Performance evaluation of Bonga rams and their progenies in different agro-ecologies of southern Ethiopia

Abstract

Monitoring studies in four selected districts of southern Ethiopia were conducted from October 2016 and June 2017 on whole sampled households with general objective of evaluating performances of Bonga rams and its progenies in the areas. A total of 320 HH were considered purposively for the household survey and 382 pregnant ewes mated with either Bonga or local ram were monitored. Descriptive statistics and comparative means of data from survey were analyzed by using SPSS, 2011 ver. 20 and an index was used for qualitative data ranking. The growth performance data were subjected to Generalized Linear Model procedures of the SAS, 2012 ver. 9.3 and Tukey Kramer test was used to compare means which were significant in the least squares analysis of variance. The growth performances of Bonga cross were 2.9±0.2, 8±0.5, 11.4±0.6, 13±0.6 and 17.4±0.8 kg for birth, two, three, four and six months’ weights, respectively and average daily gain for pre-weaning and post-weaning (ADG) weights were 92.2±5.4 and 86±4 gm respectively. Whereas for local sheep the values were 2.4±0.2, 5.5±0.5, 8.3±0.6, 9.8±0.7, and 13±0.8 kg for birth, two, three, four and six months’ weights respectively, and average daily gain for preweaning and post-weaning ADG weights were 64.8±5.5 and 63.4±4 gm, respectively. Location (except 6-month weight), genetic group, parity (P<0.001) (except, 3, 4, 6-month weights and post-ADG), season of birth (except,6-month weight and post-ADG), birth type and sex had significant (P< 0.05 and P<0.001) effect on pre-weaning and post- weaning weights. The reproductive performances of average first service (AFS) for male, AFS for female, average fist lambing (AFL) and lambing interval (LI) for Bonga crosses were 5.9±0.8, 6.3±0.8, 11.5±0.9, and 7.5±0.7 months, respectively and for local sheep the values were 8.6±1.6, 8.6±1.5, 13.9±1.6 and 8.5±1.1 months, respectively. Average litter size (ALS) of ewes mated by Bonga and local ram were 1.75±0.3 and 1.46±0.5, respectively. The reproductive performances varied (P<0.001) among locations. The survival rate of Bonga rams at Arbegona, Ezha, Damot Pulasa and Alicho Worero were 93.3, 89.3, 97.2 and 95.2% respectively. The pre and post weaning mortality rate for Bonga cross lambs at Alicho Worero (4.8 and 2.5 %), Ezha (2.1 and 0 %), Arbegona (1.1 and 1.1%) and Damot Pulasa (1.6 and 0 %), respectively significantly (P<0.001) lower than local sheep in the areas. The Bonga sheep crosses as well as rams, highly adapted to locally available feeds and waters; tolerant to disease and parasite load in the areas. The overall average body condition score (BCS) scrotal circumference (SC) and body weight of Bonga sires in the disseminated areas were 3.7, 31 cm and 51.8kg, respectively.