Comparison of Productivity and Management Practices on Dairy Herd Improvement Association (DHIA) and Non-DHIA Herds in the United States

Abstract Text: The objective of this investigation was to compare productivity and management practices between DHIA and non-DHIA herds. Data for this comparison were collected as part of the National Animal Health Monitoring System′s Dairy 2007 study, which surveyed 2,194 randomly selected dairy herds in 17 top dairy States. The survey design was a stratified random sample and all respondent data were statistically weighted to ensure that samples reflected the study population. Regression analyses were conducted and included multiple outcome variables of interest, herd size, region, and whether the operation participated in DHIA. P-values <0.05 were considered significant. Almost half of herds in the study (46.0%) used DHIA for individual-animal recordkeeping. The average size for DHIA herds was 416 cows compared with 448 cows for non-DHIA herds. A higher percentage of herds in the East region (46.7%) were enrolled in DHIA compared with herds in the West region (37.3%). There were significant productivity differences between DHIA and non-DHIA herds. DHIA herds had a higher mean rolling herd average milk production than non-DHIA herds (9,873 kg and 8,521 kg, respectively) and a longer mean calving interval (13.6 and 13.0 months, respectively). The percentage of DHIA herds that used bovine somatotropin was more than triple that of non-DHIA herds (23.8 and 7.8%, respectively). In addition, DHIA herds reported lower mortality rates for preweaned heifers than non-DHIA herds (8.3 and 9.5%, respectively). Best management practices, in general, were more widely adopted by DHIA herds than non-DHIA herds. A significantly higher percentage of DHIA herds were enrolled in quality assurance programs, used forage test results to balance rations, and fed a total mixed ration. Similarly, biosecurity practices were generally adopted by a signifcantly higher percentage of DHIA herds than non-DHIA herds. A lower percentage of DHIA herds than non-DHIA herds introduced new cattle to the operation during 2006 (36.9 and 40.9%, respectively).  Brucellosis vaccinations were also administered on a higher percentage of DHIA herds than non-DHIA herds (51.7 and 33.0%, respectively). Common cow vaccinations (BVD, IBR, PI3, and BRSV) were administered on 87.9% of DHIA herds and 68.5% of non-DHIA herds. DHIA herds had higher milk production than non-DHIA herds, and a higher percentage of DHIA herds implemented best management practices compared with non-DHIA herds.

Keywords: DHIA, productivity, management, biosecurity