title: Causes of culling in dairy cows and its relation to age at culling and interval from calving in Shiraz, Southern Iran.
abstract: This study was designed to investigate causes of culling in industrial dairy herds in Fars province and to describe the pattern of reason-specific culling with respect to age of animal and interval from calving to culling. A total number of 9 dairy herds were selected for the study and information about culling reasons, birth date, last calving date and culling date was collected for culled cows during 2005-2006. Infertility (32.6% of all culls) was the most prevalent reason of culling followed by mastitis (6.5%). The time interval from last calving to culling averaged 240 days (SD = 176) and nearly 28% of cows were culled in the first 100 days after calving. Mean age of animals at culling was 6 years (SD = 2.7) and median was 5.7 years. In Cox proportional hazard model for calving to culling interval, infertility (hazard ratio [HR] = 0.26) showed lower risk whereas mastitis (HR = 2.40), left displaced abomasum (HR = 2.60) and peripartum problems (HR = 2.60) had higher risk of culling compared with voluntary cull. In the Cox model for age at culling, risk of culling was significantly higher for infertility (HR = 1.70), left displaced abomasum (HR = 3.15), and peripartum problems (HR = 2.10) compared with voluntary culling. In conclusion, farmers tend to keep infertile cows for longer period from calving to culling while infertile cows are generally culled at younger age. Also, early culling appeared to have a high proportion of culls in the studied herds.
authors: Department of Food Hygiene and Public Health, School of Veterinary Medicine, Shiraz University, Shiraz, Iran;
authors: Maryam
authors: M
authors: Ansari-Lari
authors: Department of Animal Health Management, School of Veterinary Medicine, Shiraz University, Shiraz, Iran;
authors: Mehdi
authors: M
authors: Mohebbi-Fani
authors: Department of Internal Medicine, School of Veterinary Medicine, Islamic Azad University, Kazeroon Branch, Kazeroon, Iran.
authors: Abbas
authors: A
authors: Rowshan-Ghasrodashti
keywords: Cox model; Culling; Dairy herds; Infertility; Iran
references: Aust Vet J. 1998 Jul;76(7):482-8
references: 9700403
references: Vet Rec. 1997 Jan 11;140(2):36-9
references: 9123795
references: Prev Vet Med. 1998 Oct 9;36(4):257-71
references: 9820887
references: J Dairy Sci. 1998 Apr;81(4):966-78
references: 9594385
references: Reprod Domest Anim. 2007 Sep;42 Suppl 2:17-23
references: 17688598
references: Prev Vet Med. 1999 Jul 20;41(2-3):195-208
references: 10448946
references: J Dairy Sci. 2001 Oct;84(10):2327-35
references: 11699466
references: J Dairy Sci. 2004 Jul;87(7):2130-5
references: 15328226
references: J Dairy Sci. 2011 Mar;94(3):1568-75
references: 21338822
references: J Dairy Sci. 2011 Apr;94(4):1831-8
references: 21426972
references: Vet J. 2011 May;188(2):216-20
references: 20457532
references: J Dairy Sci. 1998 Aug;81(8):2299-305
references: 9749397