Evaluation of selection response of growth and reproduction traits in different out scaled bonga sheep community based breeding programs in kaffa zone, ethiopia

Abstract

The aim of the study was to evaluate genetic improvement and farmers perception in the outscaled Bonga sheep community-based breeding programs (CBBPs) cooperatives. Body weights, average daily gain (ADG) and reproduction traits data collected between 2012 and 2018 from 14 out scaled Bonga sheep CBBPs and survey data collected from 322 households’ interview and 43 focus group discussion of 7 communities (both CBBP participant and non-participant), were used for evaluation and farmer perception studies, respectively. Phenotypic performance was analyzed using the GLM procedures of SAS. Genetic parameters by univariate, bivariate, multivariate model for body weights, ADGs traits and age at first lambing (AFL), and repeatability models for lambing interval (LI) and litter size (LS) traits were undertaken by restricted maximum likelihood method with an animal model using WOMBAT software. Best model was chosen based on both likelihood ratio test (LRT) and Akakie information criteria (AIC). The overall least square mean ± SE of body weights in kg was 3.13±0.01, 16.07±0.07, 24.7±0.2, 30.4±0.4 and 34.04±0.84 for birth weight (BWT), weaning weight (WWT), six-month weight (SMWT), nine-month weight (NMWT) and yearling weight (YWT) respectively. For ADG from birth to weaning (ADG1), ADG from weaning to six-month (ADG2), ADG from six-month to nine-month (ADG3) and ADG from nine-month to yearling weight (ADG4) of the breed was 141.9±0.8, 98.65±2.4, 87.6±4.3 and 58.7±8.5gm/day, respectively. Also, reproductive traits of AFL, LI, annual reproductive rate (ARR), and LS least square mean ± SE was 375.2±12.5, 283.5±9.9, 2.31±0.05 and 1.45±0.01, respectively. Direct heritability estimates of univariate analysis from selected models were 0.56±0.03, 0.36±0.03, 0.22±0.04, 0.17±0.07 and 0.13±0.15 for BWT, WWT, SMWT, NMWT and YWT respectively. Similarly, for AFL, LI and LS were 0.07±0.19, 0.06±0.1, and 0.18±0.07. All studied traits have good response to selection except LS. SMWT is the selection trait and show positive trend for 11 CBBPs but negative trends for 3 of the CBBPs. Average inbreeding coefficient of Bonga sheep was 0.36% with 0.13% annual trend and 17% of amongst inbred animals. Implication of the result to future improvement program was continue selection, incorporate maternal line selection and consider her effect, conservation of prolific flocks, expanding the CBBP and continue market linkage. WWT and SMWT heritability values and importance of these traits approved the best option for selection age. Moderate to high estimated heritability and positive genetic trends indicated scope for further improvement of body weights and positive medium to high correlation among body weight expect correlated response. Further awareness creation on top ram using for those 3 CBBPs, strengthen rotation of top ram among and within CBBP cooperative to protect inbreeding, and always use breeding value for ram selection are among recommendations