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Biomedical subjects

E R Hauser

Publications and source records attributed to E R Hauser.

63 records · Page 4Linked to original sources
PubMed1981

Ovarian function in the cycling cow: relationship between gonadotropin binding to theca and granulosa and steroidogenesis in individual follicles.

Thirty-six Angus and Angus crossbred cows were used in a 3 x 2 x 2 factorial experiment designed to determine the effects of stage of the estrous cycle (day 6, 12 or 18), a long term with a single ovary (2 years) and side of previous ovulation or remaining ovary on the development of large ovarian follicles (LF; diameter greater than or equal to 8 mm). Follicular fluid estradiol-17 beta (FFE) concentration, localization of gonadotropin binding sites and granulosa cell condition were determined for each LF by radioimmunoassay, autoradiography and histological examination, respectively. No side differences were noted. However, the sample was biased by the use of equal numbers of left and right side ovulators. Compared to intact controls, one-ovary cows showed 100% compensation of LF development. Eighty-five percent of the LF studied bound follicle stimulating hormone (FSH) in the granulosa and human chorionic gonadotropin (hCG) in the theca. Thirty-eight percent also bound hCG in the granulosa. Both binding patterns were found on all days studied. Atretic follicles had lower (P less than .05) FFE concentrations than healthy follicles (r = -.59). The number of LF per cow increased (P less than .05) from day 6 (1.3) to days 12 (1.8) and 18 (2.1). Conversely, their FFE content per cow decreased (P less than .05) from 109 ng/cow on day 6 to 20 ng on; day 12 and 34 ng on day 18. The data suggested the emergency of two LF classes on day 18, one preovulatory, with exceptionally high FFE levels, the other atretic or becoming atretic, with low FFE levels.

Animals↗
PubMed1981

The influence of early age mastectomy and unilateral ovariectomy on reproductive performance of the bovine.

The effects of mastectomy and unilateral ovariectomy and their interaction during the postpartum period were examined in 26 Angus heifers. At birth, the animals were assigned to a 2 x 2 factorial arrangement of treatments: mastectomy and unilateral ovariectomy, mastectomy, unilateral ovariectomy and unoperated suckled control. Surgeries were performed at approximately 2 months of age, and animals were observed through three consecutive postpartum intervals (PP1, PP2, and PP3). There were no significant influences of mastectomy or ovariectomy on age at puberty, age at first conception or services required for first conception. Mastectomy reduced the number of days from parturition to ovulation (PP1, 32.1 vs 52.5, P less than .01; PP2, 21.6 vs 59.9, P less than .01; PP3, 20.6 vs 46.7, P less than .01) The interval from parturition to first estrus was shorter for heifers in the mastectomized group (PP1, 45.3 vs 76.2, P less than .05; PP2, 28.7 vs 69.9, P less than .01; PP3, 32.4 vs 62.3, P less than .05) as was the interval from parturition to conception during PP2 (60.0 vs 104.9, P less than .05). The interval between calvings was shorter for heifers in the mastectomized group than for controls, but the difference was significant only between the second and third parturitions: 338.5 vs 399.2 (P less than .01). Mastectomy reduced the standard deviation for the interval between parturition 2 and parturition 3 (55.9 vs 15.9; P less than .01), the interval between parturition and return to estrus in PP2 (56.3 vs 11.4; P less than .01) and the interval from calving to conception PP1 (92.2 vs 31.4; P less than .01). Unilateral ovariectomy did not have a significant influence on any of the postpartum intervals, nor were there any significant interactions.

Age Factors↗