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L D Stuart

Publications and source records attributed to L D Stuart.

24 records · Page 2Linked to original sources
PubMed1983

Ovarian activity during normal and abnormal length estrous cycles in the goat.

Ovarian and behavioral cyclicity were studied during 3-5 estrous cycles in a group of 10 multiparous, Nubian does. Changes in ovarian morphology throughout the estrous cycle were identified and photographed laparoscopically. Forty-eight estrous cycles were observed during the study and of these, 21 were abnormally short in duration (mean +/- SEM, 6.5 +/- 0.5 days). Mean duration of the estrous cycle for the 27 normal length cycles was 21.5 +/- 0.8 days. Eighteen/21 (86%) of the short cycles and 6/27 (22%) of the normal cycles were initiated during early breeding season (between September 1st and October 15th). There were no differences (P greater than 0.05) in the duration of estrus for the short (mean, 2.9 +/- 0.3 days) and normal (mean, 2.8 +/- 0.8 days) cycle groups. A total of 6/11 (55%) of the short duration cycles examined laparoscopically appeared to be anovulatory, but ovulation was observed in all normal cycles examined. The number of corpora lutea (CL) observed during normal length and short estrous cycles was 3.1 +/- 0.2 and 2.2 +/- 0.2, respectively (P less than 0.01). The cumulative percentage of does that showed morphological evidence of ovulation by the first, second and fifth day after the onset of estrus was 30%, 60% and 100%, respectively. Based on distinct differences in morphology and development, 2 types of CL were identified. The maximum visible diameter of Type I and Type II CL was 9.4 +/- 0.6 mm and 5.1 +/- 0.5 mm, respectively. These data document ovarian morphology throughout the normal and abnormal duration estrous cycle of the goat and indicate that 1) short estrous cycles observed early in the breeding season are associated with prematurely regressing CL or anovulation and 2) the ovary produces 2 morphologically distinct types of CL which differ not only in size and appearance, but also potentially in postovulatory function and longevity.

Animals↗
PubMed1983

Pituitary-ovarian relationships during the estrous cycle and the influence of parity in an inbred strain of miniature swine.

Pituitary-ovarian function was analyzed in a strain of miniature swine previously shown to produce a low ovulation rate resulting in the formation of only 8.6 corpora lutea (CL)/animal. Five multiparous (M) and four nulliparous (N) miniature pigs with a mean inbreeding coefficient of .39 were monitored for estrous behavior through four consecutive estrous cycles. Daily blood samples were collected from 5 d before to 5 d after the onset of the second, third and fourth estrus and at 48-h intervals during the remainder of the second and third estrous cycle. Laparoscopy was used to examine the ovaries 1 and 5 d after onset of the third estrus and 2 d after the beginning of the fourth estrus. For the entire group, temporal fluctuations among serum estradiol-17 beta, luteinizing hormone (LH) and progesterone concentrations and sexual behavior were similar to previously published data in standard swine breeds. Although the mean lengths of the estrous cycle were not different (P greater than .05) between parity subgroups (M, 23 +/- 1.3 vs N, 22 +/- .7 d), multiparous pigs were in estrus longer (P less than .05) than nulliparous females (M, 3.7 +/- .2 vs N, 2.2 +/- .4 d). Parity subgroups were similar with respect to the mean number of follicles forming CL (M, 8.8 +/- .7 vs N, 9.2 +/- .2). Although an average of 6.2 +/- 2.1 CL had formed by 24-h after onset of estrus in the nulliparous subgroup, no CL were detected in the multiparous subgroup at this time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Correlates of ovarian morphology, estrous behavior, and cyclicity in an inbred strain of miniature swine.

Ovarian morphology and behavioral relationships were studied in a group of nine miniature pigs with a characteristically small litter size (-5) and an average coefficient of inbreeding of 0.39. The first day of standing estrus was designed as day 0, Laparoscopy was used to evaluate and photograph ovarian activity on days 1, 5, 11, 17, and day 2 of the subsequent estrous cycle. Mean (+/-SEM) duration of estrus and the estrous cycle was 3.1 +/- 0.2 and 22.6 +/- 0.3 days, respectively. An average of 9.0 +/- 0.4 vesicular follicles developed/estrous period and 96% of the follicles showed morphologic evidence of ovulation resulting in a mean of 8.6 +/- 0.3 corpora lutea (CL) per animal. There was no significant correlation between the degree of inbreeding and number of vesicular follicles (r = 0.27) or CL (r = 0.28) developing/cycle within the experimental group. Mature preovulatory follicle and CL size ranged from 6-12 mm and 8-12 mm in diameter, respectively, and 22.5% of the newly formed CL contained distinct postovulatory stigmata. These data indicated that 1) temporal relationships of sexual behavior and gross ovarian morphology in the miniature pig were similar to descriptions previously reported for the standard pig, and 2) the reduced litter sized characteristic to this particular strain is, at least in part, due to decreased number of vesicular follicles developing during the estrous cycle.

Animals↗