Investigating the genetic background of novel behavioral indicators of robotic milking efficiency in North American Holstein cattle
Berat, Hugo
Promoteur(s) : Brito, Luiz Fernando ; Gengler, Nicolas
Date de soutenance : 27-aoû-2024 • URL permanente : http://hdl.handle.net/2268.2/21584
Détails
Titre : | Investigating the genetic background of novel behavioral indicators of robotic milking efficiency in North American Holstein cattle |
Titre traduit : | [fr] Étude du contexte génétique de nouveaux indicateurs comportementaux de l'efficacité de la traite robotisée chez les bovins Holstein d'Amérique du Nord |
Auteur : | Berat, Hugo |
Date de soutenance : | 27-aoû-2024 |
Promoteur(s) : | Brito, Luiz Fernando
Gengler, Nicolas |
Membre(s) du jury : | Beckers, Yves
Soyeurt, Hélène Schroyen, Martine Lemal, Pauline |
Langue : | Anglais |
Nombre de pages : | 132 |
Mots-clés : | [en] automated milking systems [en] behavioral genetics [en] dairy cattle [en] genetic parameters [en] milking robots |
Discipline(s) : | Sciences du vivant > Productions animales & zootechnie |
Commentaire : | hugo.berat@outlook.be |
Organisme(s) subsidiant(s) : | International Relations Department of the University of Liège |
Centre(s) de recherche : | Gembloux Agro-Bio Tech (University of Liège, Belgium) & Purdue University (USA) |
Intitulé du projet de recherche : | Genetics of cow behavioral traits |
Public cible : | Chercheurs Professionnels du domaine Etudiants |
Institution(s) : | Université de Liège, Liège, Belgique |
Diplôme : | Master en bioingénieur : sciences agronomiques, à finalité spécialisée |
Faculté : | Mémoires de la Gembloux Agro-Bio Tech (GxABT) |
Résumé
[en] The adoption of automated milking systems (AMS) across worldwide dairy farms has grown
considerably over the last few decades. Automated milking systems contribute to reducing labor costs, increasing milk performance, improving cow welfare, and generating large-scale data on a routine basis that can be used for deriving novel breeding traits. Therefore, the primary objectives of this study were to (1) derive novel behavioral traits based on AMS data and assess their phenotypic variability throughout lactation in North American Holstein cattle during lactation; and (2) estimate genomic-based variance components and genetic parameters for all these AMS-based behavioral traits. Daily AMS-derived data were available for 5,645 American Holstein cows collected by 36 robotic milking stations from 2018 to 2021. The traits evaluated included average milking time (AMT, min) and total milking time (TMT, min) within the AMS, time interval between milkings (INT, hr), number of attempted visits to the AMS (NoV), number of successful entries counted within the AMS stations (NSE), percentage of successful milkings (PSM, %), and cow preference score for each AMS unit (PCS, score unit). Variance components and genetic parameters were estimated based on repeatability models and the REML method. Heritability estimates for the traits AMT, TMT, INT, NoV, NSE, PSM and PCS were calculated using two separate models, integrating the effect of environment either between and across parities, or only between parities. The results showed similar values for the majority of traits: 0.46 - 0.46, 0.27 - 0.28, 0.08 - 0.10, 0.10 - 0.10, 0.10 - 0.11, 0.05 - 0.06 respectively. However, a notable difference was observed for the PCS trait, with values of 0.09 and 0.24 depending on the model. The SE for the heritability estimates of all traits ranged from 0.001 to 0.03. The repeatability estimates for the same traits were 0.74 - 0.71, 0.52 - 0.49, 0. 34 - 0.27, 0.29 - 0.25, 0.29 - 0.30, 0.20 - 0.18 and 0.55 - 0.53, respectively. Analyses by individual parity (1, 2, 3, and 4 +) for the PCS trait showed heritabilities ranging from 0.005 to 0.037 for both models. Positive and favorable genetic correlations for both models were observed for the following pairs of traits: AMT_PSM (0.38 - 0.35), INT_PSM (0.71 - 0.64), INT_PCS (0.50 - 0.40), and PSM_PCS (0.37 - 0.37). The other genetic correlation estimates were not found to be favorable or close to 0. All the cow behavioral traits related to AMS efficiency evaluated in this study were found to be heritable, suggesting that their inclusion in selection schemes could contribute to improving dairy cow milking efficiency and welfare in dairy farms utilizing AMS.
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