Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Dairy Science


Parturition was initiated in 25 of 29 (Trial 1) and 26 of 26 (Trial 2) Holstein cows given dexamethasone (Trial 1), 4.4 mg/100 kg body weight, or dexamethasone plus .25 mg estradiol benzoate (Trial 2) at day 273 of gestation. Parturition occurred at 45.l z +/-11.1 h (Trial 1) and 40.8 ± 9.6 h (Trial 2) after injection. Twenty-nine control cows (Trial 1) and 26 control cows (Trial 2) had average gestation lengths of 280 and 281 days, respectively. In Trial 1, calving difficulty was greater (P <.05) while birth weight of calves was 3.0 kg less (P<.05) for the induced cows compared to controls. In Trial 2, no differences in calving difficulty were found, while calf birth weight was 2.5 kg less (P <.10) for the induced cows compared to controls. Average birth weights of calves were 42.4 and 45.4 kg, Trial 1; and L~o.8 and 43.3 kg for Trial 2, for induced and control groups. Severity of udder edema did not differ for either trial. Average daily milk production for the first 9 wk of lactation was 2l~.8 kg and 27.8 kg (Trial 1) and 24.2 kg and 27.7 kg (Trial 2), for induced and control groups. In both trials, differences in milk fat or fat corrected milk were nil. Total milk production (305 day-2X-mature equivalent) was not significantly different for either trial. Changes in body weight were similar for control and induced cows in both trials. The incidence of retained placental membranes was 76 and 10'/4 (Trial 1) and 50 and 4% (Trial 2) for induced and control cows. Average days to first heat, days to firs+, service, days to conception, and services per conception for induced cows were: 58 .4, 79-9, 117.8, 2.0 (Trial l); 80.7, 81.4, 102.2, 1.64 (Trial 2); and for control cows were: 58.6, 82.3, 105.5, 1.8 (Trial l); 89.0, 91.4, 128~6, 1.94 (Trial 2). In Trial 1, the incidence of milk fever in cows with no previous history was 24 and 10'/4 for induced a"'1.d control cows. There were no differences in the incidence of metabolic disorders in Trial 2. Results of California Mastitis Tests were similar for control and induced cows in both trials. In both Trial 1 and Trial 2, fat, protein, total solids, and gamma globulin content of the colostrum did not differ between control an treatment groups;· Casein values were lower (P <.05) for the treatment group in both trials. Average daily gains from 0 to 10 weeks were .63 and .60 kg, for Trial 1; and .51 and .46 kg, for Trial 2, for induced and control calves. No differences were found in calf death loss or health disorders between groups. Similar levels of serum gamma globulin were found for both groups at 0 (before sucking) and 3 days of age in both trials. No meaningful differences were found in total serum protein, albumin, and alpha and beta globulin levels in both trials. No differences were found at birth, in chest depth, shoulder width, head circumference, hip width, and wither height of calves.

Library of Congress Subject Headings

Dairy cattle -- Parturition
Estradiol benzoate


Includes bibliographical references (pages 64-67)



Number of Pages



South Dakota State University


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Dairy Science Commons