Opportunities of Genomic Selection in the Improvement of Dairy Cattle Productivity: A Review

This review is aimed to summarize and synthesize the fragmented information in the area of genomic selection in the improvement of productivity in dairy cattle. Genomic selection has been a valuable tool for increasing the rate of genetic improvement with reduced generation interval. In addition, it can be used for selection based on genomic breeding values at an early age for superior breed with great accuracy resulting in enhanced productivity of dairy cattle populations. Genomic selection is particularly used to improve those traits with low-heritability values such as feed efficiency, reproductive traits, especially fertility including adaptation traits. The implementation of genomic selection in developed countries mainly uses purebred and hybrid of Bos taurus cattle. Most studies have found that genomic evaluation of pure breeds that serve as a large reference population for high milk production in dairy cows can bring more benefits. Since, most of the research works have been conducted using Bos taurus cattle, research focusing on the application of genomic selection on Bos indicus cattle is needed to evaluate its impact on the productivity of tropical cattle breeds. Keywords: Dairy cattle, genomic selection, productivity, genetic improvement DOI: 10.7176/ALST/98-02 Publication date:June 30th 202

Characterization of the Indigenous Goat Populations of South Gonder Based on their Morphometric Traits and Body Indices

  አህፅሮት በዳሰሳ ላይ የተደገፈ ጥናት በደቡብ ጎንደር ዞን የሞርፎሜትሪክ ባህሪያት እና የአካል መረጃ ጠቋሚዎች መሠረት በማድረግ በአገር በቀል ፍየል የምርት አቅም ላይ የምርምር ሥራ ተካሂዷል፡፡ የፍየሎችን የርባታ ባህሪያትን በተመለከተ ከ153 አባወራዎች በመጠይቅ የተደገፈ መረጃ የተሰበሰበ ሲሆን፤ የሞርፎሜትሪክ ባህሪያት መለኪያዎች ከፋርጣ ወረዳ 152፤ ከፎገራ ወረዳ 154፤ እና ከሊቦ ከምከም ወረዳ 204 በአጠቃላይ ከሁለቱም ፆታዎች በ510 ፍየሎች ላይ መረጃ ተወስዷል፡፡ በዚሁ መሠረት 19 የፍየል አካላት መለኪያ ኢንዴክሶች የሞሮፎሞትሪክ ባህሪያትን መሠረት በማድረግ ተሰልቷል፡፡ በጥናቱ በተገኘው ውጤት መሠረት የሴት ፍየሎች ለመጀሪያ ጊዜ የወለዱበት ዕድሜ 13.6 ወር ሲሆን በሁለት ወሊዶች መካከል ያለው ልዩነት 8.39 ወራት ነበር፡፡ ባንድ ጊዜ የተወለዱት የፍየል ግልገሎች መጠን 1.54 እንደሆነ ታውቋል፡፡ የፍየሎች ፆታ ከጀሮ ርዝመት፤ ከዳሌ ስፋት እና ከእግር አገዳ ቅልጥም ክብ ዙሪያ በሰተቀር በሌሎች ባህሪት ላይ ጉልህ ተፅዕኖ ነበረው (p<0.001)፡፡ በተጨማሪም ከጀሮ ርዝመት በሰተቀር የፍየሎች ዕድሜ በሁሉም የሞርፎሜትሪክ ባህሪያት ላይ የነበረው ተፅዕኖ ከፍተኛ ነበር (p<0.001)፡፡ የፎገራ ወረዳ ፍየሎች በክብደት፤ በደረት ክብ ዙሪያ፤ ከፊት እግር ጀርባ ቁመት፤ በአካል ርዝመት፤ በደርት ስፋት፤ ከኋላ እግር ፊት ቁመት፤ በዳሌ ርዝመት እና በጡት ርዝመት ከሊቦ ከምከም ወረዳ ፍየሎች የበለጡ ነበሩ፡፡ የሊቦ ከምከም ፍየሎች ከፎገራና ፋርጣ ፍየሎች ጋር ሲነፃፀሩ ጥናት በተደረገባቸው በአብዛኛዎቹ የሞርፎሜትሪክ ባህሪያት ዝቀተኛ እንደነበሩ ከጥናቱ የተገኘው ውጤት ያመላክታል፡፡ የደረት ክብ ዙሪያ እና የፊት እግር ጀርባ ቁመት ልኬቶች የሴት እና የወንድ ፍየሎችን የክብደት መጠን ለመተንበይ ቀዳማይ ባህሪያት እንደሆኑ ተለይተው ታውቀዋል፡፡ በተገኘው የፍየል አካላት መለኪያ ኢንዴክሶች መሠረት፤ የደቡብ ጎንደር ፍየሎች አጭር እግር ያላቸው እና ለወይና ደጋ አየር ንብረት የሚስማሙ ሲሆኑ ለስጋ ምርት አቅም እንዳላቸው ታውቋል፡፡ በማጠቃለያም፤ በደቡብ ጎንደር ዞን የሚገኙ አገር በቀል ፍየሎች ለስጋ ምርት እምቅ አቅም ሊኖራቻው እንደሚችል የጥናቱ ውጤት በጉልህ አመላክቷል፡፡   Abstract A survey-based study was undertaken to explore the potentials of indigenous goat populations of the South Gondar zone based on morphometric traits and body indices. Reproductive traits were obtained from 153 households through a questionnaire while morphometric measurements were taken from 510 goats of both sexes drawn from Farta (n=152), Fogera (n=154), and Libokemkem (n=204) districts. Nineteen structural and functional indices were computed from morphometric measurements. In this study, age at first kidding and kidding intervals was 13.6 and 8.39 months, respectively with an average litter size of 1.54. Sex had a significant (p<0.001) effect on all quantitative traits except ear length (EL), rump width, and canon circumference. Except for EL, the age effect was significant (p<0.001) for all morphometric traits. Goats at Fogera district had higher live weight (LW), heart girth (HG), height at withers (HW), body length, chest width, rump height, rump length, and teat length than those at Libokemkem. Goats from Libokemkem district were inferior for most of the studied morphometric traits as compared to those at Fogera and Farta. Both HG and HW were identified as best predictors of LW in both sexes. Based on the values of structural indices, the goat populations could be characterized as meat phenotype with short legs being well adapted to midland altitudes. In conclusion, goats reared in the South Gondar zone could have the genetic potential for meat production with high prolificacy