Document Type

Dissertation - Open Access

Award Date

1972

Degree Name

Doctor of Philosophy (PhD)

Department / School

Animal Science

First Advisor

T.D. Rich

Second Advisor

C.A. Dinkel

Abstract

A series of biological assays were conducted to compare physiological saline (PSS) and carboxymethylcellulose (CMC) as carriers for follicle stimulating hormone (FSH) and to determine the optimum ratio of FSH to CMC. Constant individual dosages of 0.5 mg FSH were injected into a total of 384 immature female rats in four experiments. Treatments included single injections of FSH in PSS, FSH in 1 percent CMC at ratios (mg FSH: ml CMC) OF 1:3, 1:2, 1:1, 2:1, 3:1, 5:1 and FSH in 2 percent CMC at a ratio of 1:1. Parameters of primary and secondary response were ovarian and uterine weight, respectively, at 24, 48, 72 and 96 hours post-injection. IT was concluded that ovarian and uterine growth resulting from FSH and CMC was greater than from the same quantity of FSH in PSS. The apparent optimum ratio of FSH to CMC was 1 mg FSH in 2 ml or more of 1 percent CMC. The mechanisms by which CMC tended to enhance the activity of FSH could not be determined from the data. A total of 99 yearling, commercial beef heifers was used in two experiments conducted during consecutive summers (1970 and 1971) to study ovarian response to FSH carried in CMC. Each trial was conducted in two phases to provide two data collections from each group of experimental animals. In the first experiment, all heifers were fed 1 mg melengesterol acetate (MGA) per head per day for 14 days to synchronize estrus. Seven mg FSH in 1 percent CMC injected on days 10, 12, or 14 of MGA feeding did not affect ovarian stimulation (ovulation sites or ovulation sites plus follicles ≥ 10mm) significantly. Five mg estradiol valerate (EV) injected on day 2 of MGA feeding to induce regression of luteal tissue tended to reduce ovulation rate (P<.10) in response to exogenous FSH. However, a significant phase x EV x day of injection interaction (P < .01) limited positive conclusions relative to this effect. The incidence of anovulatory heifers was relatively high (8/48 and 8/49 in phases I and II, respectively) and conception rates from a single artificial insemination at post-treatment estrus in phase II was low for all groups (0 to 29 percent). In phase I of the second experiment, total doses of 8 to 10 mg FSH in CMC (1 mg FSH:2 ml 1 percent CMC) injected as single doses on day 15 or two half-doses on days 15 and 17 of natural estrous cycles were not significant sources of variation in ovarian stimulation. In phase II, ovarian stimulation was not affected significantly by 5 mg injections of FSH on days 15 and 17 or on days 16 and 18 (total of 10 mg) of natural estrous cycles or by the same treatments repeated to one-half of each group during subsequent cycle. Five twin fetuses and nine nongravid uteri were observed in 45 heifers artificially inseminated during two estrous cycles. Data from both experiments suggested that shorter intervals from FSH injection to estrus resulted in greater ovarian stimulation.

Library of Congress Subject Headings

Ovulation
Gonadotropin
Pituitary hormones

Format

application/pdf

Number of Pages

124

Publisher

South Dakota State University

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