Genetic diversity of sires used in the Irish dairy industry Maintenance of genetic diversity in the Irish dairy industry is one of the driving motivations for having a nationally co-ordinated progeny test structure. This paper reports on analysis of co-ancestry and inbreeding trends between and among cohorts of bulls with progeny in Ireland over the past 15 years. The cohorts include bulls used widely and not included in the progeny test, bulls sourced from Ireland included in the progeny test, foreign sourced bulls included in the progeny test, and those foreign bulls not included in the progeny test. Average co-ancestry for these bulls with subsets of the cow population are also presented. The cow population is divided into those herds who have had a contract mating organised with an artificial insemination breeding company at least once in their history, versus those that have not. Fiona Hely, Francis Kearney, Andrew Cromie, Daragh Matthews and Peter Amer
Background Gene Ireland progeny test program launched in 2005 Objective to identify superior young bull candidates Panels of around 70 bulls are evaluated every year Each bull to have 100 heifer replacements recorded in 100 herds by year 4 Genomic evaluations first launched in 2009
Introduction to analysis Does the Gene Ireland progeny test program help maintain diversity Understand relationships between and within bull types
Data analysed Pedigree for Holstein Friesian milking animals Extracted pedigree of around 6.1M animals Focus on cows from 1997 onwards CFC software by Sargolzaei et al.
Dairy bull categories Male calf registration list Contract matings Progeny test panel Active AI List Elite bulls What are the Objectives of the G€N€ IR€LAND® Dairy Programme? The objective of the Gene Ireland Dairy programme is to test 60-70 bulls each year and that each bull would have 100 heifer replacements recorded in 100 herds, by year 4 of the programme. Gene Ireland Dairy is focused on three key areas: The selection of high EBI young bulls. 2. Progeny testing the young bulls on a “Targeted” set of herds. 3. Elite bulls are returned to AI. Imported foreign bulls
Dairy bull categories Imported foreign bulls Other Irish born bulls Male calf registration list Contract matings Progeny test panel Active AI List Elite bulls What are the Objectives of the G€N€ IR€LAND® Dairy Programme? The objective of the Gene Ireland Dairy programme is to test 60-70 bulls each year and that each bull would have 100 heifer replacements recorded in 100 herds, by year 4 of the programme. Gene Ireland Dairy is focused on three key areas: The selection of high EBI young bulls. 2. Progeny testing the young bulls on a “Targeted” set of herds. 3. Elite bulls are returned to AI. Imported foreign bulls
Dairy bull categories Group Irish Born Foreign Born Progeny Test PT IRL PT FOR Other O IRL O FOR Focus on bulls contributing to the top 80% of inseminations 88 bulls for progeny test inseminations (~3M) 151 bulls for other bull inseminations (~1.8M)
Progeny by bull type
Progeny by bull type PT launch
Progeny by bull type 2005 PT bulls used at 4 years old PT launch
Progeny by bull type 2005 PT bulls used at 4 years old Genomic proofs PT launch
Progeny by bull type
Relationship within category
Relationship between groups Other Irish bulls were least related to all other widely used bull types Other Foreign bulls had a higher relationship between groups Average relationship PT IRL PT FOR O IRL O FOR 0.069 0.051 0.082 0.035 0.026 0.12 0.06 0.065 0.038 0.089
Relationship between groups Other Irish bulls were least related to all other widely used bull types Other Foreign bulls had a higher relationship between groups Average relationship PT IRL PT FOR O IRL O FOR 0.069 0.051 0.082 0.035 0.026 0.12 0.06 0.065 0.038 0.089
Relationship between groups Other Irish bulls were least related to all other widely used bull types Other Foreign bulls had a higher relationship between groups Average relationship PT IRL PT FOR O IRL O FOR 0.069 0.051 0.082 0.035 0.026 0.12 0.06 0.065 0.038 0.089
Relationships with cow cohorts O FOR
Relationships with cow cohorts O FOR PT IRL
Relationships with cow cohorts O FOR PT FOR PT IRL
Relationships with cow cohorts O FOR PT FOR PT IRL O IRL
Relationships with cow cohorts O FOR PT FOR PT IRL O IRL Average relationship PT IRL PT FOR O IRL O FOR 0.069 0.051 0.035 0.06 0.082 0.026 0.065 0.12 0.038 0.089
Relationships with cow cohorts O FOR PT FOR PT IRL O IRL
Relationships with cow cohorts O FOR PT FOR PT IRL O IRL
Average inbreeding by category
Average progeny inbreeding O FOR
Average progeny inbreeding O FOR PT IRL
Average progeny inbreeding O FOR PT IRL O IRL
Average progeny inbreeding O FOR PT IRL O IRL PT FOR
Average progeny inbreeding O FOR PT IRL O IRL PT FOR
Take home messages Does the Gene Ireland progeny test program help maintain diversity? Lowest relationship within group Average relationship with cows reasonably steady Control of sire flows Potential to use genomic inbreeding measures to manage coancestry in progeny test candidates in the future
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