Abstract
The success or failure of artificial insemination (AI) depends on the quality of semen used. This
study was conducted to investigate the effect of breed, age, collection period, and ejaculate
number on semen quality collected from 15 breeding bulls available at the centre with different
ages (4 Friesian, 4 Ayrshire, 3 Jersey, 2 Simmental and 2 Boran breeds) maintained at National
Artificial Insemination Center (NAIC), Arusha, Tanzania. A total of 600 ejaculates were collected
for four weeks per month consecutively from January to May 2022, weekly per bull and twice a
day; morning (6.00 – 9.00 AM) and evening (3.00 – 6.00 PM) sessions). The ejaculates were first
examined visually for volume, color, foreign bodies, and consistency whereas sperm
concentration (SPC), progressive motility (PM) and total motility (TM) were assessed using
Computer Assisted Semen Analysis System (CASA). Viability/vitality (SPVI) and morphology
(SPNR) of sperms were analyzed microscopically after staining with Eosin-Nigrosin. Data were
subjected to SAS program and results showed that ejaculate volume, progressive motility, total
motility, sperm viability, and morphology were significantly (P<0.05) affected by age and
collection period. Simmental, Friesian, and Ayrshire bulls produced more voluminous semen
than Jersey and Boran bulls. Jersey bulls had higher (P<0.05) sperm concentrations and live
spermatozoa as compared to other bulls. Boran and Jersey’s bulls exhibited higher PM and TM
than the other bulls. The period of semen collection (morning versus evening) negatively affected
semen volume, total motility, and semen viability in which morning harvests performed better
than evening collections. Middle-aged bulls (3-5 years) produced semen of higher quality
compared to other groups (< 3 years and > 5 years old bulls). In conclusion, age, breed, period of
semen production and ejaculate number revealed significant effects on bovine semen
characteristics.
Keywords: Age; breeding bulls; collection period; ejaculate volume; semen quality
References
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Submitted : July 14, 2023
Published : October 11, 2023
ISSN: 2961-6298
DOI : 10.24018/ejfood.2023.5.5.714