Date of Award:

5-1-1979

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Life Sciences:Biology

Committee Chair(s)

Warren C. Foote

Committee

Warren C. Foote

Committee

Thomas Bunch

Committee

LeGrande C. Ellis

Abstract

Observations were made on 12 Spanish goats and 6 dairy goats from a flock in Logan, Utah, from January of 1977 to January of 1978. Estrus was detected visually and by the use of vasectomized teaser bucks. The breeding season for the majority of the goats was from September to February. Some breeding activity was observed in early March and late August. The mean estrous cycle length was 20.32 ± 7.12 days. Progesterone and LH levels were measured in 10 Spanish goats in Utah during the normal estrous cycle. Samples were taken daily through at least one cycle. LH levels were measured every six hours following the onset of estrus. Progesterone levels in the cycling goats were lowest at the time of estrus (0.2 ng/ml). The levels increased gradually to a maximum at day 10 of around 6 ng/ml. The progesterone level dropped at day -2 of the cycle. LH levels were lowest during the luteal phase of the cycle. The levels increased slightly from day -3 to day 0. LH peaks occurred an average of 24.0 ± 8.94 hours after the onset of estrus (range of 6-42 hours). Six Spanish goats and six dairy goats in Utah were treated with progesterone implants during the late breeding season (January-February). Silicone rubber implants weighing approximately 3.75 grams and containing 10% progesterone were implanted subcutaneously for 17 days. Blood samples were collected two days before the implants were placed and daily during implant treatment. After implant removal blood samples were collected every six hours for 48 hours. About 60% of the goats showed LH peaks within 48 hours of implant removal. In all but one goat that demonstrated an LH peak, the level was > 200 ng/ml. The progesterone treatment described above was repeated on nine Spanish goats and six dairy goats during the anestrous season (May-June). Before treatment the mean progesterone level was 0. 65 ± 0. 83 ng/ml. At the time of implant removal the level was 1.23 ± 1.42 ng/ml. Six hours after implant removal the progesterone level was 0.66 ± 84 ng/ml. Three goats showed LH speaks with a mean level of 23.45 ± 5.65 ng/ml at 18.0 ± 6.0 hours after implant removal. Thirteen mature goats of the five main dairy breeds from a dairy in California were treated with implants during the anestrous season and injected with 900 i.u. of PMSG at the time of implant removal. Eleven of these goats demonstrated LH peaks (> 200 ng/ml) within a 48 hour collection period following implant removal. One-hundred and ninety-three goats of the five main dairy breeds from goats' dairies in California were treated with implants and gonadotropins during the anestrous season. These goats were bred naturally following treatment. Blood samples were collected three weeks after implant removal and when possible six weeks after implant removal. The progesterone levels in blood samples taken at three weeks after implant treatment were used to correctly diagnose pregnancy in 39.3% of the sampled goats. The accuracy of pregnancy diagnosis increased to 79.4% at six weeks. Only one doe that was predicted to be non-pregnant (six week sample) was diagnosed incorrectly

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