Semester

Summer

Date of Graduation

2014

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Applied and Environmental Biology

Committee Chair

Robert A. Dailey

Committee Co-Chair

Emmett K. Inskeep

Committee Member

Joseph W. McFadden

Abstract

The aim of this study were to body condition score, 72 Holstein-Friesian dairy cows at prepartum, compare lean, moderate, and over-conditioned categories, and relate any changes associated with the various time points with reproductive success by measuring body condition score, hematocrit, total white blood cell (WBC) differential, haptoglobin (Hp) concentrations, milk yield and monitoring health status. The body condition score changed significantly with time with the greatest unit loss being in the over-conditioned cattle from d -30 to d 35 postpartum. The BCS losses for each category did not have a significant effect on reproductive success at any time. Health disorders were significantly related to parity. The health status had at d 0 to 10 and during pre-breeding (d 20 to 26) postpartum had a significant effect on reproductive success. The hematocrit values were significantly reduced at d 20 to 26 postpartum. Pregnancy success was associated with Hp and milk yield with higher Hp concentrations and higher milk yield having the highest pregnancy rate. The white blood cell differential count was significantly different at certain sampling time points for monocytes, total neutrophils, and eosinophils; with the highest concentration for each at parturition. Lymphocyte concentrations did not differ. The study revealed that body condition, hematocrit, and parity were not good indicators of reproductive success. Parity of an animal had no effect on reproductive success but its association with prevalence of disease and health disorders in early postpartum decreased pregnancy success to first artificial insemination. Likelihood of successful pregnancy was high if both Hp and milk yield were high. The WBC counts portrayed lower than normal concentrations of lymphocytes and elevated levels of total neutrophils.

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