Prediction of scrotal circumference expected progeny differences in limousin cattle
Notice bibliographique
Résumé
In the first phase, 557 Limousin bulls were placed on a Canadian \nLimousin Association postweaning gain test over 4 yr (1987 to 1991). \nBulls varied in age by 120 d. Weights (WT) and scrotal circumferences \n(SC) were collected at 28 d intervals from shortly after weaning to the end \nof the test on each bull (6 or 7 measurements per year). Hip heights (HT) \nwere collected on the second and again on the final measurement dates \neach year. Age in days (AGE) was calculated for each measurement date. \nAge of dam (AOD) was also recorded for each bull on test. Correlations of \nSC with AGE, WT and HT were high and positive (P < .0 1). Year and AOD \neffects were present (P < .001). Quadratic regression equations were \nestimated for AGE, WT and HT on SC to develop adjustment equations. \nThe resulting regression equation for the estimation of SC from AGE was: \nY = -3.02 + .131(AGE)- .000114(AGE)2 (R2 = 74.8°/o, P < .001). Age-ofdam \nadjustment factors were determined by use of indicator variables. \nAnalyses showed that age adjusted SC should be adjusted to a 4- to 10- \nyear AOD equivalent by adding .51, .31 or .36 em for dams 2, 3 or> 11 \nyears of age (P < .05). Adjustment of scrotal circumference in Limousin \nbulls to a constant, for subsequent use in national cattle evaluation, can \nbest be achieved by removing some of the variation in scrotal \ncircumference caused by environmental effects of age of dam and age, \nweight or height. \nNext, variance and covariance components were estimated for \nscrotal circumference and weaning weight from Limousin field data. \nRecords of 8,226 bulls were used to evaluate 590 sires and 661 maternal grand sires. Data included all herd book records of bulls with a recorded \nscrotal circumference and their weaning contemporaries. Analyses were \ncarried out by REML techniques employing the EM algorithm and fitting \nboth single- and two-trait models. Scrotal circumference was first fitted \nin a single-trait, sire model to obtain starting values for variances for a \nlater analysis. Likewise, weaning weight was fitted in a single-trait, sirematernal \ngrandsire model to obtain starting values for (co)variances for a \nlater analysis. Scrotal circumference and weaning weight were then \nfitted together in a two-trait model to estimate variance components. \nEstimates of variance components were calculated by equating \n(co)variances obtained from the models to their expectations. Estimates \nof heritability of scrotal circumference, direct weaning weight and \nmaternal weaning weight were .46, .25 and .19, respectively. Estimates \nof genetic correlations between scrotal circumference and direct weaning \nweight, scrotal circumference and maternal weaning weight, and direct \nweaning weight and maternal weaning weight were .14, -.22 and -.44, \nrespectively. The estimate of the environmental correlation between \nscrotal circumference and weaning weight was .59. \nFinally, the genetic parameters obtained were utilized to predict \nbreeding values. Records on 9,618 bulls were available for the prediction \nof breeding values. Two-trait, reduced animal mixed model equations for \na maternally influenced trait were utilized and solved by BLUP \nprocedures to predict the breeding values. A genetic trend in scrotal \ncircumference for animals born from 1971 to 1989 was not discernible in \nthese data.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».