Conference paper

Publication year: 1997

Pages: 159-163

Journal: Journal of Camel Practice and Research

Volume number: 4

Issue number: 2

ISSN: 0971-6777

Conference: International Conference on Camelids - Science and Productivity

Publisher: Camel Publishing House

Abstract: 

The objectives of our study were to estimate seasonal changes in serum thyroid hormones in mature male Ilamas (3 to 6 years old) under middle European conditions and to evaluate correlations to reproductive parameters. The animals were housed indoors and subjected to the natural photoperiod throughout the year. Blood was taken three times a week. Total and free serum triiodothyronine (T-3) and thyroxine (T-4) concentrations were measured by radioimmunoassay. Ejaculates were collected once a week over a period of 17 months using a modified artificial vagina for sheep.

The average serum concentration of T-3 and T-4 ranged from 1.29 ng/ml to 1.55 ng/ml and from 61.73 ng/ml to 76.04 ng/ml, respectively. The mean relation of T-4/T-3 was 50.6%. The concentration of free T-3 and free T4 ranged from 2.4 pg/ml to 3.5 pg/ml and from 5.2 ng/dl to 6.7 ng/dl, respectively. The differences between the average level of the males were significant. The thyroid hormone concentrations changed seasonally, with the highest concentration during the winter months and the lowest during the summer time. The concentrations were positive correlated with the position in range order. The serum T-3 and T-4 showed a significant positive correlation with the number of spermatozoa. Negative correlations were calculated for T-3, T-4 and fT(4) with the average ambient temperature, the maximum and minimum temperature and the hours of sunshine per day. Free T-3 was negatively correlated with semen volume (p<0.01).

Harvard Citation style: Gauly, M., Erhardt, G. and Dzapo, V. (1997) Annual changes in serum levels of thyroid hormones in male llamas (Lama glama) and their correlation with reproduction parameters, Journal of Camel Practice and Research, 4(2), pp. 159-163

APA Citation style: Gauly, M., Erhardt, G., & Dzapo, V. (1997). Annual changes in serum levels of thyroid hormones in male llamas (Lama glama) and their correlation with reproduction parameters. Journal of Camel Practice and Research. 4(2), 159-163.