Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: Michael Overton x
  • Refine by Access: All Content x
Clear All Modify Search


Objective—To determine whether 4 mg of estradiol cypionate (ECP) administered prophylactically to highrisk postparturient dairy cows decreases incidence of postpartum metritis.

Design—Randomized, placebo-controlled, triplemasked clinical trial.

Animals—250 postparturient dairy cows in a herd with postparturient hypocalcemia, retained fetal membranes, dystocia, stillbirth, or twins.

Procedure—Cows were given 4 mg of ECP (treatment) or 2 mL of vegetable oil (control) by IM injection within 24 to 36 hours of calving. Monitoring rectal temperatures and evaluation for metritis was performed once daily for 10 days. Cows with fever ≥ 39.7°C (103.5°F) were treated with 1.5 g of ceftiofur hydrochloride.

Results—When assessed by ordinal logistic regression, there were no differences between groups in incidence of mild or severe metritis. Cows that calved during the second or third quarter of the year were at increased risk of metritis, compared with those that calved during the fourth quarter. Following stratification by lactation (first and ≥ 2), it was observed that multiparous cows that did not receive antimicrobials during the first 3 days of the postparturient period were 5 times as likely to have metritis, compared with cows treated with antimicrobials on the basis of fever or other concurrent disease.

Conclusions and Clinical Relevance—Prophylactic administration of ECP to dairy cows at high risk for metritis did not reduce risk for metritis. Treating multiparous cows with antimicrobials on the basis of fever during the early postpartum period was associated with decreased incidence of metritis. (J Am Vet Med Assoc 2003;223:846–851)

Full access
in Journal of the American Veterinary Medical Association


Longevity and herd turnover rate are becoming common topics of discussion as the dairy industry strives for continuous improvement in efficiency, profitability, animal welfare, and environmental sustainability. Having the most productive animal fill each slot on a dairy makes strategic replacement and the resulting herd turnover an important tool for producers. Dairy operations can be considered to have slots available to be occupied by cows. The number of slots available is governed by dairy characteristics including parlor size and facility design. With sustainability and profitability goals, producers should aim to fill each slot with the most productive animal. The advantages of a modest surplus of replacement heifers allowing for a higher herd turnover rate are examined and shown to improve herd profitability, enhance welfare, and reduce environmental impact. A model assuming constant demand for dairy foods is presented with increased herd turnover rate leading to more milk production per cow and reduced enteric methane emissions. This analysis demonstrates that all else being equal, raising more replacements (having a relatively higher herd turnover rate and decreased herd-level longevity) improves sustainability compared to management aimed at lower herd turnover rates. Understanding the drivers of herd turnover in dairy production has important implications for the components of one health: animal well-being, food production, and environmental stewardship. The present work examines one tool toward this goal, while the companion Currents in One Health by Nguyen et al, JAVMA, January 2023, takes a broader view of many aspects of dairy sustainability.

Open access
in American Journal of Veterinary Research


Objective—To identify potential risk factors for embryonic loss before 35 to 42 days of gestation in dairy cattle.

Design—Prospective observational study.

Animals—381 cows.

Procedure—Body condition score was determined at the time of artificial insemination (AI; day 0) and on days 20, 23, and 27 and between days 35 and 41; serum progesterone concentration was measured on days 0; 20 or 21; and 23, 24, or 25. Cows were excluded from analyses if day 0 serum progesterone concentration was ≥ 1.0 ng/mL and classified as pregnant on day 23 if serum progesterone was > 1.5 ng/mL on day 20 or 21 and day 23, 24, or 25. Cows were examined via transrectal ultrasonography on day 27 or 28 and rectally palpated for pregnancy on days 35 to 41.

Results—39% of cows that were pregnant on day 23 lost their embryo by day 27, and 18% of cows that were pregnant on day 27 or 28 were not pregnant on days 35 to 41. Breeding a pregnant cow posed the greatest risk for embryonic loss at both time periods. Mean serum progesterone concentrations on day 21 or 22 and day 23, 24, or 25 were lowest for cows that lost an embryo between days 24 and 28. Cows with a linear somatic cell count score > 4.5 before AI were twice as likely to lose the embryo by 35 to 41 days, compared with cows with a score < 4.5.

Conclusions and Clinical Relevance—Results suggest that embryonic loss could be reduced by more accurate estrus detection, reducing mastitis, and strategies to improve progesterone concentration after breeding. (J Am Vet Med Assoc 2005;226:1112–1118)

Full access
in Journal of the American Veterinary Medical Association