Evaluating long term benefits of genomic selection programs in beef cattle breeding programs in Western Canada
| dc.contributor.advisor | Lardner, Dr. Bart | |
| dc.contributor.committeeMember | Larson, Kathy | |
| dc.contributor.committeeMember | Campbell, Dr. John | |
| dc.contributor.committeeMember | Moya, Dr. Diego | |
| dc.contributor.committeeMember | Asai-Coakwell, Dr. Mika | |
| dc.contributor.committeeMember | Penner, Dr. Greg | |
| dc.contributor.committeeMember | de Silva, Dr. Gleise | |
| dc.creator | Mills, Tess | |
| dc.date.accessioned | 2024-05-03T21:35:58Z | |
| dc.date.available | 2024-05-03T21:35:58Z | |
| dc.date.copyright | 2024 | |
| dc.date.created | 2024-04 | |
| dc.date.issued | 2024-05-03 | |
| dc.date.submitted | April 2024 | |
| dc.date.updated | 2024-05-03T21:35:58Z | |
| dc.description.abstract | A study was conducted to evaluate long-term benefits of genomic selection programs in natural service multi-sire breeding programs in Western Canada. A total of 24 breeding groups and 117 sires (some repeated) were followed over 6 breeding and calving years to determine the association between sire performance over multiple years, number of calves sired, calf performance, and replacement heifer performance over multiple years. To evaluate sire performance and account for the different numbers of cows and sires in each breeding group, bull prolificacy indexes (BPI) were calculated. BPI ranged from 0-4 and sires were categorized based on BPI for analysis with groups representing bottom 25% of sires BPI, middle 50%, and top 25%. Age of sires influenced sire prolificacy between yearlings, 2-year-olds, and mature sires. Twenty sires were used for 3 or more years of breeding and performance was not found to be repeatable across years. Genomic testing (EnVigour HX™, Delta Genomics, Edmonton, Alberta, Canada) was performed in two years of the six year study. EnVigour HX™ testing provided vigour scores and breed composition of the animals tested. The 2018 heifers from the cooperating producer had an average vigour score (VS) of 69% with a standard deviation of 10.5% and range of 66% with most calves having 5 breeds detected. The 2019 heifers from the cooperating producer had an average VS of 75% with a standard deviation of 11.5% and range of 58 percent. Replacement heifers produced from targeted sires in 2015 were evaluated for 1 to 3 breeding and calving seasons to evaluate grand-calf performance. A total of 16 sires produced the 74 heifers selected for replacement in 2015. A total of 171 calves were produced from the 2015-born replacement heifers between the 2018-2020 calving seasons. The top 25% of sires, based on BPI, had a higher proportion of replacement heifers retained in 2015, and therefore more grand-calves attributed to them. The bottom 25% of sires had a greater number of heifers retained over multiple calving seasons compared to the middle and top groups. Heifers born in the first 21d of the calving season tended to have more calves also born in the first cycle (R2 = 0.5239). Calving interval tended to decrease as a heifer matured across three calving cycles. There is a benefit of informed sire selection using DNA parentage. The data can help improve overall calf numbers and improve replacement heifer performance in the herd. A two-year net return analysis of using EnvigourHXTM testing in the herd was performed based on differences between low vigour score and high vigour score heifers. Total kg weaned over two parturitions was valued based on CanFax reported average market prices for 182kg steers in October 2020 and 205kg steers in October 2021. Based on cost of testing and total return there was a loss of $3,409 for the operation. Longer term analysis will need to be performed to see if costs can be recouped for genomic testing on a commercial operation. | |
| dc.format.mimetype | application/pdf | |
| dc.identifier.uri | https://hdl.handle.net/10388/15663 | |
| dc.language.iso | en | |
| dc.subject | Beef Cattle | |
| dc.subject | Parentage | |
| dc.subject | DNA | |
| dc.subject | multi-sire breeding | |
| dc.title | Evaluating long term benefits of genomic selection programs in beef cattle breeding programs in Western Canada | |
| dc.type | Thesis | |
| dc.type.material | text | |
| thesis.degree.department | Animal and Poultry Science | |
| thesis.degree.discipline | Animal Science | |
| thesis.degree.grantor | University of Saskatchewan | |
| thesis.degree.level | Masters | |
| thesis.degree.name | Master of Science (M.Sc.) |