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Nelspruit, South Africa

Scholtz M.M.,ARC Animal Production Institute | Scholtz M.M.,University of the Free State | McManus C.,Federal University of Rio Grande do Sul | Okeyo A.M.,Kenya International Livestock Research Institute | Theunissen A.,Land Reform and Rural Development
Livestock Science

Developing countries from the southern hemisphere have similarities in terms of climatic and agricultural conditions and cattle are the most important livestock species in these countries - which leads to many areas of similar interest and opportunities regarding beef cattle production. The increase in demand for meat in developing countries offers large market opportunities for livestock producers. If the productivity of beef farmers can be improved to commercial levels, it may have the potential to address poverty in these agriculturally based economies. Climate change is predicted to be highly dynamic and can have adverse effects on crop and livestock productivity. The cattle breed to be used and the production strategy to be followed in developing countries of the southern hemisphere will depend primarily on the environment and level of management. The availability of diverse cattle breed resources with adaptive and productive differences will allow breed types to be matched to different environments, management capabilities and markets. In the harsh and undeveloped areas or pastoralist systems, pure breeding with e.g. Sanga, Zebu or naturalized breeds may be the only production strategy that can be followed. In the more developed areas, crossbreeding with small indigenous cows may succeed in improving the output of beef cattle farming. It is believed that crossbreeding will gain importance in many developing counties in the southern hemisphere. It is therefore essential that crossbreeding studies be conducted where necessary, to supply information regarding heterosis and for the development of multi-breed genetic evaluations, breeding objectives and decision making. By describing production environments it may be possible to identify genotypes that are adapted to a specific environment. However, tools are needed to overlay geo-referenced data sets onto the different environments. Statistical science continues to support animal breeding and improvement, especially with respect to production traits. Traits linked to fertility and/or survival are still problematic and the appropriate quantitative breeding technology to properly handle these traits still needs to be developed. Gene or marker assisted selection may play an important role in selection for disease and parasite resistance or tolerance, since it is generally difficult to measure these traits directly. Strategies that utilize EBVs derived from genomic analyses (genomic EBVs), together with conventional mixed model methodology, may speed up the process of breeding animals with subsequent higher and more efficient production. The application of a landscape genetics approach offers the potential to greatly enhance the knowledge of how landscape heterogeneity influences the genetic population structure, gene flow, and adaptation. Results from these studies can be used to address questions related to species management and conservation. © 2011 Elsevier B.V. Source

Van Heerden S.M.,ARC Animal Production Institute | Smith M.F.,ARC Biometry Unit
Food Chemistry

The shoulder, loin and leg from P-class pork carcasses were used to determine the nutrient composition of both raw and cooked cuts. Significantly lower fat content were observed in the current study for the leg (5.21 g/100 g) and loin (6.99 g/100 g) compared to the shoulder cut (10.32 g/100 g). The overall percentage fat for all three cuts was less than 10% which is recommended by the South African Heart Mark. The cooked loin cut contained the most protein (27.50 g/100 g) of the three cooked cuts. When compared to other meat products (beef, mutton and chicken) it is clear that pork is a good source of B vitamins, especially vitamin B3. The cooked loin cut contained the least vitamin B1 (0.22 mg/100 g), B2 (0.02 mg/100 g) but the most vitamin B3 (7.09 mg/100 g), of the three cooked cuts. The 100 g cooked shoulder, loin and leg cuts provide on average 40.11% protein, 5.19% magnesium, 3.37% calcium, 24.29% phosphorus, 18.22% zinc, 22.33% iron and 22.50% vitamin B1, 2.57% vitamin B2 and 42.6% vitamin B 3 of Recommended Daily Allowances for males, age 25-50. Energy from a 100 g portion provides 5.81% of the Recommended Daily Allowances. To conclude, the pork cuts are undoubtedly a good source of nutrients that is required for good health because it is high in protein, have a low fat content and are a nutrient-packed choice for the family and compares favourably with the fat, energy, and cholesterol content of many other meats and poultry. © 2013 Elsevier Ltd. All rights reserved. Source

Basha N.A.D.,University of KwaZulu - Natal | Basha N.A.D.,University of Khartoum | Scogings P.F.,University of Zululand | Dziba L.E.,ARC Animal Production Institute | Nsahlai I.V.,University of KwaZulu - Natal
Small Ruminant Research

This study was conducted to determine the influence of plant chemical, physical and phenology properties on diet selection of Nguni goats during the dry, early wet and late wet seasons in savanna in South Africa. Diet composition was estimated by direct observation of two different adult Nguni goats randomly selected from a herd each day for 7-8. days in each season. Observations were made during active foraging periods for 2. h in the morning and 1.5. h in the afternoon. The duration of each feeding bout and the species of woody plant from which bites were cropped at each feeding station were recorded. Diet selection was determined from the relative duration of feeding. Diet preference of each species was expressed as an index calculated using the selection and relative abundance of woody species. Browse species consumed by goats were sampled and analysed to determine crude protein, neutral detergent fibre, acid detergent fibre, acid detergent lignin, condensed tannins, cellulose and hemicellulose. Diet selection varied among the three seasons. The five species most selected (utilised) by goats were Scutia myrtina, Acacia nilotica, Dichrostachys cinerea, Acacia natalitia and Chromolaena odorata. S. myrtina was the most selected species during the dry season while D. cinerea was the most selected in the wet seasons. S. myrtina was the most preferred (highest utilisation relative to availability) in the dry and early wet seasons while A. nilotica was most preferred in the late wet season. Spinescent species were generally selected more than non-spinescent species in all seasons, while fine-leaf and deciduous species were selected more than broad-leaf and evergreen ones in the wet seasons. However, preference for broad-leaf and evergreen species increased in the early wet season. Although plant chemistry varied across seasons, it did not explain the preference of goats for various plant species in this study. Instead, effects of chemistry were species-specific. In conclusion, this study demonstrates the importance of evergreen browse species as a source of fodder when deciduous species are unavailable. © 2011 Elsevier B.V. Source

Short A.,ARC Animal Production Institute | Yunusa I.A.M.,University of New England of Australia
African Journal of Range and Forage Science

Using the results from a long-term grazing trial in the Dry Highland Sourveld of the KwaZulu-Natal province, we prepared a water use efficiency value (the ratio of the increment in annual biomass to total annual evapotranspiration) for this rangeland type. Using seasonal biomass measurements recorded between March 2000 and March 2007, we developed a model for predicting the increment in annual biomass using a regression relationship between fPAR (fraction of photosynthetically active radiation intercepted by the vegetation canopy) and measured standing biomass. This regression model was used to estimate the growth rates from fPAR for the period 2001-2006. During the period 2004-2007, when complete meteorological records were available, we calculated reference or potential evapotranspiration (ET0) using the Penman-Monteith equation. To approximate actual evapotranspiration (ETa), we used the MODIS leaf area index to approximate canopy conductance component (Gs) of the Penman- Monteith equation. Using the adjusted fPAR curves as a surrogate for plant growth, and ETa, we calculated a water use efficiency value for these grasslands of 7.5 ± 0.48 kg DM mm-1 ha-1 y-1. This value relates well to other published water use efficiencies for natural rangeland. © NISC (Pty) Ltd. Source

Schoeman S.J.,University of Pretoria | Cloete S.W.P.,Private Bag X1 | Cloete S.W.P.,Institute for Animal Production | Olivier J.J.,Private Bag X1 | Olivier J.J.,ARC Animal Production Institute
Livestock Science

The small stock industry in South Africa is of crucial importance as 80% of the agricultural land is unsuitable for intensive agricultural production. The contribution of 19 resource sheep flocks and goat herds towards breeding objective formulation, genetic improvement and parameter estimation was summarized. Substantial genetic gains resulting from selection for a range of economically important traits were demonstrated, lending impetus to the development and extension of the National Small Stock Improvement Scheme (NSIS). Responses in monetary values in the respective participating small stock breeds ranged from R0.098 for the Dormer to R0.818 for the S.A. Mutton Merino per small stock unit per annum for animals born in the interval from 2000 to 2006. This response is well below what was attained in the resource flocks and in the best participating flocks and herds. Even with this less than optimal change on a national basis, the impact on the sectoral economy is substantial. When related to the cost associated with the NSIS, this improvement is highly cost-effective. The impact of research and development in the small stock industry is therefore substantial, and the small stock industry is foreseen to continue playing an integral role in the national economy. © 2010 Elsevier B.V. All rights reserved. Source

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