Flexion tests of all four limbs were performed. Lameness was graded (0–8) under each circumstance in which the horse was examined and after each flexion test. Fourteen horses (24.6%) were sound under all circumstances. Six horses were sound in hand, on the lunge, and ridden but showed a grade 1 or 2 lameness after flexion of a single limb. Sixteen horses (26.3%) were lame in hand. Twenty-four horses (42.1%) showed lameness on the lunge on a soft surface, and 23 horses (40.4%) were lame on the lunge on a firm surface. Twenty-seven horses (47.4%) showed lameness ridden; seven (12.3%) were only lame ridden. There was no significant association between age (P = .09) or work discipline (P = .1) and lameness. It was concluded that freedom from lameness in straight lines is not a reliable indicator of soundness. Some lamenesses are only apparent ridden.     

Postovulatory Effect of Intravenous Administration of Lipopolysaccharide (E. coli,O55:B5) on the Contractile Activity of the Oviduct,Ova Transport,Binding of Accessory Spermatozoa to the Zona Pellucida and Embryo Development in Sows

The effect of lipopolysaccharide (LPS) (E. coli, O55:B5), administered 18 h after ovulation in the second oestrus after weaning, on the contractile activity of the oviduct, ova transport, sperm binding to zona pellucida (ZP) and embryo development, was studied in 14 Swedish crossbred (Landrace Yorkshire) multiparous sows. The endotoxin group (E‐group) sows were administered with 300 ng/kg of LPS while the control group (C‐group) sows were administered with 5 ml of saline i.v. via an indwelling jugular cannula. Immediately after evidence of standing oestrus, a Millar^® pressure transducer was placed intraluminally about 3 cm into the mid‐isthmus, via laparotomy. Pressure recordings of the oviduct were collected from all conscious sows until slaughter. After slaughter, the genital tract opposite to the side with the transducer was retrieved, and three equal isthmic segments and the first third of the uterine horn part adjacent to the utero‐tubal‐junction (UTJ) were flushed separately to recover the ova. The intervals (mean±SD) from ovulation to slaughter (OS) and insemination to ovulation (IO) were not different between the E‐group (44.5±5.7 h; 13.3±6.5 h) and the C‐group (42.7±5.9 h; 14.8±4.1 h), respectively. Ova recovery rate (RR) in the E‐group (80.2±22.9%) did not differ from that in the C‐group (85.2±4.5%). The frequency distribution of ova recovered in the different segments did not significantly (p>0.05) differ between the groups. The E‐group showed higher cleavage rate than controls. A higher proportion of spermatozoa bound to the ZP was also found in the E‐group compared with controls. The isthmic intraluminal pressure slightly increased (p=0.07) 18 h after ovulation and immediately following LPS in the E‐group, compared with the C‐group. The frequencies of phasic pressure fluctuations were significantly (p<0.05) lower at 30 and 38 h after ovulation in the E‐ than in the C‐group. It can be concluded from the present study that a single i.v. administration of LPS (300 ng/kg body weight) to sows, 18 h after ovulation might be associated with changes in isthmic pressure and the frequency of phasic pressure fluctuations, increased numbers of spermatozoa attached to the ZP and an enhanced embryo development but not with ova transport rates.     

Reproductive response in suckling Corriedale ewes to the ram effect during the non-breeding season: Effect of postpartum condition and the use of medroxyprogesterone priming

The response to the ram effect and the use of progestagen priming was studied in postpartum suckling Corriedale ewes. Two experiments were carried out during the non-breeding season. In experiment 1, the effectiveness of the ram effect to induce fertile oestrus in postpartum ewes was determined. While no significant differences in the frequency of ewes in oestrus were found, the overall conception rate was significantly higher in ewes that were weaned at least 6 months before the study started (63.3%) than in 60–90 days postpartum ewes (45.3%, p < 0.01). In experiment 2, the influence of medroxyprogesterone acetate priming on the response to the ram effect in suckling Corriedale ewes was determined. The frequency of ewes in oestrus and conception rate between ewes that remained unprimed and 6-days-primed ewes were similar. We conclude that it is possible to induce oestrus in postpartum suckling Corriedale ewes using the ram effect during the non-breeding season and that the use of progestagen priming seems to be ineffective in improving the response of postpartum ewes to the ram effect.     

The inclusion of a daisy plant (Chrysanthemum coronarium) in dairy sheep diet. 1: Effect on milk and cheese fatty acid composition with particular reference to C18:2 cis-9, trans-11

An experiment was carried out to evaluate the effect on milk and cheese fatty acid composition of the inclusion of Chrysanthemum coronarium L., (Asteracea) into dairy sheep diet. Plots sown either with a binary mixture consisting of Lolium rigidum Gaudin and Medicago polymorpha (LM) or a ternary mixture including the above species and C. coronarium were (LMC) grazed by groups of Sarda dairy ewes during May. The botanical composition of diet, as measured by n-alkane method, showed that 34% of LMC group diet consisted of Chrysanthemum flowers and leaves. Exposure of sheep to this non-conventional forage did not affect animal performance and milk composition (fat and casein, P > 0.05) but resulted in different milk and cheese fatty acid composition. In particular conjugated linoleic acid, vaccenic acid and linoleic acid were all higher in LMC than LM groups (P < 0.05). The probable main reason was the higher proportion of linoleic acid in Chrysanthemum forage and hence in LMC than LM diet.     

Comparisons of computed tomography, contrast-enhanced computed tomography and standing low-field magnetic resonance imaging in horses with lameness localised to the foot. Part 2: Lesion identification

Reasons for performing study: No previous study compares computed tomography (CT), contrast‐enhanced computed tomography (CECT) and standing low‐field magnetic resonance imaging (LFMRI) to detect lesions in horses with lameness localised to the foot. This study will help clinicians understand the limitations of these techniques. Objectives: To determine if CT, CECT and LFMRI would identify lesions within the distal limb and document discrepancies with lesion distribution and lesion classification. Methods: Lesions in specific structures identified on CT and MR images of feet (31 limbs) from the same horse were reviewed and compared. Distributions of lesions were compared using a Chi‐squared test and techniques analysed using the paired marginal homogeneity test for concordance. Results: Lesions of the deep digital flexor tendon (DDFT) were most common and CT/CECT identified more lesions than LFMRI. Deep digital flexor tendon lesions seen on LFMRI only were frequently distal to the proximal extent of the distal sesamoid and DDFT lesions seen on CT/CECT only were frequently proximal to the distal sesamoid. Lesions identified on LFMRI only were core (23.3%) or splits (43.3%), whereas lesions identified only on CT were abrasions (29.8%), core (15.8%), enlargement (15.8%) or mineralisation (12.3%). Contrast‐enhanced CT improved lesion identification at the DDFT insertion compared to CT and resulted in distal sesamoidean impar ligament and collateral sesamoidean ligament vascular enhancement in 75% of cases. Low‐field MRI and CT/CECT failed to identify soft tissue mineralisation and bone oedema, respectively. Conclusions and potential relevance: Multiple lesions are detected with CT, CECT and LFMRI but there is variability in lesion detection and classification. LFMRI centred only on the podotrochlear apparatus may fail to identify lesions of the pastern or soft tissue mineralisation. Computed tomography may fail to identify DDFT lesions distal to the proximal border of the distal sesamoid.