The use of ultrasonography for the study of the bovine reproductive tract. II. Non-pregnant,pregnant and pathological conditions of the uterus

Real time B mode ultrasonography, with a 5 MHz transducer and a linear array scanner, was used to examine the bovine uterus. Approximately 450 dairy cows were examined either on farms or immediately prior to slaughter. Normal and pathological changes of the uterus were noted and a comparison made between ultrasound characteristics, rectal findings and gross examination at slaughter.The normal uterus in estrus, diestrus and pregnancy was found to exhibit characteristic images. These included a distinct folding of the endometrium at the time of estrus; a lack of folding and increased echogenicity at mid-diestrus; slight distension with non-echoic fluid as early as 22 days of gestation; and definitive recognition of the conceptus by day 27 of gestation.In addition, observations were made of the pathological conditions of endometritis, pyometra, mucometra, mummified and macerated fetuses. Generally, images of inflammatory conditions of the uterus were characterized by a distended lumen filled to a varying degree with partially echogenic, ‘snowy’ patches. In conditions involving fetal remnants, the images allowed visualization of the fragments.This study demonstrated that ultrasonography was useful in examining the normal uterus, being particularly helpful in differentiating questionable palpation results when uterine pathology was present.     

Pregnancy diagnosis in swine: A comparison of the technique of rectal palpation and ultrasound

The accuracy of pregnancy diagnosis in swine by rectal palpation and by ultrasound was compared using sows and gilts thirty days or more after breeding. A total of eighty-four pigs were included in this experiment and they were examined an average of thirty-nine days following breeding. Forty-nine animals were slaughtered within a few days of pregnancy examination and thirtyfive were allowed to farrow. Pregnancy status was correctly diagnosed by palpation per rectum in eighty-three of the eighty-four pigs (98.8%) and by ultrasound in eighty-one of the eighty-four pigs (96.6%) examined. The accuracy of the two methods was not significantly different.     

Rectal examination in patients with pain in the right lower quadrant of the abdomen.

OBJECTIVE--To determine whether rectal examination provides any diagnostic information in patients admitted to hospital with pain in the right lower quadrant of the abdomen. DESIGN--Casualty officer or surgical registrar recorded symptoms and signs on admission on detailed forms. Final diagnosis was noted on discharge from hospital. SETTING--District general hospital. PATIENTS--1204 Consecutive patients admitted to hospital with pain in the right lower quadrant of the abdomen as their major complaint; 1028 had a rectal examination on admission. MAIN OUTCOME MEASURES--Odds ratio for each symptom and sign related to final diagnosis. Results of multiple logistic regression analysis for acute appendicitis. RESULTS--Right sided rectal tenderness, present in 309 of those examined, was more common in patients with acute appendicitis (odds ratio 1.34, p less than 0.05). This odds ratio was considerably less than that for other clinical signs--namely, tenderness in the right lower quadrant (odds ratio 5.09), rebound tenderness (3.34), guarding (3.07), and muscular rigidity in the abdomen (5.03). In the logistic regression analysis of patients with acute appendicitis, when allowance was made for the presence or absence of rebound tenderness, rectal tenderness on the right lost its significance. Six patients had masses palpable rectally, of which three were palpable on abdominal examination; the other three patients had acute appendicitis. No other unexpected diagnoses were established, and no useful additional diagnostic information was obtained by routine rectal examination. CONCLUSION--If patients presenting with pain in the right lower quadrant of the abdomen are tested for rebound tenderness then rectal examination does not give any further diagnostic information.     

Diagnostic Use of Ultrasonography in Patients with Nodular Thyroid Disease

ObjectiveTo review the published reports pertaining to the diagnostic utility of ultrasonography for evaluation of thyroid nodules.MethodsVarious roles for diagnostic thyroid ultrasonography and screening ultrasound studies of the thyroid are discussed, and ultrasound characteristics of thyroid nodules and their association with malignant potential are described.ResultsIn two studies that correlated ultrasound findings with physical examination findings in patients with a solitary thyroid nodule detected by palpation, 16% of such patients had no corresponding nodule evident on ultrasonography, and 45% of such patients had an additional nodule detected by ultrasonography. Similarly, approximately 18% of patients with a palpable multinodular thyroid had no nodules larger than 1 cm in diameter on ultrasound studies. Thyroid nodules larger than 1 cm have been found by ultrasonography to be present in from 2 to almost 5% of the population with normal findings on examination of the thyroid. Use of screening ultrasound study of the thyroid has been suggested for patients with a history of childhood irradiation to the head and neck or a family history of thyroid cancer. Numerous investigations that have evaluated ultrasound features of thyroid nodules have suggested five characteristics as suggestive of malignant potential—hypoechogenicity, microcalcifications. irregular or microlobulated border, absent or irregular thick halo, and increased intranodular vascularity.ConclusionCorrelation of ultrasound and palpation findings will provide a comprehensive evaluation of nodular thyroid disease. Moreover, real-time ultrasonography facilitates characterization of features associated with an increased risk of a malignant lesion. High-resolution thyroid ultrasonography is a dynamic tool for endocrinologists. (Endocr Pract. 2004;10:246-252)     

Prevalence of postservice pyometra in a herd of beef cows infected with trichomoniasis: A case report

Trichomoniasis was detected in a herd of beef cows during a routine yearly reproductive examination. The examination revealed that 12.6% of the cows (75 597 ) were not pregnant. Of these, 65.3% (49 75 ) had a normal uterus and a functional corpus luteum, suggesting that they were cyclic; 21.3% (16 75 ) had pyometra; 6.7% had inactive ovaries and uterine atrophy and were not cyclic; 4% (3 75 ) had an involuting uterus, suggestive of a recent abortion; and 2.7% (2 75 ) had a mummified fetus. The herd had been on a reproductive herd health program for the past 10 years and had averaged 92-99% pregnant cows during this time. Pyometra was diagnosed by rectal palpation, and trichomonads were detected in the pyometra exudate.     

Previous handling and gentle interactions affect behaviour and heart rate of dairy cows during a veterinary procedure

Veterinary and management procedures often are aversive to the animals, resulting in physiological and behavioural stress reactions, which increase the risk of accidents and might lower performance. We investigated the effects of previous positive handling and of gentle interactions during the procedure on behaviour and heart rate in dairy cows during rectal palpation with sham insemination. Twenty cows were allocated randomly into two groups of 10 animals: handling, received additional positive handling over a period of four weeks by one person (handler); control, only routine handling by different caretakers. The week after the handling period, tests lasting 9 min, including 4 min rectal palpation, were carried out with each animal on four successive days in four situations in a balanced order: cow is alone during the test, with the handler, with an usual caretaker, or with an unknown person. Behaviour and heart rate were recorded.Previously handled animals had lower heart rate during tests (P≤0.05, n=19), kicked less when alone (P≤0.05, n=19) and tended to show less restless behaviour (P≤0.1, n=19). Cows were further calmed by gentle interactions during the test, but people differed remarkably. Cows showed less restless behaviour when gentled by the handler, both in the 4 min of rectal palpation and in the 9 min test period (each: P≤0.001, n=19). No significant stress reducing effect was found for the other two persons.In conclusion, stress reactions of cows during rectal palpation/insemination can be reduced by previous positive handling as well as by a person providing positive, gentle interactions during the procedure. The results underline the importance of positive, gentle interactions with the animals to enhance animal welfare and reduce the risk of accidents. They also show that people differ in the success to calm down the animals in aversive situations and indicate the need to investigate the characteristics responsible for the differences and identify the preconditions for a stress reducing effect in future research.     

The accuracy of rectal diagnosis of corpora lutea in water buffalo (Bubalus bubalis)

The accuracy of rectal diagnosis of corpora lutea (CL) was determined by direct inspection of the ovaries by laparoscopy in 68 suckled water buffalo (Bubalus bubalis). Thirty-eight (81%) of the 47 CL diagnosed by rectal palpation were confirmed at laparoscopy. Errors in rectal diagnosis of CL were due to failure to palpate early CL (8.5%) and to follicles (> 10 mm in diameter) raised above the ovarian surface (10.6%) being diagnosed as CL. Twenty-six (89.7%) of the 29 diagnoses of luteal tissue by the progesterone assay were confirmed. Errors were due to the presence of CL with low progesterone (10.3%). The overall accuracy of diagnosing a follicle or a CL by rectal palpation and plasma progesterone assay was 81 and 86% respectively. The study indicated that rectal palpation is as reliable as the progesterone assay for the diagnosis of CL in the buffalo.     

Rectal examination in general practice.

OBJECTIVE--To investigate factors influencing a general practitioner''s decision to do a rectal examination in patients with anorectal or urinary symptoms. DESIGN--Postal questionnaire survey. SETTING--General practices in inner London and Devon. SUBJECTS--859 General practitioners, 609 (71%) of whom returned the questionnaire. MAIN OUTCOME MEASURES--Number of rectal examinations done each month; the indication score, derived from answers to a question asking whether the respondent would do a rectal examination for various symptoms; and the confidence score, which indicated the respondent''s confidence in the diagnosis made on rectal examination. RESULTS--279 General practitioners did five or fewer rectal examinations each month and 96 did more than 10 each month. Factors significantly associated with doing fewer rectal examinations were a small partnership and being a female general practitioner, and the expectation that the examination would be repeated. Lack of time in the surgery, and a waiting time of less than two weeks for an urgent outpatient appointment were also important. General practitioners were deterred from doing rectal examinations by reluctance of the patient (278), the expectation that the examination would be repeated (141), and lack of time (123) or a chaperone (39). Confidence in diagnosis was significantly associated with doing more rectal examinations, the perception of having been well taught to do a rectal examination at medical school, and being a male general practitioner. CONCLUSIONS--Factors other than clinical judgment influence the frequency of rectal examination in general practice. Rectal examination may become commoner with the trend towards larger group practices and if diagnostic confidence is increased and greater emphasis put on rectal examination in undergraduate and postgraduate teaching.     

Ultrasonic pregnancy diagnosis in the camel

Application of ultrasound for pregnancy diagnosis has been tested and evaluated in 15 Iranian camels (Camelus dromedarius), all of which ultimately calved. Transabdominal examinations were unsuccessful, while intrapelvic application resulted in the reception of sounds characteristic for foetal life, similar to those found in other domestic animals. Signals of foetal heart, pulse of umbilical vessels and uterine artery as well as foetal movement could be recognized as distinct sounds and have been recorded for further studies. An attempt was made to verify the findings of the ultrasonic diagnosis through rectal palpation. The ultrasonic technique resulted in 12 correct and three incorrect diagnoses.     

阴道超声与宫腔镜诊断对围绝经期女性异常子宫出血病因的研究对比

目的:研究阴道超声与宫腔镜诊断对围绝经期女性异常子宫出血(Abnormal uterine bleeding,AUB)病因的对比。方法:从2012年3月到2013年3月,我院共有123例围绝经期AUB患者需行手术治疗。全部患者均于术前实施阴道超声检查及宫腔镜检查,分别归入阴道超声组及宫腔镜组,并于术后常规实施病理确诊,并将所得结果作为金标准分别对比。结果:根据术后的病理检查,最终确定患者子宫内膜为正常者4例,内膜增生44例,内膜息肉29例,黏膜下肌瘤26例,内膜癌20例。宫腔镜组在内膜增生及内膜息肉方面的诊断结果与病理检查结果最为接近,诊断结果显著优于阴道超声组,差异均有统计学意义(均P0.05)。但两组在正常内膜、黏膜下肌瘤以及内膜癌等方面的诊断结果对比,差异均无统计学意义(均P0.05)。宫腔镜组与病理检查的符合率在黏膜下肌瘤及内膜癌方面较阴道超声组与病理检查结果的符合率更高,但差异无统计学意义(P0.05)。尤其是关于内膜增生和内膜息肉的符合率,宫腔镜组显著高于阴道超声组,差异有统计学意义(均P0.05)。结论:宫腔镜诊断方案对于围绝经期女性AUB患者的诊断结果更接近于病理结果,但临床在一定条件可与阴道超声联用,以期进一步提升诊断符合率。值得临床推荐。     

Mobility of the early equine conceptus

Movement of the conceptus within the uterine lumen of barren mares was studied by daily ultrasound examinations on days 11-20 and by rectal palpation on days 15-48 (Experiment 1) and by ultrasound examinations 3 or 4 times per day at 2-4 hour intervals on days 11-16 (Experiment 2). In addition, broodfarm records were analyzed to compare side of ovulation with side of embryo attachment (Experiment 3). The vesicle was found in opposite uterine horns for 43% of the successive, daily, ultrasound examinations on days 11 and 12, 12 and 13, 13 and 14, and 14 and 15; 24% of the successive examinations on days 15 and 16; and 8% on days 16 and 17. No movement was detected after day 17. The vesicle was found in opposite horns during 41% of the successive examinations at 2-4 hour intervals on days 11, 12, 13, 14, and 15, but no movement was detected on day 16. In addition, no transuterine migration was found by rectal palpation between the day of first detection of an embryonal enlargement (mean, day 17) and day 48. During ultrasound examination on days 11-15, the vesicle was found significantly more frequently in the left horn (66% of the observations) than in the right horn (34%); however, final attachment occurred more frequently in the right horn (63% of the mares). In analyses of brood-farm records, ovulation occurred with equal frequency in left and right ovaries in barren and lactating mares, but with significantly greater frequency in the left ovary (63%) in maiden mares. Regardless of the side of ovulation, final attachment of the conceptus occurred significantly more frequently in the right horn (66%) in barren and maiden mares, but not in lactating mares.     

Concurrent Visualization of Acoustic Radiation Force Displacement and Shear Wave Propagation with 7T MRI

Manual palpation is a common and very informative diagnostic tool based on estimation of changes in the stiffness of tissues that result from pathology. In the case of a small lesion or a lesion that is located deep within the body, it is difficult for changes in mechanical properties of tissue to be detected or evaluated via palpation. Furthermore, palpation is non-quantitative and cannot be used to localize the lesion. Magnetic Resonance-guided Focused Ultrasound (MRgFUS) can also be used to evaluate the properties of biological tissues non-invasively. In this study, an MRgFUS system combines high field (7T) MR and 3 MHz focused ultrasound to provide high resolution MR imaging and a small ultrasonic interrogation region (~0.5 x 0.5 x 2 mm), as compared with current clinical systems. MR-Acoustic Radiation Force Imaging (MR-ARFI) provides a reliable and efficient method for beam localization by detecting micron-scale displacements induced by ultrasound mechanical forces. The first aim of this study is to develop a sequence that can concurrently quantify acoustic radiation force displacements and image the resulting transient shear wave. Our motivation in combining these two measurements is to develop a technique that can rapidly provide both ARFI and shear wave velocity estimation data, making it suitable for use in interventional radiology. Secondly, we validate this sequence in vivo by estimating the displacement before and after high intensity focused ultrasound (HIFU) ablation, and we validate the shear wave velocity in vitro using tissue-mimicking gelatin and tofu phantoms. Such rapid acquisitions are especially useful in interventional radiology applications where minimizing scan time is highly desirable.     

Progesterone levels and relationship with the diagnosis of a corpus luteum by rectal palpation during the estrous cycle in Zebu cows

To assess the accuracy of rectal palpation for detecting functional luteal tissue during the estrous cycle in Zebu cattle, 20 mature non-lactating Indobrazil cows were palpated twice weekly for 7 1/2 weeks. Blood samples were drawn for progesterone analyses at each palpation. Circulating serum progesterone levels were below 0.5 ng/ml from days 0-4 (Day 0 = day of estrus); they increased thereafter, reaching maximum levels of 3.1 ng/ml on days 9 and 10. Values declined sharply to less than 0.5 ng/ml on day 18. Regardless of the stage of the estrous cycle in 71.3% of the cases (117 out of a total of 164 observations) the circulating progesterone levels corresponded to the results of rectal examination. The criteria to assess this relationship were that the presence of CL as determined by rectal palpation would be accompanied by levels of progesterone higher than 0.5 ng/ml, whereas absence of CL would be accompanied by levels less than 0.5 ng/ml. The correlation was significantly higher (P<0.05) on days 5-17 (77.9%) than on days 0-4 (57.5%) and 18-20 (65%). To assess the correlation of both rectal examination and progesterone levels with the stage of the estrous cycle, we expected that on days 0-4 and 18-20 no palpable CL and progesterone levels less than 0.5 ng/ml would occur, whereas on days 5-17 palpable CL and progesterone levels higher than 0.5 ng/ml would be found. On this basis, a correlation of 45% (18 out of 40 observations) between expected and observed values was found on days 0-4, 76% (79 out of 104) on days 5-17 and 60% (12 out of 20) on days 18-20 of the estrous cycle. Of the total of 55 observations which fell outside the expected values, 71% was due to a wrong diagnosis of CL; 14.5% was due to progesterone levels higher or lower than the expected values, and 14.5% to both laboratory and rectal palpation findings.     

Post partum ovarian activity and uterine involution in the suckled swamp buffalo (Bubalus bubalis)

Ovarian activity and uterine involution were monitored by rectal palpation, oestrus detection and plasma progesterone analysis from 3 to 4 days to approximately 150 days post partum in 38 suckled swamp buffaloes (Bubalus bubalis). The intervals from parturition to regression of the corpus luteum (CL) of pregnancy and involution of the uterus were 10 and 28 ± 6 (S.D.) days respectively. First detected oestrus and first elevation of plasma progesterone (> 0.7 ng/ml) occurred at 88 ± 26 and 96 ± 22 days in 8 and 12 buffaloes respectively. During the first 150 days post partum, 26 of 38 suckling buffaloes (68%) were acyclic (anoestrus) and of 12 animals (32%) exhibiting ovarian cycles, 4 were not detected in oestrus. The tentative diagnosis, based on rectal palpation, that CL were present between days 30 and 90 after parturition (without concurrent luteal levels of progesterone in plasma) suggests that confirmation should be by laparoscopy. It is concluded that a delay in the resumption of ovarian cyclicity post partum represents an important factor contributing to the prolonged calving to conception interval in the suckled swamp buffalo.     

Diagnostic utility of musculoskeletal ultrasound in patients with suspected arthritis – a probabilistic approach

Introduction

This study aimed to assess the utility of musculoskeletal ultrasound (MSUS) in patients with joint symptoms using a probabilistic approach.

Methods

One hundred and three patients without prior rheumatologic diagnosis and referred to our clinic for evaluation of inflammatory arthritis were included. Patients were assessed clinically including joint examination, laboratory testing including acute-phase reactants, rheumatoid factor (RF) and anti citrulinated protein antibody (ACPA), and radiographs of hands and feet if clinically indicated. A diagnostic assessment was then performed by the responsible rheumatologist where the probability of a) any inflammatory arthritis and b) rheumatoid arthritis was given on a 5-point scale ranging from 0 to 20% up to 80 to 100% probability. Subsequently, an ultrasound examination of the wrist, metacarpophalangeal (MCP), proximal interphalangeal (PIP) joints 2 to 5 in both hands, metatarsophalangeal (MTP) joints 2 to 5 in both feet and any symptomatic joints was performed and the results presented to the same rheumatologist. The latter then assessed the diagnostic probabilities again, using the same scale.

Results

The rheumatologists’ certainty for presence/absence of inflammatory arthritis and rheumatoid arthritis was increased significantly following ultrasound performance. The proportion of patient for whom diagnostic certainty for inflammatory arthritis was maximal was 33.0% before and 71.8% after musculoskeletal ultrasound (P <0.001). With regard to a diagnosis of RA, the proportions were 31.1% pre-test and 61.2% post-test (P <0.001). MSUS findings agreed with the final diagnosis in 95% of patients.

Conclusion

Musculoskeletal ultrasound, when added to routine rheumatologic investigation, greatly increases the diagnostic certainty in patients referred for the evaluation of inflammatory arthritis. The changes from pre-test to post-test probability quantify the diagnostic utility of musculoskeletal ultrasound in probabilistic terms.     

Is tissue harmonic ultrasound imaging (THI) of the prostatic urethra and rectum superior to brightness (B) mode imaging? An observer study

Quality ultrasound images are an essential part of prostate brachytherapy procedure. The authors have previously reported that tissue harmonic ultrasound images (THI) are superior to brightness (B) mode for the prostate. The objective of the current study was to compare both imaging modes for visualization of the prostatic urethra and rectum.B and THI mode transrectal ultrasound images were acquired for ten patients. The prostatic urethra and rectal wall were contoured by a radiation oncologist (RO) and five observers on randomly presented images. The contours on one patient were repeated four additional times by four observers. All the images were qualitatively scored using a five-level Likert scale.The values of the Pearson product-moment correlation coefficients showed that the observers were in close agreement with the RO. Two sample paired student t-test showed that the rectum volumes with THI were significantly smaller than B-mode, but no significant difference for urethra. Two-factor analysis of variances showed significant observer variability in defining the rectum and urethra in both imaging modes. Observer consistency of the rectum volumes, estimated by standard deviations as percentages of means was significantly improved for THI. The Likert scale based qualitative assessment supported quantitative observations.The significant improvement in image quality of the prostate (reported previously) and rectum with THI may offer better-quality treatment plans for prostate brachytherapy and potential improvement in local control.     

The relationship between plasma levels of estradiol-17beta, progesterone and the consistency of the cervix in the sow

The object of this investigation was to estimate the peripheral plasma levels of estradiol-17beta and progesterone and the consistency of the cervix by rectal palpation of sows before, during and after post-weaning estrus. The tonicity of the cervix increased from approximately 4 days before the onset of heat, became firmest during estrus, and became softer again during the post-estrual period. The levels of estradiol increased before the onset of heat and reached maximum levels on the day preceding heat, then decreased to baseline. The progesterone levels remained low until post-estrus, then increased rapidly. One sow which did not come in heat constantly had a soft cervix and low hormone levels. It is concluded that estrogen might be implicated in the increased tonicity of the cervix and that rectal examination of the cervix provides valuable information on ovarian function.     

Non-Invasive Tools for the Diagnosis of Potentially Life-Threatening Gynaecological Emergencies: A Systematic Review

ObjectiveTo identify non-invasive tools for diagnosis of the major potentially life-threatening gynaecological emergencies (G-PLEs) reported in previous studies, and to assess their diagnostic accuracy.MethodsMEDLINE; EMBASE; Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library) were searched to identify all eligible studies published in English or French between January 1990 and December 2012. Studies were considered eligible if they were primary diagnostic studies of any designs, with a gold standard and with sufficient information for construction of a 2 × 2 contingency table, concerning at least one of the following G-PLEs: complicated ectopic pregnancy, complicated pelvic inflammatory disease, adnexal torsion and haemoperitoneum of any gynaecological origin. Extraction of data and assessment of study quality were conducted by two independent reviewers. We set the thresholds for the diagnostic value of signs retrieved at Sensibility ≥ 95% and LR—≤ 0.25, or Specificity ≥ 90% and LR+ ≥ 4.ResultsWe identified 8288 reports of diagnostic studies for the selected G-PLEs, 45 of which met the inclusion criteria. The methodological quality of the included studies was generally low. The most common diagnostic tools evaluated were transvaginal ultrasound (20/45), followed by medical history (18/45), clinical examination (15/45) and laboratory tests (14/45). Standardised questioning about symptoms, systolic blood pressure<110 mmHg, shock index>0.85, identification of a mass by abdominal palpation or vaginal examination, haemoglobin concentration <10 g/dl and six ultrasound and Doppler signs presented high performances for the diagnosis of G-PLEs. Transvaginal ultrasound was the diagnostic tool with the best individual performance for the diagnosis of all G-PLEs.ConclusionThis systematic review suggests that blood pressure measurement, haemoglobin tests and transvaginal ultrasound are cornerstone examinations for the diagnosis of G-PLEs that should be available in all gynaecological emergency care services. Standardised questioning about symptoms could be used for triage of patients.     

Giraffe restraint,habituation, and desensitization at the Cheyenne Mountain Zoo

The giraffe restraint device manufactured at the Cheyenne Mountain Zoo has the capability to fully support the weight of an immobilized adult giraffe in an upright posture and allow physical restraint of giraffe. The unit has been used for either chemical or physical restraint 74 times, in 22 months, on seven different adult giraffe, without animal or personnel injuries. Habituation and desensitization of the giraffe are critical prerequisites for the successful use of the giraffe restraint device. Yohimbine effectively reversed the effects of xylazine sedation of giraffe. A drug combination of detomidine and azaperone offers promise as an alternative to either physical restraint or immobilization of giraffe for selected clinical and investigative procedures. Using the restraint device it has been possible to perform tuberculin testing, venipuncture, vaginal examination, rectal palpation, rectal ultrasound, cervical catheterization, hoof-trimming, and placement of a hoof block on awake, habituated, and desensitized giraffe.     

Influence of repeated rectal ultrasound examinations on hormone profiles and behaviour around oestrus and ovulation in dairy cattle

Frequent rectal ultrasound is often used to assess time of ovulation. This study investigated whether frequent rectal ultrasound examination, affects behavioural oestrus and peri-ovulatory hormone profiles (LH, oestradiol and progesterone). Additionally, the relation between peri-ovulatory hormone profiles, oestrous behaviour and time of ovulation was studied. Oestrus was synchronised in two consecutive cycles of Holstein Friesian cattle (parity from 1 to 6; n = 24 cycles). In 12 of these cycles, time of ovulation was assessed by three-hourly rectal ultrasound (assessment of ovulation time with ultrasound group: UG) the other half served as controls (n = 12; no assessment of ovulation time group: CG). There were no significant differences between the onset of oestrus (33.8 +/- 1.6 h), duration of oestrus (13.4 +/- 0.9 h) or intensity of oestrous behaviour (1047 +/- 180 points) between UG and CG treated animals. Furthermore, LH, oestradiol and progesterone profiles were similar between UG and CG. For UG, ovulation took place 30.2 +/- 1.9 h after onset of oestrus. This interval had the largest variation (21 h) of all parameters studied, ranging between 19 and 40 h after onset of oestrus. The smallest variation (6 h) was found in the timing of ovulation in relation to the LH-peak; ovulation took place 25.3 +/- 0.6 h (range: 21.5-27.5 h) after the peak in LH. This study demonstrated that repeated rectal ultrasound does not alter behavioural oestrus or peri-ovulatory hormone profiles and is therefore a useful tool for assessing time of ovulation. Further research, using ultrasound, can now be carried out to find predictors for time of ovulation.