F.G. Owen

Relationship of physiological factors to placental retention in dairy cattle

Abstract Various physiological and environmental factors were examined for possible association with retention of the fetal membranes in a herd experiencing a high incidence of this problem. Data were collected on 116 multiparous and primiparous cows during the first lactation of the trial and 57 multiparous cows during the second lactation of the trial. No mineral or heavy metal deficiencies or toxicities were detected in the herd and injections of selenium and/or vitamins A, D and E during the prepartum period were not beneficial. Also, no common disease entity could be found in this herd. Placental retention rates observed were 28% and 42% in the first and second lactations, respectively, of this study. The incidence of retained placenta was higher in cows giving birth to twins or male calves, and following abortions, stillbirths or placental retention at the previous parturition. Seasonal effects varied, with a higher retention rate in the warm season in the first lactation and in the cold season in the second lactation. Factors examined that did not show a statistically significant relationship to the placental retention rate included: blood serum vitamin A and β-carotene concentrations; age or lactation number; calf birth weight; presence of serum antibodies to leucosis or chlamydia; incidence of milk fever or ketosis; and services per conception, days open and gestation length of the pregnancy prior to retention. Cows with retained placenta subsequently had longer postpartum intervals to first ovulation and more uterine infections, foot problems and mastitis than cows without retained placenta.

Effect of beta-carotene supplementation on periparturient health and reproduction of Holstein cows

Abstract Two trials involving 57 Holstein cows were conducted to determine the effect of feeding 300 mg supplemental beta-carotene from 30 days before expected parturition to 98 days postpartum on periparturient health and subsequent reproductive performance. Feeding supplemental beta-carotene reduced (P 0.05) on the incidence of placental retention and ovarian cysts, rate of uterine involution, fertility, milk production or somatic cell counts. Thus, benefits in health, reproduction or milk production were not generally observed from feeding supplemental beta-carotene to Holstein cows fed a diet commonly used in the United States.