ARS | Publication request: DISPOSAL REPORTING AND DISPOSITION OF CULLED COWS BY PARITY AND IN HERDS OF DIFFERENT SIZES

Submitted to: Journal of Dairy Science
Publication Type: Abstract
Publication Acceptance Date: February 28, 2005
Publication Date: July 24, 2005
Citation: Sanders, A.H., Norman, H.D. 2005. Disposal reporting and disposition of culled cows by parity and in herds of different sizes [abstract]. Journal of Dairy Science. 88(Suppl. 1):219-220.

Technical Abstract: Termination code is used to record completion of lactations, transfer, death, or reason for disposal for lactation records in the national dairy production database. The purpose of this study was to investigate the disposition of culled cows, by parity and for herds of different sizes, using termination codes. The latest available records for 8 million cows calving since 1998 were examined. Of these, 2.4 million were current records likely still in progress and 400,000 are for cows sold for dairy to herds not participating in DHIA testing. Disposal codes were available for 3.2 million cows in first through fifth parities from 1998 through 2004. Cow disposal records were paired with herd test records from the time of disposal, and difference from herd average for lactation milk and protein yields and average somatic cell score (SCS) were calculated. For cows culled for low production, milk yield was 2% less and protein yield was 4% less than herd average. In contrast, other cows had 4% higher milk yield and 2% higher protein yield than herd average in the lactation coded with disposal. Cows culled for mastitis or high SCS had SCS 22% above herd average. Other cows coded with disposal also had SCS greater than herd average, but only by 5%. For cows disposed of with at least 50 days open, those culled for reproduction had 246 days open, while others had only 165. Reproductive problems and low production were the most common reasons given for culling in first parity while mastitis or high SCS was the most common reason given in third parity and later. Yearly culling rates by termination code were calculated for 40,867 herd-years from 2000-2003, averaging >=80% records passing edits and having >=10 test days, by herd size. Overall, 33% of cows per herd-year had terminal records and 80% of these included an indication of disposition. Reporting was similar across years and herd sizes. Distribution of disposals was fairly constant across herd sizes; however, deaths and culling for low production were more common in larger herds while culling for reproductive problems was more common in smaller herds. These results indicate that termination codes can be useful indicators for several important traits.