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Testicular development in Brahman bulls.
Pedro M Aponte1, Dirk G de Rooij, Pedro Bastidas
1Department of Endocrinology, Faculty of Biology Utrecht University and of Cell Biology, University Medical Center, Padualaan 8, 3584 CH Utrecht, The Netherlands. p.m.aponte@bio.uu.nl
Theriogenology
|September 6, 2005
Summary
Brahman bulls exhibit delayed reproductive development compared to European breeds. Spermatogenesis begins around nine months, with mature Sertoli cells increasing from 10 to 14 months, indicating a longer prepubertal phase in Bos indicus.
Area of Science:
- Veterinary Science
- Reproductive Biology
- Animal Science
Background:
- Brahman bulls (Bos indicus) are crucial for introducing environmental resistance in cattle.
- Bos indicus breeds show slower reproductive development than Bos taurus breeds.
- Understanding seminiferous epithelium development is key to assessing bull fertility.
Purpose of the Study:
- To investigate the developmental timeline of the seminiferous epithelium in Brahman bulls.
- To identify the specific stages of germ cell development and Sertoli cell maturation.
- To compare the reproductive development of Brahman bulls with European breeds.
Main Methods:
- Histological analysis of testicular samples from 23 prepubertal Brahman bulls.
- Microscopic assessment of seminiferous epithelium cell populations.
- Digitization of light microscopic images for detailed cell counting.
Main Results:
- Immature Sertoli cells decreased, while mature Sertoli cells increased between 10-14 months.
- Spermatogenesis initiated around 9 months of age.
- Specific germ cell types (spermatogonia, spermatocytes, spermatids, spermatozoa) appeared at distinct ages, starting from 9.5 months.
Conclusions:
- The onset of spermatogenesis in Brahman bulls occurs around 9 months.
- A delayed start of spermatogenesis and a prolonged prepubertal period contribute to later puberty in Brahman bulls compared to Bos taurus.
- These findings provide critical insights into the reproductive maturation of Brahman cattle.