No abstract

Genetic parameters were estimated for Venda chicken body weights at hatching, and at 4 weeks, 10 weeks and 21 weeks of age. A single-trait animal model with restricted maximum-likelihood procedures was used. Random effects were additive direct and maternal genetic, common environmental and error. The heritability estimates for direct effects were 0.36, 0.25, 0.41 and 0.22 for hatch, 4 weeks, 10 weeks and 21 weeks, respectively. The maternal effects were estimated at hatch and 4 weeks of age and were not present at later ages. Common environmental effects disappeared with increasing age. There was an antagonistic relationship between direct and maternal effects. The results show potential for genetic improvement of indigenous Venda chickens through selection. Maternal effects should be considered if selection is carried out at early ages.

Two hundred and forty day old broiler chicks were used to investigate the effect of aqueous Moringa oleifera leaf extracts (AMOLE) on growth performance and carcass characteristics of broiler chicken. The birds were randomly allocated into six treatments with four replicates, and each replicate containing 10 broiler chicks; the CRD was used. The treatments contained AMOLE 0+ (positive control with antibiotic treatment), AMOLE 0-(negative control with ordinary water), AMOLE 60 (60 ml/l), AMOLE 90 (90 ml/l), AMOLE 120 (120 ml/l) and AMOLE 150 (150 ml/l) inclusion levels of AMOLE, respectively. Birds on positive control had the highest final body weight and growth rate (2392.00 g and 53.61 g respectively) and the ones on 150 ml/l of AMOLE had the least (2042.00 g and 45.37 g respectively). Results of feed intake showed that birds on positive control had the highest (84.70 g) and the ones on 90 ml/litre of AMOLE had the lowest (73.19 g); while the results of feed conversion ratio indicated that birds on AMOLE 90 and AMOLE 120 performed better than the positive control treatment. Birds on the AMOLE had similar dressing percentages though that of positive control was highest (94.93 %); while those on AMOLE 60 and AMOLE 150 had the highest large intestine and lung weights respectively. Aqueous Moringa oleifera leaf extract can be included up to 90 ml/litre in the drinking water of broiler chicken for reduced feed intake (12.83 %) and improved feed conversion efficiency (9.11) thus, AMOLE can be used to replace synthetic antibiotics as growth promoter.

The objective of this work was to estimate and compare the growth curve parameters for live weight of indigenous Venda and Naked Neck chickens and carry out some analyses to test the existence of differences in the growth pattern between these breeds. The data were collected from the two breeds of chickens that were reared from day-old to 21 weeks of age. Two hundred chickens (100 of each breed) were used. Three different non-linear models, namely Gompertz, Logistic and Richards, were used to define the growth curves of the chickens. Models were compared using Coefficients of determination (R 2 values), A parameter values, the Durbin-Watson Statistic (DW) test for autocorrelation, computing difficulty based on the number of iterations needed for convergence and size of residual variances. The R 2 were high for all models: 0.996, 0.990 and 0.997 for Gompertz, Logistic and Richards, respectively. Residual variances were 2240, 5924 and 1154 for Gompertz, Logistic and Richards, respectively. The Gompertz model was observed to be suitable for explaining the growth of the chickens. Breed differences were observed in the growth parameters of chickens. The Venda breed was observed to be late maturing and heavier at maturity while the Naked Neck was shown to have a higher growth rate, reaching maturity earlier but attaining a lighter mature weight.

___________________________________________________________________________________ AbstractAcacia trees form the third largest woody plant family in southern Africa and are an important ecological component of the bushveld vegetation that is prevalent in the Limpopo Province of South Africa. The purpose of the study was to determine types and amounts of tannins and also to evaluate the nutritive value of tree foliages, Acacia karroo, Acacia nilotica, Acacia tortilis, Acacia galpinii, Acacia sieberiana, Acacia hebeclada and Acacia rhemniana, grown in the Limpopo Province and also to determine types and amounts of tannins occurring in them. Young leaves with petioles from seven tree foliages were collected from five different trees per species at the University of the North (now University of Limpopo) in April 2003, in a completely randomized design. Packed volume ranged from 1.50 mL/g for A. karroo to 3.00 mL/g for A. hebeclada whilst water retention ranged from 3.71 g/g for A. galpinii to 4.98 g/g for A. sieberiana. These results suggest that all the tree leaves have a high intake potential. All the Acacia species had crude protein levels above 100 g/kg dry matter (DM), ranging from 103 g/kg DM for A. rhemniana to 183 g/kg DM for A. sieberiana. Crude protein levels of this magnitude in a diet are adequate to support the maintenance requirements of cattle, sheep and goats at low to medium production levels. The Acacias contained medium to high levels of neutral and acid detergent fibres with ranges of 488 to 622 and 415 to 545 g/kg DM, respectively. In vitro DM and organic matter degradabilities varied from 345 to 534 and 254 to 474 g/kg DM, respectively. Acacia hebeclada, A. sieberiana and A. galpinii contained traces of total phenolics whilst A. tortilis contained approximately 90 g/kg DM of total phenolics and A. karroo, A. nilotica and A. rhemniana contained intermediate concentrations. Extract condensed tannin (CT) content ranged from 1.1 g/kg in A. hebeclada to 80.7 g/kg in A. karroo. At level above 50 g/kg, CT tends to negatively affect intake and digestibility in ruminants. Consequently, reduced intakes of A. galpinii, A. karroo and A. tortilis could be expected because they contained CT values above 50 g/kg. Only A. nilotica showed a sharp curve in the potassium iodate test, reflecting its considerable content of hydrolysable tannins (HT). All the other species had flat curves reflecting low levels of HT in them. The results showed that all the species except for A. galpinii, A. karroo and A. tortilis are of good nutritive value and have a potential for integration into livestock feeding systems in the Limpopo Province. __________________________________________________________________________________________