Determination of an Estrous Cycle in Female Giraffes (Giraffa Camelopardalis) By Radioimmunoassay of Fecal Hormones

Date of Graduation

Summer 1997

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Thomas Tomasi

Abstract

The ability to detect reproductive cycles, specifically, the day of estrus, in giraffes has typically been done by observing male behavior. More accurate methods, such as analysis of serum and urine samples, have not been utilized due to the uncooperative nature of the species. Fecal sample analysis was used in this study because it is a non-invasive technique and has been proven to show reproductive cycles in a variety of exotic species. Three fecal samples were collected per week for four months (approximately 8 cycles per female) from the three female Giraffa camelopardalis rothschildi housed at Dickerson Park Zoo, and from two Giraffa camelopardalis reticulata housed at Baton Rouge Zoo. After extraction of the steroids from the feces via a 3:2 ethyl acetate/hexane solution, concentrations of progesterone and estradiol were determined by radioimmunoassay. The average cycle length for each female was determined by their inter-progesterone peak duration. Averages ranged from 10 to 14 days. There was a trend for male interest/breeding to occur one sample (approximately 2 days) before a progesterone peak. There was no trend with the estradiol cycles. During this study one female became pregnant and showed extended elevated levels of progesterone until a spontaneous abortion occurred. Pregnancy occurred again one month later and the elevated progesterone levels were used to monitor the pregnancy. Typical hormone cycles were developed from our data by synchronizing the cycles with the day of male behavior, but neither hormone showed significant changes throughout the cycle. Fecal analysis proved useful in detecting the estrous cycle and pregnancy, and has the benefit of being a non-invasive procedure.

Subject Categories

Biology

Copyright

© Karla Ann Rues

Citation-only

Dissertation/Thesis

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