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http://dx.doi.org/10.5713/ajas.18.0553

Evaluation of selection program by assessing the genetic diversity and inbreeding effects on Nellore sheep growth through pedigree analysis  

Illa, Satish Kumar (Network Project on Sheep Improvement, Livestock Research Station, Palamaner, Sri Venkateswara Veterinary University)
Gollamoori, Gangaraju (Network Project on Sheep Improvement, Livestock Research Station, Palamaner, Sri Venkateswara Veterinary University)
Nath, Sapna (Indian Council of Agricultural Research, National Dairy Research Institute, Division of Animal Production, Southern Research Station)
Publication Information
Asian-Australasian Journal of Animal Sciences / v.33, no.9, 2020 , pp. 1369-1377 More about this Journal
Abstract
Objective: The main objectives of the present study were to assess the genetic diversity, population structure and to appraise the efficiency of ongoing selective breeding program in the closed nucleus herd of Nellore sheep through pedigree analysis. Methods: Information utilized in the study was collected from the pedigree records of Livestock Research Station, Palamaner during the period from 1989 to 2016. Genealogical parameters like generation interval, pedigree completeness, inbreeding level, average relatedness among the animals and genetic conservation index were estimated based on gene origin probabilities. Lambs born during 2012 and 2016 were considered as reference population. Two animal models either with the use of Fi or ΔFi as linear co-variables were evaluated to know the effects of inbreeding on the growth traits of Nellore sheep. Results: Average generation interval and realized effective population size for the reference cohort were estimated as 3.38±0.10 and 91.56±1.58, respectively and the average inbreeding coefficient for reference population was 3.32%. Similarly, the effective number of founders, ancestors and founder genome equivalent of the reference population were observed as 47, 37, and 22.48, respectively. Fifty per cent of the genetic variability was explained by 14 influential ancestors in the reference cohort. The ratio fe/fa obtained in the study was 1.21, which is an indicator of bottlenecks in the population. The number of equivalent generations obtained in the study was 4.23 and this estimate suggested the fair depth of the pedigree. Conclusion: Study suggested that the population had decent levels of genetic diversity and a non-significant influence of inbreeding coefficient on growth traits of Nellore lambs. However, small portion of genetic diversity was lost due to a disproportionate contribution of founders and bottlenecks. Hence, breeding strategies which improve the genetic gain, widens the selection process and with optimum levels of inbreeding are recommended for the herd.
Keywords
Founders; Inbreeding Coefficient; Nellore Sheep; Pedigree Analysis;
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  • Reference
1 Livestock Census [internet]. Krishi Bhawan, New Delhi, India: Ministry of Agriculture Department of Animal Husbandry, Dairying and Fisheries India; 2012 [cited 2020 May 19]. http://livestockcensus.gov.in/
2 Naqvi SMK, Gowane GR. Conservation and genetic improvement of sheep in relation to rural livelihood security. In: X National Symposium on Integrated Development of Vast Biodiversity of Indigenous Livestock for Long Term Rural Livelihood Security; 2013 Feb 7-8; Pantnagar, India. pp. 31-8.
3 Gutierrez JP, Goyache F. A note on ENDOG: a computer program for analysing pedigree information. J Anim Breed Genet 2005;122:172-6. https://doi.org/10.1111/j.1439-0388.2005.00512.x   DOI
4 Meuwissen THE, Luo Z. Computing inbreeding coefficients in large populations. Genet Sel Evol 1992;24:305. https://doi.org/10.1186/1297-9686-24-4-305   DOI
5 Lacy RC. Analysis of founder representation in pedigrees: founder equivalents and founder genome equivalents. Zoo Biol 1989;8:111-23. https://doi.org/10.1002/zoo.1430080203   DOI
6 Gonzalez-Recio O, Lopez de Maturana E, Gutierrez JPJ. Inbreeding depression on female fertility and calving ease in Spanish dairy cattle. J Dairy Sci 2007;90:5744-52. https://doi.org/10.3168/jds.2007-0203   DOI
7 Gutierrez JP, Cervantes I, Molina A, Valera M, Goyache F. Individual increase in inbreeding allows estimating realized effective sizes from pedigrees. Genet Sel Evol 2008;40:359. https://doi.org/10.1186/1297-9686-40-4-359
8 Cervantes I, Goyache F, Molina A, Valera M, Gutierrez JP. Application of individual increase in inbreeding to estimate realized effective sizes from real pedigrees. J Anim Breed Genet 2008;125:301-10. https://doi.org/10.1111/j.1439-0388.2008.00755.x   DOI
9 Hill WG. A note on effective population size with overlapping generations. Genetics 1979;92:317-22.   DOI
10 Ghafouri-Kesbi F. Using pedigree information to study genetic diversity and re-evaluating a selection program in an experimental flock of Afshari sheep. Arch Anim Breed 2012;55:375-84. https://doi.org/10.5194/aab-55-375-2012   DOI
11 Food and Agriculture Organization (FAO). Secondary guidelines for development of national farm animal genetic resources management plans [cited 2015 Oct 9]. In: Woolliams JA, Gwaze GP, Meuwissen THE, et al. Management of small population at risk. Rome, Italy: Food and Agriculture Organization of the United Nations. Available from: http://www.fao.org/ag/againfo/programmes/es/lead/toolbox/Indust/sml-popn.pdf
12 Kumar S, Kumar V, Gangaraju G, Nath S, Thiruvenkadan AK. Estimates of direct and maternal (co)variance components as well as genetic parameters of growth traits in Nellore sheep. Trop Anim Health Prod 2017;49:1431-8. https://doi.org/10.1007/s11250-017-1344-2   DOI
13 SPSS. SPSS for Windows, Brief Guide, Version 14.0. Chicago, IL, USA: SPSS Inc.; 2005.
14 Ghafouri-Kesbi F. Analysis of genetic diversity in a close population of Zandi sheep using genealogical information. J Genet 2010;89:479. https://doi.org/10.1007/s12041-010-0068-0
15 Ballou JD, Lacy RC. Identifying genetically important individuals for management of genetic variation in pedigreed populations. In: Ballou JD, Gilpin M, Foose TJ, editors. Population management for survival and recovery. New York, NY, USA: Columbia University Press; 1995. pp. 76-111.
16 Frankham R. Conservation genetics. Annu Rev Genet 1995;29:305-27. https://doi.org/10.1146/annurev.ge.29.120195.001513   DOI
17 Goyache F, Gutierrez JP, Fernandez I, et al. Using pedigree information to monitor genetic variability of endangered populations: the Xalda sheep breed of Asturias as an example. J Anim Breed Genet 2003;120:95-105. https://doi.org/10.1046/j.1439-0388.2003.00378.x
18 Mokhtari MS, Shahrbabak MM, Esmailizadeh AK, Shahrbabak HM, Gutierrez JP. Pedigree analysis of Iran-Black sheep and inbreeding effects on growth and reproduction traits. Small Rumin Res 2014;116:14-20. https://doi.org/10.1016/j.smallrumres.2013.10.008   DOI
19 Caballero A, Toro MA. Interrelations between effective population size and other pedigree tools for the management of conserved populations. Genet Res 2000;75:331-43.   DOI
20 Maignel L, Boichard D, Verrier E. Genetic variability of French dairy breeds estimated from pedigree information. Proceedings of the open session of the Interbull annual meeting; 1996 Jun 23-24; Veldhoven, The Netherlands. 1996;14:49.
21 Gowane GR, Chopra A, Misra SS, Prince LLL. Genetic diversity of a nucleus flock of Malpura sheep through pedigree analyses. Small Rumin Res 2014;120:35-41. https://doi.org/10.1016/j.smallrumres.2014.04.016   DOI
22 Gowane GR, Prakash V, Chopra A, Prince LLL. Population structure and effect of inbreeding on lamb growth in Bharat Merino sheep. Small Rumin Res 2013;114:72-9. https://doi.org/10.1016/j.smallrumres.2013.06.002   DOI
23 Pedrosa VB, Santana Jr, ML, Oliveira PS, Eler JP, Ferraz JBS. Population structure and inbreeding effects on growth traits of Santa Ines sheep in Brazil. Small Rumin Res 2010;93:135-9. https://doi.org/10.1016/j.smallrumres.2010.05.012   DOI
24 Mokhtari MS, Shahrbabak MM, Esmailizadeh AK, Abdollahi-Arpanahi R, Gutierrez JP. Genetic diversity in Kermani sheep assessed from pedigree analysis. Small Rumin Res 2013;114:202-5. https://doi.org/10.1016/j.smallrumres.2013.07.001   DOI
25 Oravcova M, Krupa E. Pedigree analysis of the Former Valachian sheep. Slovak J Anim Sci 2011;44:6-12.
26 Boichard D, Maignel L, Verrier E. The value of using probabilities of gene origin to measure genetic variability in a population. Genet Sel Evol 1997;29:5. https://doi.org/10.1186/1297-9686-29-1-5
27 Barros EA, Brasil LDA, Tejero JP, Delgado-Bermejo JV, Ribeiro MN. Population structure and genetic variability of the Segurena sheep breed through pedigree analysis and inbreeding effects on growth traits. Small Rumin Res 2017;149:128-33. https://doi.org/10.1016/j.smallrumres.2017.02.009   DOI
28 Vozzi PA, Marcondes CR, Bezerra LAF, Lobo RB. Pedigree analyses in the breeding program for Nellore cattle. Genet Mol Res 2007;6:1044-50.
29 Alderson GLH. A system to maximize the maintenance of genetic variability in small populations. In: Alderson L, Bodo L, editors. Conservation of domestic livestock. Wallingford, UK: CAB International; 1992. pp. 18-29.