EVALUATION OF THE FITNESS OF THREE MATHEMATICAL MODELS TO DESCRIBE THE LACTATION CURVE OF MASTIC AND NON-MASTITIC FRIESIAN X BUNAJI COWS

N. H. MORU; P. P. BARJE; H. J. MAKUN; I. U. GADZAMA; K. MOHAMMED; S. ABUBAKAR

doi:10.51791/njap.vi.7176

Auteurs

N. H. MORU Ahmadu Bello University, P.M. B 1096 Shika-Zaria, Nigeria
P. P. BARJE Ahmadu Bello University, P.M. B 1096 Shika-Zaria, Nigeria.
H. J. MAKUN Ahmadu Bello University, P.M. B 1096 Shika-Zaria, Nigeria.
I. U. GADZAMA Ahmadu Bello University, P.M. B 1096 Shika-Zaria, Nigeria.
K. MOHAMMED Ahmadu Bello University, P.M. B 1096 Shika-Zaria, Nigeria.
S. ABUBAKAR Ahmadu Bello University, P.M. B 1096 Shika-Zaria, Nigeria.

DOI :

https://doi.org/10.51791/njap.vi.7176

Mots-clés :

Friesian x Bunaji, lactation curve, mastitic cows, goodness of fit mathematical models

Résumé

This study evaluated the fitness of three mathematical models (Wood, Wimink and Dijkstra models) in describing the lactation curve of Friesian x Bunaji cows. The data used comprised of daily milk yield record between 2000-2015 kept in the Farm Unit of the Dairy Research Programme National Animal Production Research Institute, Shika-Zaria. The Goodness of fit comparison used for the models were the root mean square error (RMSE) and adjusted coefficient of determination (R²_adj) values. Non mastitic cows of parities 1-4 had R²_adj values ranging from 0.378 Ito 0.9993 and RMSE ranging from 0.2390 to 0.4234 for the three models. Mastitc cows of parities 1-4 had R²_adj and RMSE values ranging from 0.7255-1 and 0.00002-0.2245 respectively for the three models. The results of this study shows that Dijkstra model gave best fit for parity I of non mastitc cow's lactation and parities l-4 of mastitic cow's lactation; while Wilmink model gave best fit for parities 2-4 of non mastitic cow's lactation.