Introducing human papillomavirus (HPV) primary testing in the age of HPV vaccination: projected impact on colposcopy services in Wales.

OBJECTIVE: To determine the demand for colposcopy in the Cervical Screening Wales programme after the introduction of human papillomavirus (HPV) cervical screening, which coincided with the start of screening of women vaccinated against HPV types 16/18. DESIGN: The study used a computational model that assigns screening and screening-related colposcopy events to birth cohorts in individual calendar years. SETTING: Cervical Screening Wales. POPULATION: Women aged 25-64 years from birth cohorts 1953-2007. METHODS AND MAIN OUTCOME MEASURES: We estimated the numbers of colposcopies and high-grade cervical intraepithelial lesions (CIN2+) within Cervical Screening Wales in 2018-32, using official population projections for Wales and published estimates of the effects of HPV screening and vaccination. RESULTS: Vaccination will reduce the number of colposcopies by 10% within the first 3-4 years after the national roll-out of HPV screening, and by about 20% thereafter. The number of screening colposcopies is estimated to increase from 6100 in 2018 and peak at 8000 (+31%) in 2021, assuming current screening intervals are maintained. The numbers of CIN2+ lesions follow similar patterns, stabilising at around 1000 diagnoses per year by 2026, approximately 60% lower than at present. Extending the screening intervals to 5 years for all women shows similar trends but introduces peaks and troughs over the years. CONCLUSIONS: Vaccination will not fully prevent an increase in colposcopies and detected CIN2+ lesions during the first 2-3 years of HPV-based screening but the numbers are expected to decrease substantially after 5-6 years. TWEETABLE ABSTRACT: HPV-based cervical screening will initially increase colposcopy referral. In 6 years, this increase will be reversed, partly by HPV vaccination.

Seasonal fluxes of carbon monoxide from an intensively grazed grassland in Scotland.

Fluxes of carbon monoxide (CO) were measured using a fast-response quantum cascade laser absorption spectrometer and the eddy covariance method at a long-term intensively grazed grassland in southern Scotland. Measurements lasted 20 months from April 2016 to November 2017, during which normal agricultural activities continued. Observed fluxes followed a regular diurnal cycle, peaking at midday and returning to values near zero during the night, with occasional uptake observed. CO fluxes correlated well with the meteorological variables of solar radiation, soil temperature and soil moisture content. Using a general additive model (GAM) we were able to gap fill CO fluxes and estimate annual fluxes of 0.38 ±â€¯0.046 and 0.35 ±â€¯0.045 g C m-2 y-1g C m-2 y-1 for 2016 and 2017, respectively. If the CO fluxes reported in this study are representative of UK grasslands, then national annual emissions could be expected to be in the order of 61.91 (54.3-69.5) Gg, which equates to 3.8% (3.4-4.3%) of the current national inventory total.

Benchmarking of surgical complications in gynaecological oncology: prospective multicentre study.

OBJECTIVE: To explore the impact of risk-adjustment on surgical complication rates (CRs) for benchmarking gynaecological oncology centres. DESIGN: Prospective cohort study. SETTING: Ten UK accredited gynaecological oncology centres. POPULATION: Women undergoing major surgery on a gynaecological oncology operating list. METHODS: Patient co-morbidity, surgical procedures and intra-operative (IntraOp) complications were recorded contemporaneously by surgeons for 2948 major surgical procedures. Postoperative (PostOp) complications were collected from hospitals and patients. Risk-prediction models for IntraOp and PostOp complications were created using penalised (lasso) logistic regression using over 30 potential patient/surgical risk factors. MAIN OUTCOME MEASURES: Observed and risk-adjusted IntraOp and PostOp CRs for individual hospitals were calculated. Benchmarking using colour-coded funnel plots and observed-to-expected ratios was undertaken. RESULTS: Overall, IntraOp CR was 4.7% (95% CI 4.0-5.6) and PostOp CR was 25.7% (95% CI 23.7-28.2). The observed CRs for all hospitals were under the upper 95% control limit for both IntraOp and PostOp funnel plots. Risk-adjustment and use of observed-to-expected ratio resulted in one hospital moving to the >95-98% CI (red) band for IntraOp CRs. Use of only hospital-reported data for PostOp CRs would have resulted in one hospital being unfairly allocated to the red band. There was little concordance between IntraOp and PostOp CRs. CONCLUSION: The funnel plots and overall IntraOp (≈5%) and PostOp (≈26%) CRs could be used for benchmarking gynaecological oncology centres. Hospital benchmarking using risk-adjusted CRs allows fairer institutional comparison. IntraOp and PostOp CRs are best assessed separately. As hospital under-reporting is common for postoperative complications, use of patient-reported outcomes is important. TWEETABLE ABSTRACT: Risk-adjusted benchmarking of surgical complications for ten UK gynaecological oncology centres allows fairer comparison.

Predictors of complications in gynaecological oncological surgery: a prospective multicentre study (UKGOSOC-UK gynaecological oncology surgical outcomes and complications).

BACKGROUND: There are limited data on surgical outcomes in gynaecological oncology. We report on predictors of complications in a multicentre prospective study. METHODS: Data on surgical procedures and resulting complications were contemporaneously recorded on consented patients in 10 participating UK gynaecological cancer centres. Patients were sent follow-up letters to capture any further complications. Post-operative (Post-op) complications were graded (I-V) in increasing severity using the Clavien-Dindo system. Grade I complications were excluded from the analysis. Univariable and multivariable regression was used to identify predictors of complications using all surgery for intra-operative (Intra-op) and only those with both hospital and patient-reported data for Post-op complications. RESULTS: Prospective data were available on 2948 major operations undertaken between April 2010 and February 2012. Median age was 62 years, with 35% obese and 20.4% ASA grade ⩾3. Consultant gynaecological oncologists performed 74.3% of operations. Intra-op complications were reported in 139 of 2948 and Grade II-V Post-op complications in 379 of 1462 surgeries. The predictors of risk were different for Intra-op and Post-op complications. For Intra-op complications, previous abdominal surgery, metabolic/endocrine disorders (excluding diabetes), surgical complexity and final diagnosis were significant in univariable and multivariable regression (P<0.05), with diabetes only in multivariable regression (P=0.006). For Post-op complications, age, comorbidity status, diabetes, surgical approach, duration of surgery, and final diagnosis were significant in both univariable and multivariable regression (P<0.05). CONCLUSIONS: This multicentre prospective audit benchmarks the considerable morbidity associated with gynaecological oncology surgery. There are significant patient and surgical factors that influence this risk.

The effect of dietary alterations during rearing on growth, productivity, and behavior in broiler breeder females.

Parent stocks of meat birds are severely feed restricted to avoid obesity-related health and fertility problems. This restriction often leads to chronic hunger, accompanied by stereotypic behavior. Research based in the United Kingdom has shown that using diets containing fiber and appetite suppressants may relieve some of the symptoms of hunger. However, few data are available regarding North American-sourced ingredients or nondaily feeding regimens. This study investigated the effects of 2 alternative diets, in combination with 2 feeding frequencies on growth, productivity, and behavior in broiler breeders. Six dietary treatments were tested, each with 5 replicate pens of 12 or 13 birds. Control diets consisted of a commercial crumble, fed on a daily or skip-a-day (SAD) basis. Alternative diets included soybean hulls as a fiber source, and calcium propionate as an appetite suppressant of either a feed-grade or purified quality, fed on either a daily or SAD basis. Birds were weighed weekly and egg production was recorded daily. Video cameras were used to record behavior during and following the morning feeding bout every 2 wk from 11 to 28 wk. Data were analyzed with a mixed model ANOVA, with repeated measures. Diet, feeding frequency, time, or an interaction of the 3 had significant effects on all observed behavior during rearing. These differences appeared to diminish during lay, with most stereotypic behavior no longer present. Very little object pecking and aggression was observed during and immediately following feeding bouts; however, daily-fed control birds still displayed this behavior more often, especially during rearing (P = 0.015). During feeding bouts, SAD birds feather pecked (P = 0.003) and rested more (P = 0.0002) than daily-fed birds. Control birds feather pecked most often (P = 0.033) after feeding bouts. Overall, the feed-grade diet appeared most effective at reducing hunger-related behavior, and the control diet appeared the least effective. There was little conclusive evidence to show that daily feeding was more effective at reducing hunger.

The effect of dietary alterations during rearing on feather condition in broiler breeder females.

In commercial production, broiler breeders are severely feed restricted to maintain healthy BW. This restriction can induce stereotypic behavior, including feather pecking, which has negative welfare implications for both the victim and performer. It has been suggested that the problem may be symptomatic of chronic hunger or the frustration of feeding motivation. In this study, we determined whether feather condition, as an indirect measure of feather pecking, could be improved via dietary manipulation. Six dietary treatments were tested, each with 5 replicate pens of 9 to 12 birds. Control diets (C) were fed on a daily or skip-a-day (SAD) basis. Alternative diets included soybean hulls as a bulking ingredient and calcium propionate (CaP) as an appetite suppressant of either a feed grade (F) or purified (P) quality. Both alternative diets were fed on either a daily or SAD basis. Five or 6 birds were randomly chosen from each pen and feather scored at 10, 14, 20, 26, and 36 wk of age. Six body parts (neck, back, wings, legs, vent area, tail) were given a score from 0 to 5 (0 = no feather damage, and 5 ≥ 50% feather loss with tissue damage). Scores were summed for each bird and averaged for each pen. Data were analyzed with room and feeding frequency as main factors and diet as the subfactor with repeated measures. There was an interaction between diet and time (P < 0.01) with the feather condition of the C birds worsening more quickly in comparison with the F and P birds. There was an interaction between feeding frequency and time (P = 0.015), with SAD-fed birds scoring better than daily-fed birds at 20, 26, and 36 wk. This interaction could indicate that SAD feeding increased satiety after the birds became accustomed to the schedule. Because feather condition was better with the alternative diets, this may indicate a reduction in stereotyped feather pecking with these diets. This suggests that the alternative diets increase satiety compared with the control diets.

Patient-reporting improves estimates of postoperative complication rates: a prospective cohort study in gynaecological oncology.

BACKGROUND: Most studies use hospital data to calculate postoperative complication rates (PCRs). We report on improving PCR estimates through use of patient-reporting. METHODS: A prospective cohort study of major surgery performed at 10 UK gynaecological cancer centres was undertaken. Hospitals entered the data contemporaneously into an online database. Patients were sent follow-up letters to capture postoperative complications. Grade II-V (Clavien-Dindo classification) patient-reported postoperative complications were verified from hospital records. Postoperative complication rate was defined as the proportion of surgeries with a Grade II-V postoperative complication. RESULTS: Patient replies were received for 1462 (68%) of 2152 surgeries undertaken between April 2010 and February 2012. Overall, 452 Grade II-V (402 II, 50 III-V) complications were reported in 379 of the 1462 surgeries. This included 172 surgeries with 200 hospital-reported complications and 231 with 280 patient-reported complications. All (100% concordance) 36 Grade III-V and 158 of 280 (56.4% concordance) Grade II patient-reported complications were verified on hospital case-note review. The PCR using hospital-reported data was 11.8% (172 out of 1462; 95% CI 11-14), patient-reported was 15.8% (231 out of 1462; 95% CI 14-17.8), hospital and verified patient-reported was 19.4% (283 out of 1462; 95% CI 17.4-21.4) and all data were 25.9% (379 out of 1462; 95% CI 24-28). After excluding Grade II complications, the hospital and patient verified Grade III-V PCR was 3.3% (48 out of 1462; 95% CI 2.5-4.3). CONCLUSION: This is the first prospective study of postoperative complications we are aware of in gynaecological oncology to include the patient-reported data. Patient-reporting is invaluable for obtaining complete information on postoperative complications. Primary care case-note review is likely to improve verification rates of patient-reported Grade II complications.

European consensus statement on expert colposcopy.

BACKGROUND: Following the publication of the European consensus statement on standards for essential colposcopy in 2020, the need for standards relating to more complex and challenging colposcopy practice was recognised. These standards relate to colposcopy undertaken in patients identified through cervical screening and tertiary referrals from colposcopists who undertake standard colposcopy only. This set of recommendations provides a review of the current literature and agreement on care for recognised complex cases. With good uptake of human papillomavirus (HPV) immunisation, we anticipate a marked reduction in cervical disease over the next decade. Still, the expert colposcopist will continue to be vital in managing complex cases, including previous cervical intraepithelial neoplasia (CIN)/complex screening histories and multi-zonal disease. AIMS: To provide expert guidance on complex colposcopy cases through published evidence and expert consensus. MATERIAL & METHODS: Members of the EFC and ESGO formed a working group to identify topics considered to be the remit of the expert rather than the standard colposcopy service. These were presented at the EFC satellite meeting, Helsinki 2021, for broader discussion and finalisation of the topics. RESULTS & DISCUSSION: The agreed standards included colposcopy in pregnancy and post-menopause, investigation and management of glandular abnormalities, persistent high-risk HPV+ with normal/low-grade cytology, colposcopy management of type 3 transformation zones (TZ), high-grade cytology and normal colposcopy, colposcopy adjuncts, follow-up after treatment with CIN next to TZ margins and follow-up after treatment with CIN with persistent HPV+, and more. These standards are under review to create a final paper of consensus standards for dissemination to all EFC and ESGO members.

Cervical cancer incidence in young women: a historical and geographic controlled UK regional population study.

BACKGROUND: The commencing age of cervical screening in England was raised from 20 to 25 years in 2004. Cervical cancer incidence in young women of England is increasing. It is not clear if this is due to either greater exposure to population risk factors or reduced cervical screening. METHODS: We measured if the relative risk of cervical cancer in younger women (20-29 years) of the north-east of England (NE) differed to that of women aged 30yrs and above since 2004. We also measured average annual percentage change (AAPC) in the 3 yr moving average incidence for all age-groups. Regional screening coverage rate and population risk factors were reviewed. Comparisons were made with Wales where screening continues to commence from the age of 20yrs. RESULTS: Cervical cancer incidence in women aged 20-29 increased annually by an average of 10.3% between 2000 and 2009. The rise in women aged 30-39 was less steep (3.5%/year) but no significant rise was observed in women aged 40-49. Socioeconomic factors remained stable or improved during the time period except for the incidence of chlamydia, herpes simplex and in particular, genital warts, which increased significantly in young women. Data from Wales show similar results. CONCLUSION: The incidence of cervical cancers in young women of the NE is increasing. The rise in incidence is unrelated to the change in screening policy in 2004. Close monitoring of incidence in young women and a greater attempt to reverse the current decline in screening coverage of women aged 25-29 years are recommended.

Risk of epithelial ovarian cancer in asymptomatic women with ultrasound-detected ovarian masses: a prospective cohort study within the UK collaborative trial of ovarian cancer screening (UKCTOCS).

OBJECTIVE: To estimate the risk of primary epithelial ovarian cancer (EOC) and slow growing borderline or Type I and aggressive Type II EOC in postmenopausal women with adnexal abnormalities on ultrasound. METHODS: This was a prospective cohort study in the ultrasound group of the UK Collaborative Trial of Ovarian Cancer Screening of postmenopausal women with ultrasound-detected abnormal adnexal (unilocular, multilocular, unilocular solid and multilocular solid, solid) morphology on their first scan. Women were followed up through the national cancer registries and by postal questionnaires. Absolute risks of EOC and borderline, Type I and Type II EOC within 3 years of initial scan were calculated. RESULTS: Of 48 053 women who underwent ultrasound examination and had complete scan data, 4367 (9.1% (95% CI, 8.8-9.3%)) had abnormal adnexal morphology. Median follow-up was 7.09 (25(th) -75(th) centiles, 6.03-7.92) years. Forty-seven (32 borderline or Type I, 15 Type II) were diagnosed with EOC. The overall absolute risk of EOC associated with abnormal adnexal morphology was 1.08% (95% CI, 0.79-1.43%); for borderline and Type I it was 0.73% (95% CI, 0.5-1.03%); and for Type II it was 0.34% (95% CI, 0.33-0.79%). In the subgroup (n = 741) with solid elements (unilocular solid, multilocular solid and solid) overall absolute risk was 4.45% (95% CI, 3.08-6.20%), for borderline and Type I it was 3.1% (95% CI, 1.9-4.6%) and for Type II it was 1.3% (95% CI, 0.6-2.4%). 11 982 women had both ovaries visualized and normal annual scans throughout the 3-year follow-up period. In this group, no borderline or Type I and eight Type II cancers were diagnosed. CONCLUSION: Asymptomatic postmenopausal women with ultrasound-detected adnexal abnormalities with solid elements have a 1 in 22 risk for EOC. Despite the higher prevalence of Type II EOC, the risk of borderline or Type I cancer in women with ultrasound abnormalities seems to be higher than does the risk of Type II cancer. This has important immediate implications for patients with incidental adnexal findings as well as for any future ultrasound-based screening.

Future considerations in poultry nutrition.

Following is invited commentary on the symposium "A Crystal Ball Look into the Future of…" delivered July 16, 2011, at the Poultry Science Association's 100th annual meeting, St. Louis, Missouri. The symposium examined various aspects that will impact the future of poultry production over the next 10 to 20 yr. Topics included genetics, nutrition, incubation, and bird health. This paper deals with various aspects of future issues affecting global feeding and nutrition of poultry.

A questionnaire survey to study the effect of colposcopy training in Europe.

The objective of the study was to see if colposcopy training can provide a measurable effect. A questionnaire containing 10 clinical scenarios requiring colposcopy was completed by delegates attending three colposcopy training courses in Europe. A total of 128 and 132 questionnaires were returned pre- and post-training, respectively. The means and standard deviations for the number of correctly assessed scenarios were M = 4.21, SD = 1.71 at pre-training and M = 5.05, SD = 1.82 at post-training. The χ(2)-test showed a statistically significant difference in the proportions of correct answers at pre- and post-training for five questions. The two factor ANOVA showed that there is a statistically significant difference between the pre- and post-training measures (F((2,124)) = 17.13, p < 0.001) although the effect of training is not the same for all three locations. Trainees' results show that there is a positive effect of training. The questionnaire may be used as a quality tool for measuring the effectiveness of training for colposcopy.

Antimicrobial activity of butyrate glycerides toward Salmonella Typhimurium and Clostridium perfringens.

The antimicrobial activities of n-butyric acid and its derivatives against Salmonella Typhimurium and Clostridium perfringens were studied. n-Butyric acid and its derivatives (monobutyrin and a mixture of mono-, di-, and tri-glycerides of butyric acid) were added at different concentrations (ranging from 250 to 7,000 mg/kg to a media inoculated with either Salmonella Typhimurium or C. perfringens. The antimicrobial activity of butyric acid against C. perfringens was measured at 2 bacterium concentrations and 2 inoculations involving ambient aerobic or anaerobic conditions. The most effective antimicrobial activity for Salmonella Typhimurium was observed with n-butyric acid, with 90% inhibition rate at a concentration of 1,500 mg/kg. Although minimal inhibition for Salmonella Typhimurium was observed with butyric acid glycerides, lipase addition to a mixture of mono-, di-, and triglycerides of butyric acid increased (P < 0.01) antimicrobial activity of these derivatives. Antimicrobial activity of butyric acid and its derivative against C. perfringens was higher when using a moderate initial inoculation concentration (10(5)) compared with a higher initial concentration (10(7)) of this bacterium. At a lower inoculation of C. perfringens (10(5)), >90% inhibition rate by all butyric acid glycerides was observed with prior aerobic inoculation at 2,000 mg/kg, whereas using anaerobic inoculation, only 50% monobutyrin maintained >90% inhibitory effect at 3,000 mg/kg. The antimicrobial effect of monobutyrin against C. perfringens was generally higher (P < 0.01) for 50% monobutyrin than for 100% monobutyrin. Either a mixture of butyric acid derivatives or 50% monobutyrin decreased (P < 0.01) C. perfringens in a media containing intestinal contents whereas only 50% monobutyrin decreased (P < 0.01) Salmonella Typhimurium within a media containing cecal contents from mature Leghorns. These results show that n-butyric acid and 50% monobutyrin could be used to control Salmonella Typhimurium or C. perfringens in poultry species.

A 4 year observation of gastrointestinal nematode egg counts, nemabiomes and the benzimidazole resistance genotypes of Teladorsagia circumcincta on a Scottish sheep farm.

Anthelmintic resistance threatens the sustainability of sheep production globally. Advice regarding strategies to reduce the development of anthelmintic resistance incorporates the outcomes of modelling exercises. Further understanding of gastrointestinal nematode species diversity, and population dynamics and genetics (which may vary between species) is required to refine these models; and field studies combining faecal egg outputs, species composition and resistance genetics are needed to calibrate them. In this study, faecal samples were taken from ewes and lambs on a commercial farm in south-eastern Scotland at approximately 3 t-4 week intervals between spring and autumn over a period of 4 years. Faecal egg counts were performed on these samples, and L3 were collected from pooled coprocultures. Deep amplicon sequencing was used to determine both the species composition of these L3 and the proportions of benzimidazole-resistant single nucleotide polymorphisms in the isotype-1 ß-tubulin locus of the predominant species, Teladorsagia circumcincta L3. Despite consistent management throughout the study, the results show variation in gastrointestinal nematode species composition with time and between age groups, that was potentially associated with weather conditions. The F200Y benzimidazole resistance mutation is close to genetic fixation in the T. circumcincta population on this farm. There was no evidence of variation in isotype-1 ß-tubulin single nucleotide polymorphisms frequency between age groups, and no genetic evidence of reversion to benzimidazole susceptibility, despite targeted benzimidazole usage. This study highlights the need to include speciation when investigating gastrointestinal nematode epidemiology and anthelmintic resistance, and serves as an example of how genetic data may be analysed alongside species diversity and faecal egg counts, when markers for other anthelmintic classes are identified.

European consensus statement on essential colposcopy.

This European consensus statement on essential colposcopy provides standards for the general colposcopist seeing women referred for colposcopy with an abnormal cervical screening test (including cytology and HPV tests) or with a clinically suspicious cervix. The article gives guidance regarding the aims and conduct of colposcopy. Recommendations are provided on colposcopy technique, the management of common colposcopy issues, treatment and follow-up of after treatment of CIN or early stage cervical. Colposcopists should make an informed decision on the management of each individual that is referred and organize appropriate follow-up. Cervical cancer is still a major health issue and the quality of care can only improve if there is a structured guidance for women with an abnormal smear or suspicious cervix.

Dietary lipids differentially affect membranes from different areas of rooster sperm.

The present work aimed to compare the effect of dietary flax with other oil sources on rooster sperm membranes and on semen characteristics. White Leghorn roosters (16 per diet) were fed 1 of 4 treatments: control diet (CON), or a diet containing corn oil (CORN), fish oil (FISH), or flax seed (FLAX) as the lipid source. Semen from 4 birds (30 wk old) of each treatment was pooled, the sperm head (HM) and body membranes (BM) were isolated, and lipids were extracted and analyzed. Aspects of lipid composition tested were as follows: percentage of individual fatty acids (C14:0 to C24:1) in total fatty acids, percentage of fatty acid categories [saturated, monounsaturated, polyunsaturated (PUFA), n-3 and n-6 PUFA, and n-6:n-3 ratio] within total fatty acids, and percentage of phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol, phosphatidylserine, and sphingomyelin] in total phospholipids. Sperm characteristics evaluated were as follows: volume, concentration, viability, percentage of motile cells, average path velocity, track speed, progressive velocity, lateral head displacement, straightness, and linearity. Diet did not affect membrane phospholipid ratios in either membrane but modified major fatty acids within certain phospholipids. Birds fed FISH and CORN showed, respectively, the highest and the lowest n-3 in sperm, causing reciprocal significant changes in n-6:n-3 ratio. Feeding FLAX caused intermediate effects in n-3, with values significantly lower than FISH but higher than CORN in HM (PC, PE, and phosphatidylinositol) and PC in BM (P < 0.05). In the PE phospholipids, FISH, followed by FLAX, increased n-3 in BM and decreased n-6 PUFA in HM. Sperm concentration was specifically correlated with the amount of 20:4n-6 in FLAX and 22:4n-6 in CON. In FLAX diets, straightness correlated with C18:0, n-3, and n-6:n-3 ratio. Diets containing distinct lipid sources differentially modify the lipid contents of HM and BM, with minor effects on sperm characteristics. Flax seed produced changes similar to fish oil and could be used as a substitute.

Development and evaluation of a dynamic model of calcium and phosphorus flows in layers.

Phosphorus is an essential nutrient involved in most metabolic processes. Most of the interest in Ca metabolism relates to eggshell formation. Although the eggshell is composed of Ca carbonate, metabolism of both Ca and P is closely related such that a deficiency in one can interfere with proper utilization of the other. To understand Ca and P metabolism properly, modeling can be of paramount importance. A new dynamic and mechanistic model of P and Ca metabolism in layers has been developed to simulate diurnal changes in Ca and P and the hourly requirement of the layer for those minerals. The model consists of 8 state variables representing Ca and P pools in the crop, stomachs, plasma, and bone. The flow equations are described by Michaelis-Menten or mass action forms. An experiment that measured Ca and P uptake in layers fed different Ca concentrations during shell-forming days was used for model evaluation. The experiment showed that Ca retained in body and egg decreased from 62.5 to 50.5% of Ca intake when the Ca in diet was increased from 25 to 45 mg/g of feed. The model simulations were in agreement with the trend. Predictions of Ca retention in bone and egg were 63.2, 56.1, and 55.3% for low, medium, and high dietary Ca concentrations. The experimental results showed that P retention in body and egg increased significantly from 11.5% of absorbable P intake at the lowest Ca inclusion concentration to 24.1% at the highest. The model also predicted an increase in P retention in bone and egg from 8.4 to 25.4% of absorbable P intake at the lowest and highest concentration of Ca inclusion, respectively. The advantage of the model is that absorption and utilization can be monitored on an hourly basis and that adjustments can be made accordingly. The model successfully showed how the availability of one mineral affects the utilization of the other and is a useful tool to evaluate feeding strategies aimed at reducing P excretion to the environment in poultry manure.

Effect of dietary omega-3 and omega-6 fatty acids on clotting activities of Factor V, VII and X in fatty liver haemorrhagic syndrome-susceptible laying hens.

1. The relationship between concentrations of omega-3 and omega-6 fatty acids in plasma and Factor V, VII and X clotting activities was determined using a crossover feeding trial with diets supplemented with either soy oil or flax oil. 2. Laying hens on the soy diet, which is high in omega-6 fatty acids, had substantially higher clotting activity for all three factors compared to laying hens on the flax diet that was high in omega-3 fatty acids. 3. Positive associations were seen between liver haemorrhage score and the percentage of liver weight and between the percentage of liver weight and the severity of haemorrhagic and fatty changes seen on histology. 4. These results support the hypothesis that concentrations of omega-6 and omega-3 fatty acids in plasma affect clotting activity; however, there was no relationship between the extent of liver haemorrhages and the composition of plasma fatty acids.

Assessment of the nitrogen correction factor in evaluating metabolizable energy of corn and soybean meal in diets for broilers.

Three experiments were carried out to determine AME and AMEn of corn and soybean meal (SMB) in diets for growing broilers. In experiments 1 and 2, ingredient-specific basal diets or a combination of these basal diets with corn and SBM were prepared. For corn, the substitution was 25, 50, or 75% of the total diet, whereas SBM substitution was at 10, 20, or 30%. In experiment 1, birds were fed the experimental diets continuously from 0 to 33 d, and AME and AMEn were determined during 9 to 12 d and 30 to 33 d of age. In experiment 2, birds were fed the experimental diets only around the time of the collection period. The AMEn of corn was 95 to 97% of corresponding AME, whereas for SBM, AMEn was 93 to 88% of AME. Linear regression was used as an alternative method of calculating ingredient energy values resulting in a significant regression of diet AME and AMEn content on inclusion level, for each period of time and for each ingredient (corn and SBM). Based on varying inclusion levels of test ingredients in the diet, the extrapolated AME and AMEn of corn were estimated more precisely (R2 = 0.90 to 0.95) than those of SBM (R2 = 0.57 to 0.85), suggesting that the variability of AME and AMEn is better explained by a linear regression of AME or AMEn on percentage of inclusion. For corn, AME and AMEn were little affected by age, and the effect of N correction was consistent at around 3%. Determined energy values of SBM were more variable. Experiment 3 was conducted to assess the effect of formulating diets based on either AME or AMEn on broiler performance. A 2-sample t-test was implemented examining AME vs. AMEn formulation. The analyses for numerous production and carcass traits were nonsignificant except for the case of less abdominal fat in birds fed diets formulated to AME rather than AMEn (P < 0.01). These results showed that the use of the N correction imposed a penalty to corn of 3 to 5% and SBM of 7 to 12%.