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Organic dairy production

herd characteristics and genotype by environment interactions

Ahlman, Therese (2010). Organic dairy production. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2010:59
ISBN 978-91-576-7472-2
[Doctoral thesis]

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Abstract

The aim of this thesis was to gain further knowledge about the performance of cows in organic dairy production and their ability to adapt to the organic production environment. Milk production traits, fertility traits, somatic cell count (SCC) and longevity traits were analysed in organic and conventional herds and the reasons for culling in the two systems were investigated. Furthermore, the genetic correlation between traits expressed in organic and conventional production was estimated to assess the occurrence of genotype by environment interaction (GxE). The data contained records from almost all organic and conventional herds in Sweden. This thesis shows that performance of organically managed dairy cows differs from conventionally managed cows. Cows in organic herds had lower production, better fertility and higher SCC than cows in conventional herds. However, the performance of cows in organic production depended to a large extent on the lower milk production level. At a given production level, organically managed cows had slightly worse fertility but equal SCC as cows in conventional herds. Cows stayed longer in organic herds than in conventional herds and the main reason for culling differed between the production systems. The main reason for culling in organic production was poor udder health followed by low fertility. In conventional production the main reason for culling was low fertility followed by poor udder health. The results indicate that organic farmers are more concerned about udder health than conventional farmers are. Genetic correlations for production, fertility, SCC and longevity, estimated in organic and conventional dairy production were in general close to unity. The results indicate that current breeding values for Swedish Red bulls, estimated in conventional production, are adequate for organic production. Weak GxE was found for fertility traits in Swedish Holstein cows, indicating that some cows of this breed are better suited for organic production than others. However, the magnitude of GxE does not justify development of a separate breeding programme for the organic population today.

Authors/Creators:Ahlman, Therese
Title:Organic dairy production
Subtitle:herd characteristics and genotype by environment interactions
Year of publishing :2010
Volume:2010:59
Number of Pages:60
Papers/manuscripts:
NumberReferences
ALLI. Sundberg, T., Berglund, B., Rydhmer, L., Strandberg, E. (2009). Fertility, somatic cell count and milk production in Swedish organic and conventional dairy herds. Livestock Science 129, 176-182. II. Sundberg, T., Rydhmer, L., Fikse, W.F., Berglund, B., Strandberg, E.(2010). Genotype by environment interaction of Swedish dairy cows in organic and conventional production systems. Acta Agriculturae Scandinavica, Section A, Animal Science 60, 65-73. III. Ahlman, T., Berglund, B., Rydhmer, L., Strandberg, E. (2010). Culling reasons in organic and conventional dairy herds and genotype by environment interactions for longevity. (Submitted to Journal of Dairy Science).
Place of Publication:Uppsala
ISBN for printed version:978-91-576-7472-2
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:dairy cows, organic husbandry, organic agriculture, animal performance, milk production, fertility, reproduction, somatic cell count, longevity, culling, selection criteria, genotype environment interaction, genetic correlation
Keywords:organic production, milk production, fertility, reproduction, somatic cell count, longevity, culling, cow, cattle
URN:NBN:urn:nbn:se:slu:epsilon-3098
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-3098
ID Code:2354
Department:(VH) > Dept. of Animal Breeding and Genetics
Deposited By: Therese Ahlman
Deposited On:23 Sep 2010 00:00
Metadata Last Modified:02 Dec 2014 10:17

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