Testosterone response to synthetic gonadotropin releasing hormone injection in Sahiwal-Friesian crossbred bulls

Ramakrishnan P., . and Mohamed Ariff Omar, . and Murugaiyah M., . and Mohamad Aziz Dollah, . Testosterone response to synthetic gonadotropin releasing hormone injection in Sahiwal-Friesian crossbred bulls. pp. 145-150. ISSN 0128-0686

A study was conducted to determine the effects of seven dose levels of a single intramuscular injection of a synthetic gonadotropin releasing hormone (GnRH) on plasma testosterone response in five Sahiwal-Friesian crossbred bulls aged between 23 and 25 months. The GnRH doses were 0 0.005 0.01 0.02 0.04 0.08 and 0.16 ug/kg body weight. Blood samples were collected at 0 0.25 0.5 1 1.5 2 2.5 3 4 5 6.0 and 7.0 h post-injection of GnRH from 0900 to 1600 h. A small GnRH dosage of only 0.005 ug/kg body weight was observed to be adequate in inducing a maximum peak response in testosterone level. Increasing the dose of GnRH by a 32-fold range did not influence significantly (p 0.05) the height of testosterone response peak or testosterone area under the response curves. The optimal time to measure the height of the testosterone response peak was found to be between 2 h and 3 h post-injection of GnRH. The high correlation (r 0.83 p 0.01) between the testosterone response peak and area under the response curve showed that a single blood sample collected at an appropriate time might be a suitable alternative to the measurement of area under the response curve which needs a series of blood samplings

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Abstract

A study was conducted to determine the effects of seven dose levels of a single intramuscular injection of a synthetic gonadotropin releasing hormone (GnRH) on plasma testosterone response in five Sahiwal-Friesian crossbred bulls aged between 23 and 25 months. The GnRH doses were 0 0.005 0.01 0.02 0.04 0.08 and 0.16 ug/kg body weight. Blood samples were collected at 0 0.25 0.5 1 1.5 2 2.5 3 4 5 6.0 and 7.0 h post-injection of GnRH from 0900 to 1600 h. A small GnRH dosage of only 0.005 ug/kg body weight was observed to be adequate in inducing a maximum peak response in testosterone level. Increasing the dose of GnRH by a 32-fold range did not influence significantly (p 0.05) the height of testosterone response peak or testosterone area under the response curves. The optimal time to measure the height of the testosterone response peak was found to be between 2 h and 3 h post-injection of GnRH. The high correlation (r 0.83 p 0.01) between the testosterone response peak and area under the response curve showed that a single blood sample collected at an appropriate time might be a suitable alternative to the measurement of area under the response curve which needs a series of blood samplings

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Item Type:	Article
Additional Information:	Summaries (En Ms)
AGROVOC Term:	TORO
AGROVOC Term:	INYECCION
AGROVOC Term:	HORMONA LIBERADORA DE GONADOTROPINA
AGROVOC Term:	HORMONAS SINTETICAS
AGROVOC Term:	TESTOSTERONAS
Depositing User:	Ms. Norfaezah Khomsan
Last Modified:	24 Apr 2025 05:56
URI:	http://webagris.upm.edu.my/id/eprint/20848

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