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Time series analysis of economic traits in Sahiwal cattle

Indian Agricultural Research Journals

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Title Time series analysis of economic traits in Sahiwal cattle
 
Creator GANDHI, R S
SINGH, SURENDRA
SACHDEVA, G K
 
Subject Cyclical components; Economic traits; Milk yield; Monthly indices; Periodicity; Periodic function; Seasonal components
 
Description The data on 2144 lactation records of 681 Sahiwal cows spread over 42 years (1965–2005) were analyzed for evolving correction factors to adjust the data for non-genetic factors by time series analysis. The traits considered were age at fist calving (AFC), lactation total milk yield (LTMY), lactation 305–day or less yield (L305DMY), lactation length (LL), calving interval (Cl) and service period (SP). The overall least squares population means for these traits were 1155.07±20.51 days, 2162.68±25.39 kg, 2030.19±19.96 kg, 295.71±2.61 days, 410.63±3.57 days and 119.57±3.31 days, respectively. The seasonal and cyclical components of these traits were isolated. A periodicity of 7, 5, 6, 7, 7 and 5 years was observed in the above traits. The periodic function was fitted and it explained maximum variation in the above traits ranging from 27.89% (LL) to 83.77% (AFC) revealing the periodicity of data over the years for majority of traits. Hence, animal breeding data has to be adjusted for cyclicity over the years. Further, the monthly/seasonal indices estimated by ratio to trend method accounted for more environmental fluctuations and were more appropriate for decomposing the time series data than link relative metho
 
Publisher Directorate of Knowledge Management in Agriculture
 
Contributor
 
Date 2011-01-06
 
Type info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion

 
Format application/pdf
 
Identifier http://epubs.icar.org.in/ejournal/index.php/IJAnS/article/view/2930
 
Source The Indian Journal of Animal Sciences; Vol 79, No 3 (2009)
0367-8318
 
Language eng
 
Relation http://epubs.icar.org.in/ejournal/index.php/IJAnS/article/view/2930/1017
 
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