Validation et développement de méthodes pour le suivi de la croissance pré-sevrage des génisses laitières

Authors: Hasnaoui, Marwa
Advisor: Charbonneau, ÉdithSantschi, Débora
Abstract: The objectives of the project presented in this thesis were to validate the use of heart girth measurement in dairy calves during the pre-weaning period to estimate body weight and average daily gain, as well as to verify if other body measurements would also be effective in predicting body weight. Scale body weight and various parameters related to body size (heart girth, withers height, hip height and hip width) of 329 dairy Holstein heifers were collected from two dairy farms located in Quebec. The measurements were taken three times a week during the first three weeks of life and every two weeks until the week following weaning, which was at 76 days of life. The results of this study confirmed the feasibility of using heart girth or other body parameters to predict body weight before weaning of dairy calves. The resulting body weight prediction equation with the highest correlation and the lowest root mean squared percentage error used the heart girth. This equation showed no predictive bias compared to the main equations actually used, which showed slight bias when predicting calf body weight. However, the results suggest a better prediction of the average daily gain of pre-weaning dairy calves with the equation used locally.
Document Type: Mémoire de maîtrise
Issue Date: 2019
Open Access Date: 18 October 2019
Grantor: Université Laval
Collection:Thèses et mémoires

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