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A Multivariate approach to modeling shapes of individual Lactation Curves in Cattle

Macciotta, Nicolò Pietro Paolo and Vicario, Daniele and Dimauro, Corrado and Cappio Borlino, Aldo (2004) A Multivariate approach to modeling shapes of individual Lactation Curves in Cattle. Journal of Dairy Science, Vol. 87 (4), p. 1092-1098. eISSN 1525-3198. Article.

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Abstract

Milk test-day records of 5728 lactations of Italian Simmental cows were analyzed with multivariate factor analysis in order to extract 2 common factors, whose scores were used as quantitative measures of 2 main features of lactation curve shape—i.e., the increasing rate of yield in the first part of lactation and the rate of decline of milk yield after the lactation peak. The 2 indices, objectively derived from the correlation matrix of original test-day records, showed a high discriminant power in separating lactation curves with different shapes. The weak correlation between the 2 factors (0.11), together with the high correlation of factors and the total 305-d yield (about 0.70), suggests that an increase in lactation yield could be achieved by acting only on one of the 2 factors related to lactation-curve shape, with the other kept constant at a medium or low value. The suitability of the 2 factors as descriptors of lactation patterns has been confirmed by the relationships found between factor scores and the main environmental effects known to affect the shape of the lactation curve, such as parity and season of calving.

Item Type:Article
ID Code:1072
Status:Published
Refereed:Yes
Uncontrolled Keywords:Lactation curve, lactation peak, test day, multivariate factor analysis
Subjects:Area 07 - Scienze agrarie e veterinarie > AGR/17 Zootecnica generale e miglioramento genetico
Area 07 - Scienze agrarie e veterinarie > AGR/19 Zootecnica speciale
Divisions:001 Università di Sassari > 01 Dipartimenti > Scienze zootecniche
Publisher:American Dairy Science Association
eISSN:1525-3198
Deposited On:18 Aug 2009 10:04

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