Genetically reducing boar taint using low-taint lines is considered the most sustainable and economic long-term alternative to surgical castration of male pigs. Owing to the high heritability of the main boar taint components (androstenone, skatole and indole), breeding is an excellent tool for reducing the number of tainted carcasses. To incorporate boar taint into breeding programmes, standardized performance testing is required. The objective of this study was to develop and formally present a performance test for the main boar taint compounds on live breeding candidates. First, a standardized performance test for boar taint was established. A biopsy device was developed to extract small tissue samples (200 to 300 mg) from breeding candidates. Quantification of boar taint components from these small samples using specialized chemical extraction methods proved accurate and repeatable (r = 0.938). Following establishment of the method, biopsy samples of 516 live boars (100 to 130 kg live weight) were collected in the second step. Various mixed linear models were tested for each boar taint compound; models were ranked in terms of their information content. Pedigree information of 2245 ancestors of biopsied animals was included, and genetic parameters were estimated using univariate and multivariate models. Androstenone (in μg/g liquid fat (LF): mean = 0.578, σ = 0.527), skatole (in μg/g LF: mean = 0.033, σ = 0.002) and indole (in μg/g LF: mean = 0.032, σ = 0.002) levels obtained by biopsy were plausible. Heritability estimates for androstenone calculated with univariate (0.453) and multivariate (0.452) analyses were comparable to those in the literature. Heritabilities for skatole (0.495) and indole (0.550) were higher than that for androstenone. Genetic and phenotypic correlations were similar to those published previously. Our results show that data on boar taint compounds from small adipose samples obtained by biopsy provide similar genetic parameters as that described in the literature for larger samples and are therefore a reliable performance test for boar taint in live breeding candidates.

Introduction. The Chinese jujubetree always presents some unfavorable performances because its vegetativegrowth is very vigorous. Our study was conducted to apply root pruning totest whether it can effectively inhibit the vigorous vegetative growthby regulating the competitive ability of the root system for waterand nutrients. Materials and methods. For our experiment,roots were cut at three different distances from the trunk (light,moderate and severe root pruning) on both inter-row sides of jujubetrees to the depth of 20 cm. Roots of control jujube trees werenot pruned. Then we determined for three years the competitive indicatorsof Chinese jujube trees including the length, number and thicknessof primary branches; photosynthetic characteristics and nutrientconcentrations of leaves; hormone contents in the jujube head, flowernumber and fruiting percentage, yield, and fruit quality. Resultsand discussion. In the early stage after root treatment,root pruning decreased lots of indicators such as concentrationsof nitrogen, phosphorus, and potassium in leaves, photosynthesis, transpiration,stomatal conductance, and intercellular CO2 concentrationof leaves, relative to the same indicators as the control group. Withthe gradual emergence of new roots, these indexes appeared to have adversepatterns with respect to those in the early stage after root pruning. Comparedwith the control, root pruning significantly decreased the lengthand number of primary branches and flower number, but thickenedprimary branches, enhanced fruiting percentage and increased the amountof ethylene release of the jujube head in the whole experiment.Fruit quality was improved with root pruning, as indicated by increasesin vitamin C and total sugar and a decrease in titrable acidity.No effects of root pruning were noticed on yield. From our results,we conclude that the removal of the root system at a distance ofthree times the trunk diameter (severe pruning) from the trunk isthe most effective in regulating the competitive ability of theChinese jujube tree.

The days of being able to ascertain instrument performance by simply peering through the eye pieces at a specimen are gone. However, users and granting agencies need to be confident that data collected on these instruments is uniform and quantifiable both over time and between instruments. Ideally, a LASER should not fluctuate, illumination should be completely uniform, and colors should be perfectly aligned. To check the current performance of imaging equipment, we conducted a worldwide research study utilizing three image-based tests: long-/short-term illumination stability, co-registration of signals across various wavelengths, and field illumination uniformity. To differentiate between “acceptable” and “unacceptable” performance, the deviation in illumination power could not exceed 10% (long term) or 3% (short term), the difference in the center-of-mass of imaged multicolored beads could not exceed >1 pixel between different wavelengths, and field illumination values could not exceed 10% (horizontal) or 20% (diagonal) deviation. This study established the current state of microscope performance through simple, efficient, and robust tests, while defining relative standards to assist cores in maintaining their instruments in optimal operating conditions. We developed cross-platform performance standards that will improve the validity of quantitative measurements made using various light microscopes.

Genetic growth curves of boars in a test station were predicted on daily weight records collected by automated weighing scales. The data contained 121 865 observations from 1477 Norwegian Landrace boars and 108 589 observations from 1300 Norwegian Duroc boars. Random regression models using Legendre polynomials up to second order for weight at different ages were compared for best predicting ability and Bayesian information criterion (BIC) for both breeds. The model with second-order polynomials had best predictive ability and BIC. The heritability for weight, based on this model, was found to vary along the growth trajectory between 0.32–0.35 for Duroc and 0.17–0.25 for Landrace. By varying test length possibility to use shorter test time and pre-selection was tested. Test length was varied and compared with average termination at 100 kg, termination of the test at 90 kg gives, e.g. ∼2% reduction in accuracy of estimated breeding values (EBV) for both breeds and termination at 80 kg gives ∼5% reduction in accuracy of EBVs for Landrace and ∼3% for Duroc. A shorter test period can decrease test costs per boar, but also gives possibilities to increase selection intensity as there will be room for testing more boars.

Introduction. Le contrôle sanitaire des bananes, essentiel pour assurer la qualité après-récolte du produit commercialisé, dépend beaucoup des techniques d'application des fongicides. Une enquête réalisée in situ en Martinique a mis en évidence des temps et des techniques d'application des produits fongicides variables. Différentes techniques ont été expérimentées pour définir les meilleures conditions opératoires. Matériel et méthodes. Plusieurs facteurs qui, au stade du hangar, peuvent influencer l'efficacité des applications de fongicides après-récolte ont été étudiés : l'emploi ou non d'alun, le temps d'application, le type et le débit des buses, l'angle des pulvérisations. Les traitements ont été réalisés sur fruits après inoculation contrôlée avec Colletotrichum musae sur blessures et sur couronnes. Les fruits ont ensuite été conservés 8 j à 14 °C, puis mis en maturation en simulation industrielle (24 h ; 1 L éthylène × m-3) avant d'être stockés 5 j à 22 °C. La surface des nécroses ou l'altération des pédoncules ont alors été mesurées. Résultats et discussion. L'alun ajouté à du thiabendazole a diminué l'efficacité du fongicide utilisé seul. Le temps d'aspersion a eu un effet sur la performance des produits fongicides, une application de 30 s étant le minimum souhaitable. La combinaison de l'imazalyl au thiabendazole ou au bitertanol a eu un effet favorable pour le contrôle du chancre dans les pourritures de couronne. La comparaison des débits testés a montré qu'un débit de buse de l'ordre de 0,4 L × min-1, appliqué pendant 30 s, garantissait le passage effectif de la solution fongicide entre les fruits et les bouquets. La taille des gouttes (fines ou grosses gouttelettes) a peu d'incidence quand le volume pulvérisé et le temps de contact sont respectés (5 L par tray pendant 30 s). Les performances ont été améliorées en utilisant un tray tubulaire "sans fond " , faisant intervenir une pulvérisation par-dessus et par-dessous. Conclusion. L'action réelle des fongicides est directement liée à une qualité d'application qui intègre le temps et le débit. Les préconisations données, liées à une inoculation expérimentale sévère, sont probablement surestimées ; elles peuvent cependant servir de référence dans les situations où la qualité sanitaire laisse à désirer.

Estimates of genetic parameters for beef production traits were obtained for Piemontese cattle. Data were from 988 young bulls station-tested from 1989 till 1998. Bulls entered the station at 6 to 8 weeks of age and, after an adaptation period of 3 months, were tested for growth, live fleshiness and bone thinness. Length of test was 196 days. Growth traits considered were gain at farm, gain during the adaptation period, gain on test and total gain at the station. Six different fleshiness traits and bone thinness were scored on live animals at the end of the test using a linear system. Live evaluations of fleshiness were adjusted for the weight at scoring in order to provide an assessment of conformation independent of body size. Genetic parameters were estimated using animal models. Heritability of live-weight gain ranged from 0·20 in the adaptation period to 0·60 for total gain at the station. Genetic correlations between gains at station in different periods were high (from 0·63 to 0·97). Residual correlation between gain during the adaptation period and gain during test was negative, probably due to the occurrence of compensatory growth of the animals.

Live fleshiness traits and bone thinness were of moderate to high heritability (from 0·34 to 0·55) and highly correlated indicating that heavy muscled bulls also have thin bones. Accuracy of breeding values and therefore response to selection were improved by multiple trait analysis of the live fleshiness traits and bone thinness. Overall weight gain at the station had a moderate negative genetic correlation with all live fleshiness traits and bone thinness (from –0·11 to –0·39).

Restricted maximum likelihood analyses fitting an animal model were conducted to estimate genetic parameters with a pooled-data set of performance tests (growth traits and food intake) on 661 bulls and progeny tests (growth traits and carcass traits) on 535 steers. Traits studied included concentrate intake (CONC), roughage intake (ROU), TDN conversion (TCNV), TDN intake (TINT) of bulls; rib eye area (REA), marbling score (MARB), dressing proportion (DRES) and subcutaneous fat depth (SCF) of steers. Body weight at start (BWS), body weight at finish (BWF) and average daily gain (ADG) of all animals were measured. Estimated heritabilities were 0·18 (CONC), 0·71 (ROU), 0·11 (TCNV) and 0·36 (TINT); 0·02 (REA), 0·49 (MARB), 0·15 (DRES), 0·15 (SCF), and from 0·20 to 0·38 for growth traits. Genetic correlations of ROU were different from those of CONC, probably due to inconsistent restrictions on concentrate intake; those of TINT with the weights, ADG and SCF were high. MARB showed positive genetic correlations with growth traits and low correlations with TINT and SCF. High potentiality for improvement of marbling score was suggested.

Bivariate individual animal model estimates of genetic and environmental correlations between reproduction traits (number born alive and average piglet weight) and performance test traits (ultrasonic backfat depth, average daily food intake, average daily gain and food conversion ratio) of Landrace pigs were calculated. The estimates were produced using a derivative-free restricted maximum likelihood algorithm to calculate likelihoods for different combinations of covariance parameters. A quadratic approximation to the likelihood surface was used to estimate the maximum likelihood values with respect to the covariance parameters. For all combinations of performance test traits with reproduction traits the resulting genetic and residual correlation estimates were low, with a maximum absolute value of 0·233 for the genetic correlation between food conversion ratio and number born alive. Standard errors of genetic correlation estimates were between 0·11 and 0·15. There is expected to have been little effect upon reproduction traits from the rigorous selection carried out upon performance test traits over the years. When incorporating reproduction data into best linear unbiased prediction analysis procedures it should be possible to analyse performance test and reproduction traits from this population separately, thereby making savings on computer resources and time required for the analysis of all traits.

Puberty during performance test and the effect of reproductive maturity and performance on test on superovulatory response were investigated using Simmental heifers.

Three generations of Simmental heifers (no. = 110) were performance tested for beef characteristics between 23 and 49 weeks of age over 3 years successively. Embryo recoveries were performed at 52 and 61 weeks of age following the end of the performance test. The onset of puberty was observed in 26 of 30 (87%) heifers in the 3rd year. The mean age at puberty was 284·7 (s.e. 6·63) days. Age at puberty was not significantly related to daily live-weight gain (1·5 (s.e. 0·02) kg) up to the onset of puberty. Heifers experienced zero to six oestrous cycles before initiation of the first superovulatory treatments. There was a non-significant tendency (P > 0·05) for heifers that were not cyclic to produce the highest yields of viable and grade 1 embryos at the first embryo recovery.

Performance test characteristics recorded were: total food intake (1604·0 (s.e. 13·2) kg), total energy intake (1852·0 (s.e. 169·0) MJ metabolizable energy) and live-weight gain (263·9 (s.e. 2·2) kg) during test; live weight (486·5 (s.e. 31·5) kg), backfat depth (5·6 (s.e. 15) mm) and muscle score (9·6 (s.e. 0·10) units) at the end of test and estimated breeding value for the selection index (+£7·00 (s.e. 0·76)). These were used as independent variables in general linear models to study their relationship with various measures of superovulatory response. Recovery rate of ova and embryos; and the yields of viable and grade 1 embryos were not related to any aspects of performance on test.

In conclusion, superovulation and embryo recovery were affected by reproductive maturity at the time of gonadotropin treatment and these procedures may be more effective in juvenile heifers before the establishment of cyclicity. Embryo production from 12- to 15-month-old Simmental heifers following a beef performance test was not related to their performance on test.

Forty-nine bulls, 27 Limousin × Friesian and 22 Charolais × Friesian, were evaluated and slaughtered in four batches of about equal size over 4 weeks. Each batch was of one breed. Age, live weight at evaluation and subjective assessments of fatness and conformation were recorded together with fat and muscle measurements by the Delphi, Meritronics, Scanogram, Vetscan, Kaijo Denki, Warren and the Velocity of Sound ultrasonic machines. Experienced operators were used to assess the performance of machine/operator combinations likely to be achieved in bull performance testing in the field. Fat thicknesses and areas, and m. longissimus areas were taken at the 10th rib and 13th rib, and 3rd lumbar regions by most machines. For the Delphi and Meritronics machines, fat thicknesses only were taken; for the Velocity of Sound machine, time interval measurements and anatomical distances were taken at the shoulder, mid back, lumbar and hind limb regions. The left side of each carcass was fully separated into lean, subcutaneous fat, intermuscular fat, bone and waste. All measurements were examined as potential predictors of carcass composition in step-wise regression in a model which included week of evaluation, breed and live weight at evaluation as the first independent variable. On the whole, scanning machines had a higher precision than A-mode machines, with the Velocity of Sound machine achieving the highest precision for carcass lean (g/kg) (residual s.d. = 13·0) and fat (g/kg) (residual s.d. = 14·1). None of the linear and area measurements taken on the carcass achieved the degree of precision of the Velocity of Sound, Scanogram and Vetscan machines.

The statistical methods for the estimation of genotype–environment interactions based on the concept of genetic correlation are reviewed and the implications of genotype–environment interactions in selection and in performance testing of genetic stocks discussed. From comparative testing of commercial poultry stocks there is overwhelming evidence for the occurrence of stock–testing station interactions. However, the relative importance of the effects may vary considerably between performance traits and between testing situations. In general, the consequences of genotype–environment interactions appear to be more serious in egg production stocks than in broiler stocks. For laying rate and viability particularly large effects have to be expected.