Life Sciences Commons^™

The Autumn Feed Problem In Beef Cattle Management, D J. Barker, P. J. May

Journal of the Department of Agriculture, Western Australia, Series 4

In south-western Australia all grazing stock face a period of 'inadequate' nutrition each autumn.

The Department of Agriculture's beef production research programme has for some years sought solutions to this problem, and the results from the programme have been used to develop strategies for achieving satisfactory production levels at least cost during autumn.

This article discusses the resulting techniques, and the research on which they are based.

Testicular Steroid Secretion In Response To Gnrh-Mediated Lh And Fsh Release In Bulls, B. D. Schanbacher, S. E. Echternkamp

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Assay of frequently collected blood samples in four mature Hereford bulls indicated the existence of a tonic mechanism for the secretion of luteinizing hormone (LH) and follicle stimulating hormone (FSH), i.e., their episodic release was not observed. Increased plasma concentrations of LH and FSH, however, were obtained in response to an intravenous injection of 500 µg of gonadotropin releasing hormone (GnRH). These gonadotropins showed similar secretory profiles after GnRH, but the relative magnitude of the LH response (30-fold) was considerably greater than that of the FSH response (sevenfold).

Concentrations of testosterone in jugular and spermatic vein blood were increased sevenfold …