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Modelling extended lactation curves for milk production traits in Italian Holsteins

Steri, Roberto and Cappio Borlino, Aldo and Macciotta, Nicolò Pietro Paolo (2009) Modelling extended lactation curves for milk production traits in Italian Holsteins. Italian Journal of Animal Science, Vol. 8 (Suppl. 2), p. 165-167. ISSN 1828-051X. Article.

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Abstract

Test day records of milk production traits (milk yield, fat and protein percentage, and somatic cell score) of 45,132 Italian Holstein cows were analyzed with seven mathematical models in order to assess the main features of lactations of different length. Lactations curves were grouped according to parity (1, 2, and 3) and lactation length (1<350d; 2=from 351 to 450d; 3=from 451 to 650d; 4=651 to 1000d). Models with a larger number of parameters showed better fitting performances for all classes of length for milk yield, whereas poor fitting was observed for fat and protein percentages and SCS in the 651-1000d class. In lactation with length>650d, peak yield was about 31, 37, and 39 kg for first, second, and third parity respectively; peak was predicted at around 60 and 40 days for younger and older animals respectively. The asymptotic level of production was below 10 kg.

Item Type:Article
ID Code:3020
Status:Published
Refereed:Yes
Uncontrolled Keywords:Dairy cattle, extended lactations, mathematical models
Subjects:Area 07 - Scienze agrarie e veterinarie > AGR/17 Zootecnica generale e miglioramento genetico
Divisions:001 Università di Sassari > 01 Dipartimenti > Scienze zootecniche
Publisher:Avenue media on behalf of Scientific Association of Animal Production (ASPA)
ISSN:1828-051X
Publisher Policy:Depositato per gentile concessione dell'ASPA
Additional Information:Relazione presentata al 18. Congresso nazionale ASPA, Palermo, 9-12 giugno 2009.
Deposited On:18 Sep 2009 12:49

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