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Sexual maturation in the bull
N Rawlings1, A C O Evans, R K Chandolia
1Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada. norman.rawlings@usask.ca
Reproduction in Domestic Animals = Zuchthygiene
|July 25, 2008
Summary
Sexual maturation in bull calves involves slow testicular growth initially, followed by rapid development and puberty around 37-50 weeks. Early gonadotropin secretion is crucial for initiating this process.
Area of Science:
- Veterinary Science
- Reproductive Biology
- Endocrinology
Background:
- Sexual maturation in bull calves is a complex process involving testicular development and hormonal changes.
- Understanding the timeline and key events is vital for breeding programs and animal health.
Purpose of the Study:
- To review the process of sexual maturation in bull calves.
- To detail the stages of testicular growth, germ cell development, and hormonal profiles during maturation.
Main Methods:
- This is a review article, synthesizing existing research on bull calf sexual maturation.
- Analysis of data on testicular growth, cell populations (Leydig, Sertoli), germ cell differentiation, and serum hormone levels (LH, FSH, testosterone).
Main Results:
- Testicular growth is slow until 25 weeks, then rapid until puberty (37-50 weeks).
- Spermatogenesis and mature spermatozoa appear between 32-40 weeks.
- Hormonal profiles show an early peak in LH (12-16 weeks) and increasing testosterone during rapid testicular growth.
Conclusions:
- Early postnatal gonadotropin secretion plays a pivotal role in initiating sexual maturation in bull calves.
- Testicular development involves distinct phases of cell proliferation and differentiation.
- Hormonal feedback mechanisms regulate the progression of maturation.
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