390 likes | 395 Views
History of Jersey Young-Sire Development Programs in the United States. H. DUANE NORMAN Animal Improvement Programs Laboratory http://aipl.arsusda.gov Agricultural Research Service, USDA Beltsville, MD 20705-2350 dnorman@aipl.arsusda.gov 301-504-8334. Why Attend?.
E N D
History of JerseyYoung-Sire Development Programs in the United States H. DUANE NORMAN Animal Improvement Programs Laboratory http://aipl.arsusda.gov Agricultural Research Service, USDA Beltsville, MD 20705-2350 dnorman@aipl.arsusda.gov 301-504-8334
Why Attend? • The future competitiveness of the breed will be determined primarily by the number and quality of young AI bull sampled. …
Two Key Questions • Should we be getting more bulls sampled? • Does there need to be any change in the quality of bulls sampled?
Successful progeny test (PT) • Selection of bulls with high pedigree merit • Early semen collection • Rapid semen distribution and use in milk-recorded herds • Daughters with unique ID, recorded pedigrees, and kept until milking
PT accuracy and impact • Accuracy of PT evaluations • Number of daughters • Daughter distribution across herds • Impact on genetic improvement • Number of bulls sampled • Intensity of culling of PT bulls
Data sources • National USDA database • ID information from DHI and breed associations • Bull entry into PT programs and semen distribution dates from NAAB
PT definitions • Bulls • U.S. AI organization • 10–29 months old at semen release • NAAB controller code between 1 and 222 • Daughters • Born 8–42 months after bull entered AI sampling • Usable 1st-lactation record • First 125 to calve in DHI herds
In a 1984 Jersey Journal: • The higher the percentage that Jersey dairyman breed to young bulls (even if this percentage is as high as 90%), the greater the genetic improvement you will make as a breed.
Why? • If you breed 90% to young bulls, the proven bulls will not be used widely, i.e. they’re primarily used to sire the next generation of young bulls entering AI.
Clarification of Hypothetical: • Question: Why does genetic progress continue to increase as percentage bred to young bulls increases to 90%. • Answer: Because you can sample more young bulls. You sample 6X as many bulls with 90% PT use as you can with 15% PT use.
Conclusions • Little change in age of PT bull at semen release • Decrease in age of PT bulls at daughter birth (4.5 mo for Holsteins and Jerseys) • Taking longer than Holsteins by 2 months to get semen used. HELP here!
Conclusions • Decrease in age of PT bulls at daughter calving (5 to 6 mo) OK here • Number of PT daughters up some. Better to increase a little yet. HELP here!
Conclusions • More education on expectation from young PT bulls. Most people underestimate the value of high pedigree indexed young bulls. HELP here!
PT Active AI? Conclusions (continued) • 1 in 5 PT Jerseys returned to active service compared with 1 in 7 Holsteins, but not 1 in 10 as often floated
Objectives • Summarize characteristics of PT programs related to effectiveness and timeliness • Examine distribution of PT daughters • Determine selection intensity after evaluation of PT bulls