MSCAGR (Animal Science) / Department of Animal science / The quality of cryopreserved Boer goat semen may be influenced by the source and concentration of energy supplements in the extender. The aim of the study was to improve the protocols for cryopreservation of Boer goat spermatozoa using different disaccharides concentrations as supplements in tris- egg yolk extender. Two experiments were carried out to investigate the effect of (a) addition of three disaccharides (maltose, sucrose and trehalose) and (b) disaccharides combination (maltose and trehalose) at different concentrations using tris-egg yolk extender. For experiment 1: the study was replicated six times and was conducted in a 3 x 2 x 2 factorial arrangement with three different sugars (sugars: maltose, sucrose and trehalose), two sugar concentrations (0.12g and 0.22g) and two evaluation times (0 hours before cryopreservation and 120 hours after cryopreservation). For experiment 2: the study was replicated six times and was conducted in a 2 x 2 factorial arrangement with two sugar concentrations (0.12g and 0.22g) and two evaluation times (0 hours before cryopreservation and 120 hours after cryopreservation). Semen ejaculates were collected at 7.00-9.00 am from three Boer goats twice per week. After collection, the semen samples were pooled and diluted with tris-egg yolk extender at the ratio of 1:7 (semen to extender). Sperm quality (progressive motility, non- progressive motility, kinetic motions, viability (live/dead) and morphology) were analyzed using computer aided sperm analyzer (CASA). For experiment 1: sucrose 0.12g had higher progressive motility (PM %) when compared to maltose, and trehalose at 0h but reduced after cryopreservation. Sucrose 0.12 showed high percentage of kinetic motions (straightness and average path velocity) when compared to other sugars at 0 hours. More morphological defects M (CH) were revealed by maltose 0.12 at 0 hours. Sugar type (ST) and evaluation time (ET) showed no significant difference (P>0.05) in progressive motility (PM %), sperm kinetic motion, sperm viability and morphology. For experiment 2: mixed/combined 0.12g (maltose and trehalose) revealed more progressive motility (PM %) at 0h and reduced after cryopreservation. Table 6 and 9: of experiment 1 and 2 showed an interaction caused by sugar concentration level and evaluation time (L X ET) on the percentage of cut head M (CH%) and coiled M(C%) morphological abnormalities. In conclusion addition of maltose 0.12g to the extender showed almost similar results with that of trehalose at 0h and 120h. Therefore addition of maltose and trehalose to the extender might improve the quality of Boer goat spermatozoa prior and post cryopreservation. / NRF

Thesis (Ph.D. (Animal Nutrition)) -- University of Limpopo, 2016 / Refer to document

A genetic study of four commercial goat breeds in South Africa was performed using microsatellite markers. The commercial breeds included the Boer goat, Savanna, Kalahari Red and the Angora goat. Indigenous goat populations from Delftzijl and Groblersdal were also included in this study. Seventeen microsatellite markers were tested to determine the genetic variation. Genetic variation within the breeds were relatively high with heterozygosity values ranging from 57% for the Boer goat, 68% for the Kalahari Red, 69% for the Savanna goats and 70% for the Angora goats. First values indicated that the Savanna and Boer goat are genetically the closest (0.114), while the Kalahari Red and Boer goat are the least related (0.237). Phenotypic measurements included height, length, depth, heart girth, pelvic length and width for a phenotypic description. Significant differences were observed in the phenotypic measurements among all the breeds. The genetic and phenotypic differences indicate that these goats can be distinguished as different breeds. Results of this study contribute genotypic information of the commercial goats in South Africa. Copyright / Dissertation (MSc)--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted

Thesis (M. Sc. Agriculture (Animal Production)) -- University of Limpopo, 2022 / Weighing scales are typically out of reach for small-scale farmers due to expensive cost and a lack of operational expertise. However, understanding body weight and its relationship to linear body measures are critical for farmers making management decisions. Single nucleotide polymorphisms (SNPs) are significant because they influence the coding area of the DNA, leading to changes to the amino acid sequences, which might affect the animal's phenotype. The current study sought to find genetic indicators of the insulin-like growth factor 1 gene that may be exploited for breeding selection in order to improve the growth traits of Kalahari Red goats. The research was carried out at the Zuurfontein farm in Polokwane. As experimental animals, fifty (n = 50) Kalahari Red goats (8 males and 42 females) aged 2 to 3 years were used. A balance weighing scale was used to record body weight, and a measuring tape was used to capture linear body measures. Blood samples were obtained from the jugular vein once per animal using vacutainer blood collecting tubes. The deoxyribonucleic acid (DNA) was extracted and purified according to the methodology provided by Noegen's Genomic DNA isolation kit. Pearson’s correlation was used to achieve the correlation between the growth traits, Simple linear regression was performed to predict body weight from linear body measurements, Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) was utilized to discover the single nucleotide polymorphism, Chi-square test (χ2) was performed to assess the allele frequencies for Hardy-Weinberg equilibrium and General Linear Model (GLM) was performed for marker-trait association analysis. The mean square error (MSE) and coefficient of determination (R2) were exercised to choose the best regression model. Correlation results indicated a high positive significant correlation (P < 0.01) among BW and RH (r = 0.69), BL (r = 0.92), HG (r = 0.91), WH (r = 0.85) in bucks. While it does, all the linear body measurements indicated a high positive significant correlation (P < 0.01) expect SH (r = 0.41) which had a positive significant correlation (P < 0.05). Simple linear regression findings highlighted that BL had minimum MSE and highest R2 in bucks while in does HG had minimum MSE and highest R2. PCR-RFLP results indicated that two fragment patterns (two fragments and one fragment) were identified. Two genotypes were identified, KK with one fragment and KM with two fragments. The genotype frequency of KK was higher than that of KM and K allele had a higher allelic frequency than the M allele. The χ2 results showed that the Kalahari Red goats population used was not in Hardy Weinberg equilibrium (HWE) (χ2 = 0.39*). Marker-trait association findings by GLM indicated that the genotypes (KK and KM) had no association with the growth traits measured. In conclusion, correlation findings suggest that BW had a higher relationship with BL and HG in Kalahari Red goats. The regression results suggest that in bucks, an increase of 1 cm of BL might increase body weight by 1.24 kg, whereas it does, a 1 cm increase of HG might increase the body weight by 0.73 kg. The χ2 results suggest that the studied population gene and genotypic frequencies keep on changing from generation to generation and the marker-traits association results suggest that the genotypes identified had no relationship with growth traits in Kalahari Red goats. Further studies need to be conducted on single nucleotide polymorphism of IGF-1 and their relationship with growth traits using a larger sample, more growth traits and targeting more exons. / National Research Foundation (NRF)

Department of Animal Science / PhD (Agric)

MSCAGR (Animal Science) / Department of Animal Science / The Boer goat (Capra hircus) is one of the most desirable goat breeds for meat production. The impact of cryopreservation on the viability of its semen depends on the extenders, freezing and thawing methods. This study evaluated the effects on sperm viability in Boer goat semen extended using Bioxcell, Biladyl and Ham’s F10, and frozen in semen straws placed on a rack at 4, 5, 6 or 7 cm above the surface of liquid nitrogen. After storage in liquid nitrogen for 7 days, the frozen semen was thawed at 37 oC for 30 seconds or 90 oC for 5 seconds. Samples of sperm were also frozen to -196 oC in a programmable freezer, as the control regime for the freezing treatments. Sperm morphology, motility and viability were evaluated using the computer aided sperm analysis (CASA) system in a randomised design in which the treatments were in a 3 (extender) X 5 (freezing regime) and X 2 (thawing regime) factorial arrangement. The extenders Bioxcell and Biladyl were affected in the total motility, progressive motility and static (P<0.01), the motility was overall maintained only in straws placed at 5 cm above the liquid nitrogen level, with significant difference for the interaction extender X freezing regime in the total motility (p<0.01), non-progressive motility (p<0.05) and progressive motility (p<0.01), the 37 oC for 30 sec thawing regime had significantly more (P<0.05) in cut-head spermatozoa. Ham’s F10 extender had significantly lower normal spermatozoa (P<0.05) compare to Biladyl and Bioxcell extenders. In conclusion, the extender type, freezing and thawing regime were important factors for consideration in goat semen / NRF