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Titolo:
BREEDING OBJECTIVES FOR PASTURE BASED DAIRY PRODUCTION SYSTEMS
Autore:
VISSCHER PM; BOWMAN PJ; GODDARD ME;
Indirizzi:
ROSLIN INST ROSLIN EH25 9PS MIDLOTHIAN SCOTLAND VICTORIAN INST ANIM SCI ATTWOOD VIC 3049 AUSTRALIA
Titolo Testata:
Livestock production science
fascicolo: 2, volume: 40, anno: 1994,
pagine: 123 - 137
SICI:
0301-6226(1994)40:2<123:BOFPBD>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
ECONOMIC WEIGHTS; MILK-PRODUCTION; PRODUCTION CIRCUMSTANCES; OUTPUT LIMITATIONS; SELECTION INDEXES; HERD LIFE; CATTLE; IMPROVEMENT; PARAMETERS; DERIVATION;
Keywords:
DAIRY CATTLE; BREEDING OBJECTIVES; ECONOMIC WEIGHTS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
28
Recensione:
Indirizzi per estratti:
Citazione:
P.M. Visscher et al., "BREEDING OBJECTIVES FOR PASTURE BASED DAIRY PRODUCTION SYSTEMS", Livestock production science, 40(2), 1994, pp. 123-137

Abstract

The aim of the study was to derive economic weights for milk production traits (milk, fat, and protein yield), survival, and mature body size for pasture based production systems. Economic weights were derivedusing a herd model and differentiating a profit function with respectto the traits of interest. Scaling was taken into account by assumingthat the total feed supply per farm was constant and at an economically optimum level. Relative economic weights were expressed in genetic standard deviations. To investigate the robustness of the method to derive economic weights, economic weights were calculated for 11 different sets of herd parameters, varying production levels, average herd life, costs and returns. Protein yield had the highest relative economicweight, followed by survival and mature body size. The latter traits were approximately half as important as protein yield, with the economic weight for body size negative. Fat and milk yield were approximately equally important and 40% as important as protein yield. Milk (volume) yield had a negative economic weight. Economic weights were fairly robust to changes in herd parameters, and it was concluded that the method of calculating economic weights, using a herd model and constraining the total energy supply, was appropriate for pasture based production systems.

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Documento generato il 27/09/20 alle ore 22:38:30