Modeling lactation curves of Polish Holstein-Friesian cows. Part I: The accuracy of five lactation curve models
Agnieszka Otwinowska-Mindur , Ewa Ptak , Wojciech Jagusiak , Alicja Satoła
AbstractThe objective of this study was to compare five mathematical functions used for modeling lactation curves and to choose the most suitable one for Polish Holstein-Friesian cows. The data used were 1,944,818; 1,548,700; and 1,081,107 test-day milk yields from 220,487 first, 181,165 second, and 128,774 third lactations. Five models were fitted to the test-day data: the Ali and Schaeffer (ALI), Guo (GUO), and Wilmink (WIL) functions, and thirdorder (LEG3), and fourth-order (LEG4) Legendre polynomials. The milk lactation curves were fitted using a multiple-trait prediction method. Several criteria based on the analysis of residuals were used to compare the models. Of the five models, five-parameter functions (ALI and LEG4) gave the best goodness of fit for standard lactations (305-d), whereas three-parameter functions (GUO and WIL) were the worst. For extended lactations (400-d), the ALI function ensured the most correct prediction.
|Journal series||Journal of Animal and Feed Sciences, ISSN 1230-1388, (A 20 pkt)|
|Publication size in sheets||0.5|
|Keywords in English||dairy cow, lactation curve, multiple-trait prediction method, goodness of fit|
|Publication indicators||= 4; : 2014 = 0.681; : 2013 = 0.591 (2) - 2013=0.639 (5)|
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