http://hdl.handle.net/123456789/131 2026-04-04T06:21:13Z 2026-04-04T06:21:13Z OLUGBENGA, ATANDA ADEDEJI http://hdl.handle.net/123456789/1329 2022-02-18T13:54:10Z 2021-02-01T00:00:00Z

DETERMINANTS OF ONSET OF PUBERTY IN WEST AFRICAN DWARF BUCKS RAISED UNDER INTENSIVE MANAGEMENT OLUGBENGA, ATANDA ADEDEJI Production of the West African Dwarf (WAD) goat plays a vital role in the livelihood of rural populations as its sales either as live animal or meat augments household income. The determination of the onset of sexual maturity in male domestic animals, defined by the first appearance of mature spermatozoa in the cauda epididymis is vital in andrological studies. There is a dearth of information on the onset of puberty in WAD bucks raised under intensive management resulting in sub-optimal utilization of theirversed reproductive potential. This study was designed to investigate somatic parameters, testosterone concentration, spermiogram, testicular and epididymal histology as indicators of onset of puberty in WAD bucks raised under intensive management. Sixty WAD kid bucks, obtained from 80 oestrus-synchronised and naturally mated adult WAD does were used for the study. The kids were nursed by the dams till sixth week post-kidding and thereafter fed forage supplemented with concentrate at 500 g/animal/day till end of the experiment. Water was provided ad libitum. Body Weight, Somatic parameters: [(Scrotal Length (SL), Scrotal Circumference (SC), Crown-Rump Length (CRL), Height At Withers (HAW)] and blood sample for serum testosterone were obtained from the bucks weekly (1-18 weeks). Epididymal semen characteristics (sperm motility and concentration), testicular and epididymal histology were investigated weekly (4-18 weeks). Data were analyzed using correlation regression and one-way ANOVA at α 0.05. Body weight and somatic parameters of bucks increased significantly during the first twelve weeks, while no significant increase was observed from weeks 12-18. Age was positively correlated with SL (r = 0.912), SC (r = 0.804), CRL (r = 0.625), HAW (r = 0.691) from 1-12 weeks. Testosterone concentration fluctuated in the first eight weeks of life with a non-significant increase from week 9 - 12. There was a significant increase in testosterone concentration in the bucks between weeks 12 (6.12+0.15) and 13 (10.20 ± 0.68ng/mL). Testosterone concentration peaked at week 14 (11.25 ± 1.75 ng/mL) but thereafter declined till week 18. Sperm motility and concentration significantly increased from 60.50±10.08 to 82.30 ±15.70 % and 89.30 ± 9.20 x 106 to 125.3 ± 16.70 x 106 sperm/mL respectively, between weeks 13 and 14. Canalisation of the seminiferous tubules was absent in the bucks till week 12. The first observation of elongated spermatids in the lumen of seminiferous tubules was at week 12, while mature spermatozoa were first observed in the cauda epididymis at week 13. Epididymal epithelium changed from simple cuboidal (4-12 weeks) to pseudo-stratified columnar (12-18 weeks). Luminal diameter of seminiferous tubule and ductal diameter of epididymis significantly increased between weeks 13 and 14 from 32.73 ± 0.44 to 78.59 ± 9.18μm and 68.52 ± 12.35 to 102.14 ± 23.76 μm, respectively with no significant difference thereafter. Marked changes in somatic parameters, testosterone concentration, epididymal semen characteristics, testicular and epididymal histology were indicative of the onset of puberty which occurred between weeks 13 and 14 post-kidding in West African Dwarf bucks raised under intensive management. This period is therefore recommended as the earliest time for harvesting of semen for andrological purposes.

2021-02-01T00:00:00Z RAJI, LUKMAN OLADIMEJI http://hdl.handle.net/123456789/336 2019-03-26T09:56:59Z 2017-10-01T00:00:00Z

APPLICATION OF SOME BIOMETRICAL CORRELATES IN THE DETERMINATION OF OPTIMUM BREEDING AGE IN THE WEST AFRICAN DWARF BUCK RAJI, LUKMAN OLADIMEJI Sexual maturity of male animals begins at puberty and peaks at the Optimum Breeding Age (OBA), which marks attainment of maximum functionality of the gonads. Despite the high socio-economic importance of goats, the OBA of the West African Dwarf Buck (WADB) is yet to be determined. Therefore, the OBA in the WADB was investigated using biometrical correlates. A field study involving 450 semi-intensively raised WADB was conducted from October, 2012 to October, 2013. The bucks were in 15 equal groups (1-15 months old) for the determination of Body Score (BS), Body Weight (BW) and Scrotal Circumference (SC). Six bucks were randomly selected per group for subsequent studies. The bucks were electroejaculated to evaluate semen volume, normal spermatozoa, spermatozoa motility, livability and concentration, using standard methods. The TV determined ultrasonographically using Prolate Ellipsoid Formula (TVPEF) and Prolate Spheroid Formula (TVPSF) were contrasted with TV obtained by conventional Water Displacement Method (TVWDM). Testicular morphometry [Seminiferous Tubular Diameter (STD) and Germinal Epithelial Height (GEH)] and testosterone profile were evaluated using Motic Images Plus software and ELISA technique, respectively. Data were analysed using descriptive statistics, Pearson correlation and ANOVAat α 0.05. The BS (r = 0.2), BW (r=0.9) and SC (r=0.8) correlated significantly with age. The BW significantly increased from 3.4±0.1 kg at one month to 13.6±0.1 kg at 15 months. The SC significantly increased from 7.9±0.1 cm at one month to 17.6±0.2 cm at 15 months. Azoospermia, first appearance of spermatozoa and best quality semen were observed in the bucks’ ejaculate at 1-5, 6 and 8-15 months, respectively. Spermiogram showed that semen volume, normal spermatozoa, spermatozoa motility, livability and concentration increased significantly from 0.2±0.1 mL, 87±2.7%, 85±4.0%, 88±3.7% and 1.7±0.0 × 109Cells/mL, respectively at six months to 0.3±0.1 ml, 92±3.4%, 93±5.0%, 93±4.6% and 2.1±0.1 × 109Cells/mL, respectively at eight months. The TVPEF, TVPSF and TVWDM significantly increased from 16.1±0.1, 23.6±1.7 and 16.2±0.1cm3, respectively at one month to 28.3±0.2, 40.0±0.3 and 28.5±0.3 cm3, respectively at eight months. Comparison of TV procedures showed that TVPEF did not significantlydiffer from TVWDM, while TVPSF was significantly higher than TVWDM. The STD and GEH significantly increased from 83.1±0.2 µm and 28.4±0.2 µm, respectively at one month to 574.1±0.3µm and 197.5±0.3 µm, respectively at eight months. The testosterone concentrations increased significantlyfrom 0.1±0.0 ng/ml at one month to 4.7±0.2 ng/mL at eight months. In the parameters studied (excluding BW and BS), there were no significant increases from eight months to 15 months. An optimum breeding age of eight months in semi-intensively raised West African Dwarf buckswas established. Ultrasonographic evaluation of testicular volume using the Prolate Ellipsoid Formula is a valuable non-invasive method for the determinationof optimum breeding age in West African Dwarf bucks. Keywords: Biometrical correlates, Optimum breeding age, Testicular ultrasonography, Semi- intensive, WestAfrican DwarfBucks. Word count: 455

2017-10-01T00:00:00Z