منابع مشابه
Modeling extended lactations of Holsteins.
Modeling extended lactations for the US Holsteins is useful because a majority (>55%) of the cows in the present population produce lactations longer than 305 d. In this study, 9 empirical and mechanistic models were compared for their suitability for modeling 305-d and 999-d lactations of US Holsteins. A pooled data set of 4,266,597 test-day yields from 427,657 (305-d complete) lactation recor...
متن کاملModeling extended lactations of dairy cows.
Nine mathematical models were compared for their ability to predict daily milk yields (n = 294,986) in standard 305-d and extended lactations of dairy cows of Costa Rica. Lactations were classified by parity (first and later), lactation length (9 to 10, 11 to 12, 13 to 14, 15 to 16, and 16 to 17 mo), and calving to conception interval (1 to 2, 3 to 4, 5 to 6, 7 to 8, and 9 to 10 mo). Of the nin...
متن کاملEconomics of extended lactations in dairying
Introduction Whole-farm analysis of alternative lactation regimes Case study farm number one Description of farming system one Whole-farm results of farming system one Case study farm number two Description of farming system two Whole-farm results of farming system two General discussion of results Conclusions References Appendix Abstract. This paper deals with the economic analysis and managem...
متن کاملGenetic Relationship of Productive Life, Production and Type Traits of Korean Holsteins at Early Lactations.
The present study was performed to study the genetic relationship of productive life with production and type traits of Korean Holsteins at first three lactations. The data for the analysis from 56,054, 28,997, and 11,816 animals of first, second and third parity cows which were born from 2006 to 2011 were collected by Dairy Cattle Improvement Center, National Agricultural Co-operative Federati...
متن کاملGenetic and phenotypic parameters of lactations longer than 305 days (extended lactations).
Test-day milk yield and somatic cell count data over extended lactation (lactation to 540-600 days) were analysed considering part lactations as different traits and fitting random regression (RR) models. Data on Australian Jersey and Holstein Friesian (HF) were used to demonstrate the shape of the lactation curve and data on HF were used for genetic study. Test-day data from about 100 000 cows...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 2007
ISSN: 0022-0302
DOI: 10.3168/jds.2006-790