In a study over two breeding seasons, we assessed the effect of dietary energy and protein levels on body mass, body condition and the production of fertile eggs by male ostriches. During the first season, birds were fed diets with…
Data on 17258 weaning weight records of calves from a crossbreeding project were utilized to investigate the problem of collinearity and its effect on the estimation of direct, maternal and the non-additive genetic effects. Several criteria were used to detect the near-dependency…
Data on 17348 weaning weight records from a beef cattle crossbreeding operation were used to determine the effect of outliers on regression coefficients. Different criteria were used for detecting potential influential points. Eliminating a small number (932 or 5.4 %)…
Different combinations of saturated and unsaturated fatty acids were fed to broilers to establish their effect on the fatty acid composition of the broiler carcass and the abdominal fat pad. Six combinations of Canola acid oil (CAO, high levels of…
The aims of this research were to study goat production in the rural areas of South Africa and to explore the impact of intervention objectives, namely an increase in kidding percentage and a decrease in kid losses (mortalities, theft and…
Data collected on birth and weaning weight traits of beef cattle calves over the period of 1968 to 1992 with varying levels of Angus and Charolais genes, ranging from 0% to 75%, were analysed to determine possible optimum breeding levels…
The aim of this study was to measure the effects of stage of maturity and level of nitrogen (N) fertilisation of Panicum maximum cv. Gatton on intake, ruminal fermentation and the partial digestibility of organic matter (OM) in sheep grazing…
The aim of this study was to evaluate the effect of level of nitrogen (N) fertilisation and stage of maturity on certain qualitative parameters and dry matter (DM) production of Panicum maximum cv. Gatton during autumn. Treatments included seven levels…
Genetic parameter estimates for scrotal circumference (SC), testis diameter (TD) and two-tooth liveweight (LW) were obtained for 1380 two-tooth Merino rams born from 1986 to 1998 on the Tygerhoek Experimental Farm. The effect of SC of service sires (n =…
Data used for this study were collected on the Carnarvon Afrino flock from 1986 to 1998, and include data records on several subjectively assessed traits, body weight and fleece traits of 3291 animals, the progeny of 127 sires and 772…
The objective of this experiment was to test the proposition that fatter pigs, when fed a high crude protein (CP) diet, would attempt to correct the effects of excess fattening on body composition by returning to a state that is…
The nitrogen (N) retention response to the abomasal infusion of amino acids in South African Mutton Merino ram lambs fed a standard finishing diet was investigated. The basal diet consisted of (g/kg air dry weight): 300 lucerne, 80 wheat straw,…
Five populations with varying percentages of animals in full-sib families were simulated. For each population, three combinations of additive and dominance genetic variances of different relative magnitudes were considered, thereby creating fifteen sub-populations. Constant residual variance was used in all…
The chemical composition and in vitro dry matter digestibility (IVDMD) of untreated and ammoniated crop residues, sampled at various sites in the North West Province of South Africa, were investigated. The mean IVDMD of maize residues obtained by means of…
Field data for the period 1976 to 1998 from South African and Namibian Afrikaner, Drakensberger, SA Angus and Simmentaler beef cattle breeds was used to investigate two fertility traits, calving rate (CR) and calving success (CS). Calving rate, a lifetime…
Feeding costs of animals is a major determinant of profitability in livestock production enterprises. Genetic selection to improve feed efficiency aims to reduce feeding cost in beef cattle and thereby improve profitability. This study estimated genetic (co)variances between weaning weight…
Pedigree and race run data from Thoroughbreds racing in Southern Africa, covering the period 1986-2002 (63 146 horses in pedigree data-set and 778 532 race runs), were analysed in order to study genetic and environmental factors affecting the incidence of…
This study deals with the effects of different hatcher temperatures on hatching traits in modern commercial broiler eggs during the last five days of incubation. The hatching eggs were obtained from a 52-wk old (Ross 308) flock. All eggs were…
The actual level of inbreeding and the effect of inbreeding depression on yearling body weight and fleece traits in the South African Dohne Merino population were investigated. All available pedigree data, which comprised of 266 268 records (302 169 animals…
To test whether animals grown under ideal temperature conditions would have different growth parameters to animals grown in more conventional housing, sixty Large White x Landrace male pigs from three genotypes were housed in six temperature-controlled chambers. The results were…
