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Selection, maternal effects and inbreeding in reindeer husbandry

Rönnegård, Lars (2003). Selection, maternal effects and inbreeding in reindeer husbandry. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae. Agraria, 1401-6249 ; 370
ISBN 91-576-6400-5
[Doctoral thesis]

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Abstract

In extensive grazing systems where several owners’ flocks are allowed to mix, selection strategies will also interact, due to gene flow between flocks. The aim of the thesis was to analyse breeding schemes in terms of genetic gain and rate of inbreeding (ΔF), given the complexity of ownership and interaction of selection strategies within a mixing reindeer population. The data, collected between 1986 and 1997 in the reindeer herding district of Ruvhten Sijte, Sweden, comprised 12,500 records of autumn calf weights. The mean phenotypic difference in calf weights between selected and non-selected flocks was 0.67 kg after 11 years of selection in Ruvhten Sijte. The genetic difference was 0.35 kg and the realized heritability was 0.2. Based on the realized heritablility, it was shown that if all owners had applied selection, the genetic response would have been 2 kg (corresponding to an annual genetic gain of 0.4% of the phenotypic mean, including the initial lag due to age structure). The relationships between life-time patterns of female weight, calving incidence and offspring weight were examined. A female rearing a calf was shown to weigh 3.1 kg less in winter than one not rearing a calf. The regression coefficient of calf autumn weight on female weight the previous winter was 0.26. Detailed life-history patterns were obtained for females aged 1 – 15 years. The expected long-term genetic contribution method to predict genetic gain and ΔF in selected populations was developed to include maternal effects. It was shown that variation in inherited maternal effects influences ΔF more than does variation in non-inherited maternal effects. Furthermore, population structures affect ΔF much more when there are maternal effects, than direct genetic effects alone, especially in populations with large family size. This method was used to evaluate different selection schemes in reindeer husbandry, with different proportions of a population included in each scheme. It was shown that for reindeer population sizes greater than 2,000 there is no risk of inbreeding effects.

Authors/Creators:Rönnegård, Lars
Title:Selection, maternal effects and inbreeding in reindeer husbandry
Year of publishing :February 2003
Volume:370
Number of Pages:32
Papers/manuscripts:
NumberReferences
ALLI. Rönnegård, L. & Danell, Ö. 2001. Gene flow and potential selection response in age-structured subpopulations having a common male pool. Animal Science 72: 427-440. II. Rönnegård, L. Forslund, P. & Danell, Ö. 2002. Lifetime patterns in adult female mass, reproduction and offspring mass in semidomesticated reindeer (Rangifer tarandus tarandus). Canadian Journal of Zoology 80:2047-2055. III. Rönnegård, L. & Danell, Ö. 2003. Genetic response to selection on reindeer calf weights. Rangifer (in press). IV. Rönnegård, L. & Woolliams, J.A. 2003. Predicted rates of inbreeding with additive maternal effects. Genetical Research (Submitted for publ.). V. Rönnegård, L., Woolliams, J.A. & Danell, Ö. 2003. Breeding schemes in reindeer husbandry (Submitted for publ.).
Place of Publication:Uppsala
ISBN for printed version:91-576-6400-5
ISSN:1401-6249
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:L Animal production > L10 Animal genetics and breeding
Subjects:Not in use, please see Agris categories
Agrovoc terms:reindeer, animal breeding, gene flow, random mating, breeding methods, genetic inheritance, population structure, extensive husbandry, sweden
Keywords:breeding programme, communal grazing, randombred populations, Rangifer tarandus tarandus, semidomestic reindeer, gene flow
URN:NBN:urn:nbn:se:slu:epsilon-8
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-8
ID Code:156
Department:(NL, NJ) > Institutionen för husdjursgenetik (fr.o.m. 960101)
Deposited By: Lars Rönnegård
Deposited On:14 Feb 2003 00:00
Metadata Last Modified:02 Dec 2014 10:01

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