Anorectal function after long-term transanal colonic irrigation

AIM

The increased use of transanal colonic irrigation (TAI) warrants study of its effects on anorectal function after long term use.

METHOD

Anorectal physiology tests were performed in 12 patients with chronic idiopathic constipation (CC) and 10 with idiopathic faecal incontinence (FI) [median 55 years (range 21-70)] before and after a median 68 (range 32-113) months use of TAI.

RESULTS

In CC median, urge rectal volume increased from 121 (70-264) to 268 ml (69-484) (P = 0.05) whereas rectal compliance, volume at first sensation, maximum tolerable rectal volume, anal sensory level, median anal resting and squeeze pressures were unaltered. In FI median, urge volume increased from 125 (range 50-221) to 158 ml (range 97-287) (P = 0.033) and maximum tolerable volume increased from 156 (80-321) to 253 ml (162-332) (P = 0.047). Median anal resting pressure decreased from 48 (29-100) to 32 cmH(2) O (12-79) (P = 0.011) and anal squeeze pressure decreased from 69 (30-107) to 38 cmH(2) O (30-70) (P = 0.017). Rectal compliance, volume at first sensation and anal sensory level were unaltered.

CONCLUSIONS

As rectal compliance was unaltered, it is likely that the increased rectal tolerable volume is explained by patients adapting to irrigation rather than by changes in the property of the mechanical rectal wall. As anal sphincter function was deteriorated only in FI, we suggest that this is because of the natural history of FI rather than any effect of long term TAI.

Comparing two low-energy diets for the treatment of knee osteoarthritis symptoms in obese patients: a pragmatic randomized clinical trial

OBJECTIVES

To evaluate in a prospective, randomized clinical trial (RCT), symptom response among obese knee osteoarthritis (OA) patients following a feasible, intensive weight-loss program for 16 weeks.

METHODS

Eligible patients were obese [body mass index (BMI)>30 kg/m(2)]; >50 years old, with primary knee OA. Participants were randomized to either a very-low-energy diet (VLED) or a low-energy diet (LED) (415 kcal/day and 810 kcal/day, respectively), using commercially available formula foods - only for the first 8 weeks, managed by dieticians. The 8 weeks were followed by an additional 8-week period of a hypo-energetic diet consisting of normal food plus meal replacements (1200 kcal/day). The primary endpoint was the number of patients responding according to the Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) responder criterion. The statistical analysis was based on a non-responder intention-to-treat (ITT) population (baseline observation carried forward).

RESULTS

One hundred and ninety two patients (155 (80.7%) females) with a mean age 62.5 years [standard deviation (SD) 6.4; range 50-78 years]; average BMI 37.3 (SD 4.8) were included. At 16 weeks, similar proportions of the VLED and LED groups, 59 (61.5%), and 63 (65.6%) patients, respectively, met the OMERACT-OARSI responder criteria, with no statistical significant difference between the groups (P=0.55). Combining the groups the pooled estimate was 64% meeting the responder criteria [95% confidence interval (CI) 57%, 70%]. There was an overall reduction in pain, corresponding to an average pain reduction on the visual analogue scale (VAS) of 11.1 (95%CI 13.6, 8.5) in the combined groups. At week 16 weight loss in the combined groups was 12.8 kg (95%CI: 11.84-13.66; P<0.001). 71% lost > or =10% body weight in both diet groups, with a pooled estimate of 74% (95%CI: 68-80%).

CONCLUSION

No clinically significant differences were found between the 415 kcal/day and 810 kcal/day diets. A 16-week formula-diet weight-loss program resulted in a fast and effective weight loss with very few adverse events resulting in a highly significant improvement in symptoms in overweight patients with knee OA.

Energy production, nutrient recovery and greenhouse gas emission potentials from integrated pig manure management systems

Improper management of pig manure has resulted in environmental problems such as surface water eutrophication, ground water pollution, and greenhouse gas emissions. This study develops and compares 14 alternative manure management scenarios aiming at energy and nutrient extraction. The scenarios based on combinations of thermal pretreatment, anaerobic digestion, anaerobic co-digestion, liquid/solid separation, drying, incineration, and thermal gasification were compared with respect to their energy, nutrient and greenhouse gas balances. Both sole pig manure and pig manure mixed with other types of waste materials were considered. Data for the analyses were obtained from existing waste treatment facilities, experimental plants, laboratory measurements and literature. The assessment reveals that incineration combined with liquid/solid separation and drying of the solids is a promising management option yielding a high potential energy utilization rate and greenhouse gas savings. If maximum electricity production is desired, anaerobic digestion is advantageous as the biogas can be converted to electricity at high efficiency in a gas engine while allowing production of heat for operation of the digestion process. In conclusion, this study shows that the choice of technology has a strong influence on energy, nutrient and greenhouse gas balances. Thus, to get the most reliable results, it is important to consider the most representative (and up-to-date) technology combined with data representing the area or region in question.

Rectal motility after sacral nerve stimulation for faecal incontinence

Sacral nerve stimulation (SNS) is effective against faecal incontinence, but the mode of action is obscure. The aim of this study was to describe the effects of SNS on fasting and postprandial rectal motility. Sixteen patients, 14 women age 33-73 (mean 58), with faecal incontinence of various aetiologies were examined. Before and during SNS, rectal cross-sectional area (CSA) and ano-rectal pressures were determined with impedance planimetry and manometry for 1 h during fast and 1 h postprandially. Neither in the fasting state nor postprandially did SNS affect the number of single rectal contractions, total time with cyclic rectal contractions, the number of aborally and orally propagating contractions, the number of anal sampling reflexes or rectal wall tension during contractions. Postprandial changes in rectal tone were significantly reduced during SNS (P < 0.02). Before SNS, median rectal CSA was 2999 mm(2) (range: 1481-3822) during fast and 2697 mm(2) (range: 1227-3310) postprandially (P < 0.01). During SNS, median rectal CSA was 2990 mm(2) (1823-3678) during fast and 2547 mm(2) (1831-3468) postprandially (P = 0.22). SNS for faecal incontinence does not affect phasic rectal motility but it impairs postprandial changes in rectal tone.

Urinary excretion of kallikrein before and after operation for aldosterone-producing adenoma

Urinary kallikrein excretion (UKal), determined by the esterase method, was measured in 10 normotensive volunteers, 10 patients with essential hypertension and in 7 patients with primary aldosteronism before and after operative removal of the adenoma. UKal values were low in 5 of the patients with essential hypertension. Preoperative UKal values in the patients with aldosteronism did not differ significantly from those of the normal subjects, but decreased in all after operation in parallel with changes in urinary excretion of tetrahydroaldosterone and plasma aldosterone concentration. The study supports the assumption of an association between the renal kallikrein-kinin system and the mineralocorticoid state in man.

On the pathogenetic role of prostaglandins in Bartter's syndrome

Two patients, one with Bartter's syndrome and one with severe abuse of diuretics, were investigated before and after indomethacin treatment. Before indomethacin the two patients showed a similar pattern of hypokalaemic alcalosis, secondary hyperaldosteronism, and increased urinary excretion of PGE2 and kallikrein. After a few days on peroral indomethacin medication the hypokalaemia was significantly improved, the plasma renin activity, and the urinary excretion of aldosterone, PGE2 and kallikrein were normalized in both patients. It is concluded that the beneficial effect of indomethacin cannot be used as a proof of prostaglandin overproduction as the primary defect in Bartter's syndrome.

Prostaglandins, renin, aldosterone, and catecholamines in preeclampsia

Urinary excretion of prostaglandin E2 (PGE2) and F2 alpha (PGF2 alpha), plasma concentrations of renin (PRC), aldosterone (PAC), noradrenaline (PNA) and adrenaline (PA) were determined in the third trimester of pregnancy, 5 days and 3 months after delivery in preeclampsia and normotensive pregnant and non-pregnant control subjects. PGE2 was higher in pregnant control subjects than in non-pregnant subjects, but reduced to non-pregnant level in preeclampsia. PGF2 alpha was the same in preeclampsia and normotensive pregnancy but higher than in the non-pregnant group. PRC and PAC were increased during pregnancy, but considerably lesser in preeclampsia than during normotensive pregnancy. PNA and PA were the same in all three groups. All parameters were normal 3 months after delivery. There were no correlations between any of the hormones and blood pressure in any of the groups. PGE2 was positively correlated to PRC. The lack of renal PGE2 in preeclampsia might be responsible for the decrease in renal blood flow and sodium excretion, and the changes in PRC and PAC are supposed to be secondary to changes in PGE2. It is hypothesised that preeclampsia is a state of prostaglandin deficiency.

Urinary prostaglandin E2 and F2 alpha excretion in nephrotic syndrome during basal conditions, after water loading, and after remission of the syndrome

The urinary excretion rate of prostaglandin E2 (PGE2) and prostaglandin F2 alpha (PGF2 alpha) was determined in patients with the nephrotic syndrome both before and after an oral water load in 21 patients and 17 control subjects, and before and after remission of the syndrome in 8 of the patients. In the nephrotic syndrome PGE2 excretion rate varied considerably during basal conditions, remission was accompanied by an increase in the PGE2 excretion, and both basal PGF2 alpha excretion rate and the normal response in PGF2 alpha water loading were reduced. A significant, positive correlation was found between urine flow rate and excretion rate of PGE2 in the periods with the largest urine flow rate in both patients and control subjects. It is suggested that a relatively suppressed renal prostaglandin production may be a pathogenetic factor for sodium and water retention in the nephrotic syndrome, although it cannot be excluded that the abnormal prostaglandin excretion pattern is secondary, at least partially, to the reduction of urine flow rate.

Long-term outcome and safety of transanal colonic irrigation for neurogenic bowel dysfunction

STUDY DESIGN

Long-term follow-up study.

OBJECTIVES

Short-term results find transanal colonic irrigation (TAI) favourable in the treatment of neurogenic bowel dysfunction (NBD). Therefore, long-term results need to be described.

SETTING

Department of Surgery P, Aarhus University Hospital, Denmark.

METHODS

Between 1994 and 2007, 211 (115 female) patients with NBD (age: 7-81 years (median 49)) were introduced to TAI. One hundred and seventy-three patients had spinal cord injury and 38 had other neurological disorders. Data were obtained from hospital records and a mailed questionnaire. Treatment was considered successful in patients still using TAI, patients who had used TAI until they died and patients whose symptoms had resolved while using TAI.

RESULTS

Successful outcome was achieved in 98 (46%) patients after a mean follow-up of 19 months (range 1-114 months). A Kaplan-Meier plot showed a dropout of 20% in the first 3 months. After 3 years, the rate of success was 35% and remained almost unchanged afterwards. A regression analysis showed male gender (odds ratio (OR) 2.1), mixed symptoms (OR 2.9) and prolonged colorectal transit time (OR 2.4) to be significantly associated with successful outcome. One non-lethal bowel perforation occurred in approximately 50,000 irrigations (0.002%), whereas minor side effects were observed in 48%.

CONCLUSION

After a mean follow-up of 19 months, 46% was successfully treated. The rate of success was 35% after 3 years and remained almost unchanged afterwards. TAI is safe and can be introduced to most patients suffering from NBD.

Cost-effectiveness of transanal irrigation versus conservative bowel management for spinal cord injury patients

STUDY DESIGN

Cost-effectiveness analysis following international guidelines and taking the societal viewpoint.

OBJECTIVES

To estimate the cost-effectiveness of transanal irrigation using a self-administered irrigation system when compared with conservative bowel management.

SETTING

A randomized clinical trial was conducted at five spinal centres situated in Denmark, Germany, Italy, United Kingdom and Sweden. Estimates of resources and unit costs were made for the German health care system.

METHODS

Efficacy outcomes were drawn from a randomized controlled trial conducted in 2003-2005. Adult spinal cord-injured patients with neurogenic bowel dysfunction were randomized to 10 weeks with either transanal irrigation using Peristeen Anal Irrigation or to conservative bowel management. Costs were calculated based on results from the clinical trial and on 24 interviews conducted in Germany. Unit costs were obtained from the Federal Statistical Office Germany and product list prices.

RESULTS

When comparing outcome measures at termination, transanal irrigation significantly reduced symptoms of neurogenic bowel dysfunction. Product-related costs were higher for transanal irrigation using the self-administered system; however, costs for a carer to help with bowel management and changes/washing due to leakage were lower. For transanal irrigation, costs associated with urinary tract infections and patient time spent were reduced. Thus, the total cost to society is lower when patients use transanal irrigation. The results were shown to be robust in the sensitivity analysis.

CONCLUSION

Transanal irrigation using a self-administered system reduces symptoms of neurogenic bowel dysfunction and results in a lower total cost to society than conservative bowel management.

SPONSORSHIP

The study was supported by Coloplast A/S.

Sacral nerve stimulation for faecal incontinence alters colorectal transport

Background

Sacral nerve stimulation reduces the frequency of defaecation in patients with faecal incontinence. The aim of this study was to examine the mechanism behind the reduced number of bowel movements in incontinent patients treated with sacral nerve stimulation.

Methods

The study included 20 patients with faecal incontinence and a positive percutaneous nerve evaluation test: 19 women and one man, with a median age of 63 (range 28–78) years. Colorectal scintigraphy was performed to assess colorectal emptying at defaecation before and after implantation. Segmental colorectal transit times were determined using radio-opaque markers.

Results

The median frequency of defaecation per 3 weeks decreased from 56 (range 19–136) to 26 (range 12–78) (P &lt; 0·002). At defaecation, antegrade transport from the ascending colon decreased from a median score of 8 (range 0–23) to 0 (range 0–11) per cent (P = 0·001), while retrograde transport from the descending colon increased from a median score of 0 (range 0–14) to 2 (range 0–30) per cent (P = 0·039). The median defaecation score was unchanged. There was a non-significant increase in median total gastrointestinal transit time from 2·5 (range 0·9–6·2) to 3·3 (range 0·8–6·2) days (P = 0·079).

Conclusion

Sacral nerve stimulation reduces antegrade transport from the ascending colon and increases retrograde transport from the descending colon at defaecation. This may prolong colonic transit time and increase the storage capacity of the colon.

The pattern of colorectal dysfunction changes with time since spinal cord injury

BACKGROUND

Cross-sectional studies suggest that colorectal dysfunction after spinal cord injuries (SCI) worsens as time goes by. However, follow-up studies are needed to prove this.

STUDY DESIGN

Prospective study.

OBJECTIVE

To describe long-term colorectal function in SCI patients.

SETTING

Members of the Danish Spinal Cord Injuries Association.

METHODS

In 1996, 424 members of the Danish Paraplegic Association answered a detailed questionnaire describing their colorectal function. In 2006, those who continued as members (n=284) received an identical questionnaire. Data for patients responding both in 1996 and in 2006 (n=159) were compared.

RESULTS

In 1996, 25% of the respondents reported that colorectal dysfunction had some or a major impact on their quality of life. At follow-up 10 years later, it was 38% (P<0.005). In 1996 11% defecated less than every second day and 16% spent more than 30 min at each defecation; in 2006, it was 19% (P<0.01) and 25% (P<0.00001), respectively. Digital anorectal stimulation or evacuation was performed at least once every week by 48% in 1996 and by 56% in 2006 (P<0.0001). Fecal incontinence was reported at least once a month by 22% in 1996 and by 17% in 2006 (P<0.001).

CONCLUSION

While the frequency and severity of constipation-related symptoms increase with time since SCI, there is a decrease in the frequency of fecal incontinence.

The sperm chromatin structure assay as a diagnostic tool in the human fertility clinic

BACKGROUND

Sperm DNA integrity has been shown to be necessary for achieving and sustaining embryo development. The objective was to evaluate the sperm chromatin structure assay (SCSA) as a diagnostic tool in clinical practice for intrauterine insemination (IUI), in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatments.

METHODS

A total of 385 semen samples from 234 couples were frozen for SCSA, and smears were prepared for morphology: 48 IUI, 139 IVF and 47 ICSI. The main SCSA variables were DNA fragmentation index (DFI), standard deviation of DFI (SD-DFI) and high DNA stainability (HDS), and the reproductive outcomes were biochemical pregnancy (BP), clinical pregnancy (CP) and implantation ratio (IR).

RESULTS

The results showed no significant difference in the fertility variables BP, CP and IR when <27% DFI was used between the IVF and ICSI groups. A low number of patients received IUI with low success rate, and statistical analysis was therefore not performed. Ongoing pregnancy was achieved for both IVF and ICSI couples with DFI levels >27%, and six couples in ICSI treatment achieved CP full-term. DFI >27% had a high prognostic power for predicting no CP for IVF patients, with a specificity of 97%. Couples diagnosed with male infertility had a significantly higher level of DFI compared to couples with idiopathic fertility. Sperm head morphology showed low but significant correlations with the SCSA variables.

CONCLUSION

SCSA is a useful tool in andrological diagnosis and contributes with a prognosis for the fertility outcome of conventional IVF. Although full-term pregnancy can be achieved with assisted reproductive techniques with a DFI >27%, the probability of a successful pregnancy may be reduced.

Neurogenic bowel dysfunction score

STUDY DESIGN

Cross-sectional questionnaire study.

OBJECTIVES

To develop and validate a symptom-based score for neurogenic bowel dysfunction (NBD): NBD score.

SETTING

University Hospital of Aarhus, Denmark.

METHODS

A questionnaire including questions about background parameters (n=8), faecal incontinence (n=10), constipation (n=10), obstructed defecation (n=8), and impact on quality of life (QOL) (n=3) was sent to 589 Danish spinal cord injured (SCI) patients. The reproducibility and validity of each item was tested in 20 and 18 patients, respectively. Associations between items and impact on QOL were determined by logistic regression analysis. The NBD score was constructed from items with acceptable reproducibility and validity that were significantly associated with impact on QOL. Based on odds ratios for associations between items and impact on QOL, each item was given a corresponding number of points in the NBD score.

RESULTS

A total of 424 SCI patients responded. The following 10 items met the criteria above: frequency of bowel movements (0-6 points), headache, perspiration or discomfort before or during defecation (0-2 points), tablets and drops against constipation (0-2 points each), time used for each defecation (0-7 points), frequency of digital stimulation or evacuation (0-6 points), frequency of faecal incontinence (0-13 points), medication against faecal incontinence (0-4 points), flatus incontinence (0-2 points) and perianal skin problems (0-3 points). Differences in NBD score among patients reporting no, little, some or major impact on QOL were statistically significant (all P<0.001).

CONCLUSION

Based on valid and reproducible questions, we have constructed a score for NBD that is correlated to impact on QOL.

Increasing storage time of extended boar semen reduces sperm DNA integrity

There is an extensive use of artificial insemination (AI) in the pig industry. Extended liquid boar semen may be used for insemination for up to 5 days after collection. The objective of this study was to determine the changes in sperm quality, when boar semen was extended and stored at 18 degrees C for up to 72 h post-collection. The study included three ejaculates from five boars, for each of the four breeds: Duroc, Hampshire, Landrace and Danish Large White (n=60 ejaculates). The sperm chromatin structure assay (SCSA) showed an increase in DNA fragmentation index (DFI) after 72 h of incubation (P<0.001), with no differences between breeds (P=0.07). For two Hampshire boars, all ejaculates had a large increase in DFI after 24 h of incubation. The standard deviation of DFI (SD-DFI) differed between breeds, with the SD-DFI for Hampshire being significantly greater than for the other breeds. The SD-DFI did not change during the 72 h of storage. Sperm viability was determined using SYBR-14 and propidium iodide in combination with flow cytometry. The sperm viability did not differ between breeds (P=0.21), but a difference in viability during storage (P<0.001) was detected. In conclusion, the SCSA cytogram patterns were consistent for different ejaculates within boars and storage of extended boar semen at 18 degrees C for 72 h significantly decreased the integrity of sperm DNA.

Discrepancies in the determination of sperm concentration using Bürker-Türk, Thoma and Makler counting chambers

Determination of sperm concentration by use of a haemocytometer or counting chamber is an important step in semen evaluation and is also used for calibration or validation of instruments. Three experiments were carried out to determine the precision and accuracy of the Makler chamber, the Thoma haemocytometers (50 and 100 microm deep, TH-50, TH-100) and the Bürker-Türk (BT) haemocytometer. The first experiment confirmed that precision in sperm count by use of the haemocytometers (TH-50 and BT) can be increased if a higher number of sperm are counted. In contrast, the precision of the Makler chamber was relatively unaffected by the number of sperm counted and the coefficient of variation for this chamber was significantly (P < 0.05) higher than for the two haemocytometers. Experiment 2 confirmed the low precision of the Makler chamber and also showed that the TH-50 haemocytometer underestimated sperm concentration by approximately 25% in comparison to the Makler chamber and the BT haemocytometer. Experiment 3 demonstrated a slight underestimation of sperm count by the TH-100 haemocytometer in comparison to the BT haemocytometer, but both haemocytometers yielded acceptable precision (coefficients of variation were 10.4% and 9.4%, respectively). In comparison, the precision of the Makler chamber was significantly poorer (coefficient of variation 18.6%). When used for validation of a flow cytometric method which determines sperm concentration, the Makler chamber caused a higher degree of scattering of the points around the regression line than when the flow cytometric method was validated against the BT haemocytometer. It thus appears that the poor precision of the Makler chamber also affects the accuracy. It is concluded that duplicate counts by at least two technicians is recommended to achieve high precision but, that particular caution should be exerted with regard to the precision and accuracy of the used counting device.

Variability and laboratory factors affecting the sperm chromatin structure assay in human semen

During the past decade, the sperm chromatin structure assay (SCSA) has become an important tool for assessing semen quality in the human andrology laboratory. The SCSA uses the metachromatic properties of the fluorescent dye acridine orange (AO) in combination with flow cytometry to determine the sperm DNA susceptibility to denaturation in situ. The objective of this study was to evaluate laboratory factors affecting the SCSA and the variation between replicates. Semen ejaculates from 3 healthy volunteers were analyzed using the SCSA protocol as described by Evenson and Jost (2000), determining the X-mean, Y-mean, DNA fragmentation index (DFI), standard deviation of DFI (SD-DFI), and high DNA stainability (HDS). In experiment 1, the effects of thawing time, time of day, day, laboratory technician, donor, and incubation period before analysis were investigated. In experiment 2, the effects of sheath fluid, AO equilibration buffer, day, laboratory technician, donor, and incubation period before analysis were investigated. A significant difference was found between the 3 donors with respect to the X-mean, Y-mean, DFI, SD-DFI, and HDS. It was shown that incubation of the semen samples on ice postthaw had a significant effect on the X-mean, Y-mean, DFI, and SD-DFI. The laboratory technician conducting the analysis accounted for up to 15.4% for the variation of the SCSA measurements. The time of day affected the variation for the Y-mean (23.5% of the total variation of the Y-mean), and the day affected the variation for the X-mean (82.8% of the total variation of the X-mean). Incubation on ice for 5 to 25 minutes postthaw had a significant effect on the DFI and SD-DFI in both experiments. This study shows that several protocol steps in the SCSA affect the results obtained from the assay. Precise protocol description and standardization of the SCSA are therefore essential to achieve high agreement within and between different laboratories.

DNA integrity in sexed bull sperm assessed by neutral Comet assay and sperm chromatin structure assay

During the production of sex-sorted spermatozoa from bull semen, the cells are exposed to a number of potential hazards including: dilution, centrifugation, incubation, exposure to DNA stains and laser light. These factors may affect the survival capacity and fertilization potential of the sperm. The objective of this study was to determine whether sex-sorted bull spermatozoa have more DNA damage than sperm from conventional processed bull semen. Two methods were used to determine DNA integrity: the neutral Comet assay (NCA) and the sperm chromatin structure assay (SCSA). The NCA showed that the conventional samples had a higher tail moment (TM) (P < 0.017) than the sorted samples and that there was no difference between the samples in tail length (TL) (P = 0.36). The SCSA showed that the DNA fragmentation index (DFI) was higher for conventional than the sorted samples (P = 0.011), but the standard deviation of DFI (SD-DFI) was higher for the sorted samples (P < 0.001). We conclude that the NCA and SCSA can be used in assessing DNA integrity in bovine sperm and that cell sorting by flow cytometry improves the integrity of the sperm cell population. Additionally the results from the SCSA indicated that the sex-sorted sperm had less homogenous sperm chromatin. In the future assessment of sperm DNA integrity may be used to select bulls for sperm sex sorting and optimizing sperm sex sorting procedures.

Implementation of flow cytometry for quality control in four Danish bull studs

A flow cytometric method for simultaneous determination of sperm concentration and viability has recently been developed. In 2001, four Danish bull studs purchased flow cytometers and eight technicians were trained for routine analysis of raw and frozen-thawed semen. After initial training of the technicians, an experiment was carried out to document the precision of the system. The aim was also to assess if flow cytometric determination of sperm concentration could result in a more uniform production of semen doses. Results of this experiment showed high precision in the determination of sperm concentration and coefficients of variation were 3.5 and 2.4% for raw and frozen-thawed semen, respectively. Sperm viability was also assessed with high precision and coefficients of variation were 0.9% for raw semen and 1.7% for frozen-thawed semen. Furthermore, the experiment showed that package of semen doses after flow cytometric determination of sperm concentration in the raw semen results in a significantly smaller variation in the number of sperm per dose. In the second experiment, frozen semen was exchanged between the participating studs and were analysed by flow cytometry as well as by microscopic assessments by the eight technicians. Results show that the average correlation between technicians were 0.38 for motility assessments while flow cytometric agreement between technicians was significantly higher (average correlation was 0.86 for sperm viability and 0.92 for sperm concentration). The experiment also showed very high agreements between assessments within lab technician (correlations r=0.98 (sperm concentration) and r=0.99 (sperm viability)). Experiment 3 revealed that straws from the same batch varies in both concentration and viability. It is concluded that flow cytometric determination of sperm concentration and viability can be used to improve semen assessment by AI studs and result in a better quality control.