Document Type : Research Paper
Authors
Abstract
The present investigation was undertaken to study reason of culling, non genetic effects and genetic parameters of longevity with two method linear model and Weibull. A data set of information from Holstein dairy cows of Isfahan province (Iran) was used for this study. The culling date of 36340 animals from 65 herds recorded in 1993-2014 was used. From 33219 culled cows in these years were 27.9 and 72.1 percent for voluntary and involuntary culling respectively. Lifespan and Length of productive life (LPL) were analyzed for longevity. Functional productive life (FPL) was estimated by adjusting LPL for first lactation milk yield relative to herd average. The mean of lifespan and length of productive life were estimated to be 954 and 1710 (days) respectively. The results with GLM procedure showed that HYS and age at the first calving had significant on length of productive life. The results with Lifereg procedure with Weibull function showed that effects of herd, year of first calving (p
Keywords
1. دادار م، اسدیان ا، شرف ش و آقاشاهی ع (1386) بررسی عوامل مؤثر برصفات ماندگاری در گاوداری‌های صنعتی اصفهان. مجموعه مقالات دومین کنگره علوم دامی. کرج.
2. دادپسند طارمسری م، میرائی آشتیانی ر، مرادی شهربابک م و واعظ ترشیزی ر (1385) برآورد پارامترها و روند ژنتیکی طول عمر تولیدی گاوهای هلشتاین ایران با استفاده از مدل‌های تجزیه بقاء. علوم کشاورزی ایران. ۳۷(۴): ۷۳۷-۷۴۴.
3. روزبان جوانمردی ج و امینی زارع ر (1390) بررسی علل حذف در گاوداری های هلشتاین. وب سایت تخصصی صنایع غذایی.
4.زکی‌زاده س، ساور سلفی س و فروغی ع (1389) برآورد وراثت‌پذیری و بررسی عوامل مؤثر بر طول عمر واقعی و تولیدی گاوهای نژاد براون سوئیس. چهارمین کنگره علوم دامی ایران. کرج.
5. عبدالمحمدی ع، مرادی شهربابک م، میرائی آشتیانی ر و صیادنژاد م (1383) برآورد پارامترهای ژنتیکی طول عمر تولیدی و ارتباط آن با صفات تولیدی در گاوهای هلشتاین. مجموعه مقالات اولین کنگره علوم دامی. کرج.
6. وطن‌خواه م (1389) تجزیه زنده‌مانی بره‌های لری بختیاری از تولد تا سن یک‌سالگی. گزارش نهایی پروژه تحقیقاتی. مرکز تحقیقات کشاورزی و منابع طبیعی استان چهارمحال و بختیاری. مؤسسه تحقیقاتی علوم دامی کشور.
7. Berglund B (2008) Genetic improvement of dairy cow reproductive performance. Reproduction in Domestic Animal. 43(2): 89-95.
8. Bond K (2013) Culling factors and culling management strategies on dairy farms. Available at: http://www.cpd-solutions.com
- 9. Caraviello DZ, Weigel KA and Gianola D (2004) Comparison between a Weibull proportional hazard model and linear model for predicting the genetic merit of us jersey sires for daughter longevity. Journal of Dairy Science. 87: 1469-1476.
- 10. Dkkers JCM (1993) Theoretical basis for genetic parameters of herd life and effects on response to selection. Journal of Dairy Science. 76: 1433-1443.
- 11. Egger-Danner C (2015) Invited review: overview of new traits and phenotyping strategies in dairy cattle with a focus on functional traits. Animal. 9(2): 191-207.
- 12. Forbes D, Gayton S and Mckeogh B (1999) Improving the longevity of cows in the UK dairy herd. Report for the Milk Development Council on the results of the longevity project.
- 13. Hare E, Norman HD and Wright JR (2006) Survival rates and productive herd life of dairy cattle in the United States. Journal of Dairy Science. 89: 3713-3720.
- 14. Meyer K (2007) Wombat version 1.0 user notes. Uni New England. Armidale. NSW. Asturalia.
- 15. Pachova E, ZavaDilova E and Solkner J (2005) Genetic evaluation of length of productive life in Holstein cattle in the Czech Republic. Czech Journal of Animal Science. 50: 493-498.
- 16. SAS (1996) Release 6.11, SAS Institute Inc., Cary, North Carolina, USA.
- 17. Sewalem A, Kistemarker GJ, Ducrocq V and Van Doormaal BJ (2005) Genetic analysis of herd life in Canadian dairy cattle one lactation basis using a weibull proportional hazard model. Journal of Dairy science. 88: 365-375.
- 18. Van Doormaal B (2009) A closer look at longevity. Canadian Dairy Network. Available at: http://www. cdn-ca.
- 19. Vollema AR and Groen AF (1998) A comparison of breeding value predictors for longevity using a linear model and survival analysis. Journal of Dairy Science. 81: 3315-3320.
- 20. Vukasinovic N, Moll J and Kunzi N (1995) Genetic relationships among longevity, milk production, and type traits in Swiss Brown cattle. Livestock Production Science. 41: 11-18.
- 21. Wang T, Fernando RL and Kachman SD (2002) Matvec User’s Guide. Version 1.03. Available: http://statistics.unl.edu/faculty/steve/software/matvec/.
- 22.Yazdi MH, Visscher PM, Duccroq V and Thompson R (2002) Heritability, reliability of genetic evaluations and response to selection in proportional hazard models. Journal of Dairy Science. 85: 1563-1544.
)