environment, predicted nitrogen use efficiency, milk urea, predicted N intake
Abstract :
[en] Nitrogen use efficiency (NUE) of dairy cows is an important trait that farmers as an indicator of sustainability in dairy production. However, many traits definition may represent NUE of dairy cows involving multiple N-related traits. The purposes of our research were: (1) to explore the curves of N-related traits in the first 50 days in milk (DIM); (2) to analyze the relationship between predicted NUE (PNUE), predicted N losses (PNL), predicted N intake (PNintake), and milk urea (MU). PNUE, PNL, and PNintake were predicted based on milk mid-infrared spectra, parity, and milk yield. Each N-related trait was divided between primiparous and multiparous. After editing, the data included 143,595 records within 5 to 50 DIM from 53,660 cows on 766 farms. The genetic parameters were estimated using a multiple-trait repeatability model. In the first 50 DIM, the multiparous PNUE, PNL, PNintake, and PNout were all greater than the first class, but MU was reversed. In addition, the PNL and PNintake increased as DIM increased, but PNUE decreased gradually. MU first decreased and then increased (around DIM 17 was the minimum). The range of estimated heritabilities for PNUE, PNL, MU, and PNintake in the first and second class were from 0.09 to 0.19. Among the different traits, the novel N traits (PNUE, PNL, and PNintake) had a low genetic correlation with MU (from –0.14 to 0.03), but the genetic correlation between PNL and PNintake was high (from 0.76 to 0.94). Therefore, we believe that the novel N traits are different from MU, and PNL is affected by PNintake.
Disciplines :
Zoology
Author, co-author :
Chen, Yansen ; Université de Liège - ULiège > TERRA Research Centre
C., Grelet
Vanderick, Sylvie ; Université de Liège - ULiège > TERRA Research Centre > Animal Sciences (AS)
Gengler, Nicolas ; Université de Liège - ULiège > TERRA Research Centre > Animal Sciences (AS)
Language :
English
Title :
Relationship between proxies of nitrogen use efficiency for dairy cows in early lactation
Publication date :
01 September 2021
Event name :
72nd Annual Meeting of the European Federation of Animal Science
Event organizer :
EAAP - European Federation of Animal Science
Event place :
Davos, Switzerland
Event date :
30 August-03 September 2021
Audience :
International
Peer reviewed :
Peer reviewed
References of the abstract :
Nitrogen use efficiency (NUE) of dairy cows is an important trait that farmers as an indicator of sustainability in dairy production. However, many traits definition may represent NUE of dairy cows involving multiple N-related traits. The purposes of our research were: (1) to explore the curves of N-related traits in the first 50 days in milk (DIM); (2) to analyze the relationship between predicted NUE (PNUE), predicted N losses (PNL), predicted N intake (PNintake), and milk urea (MU). PNUE, PNL, and PNintake were predicted based on milk mid-infrared spectra, parity, and milk yield. Each N-related trait was divided between primiparous and multiparous. After editing, the data included 143,595 records within 5 to 50 DIM from 53,660 cows on 766 farms. The genetic parameters were estimated using a multiple-trait repeatability model. In the first 50 DIM, the multiparous PNUE, PNL, PNintake, and PNout were all greater than the first class, but MU was reversed. In addition, the PNL and PNintake increased as DIM increased, but PNUE decreased gradually. MU first decreased and then increased (around DIM 17 was the minimum). The range of estimated heritabilities for PNUE, PNL, MU, and PNintake in the first and second class were from 0.09 to 0.19. Among the different traits, the novel N traits (PNUE, PNL, and PNintake) had a low genetic correlation with MU (from –0.14 to 0.03), but the genetic correlation between PNL and PNintake was high (from 0.76 to 0.94). Therefore, we believe that the novel N traits are different from MU, and PNL is affected by PNintake.
