This study has aimed to compare Repeatability (RP-TDm) and Random-Regression Test Day models (RR-TDm) in genetic evaluations of milk (M), fat (F) and protein (P) yields in Rendena breed. Variance estimations for Milk (M), Fat (F) and Protein (P) were obtained on a sample of 43,842 TD belonging to 2,692 animals controlled over 15 years (1990-2005). RP-TDm estimates of h2 were of 0.21 for M and 0.17 for both F and P, whereas RR-TDM provided a trend of h2 ranging from 0.15-0.34 for M, 0.15-0.31 for F and 0.10-0.24 for P. Both RP-TDm and RR-TDm results agreed with literature, even though RR-TDm provided a pattern of h2 along the lactation different from other studies, with the lowest h2 at the beginning and at the end of lactation. PSB, MAD and -2Log L parameters revealed lower power of RP-TDm as compare with the RR-TDm.

Test day-milk yields variance component estimation using repeatability or random regression models in the Rendena breed

SARTORI, CRISTINA;MANTOVANI, ROBERTO
2009

Abstract

This study has aimed to compare Repeatability (RP-TDm) and Random-Regression Test Day models (RR-TDm) in genetic evaluations of milk (M), fat (F) and protein (P) yields in Rendena breed. Variance estimations for Milk (M), Fat (F) and Protein (P) were obtained on a sample of 43,842 TD belonging to 2,692 animals controlled over 15 years (1990-2005). RP-TDm estimates of h2 were of 0.21 for M and 0.17 for both F and P, whereas RR-TDM provided a trend of h2 ranging from 0.15-0.34 for M, 0.15-0.31 for F and 0.10-0.24 for P. Both RP-TDm and RR-TDm results agreed with literature, even though RR-TDm provided a pattern of h2 along the lactation different from other studies, with the lowest h2 at the beginning and at the end of lactation. PSB, MAD and -2Log L parameters revealed lower power of RP-TDm as compare with the RR-TDm.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11577/2470576
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 6
  • ???jsp.display-item.citation.isi??? 5
social impact