Heterosis in the components of lactation curves of Girolando cows

Autor: Darlene dos Santos Daltro, Alessandro Haiduck Padilha, Luís Telo da Gama, Marcos Vinícius Gualberto Barbosa da Silva, João Claudio do Carmo Panetto, Juliana Dementshuk Machado, José Braccini Neto, Jaime Araujo Cobuci
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Italian Journal of Animal Science, Vol 18, Iss 1, Pp 267-278 (2019)
Druh dokumentu: article
ISSN: 1828-051X
1828051X
DOI: 10.1080/1828051X.2018.1507627
Popis: The objective of this study was to evaluate the effect of heterosis on the lactation curve components of Girolando cattle obtained by fitting different mathematical models. Data consisted of 258,891 test day milk yield records of the first lactation from 37,965 cows of Minas Gerais State (Brazil) between 1998 and 2014. Those cows were from the Holstein breed (H), Gyr breed (G) and six genetic cross-breedings of Holstein × Gyr, (1/4H, 3/4G (1/4H); 3/8H, 5/8G (3/8H); 1/2H, 1/2G (1/2H), 5/8H, 3/8G (5/8H); 3/4H, 1/4G (3/4H); 7/8H, 1/8G (7/8H)), which is officially named as Girolando breed in Brazil. The Wood’s linear model (WDlin), Wood’s non-linear model (WDnlin), Wilmink’s model (WL) and Ali and Schaeffer’s model (ASH) were used for estimating the peak milk yield (PY), time to peak yield (PT), 305-day milk yield (TMY) and four different persistency measures (P, P2:1, P3:1 and P3:2). Regardless of the fitted model, the highest estimates of PY and TMY were for the H group. The heterosis effect was significant (p
Databáze: Directory of Open Access Journals
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