Preliminary genetic parameters for nodule traits of ostrich skins were estimated to examine whether genetic improvement of skin quality is feasible. Average nodule size and density per dm² were determined on five localities on each of 439 ostrich skins. An…
Two fixed regression testday models were applied for variance component estimation and prediction of breeding values for somatic cell score, using testday records of the first three lactations of South African Holstein and Jersey cows. The first model (ML-model) considered…
Methodology has been developed to implement testday models in the national genetic evaluation of dairy breeds for production traits in South Africa. Positive definite covariance matrices have been estimated, using multitrait, multi-lactation, fixed regression testday BLUP animal models, including testday…
Data from 2801 individuals (born from 1996 to 2002) were used to obtain heritability (h2) estimates for five objectively measured and six linearly assessed type fleece traits (scored on a 1-50 point scale) from the Tygerhoek Merino flock. Correlations of…
Kidney Fat Index (KFI) is the most used indicator of body condition for African ungulates and regarded most reliable. The possible use of Metatarsus Marrow Dry Weight (MMDW) as an alternative for KFI and femur marrow dry weight as indices…
Genetic parameters for growth traits in the South African Brahman breed were estimated using ASREML from data records of birth weight (BWT) = 41 509, weaning weight (WWT) = 37 705, yearling weight (YWT) = 22 682 and final weight…
(Co)variance components for linear type traits of South African Jerseys and Holsteins were estimated. Heritability estimates are mostly in agreement with other studies although some estimates for the Jersey population are lower. Genetic trends for conformation traits of the South…
Genetic selection to improve feed efficiency aims to reduce the cost of feeding costs in beef cattle production and thereby improve profitability. The aim of this study was to estimate genetic (co)variances to compare residual feed intake (RFI) and feed…
A study with the aim to evaluate the effects of different dietary energy concentration (8.23, 9.77 and 11.32 MJ ME/kg DM) on scrotal, testicular and semen characteristics of young Dorper rams was conducted during the breeding season. Thirty-six 11-12 month…
A study with the aim of evaluating the reversibility of the nutritionally induced changes in the scrotal and testicular characteristics of young rams was conducted. Thirty-six Dorper rams, 11 to 12 months of age were randomly divided into three groups…
An objective was defined for a breeding program in South Africa to improve the female fertility of the national herd. The aim of the study was to change the approach of defining a trait based on female fertility and to…
A trial was conducted to determine the effect of egg-weight on the hatchability and growth performance of chickens. Large and medium eggs of New Hampshire (NH) and Rhode Island Red (RIR) hens were grouped in four categories, according to their…
Four different goat ecotypes are recognized in Namibia. These ecotypes represent a unique genetic resource due to their adaptation to the different environmental conditions. Sufficient phenotypic characteristics exist that distinguish between the ecotypes. This study is a first attempt to…
Six ruminally-cannulated cows were assigned to a 2 x 3 changeover experiment with two periods to determine the effect of supplemental biotin on in vitro fibre fermentation kinetics. All the cows received the same basal diet but with different biotin…
Thirty two Döhne Merino lambs with an initial mean (± s.d.) body weight of 30.3 ± 2.5 kg were used in a randomised block experiment to determine the effect of an exogenous fibrolytic enzyme preparation (Abo 374) on body weight…
A study with the aim of developing a protocol for the successful cryopreservation and thawing of African lion (Panthera leo) sperm was conducted. Semen from six chemically immobilized adult lion males was collected by electro-ejaculation and frozen using Biladyl and…
The energy and nitrogen retention of Merino and Dohne Merino lambs offered a feedlot diet were measured. The energy retentions of the two breeds were relatively similar (0.96 vs. 1.00 MJ/kg BW0.75), but the Merino lambs had a higher nitrogen…
The weight and protein distribution, as well as the essential amino acid composition of the carcass, internal and external offal of Merino and Dohne Merino male lambs were investigated. Differences in the weight and protein distribution, as well as the…
The whole empty body essential amino acid composition of finishing Merino and Dohne Merino male lambs was investigated. The amino acid requirements for growth vary considerably between these two breeds. Hence, it appears that whole empty body amino acid profiles…
The chemical score of microbial protein revealed the order of limiting amino acids for whole empty body growth of Merino and Dohne Merino lambs as histidine, methionine, leucine, arginine and phenylalanine. Microbial protein is unable to provide a similar duodenal…
