A simulation study was carried out to investigate the effect of selection on the estimation of genetic parameters for butterfat production in dairy cattle. It was found that selection leads to a substantial overestimation of fixed effects and variance components…
This study was conducted to evaluate direct and correlated selection responses to selection for total weight of lamb weaned per ewe joined (TWW), number of lambs born (NLB), number of lambs weaned (NLW) and weaning weight (WW). Data from the…
Italian ryegrass (Lolium multiflorum cv. Midmar) is often fertilized with high levels of nitrogen (N) in order to ensure maximum dry matter (DM) yields. This practice also increases the N content of herbage. This study was conducted to determine whether…
This study presents the first results on the evaluation and selection of polymorphic microsatellite markers for the genetic characterization of native chicken populations in southern Africa. Blood samples for DNA extraction were obtained from five chicken lines from South Africa…
The aim of this experiment was to determine the effect of using a heavy or a light calibre rifle for night cropping of impala (Aepyceros melampus) on meat quality (pH, colour, cooking and drip loss, tenderness). The effect of gender…
This article proposes the Bayesian approach to solve problems arising in animal breeding theory. General elements of Bayesian inferences, e.g. prior and posterior distributions, likelihood functions, and the solving of the random effects in the case of the mixed linear…
The objective of this study was to determine the undegradable dietary protein requirements of veal calves. Two experiments were carried out with Holstein bull calves from 3-10 days of age until slaughter at 20 weeks of age. Both experiments were…
The aim of this study was to investigate the effect of thermal conditioning of broiler chickens during embryonic development on subsequent performance under standard rearing conditions. During incubation eggs from 32-, 45- and 56-week old Ross 308 broiler parent stock…
A direct observation technique was used to establish the foraging behaviour of Boer goats, Nguni goats, Pedi sheep and Dorper sheep. According to the Chi-square dissimilarity measure, plant-form (grass, forbs, woody) differences between the diets of goats and sheep were…
There is a paucity of literature characterizing response to varying levels of feed intake in goats. A controlled experiment was designed at Prairie View A&M University (PVAMU) with purebred goats, to measure feed intake, and its subsequent effects on growth…
The objective of this study was to investigate the effect of level of rumen protected conjugated linoleic acid (CLA) 35 on milk yield and composition in Saanen goats. Eight multiparous goats were used in an eight animals and four periods…
The effect of changing dietary energy and crude fibre concentrations on the utilization of metabolizable energy (ME) was investigated in four growing ostrich chicks by addition of lucerne meal to a maize-lucerne based diet. The experiment was carried out in…
Data on cumulative feed intake, growth rate and chemical body constituents of 24 ostrich chicks, from a comparative slaughter experiment, were utilized to describe patterns of efficiency of feed utilization, deposition rates of protein, fat and body energy, as well…
The study was undertaken to assess the influence of various environmental effects, e.g. sex, age of dam, month of birth and mating types (black X black, black X grey, grey X black and grey X grey) on pelt traits of…
In animal breeding, selection decisions are often made amongst animals from separate environmental groups. Production data in these groups may differ both in mean and variance. In South Africa, yearling weights of beef cattle are recorded in two different phases…
The Texas A&M University (TAMU) Beef Cattle Production model was expanded to include basic concepts of quantitative genetics. The traits simulated were birth weight, yearling weight, mature weight and milk production. The progeny inherited attributes from both the sire and…
Ninety bull calves of five Bonsmara strains, viz. Edelheer (E), T-49 (T), Wesselsvlei (W), Roodebos (R) and Belmont Red (BR), and two Nguni sub-populations, viz. Bartlow (B) and non-Bartlow (NB), were fattened under intensive feeding conditions and serially slaughtered at…
A questionnaire-based survey was conducted among a purposive sample of 60 small-scale cattle farmers in the Mopeane Rustenburg district, all of whom owned five or more head of cattle. Results showed that small-scale cattle farming is a part-time activity for…
