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In southern Africa game farming has become an effective way of using underutilised resources and a valuable method of preserving and increasing wildlife numbers. However, little is known about the mineral requirements of wild animal species or the assessment of the mineral nutritional status of these species. To establish criteria for estimating the copper (Cu) nutritional status of wildlife, current knowledge about Cu metabolism and criteria for domestic animals has been used. Since the Cu metabolism of ruminants differs substantially from that of non-ruminants, Cu metabolism in domestic species such as cattle and sheep representing wild ruminants, and pigs and horses as non-ruminant species, has been scrutinised to propose criteria for wild bovids in southern Africa. In the adequate range of dietary Cu intakes, literature suggests that hepatic Cu concentrations in ruminants increase linearly with an increase in Cu intake, allowing a relatively reliable measure of sufficiency. In non-ruminants, hepatic Cu concentrations follow a lag phase during which hepatic Cu concentrations remain relatively constant with increasing dietary Cu intakes of more that 25 times their requirements. A consequence is that non-ruminants can tolerate much higher dietary levels of Cu compared to ruminants. It is proposed that at liver Cu concentrations of < 20 mg/kg dry matter (DM), a wild ruminant could benefit from Cu supplementation; liver Cu concentrations of between 20 and 300 mg Cu/kg DM suggest an adequate Cu intake; concentrations of 300 to 500 mg/kg DM indicate a potentially unhealthy accumulation of Cu, while liver Cu concentrations of > 500 mg/kg DM indicate that the animal probably consumed more Cu than required and might be at risk of developing Cu toxicosis. [ABSTRACT FROM AUTHOR]

The concentration of trace elements in the liver is used as an indicator of the mineral nutritional status of an animal, as a benchmark of environmental mineral exposure, to follow the metabolism of an element in the body and for various other purposes. Concentrations are expressed on a wet (fresh) liver basis or on a dry liver basis. From a literature search and evidence from an analytical laboratory, large variations (varying from < 20% to > 40%) have been recorded on the percentage of moisture in the livers of ruminants. Such variations potentially compromise the interpretation of results on mineral concentrations in livers, and preclude robust comparisons between studies. Among the factors that can affect the moisture content of livers are: inconsistencies in sampling and preparation of liver samples; exposure to toxic substances; ill-health of the animal; fat content of the liver; and age of the animal. It was estimated that the mean dry matter (DM) content of the livers of healthy ungulates containing less than 1% liver fat is between 27.5% and 28.5%, and on a fat-free basis 25--26% DM. For routine analyses of liver samples it is suggested that to limit variations owing to differences in liver moisture content, liver mineral concentrations should be expressed on a DM basis, and for in-depth scientific studies on mineral metabolism on a dry, fat-free basis. However, if mineral concentrations are expressed on a wet basis, it is advisable to supply the liver DM content as well. [ABSTRACT FROM AUTHOR]

With the congress theme of 'Golden Innovations for Sustainable Animal Agriculture', it would be opportune to look not only at innovations with present and future potential, but at those 'golden innovations' that have been achieved and established over more than five decades. Many of these innovations still form the basis of many aspects of present-day sustainable animal agriculture in southern Africa. This brief review covers three areas, namely the history of the South African Society for Animal Science (SASAS), achievements of animal scientists, mainly in the earlier years of the Society, and the coming of age of professionalism in the animal science profession. The South African Society of Animal Production (SASAP) was founded on 28 April 1961 in Pretoria. The name was later changed to the South African Society for Animal Science. The theme of the first congress of SASAP was 'Efficiency in Production', a theme that is still relevant. In 1971 the South African Journal of Animal Science (SAJAS) was initiated, and by 2017 the 47th volume has been published. A large amount of knowledge that is applicable to local conditions has accumulated and should be drawn upon to avoid 'reinventing the wheel'. In the 1950s to 1970s, Professor Jan Bonsma developed the concept of functional efficiency of cattle and principles that focused on adaptability and sustainability. Extensive research was conducted on the feeding of urea and phosphorus to grazing livestock, leading to the practice of urea-containing rumen-stimulating winter supplementation of ruminants. South Africa was considered a world leader in the field of supplementary feeding practices. South Africa has a proud history in the discipline of animal genetics and the practical application of breeding principles to enhance livestock productivity, and is in the forefront with studies on the genomics of livestock in southern Africa. SASAS was instrumental in establishing the professional status of animal scientists in South Africa. The vision is that an animal scientist should be identified as the expert in his/her field and the best qualified person to advise on matters such as animal breeding, nutrition and general management of livestock. SASAS council also acts as a mouthpiece for and custodian of animal scientists. The society protects the interests of animal scientists, is pro-active in promoting animal science, and acts as a watchdog over the professional activities of members. [ABSTRACT FROM AUTHOR]

Wood ash is a mineral source that is readily available in most subsistence farming communities. The potential use of wood ash as a mineral source in animal nutrition is evaluated and reviewed. The predominant mineral in wood ash is calcium (Ca), and thus a potential Ca source in animal diets. However, the wide, sourcedependent variations of Ca and other minerals in wood ash are limiting factors in the extensive use of ash in livestock diets. Ca sources with a less variable mineral composition such as feed lime (CaCO3) and limestone are therefore preferable. This restricts the inclusion of wood ash in diets except where a good estimate of its Ca content is available. Specific situations exist under subsistence farming conditions in which wood ash could be used as a Ca supplement, for example when kitchen waste high in cereal products or cassava tuber meal that is low in Ca is fed to livestock. Variation in the concentrations of most trace elements in wood ash is even wider than that of Ca. However, it is suggested that trace elements in wood ash formed when combustion is at temperatures below 500 °C have a relatively high bioavailability. Therefore, wood ash could be a valuable source of trace elements under subsistence farming conditions. Wood ash is an alkaline product which has been utilized in the alkaline treatment of roughages to improve digestibility and also to reduce the tannin content of feedstuffs. Contrary to other hazardous alkali such as NaOH used in the treatment of feedstuffs, wood ash is a non-corrosive alkali. It is suggested that these treatments would be feasible under resourcelimited farming conditions. However, attention will have to be given to the problem that products containing ash would have a high Ca to P ratio which could result in a phosphorus deficiency in livestock. [ABSTRACT FROM AUTHOR]

In resource-limited livestock production systems, the supplementing of mineral supplements is often not feasible because of economic constraints and possibly a lack of appropriate information. Wood ash is a pure mineral source that is usually readily available in many subsistence farming communities. As a starting point in evaluating its use in animal nutrition, factors affecting the mineral composition of wood ash are evaluated in this review. A survey on the composition of the wood ash from subtropical tree species in South Africa, and reports from many other countries, demonstrated that wood ash is primarily a calcium (Ca) source, though ash from a homestead fire may differ in composition if fire-making material other than wood is used. However, there is wide variation in Ca levels in wood ash compared to other Ca sources such as feed lime (CaCO3) and limestone. Furthermore, as is typical of most waste- and by-products the concentration of other elements, especially trace elements in wood ash, varies considerably, even within tree species. In this evaluation, factors that have a major influence on mineral composition in wood ash are tree species, tree components such as bark vs. wood ash, and also the temperature when burning wood. It is therefore concluded that because of the wide variation in the composition of wood ash, it is advisable to perform chemical analyses on ash available in a region before implementing feeding programmes. However, analysis for minerals is costly and will remain an obstacle in the sound application of ash in resource-limited areas. Furthermore, owing to the wide variation in mineral composition, it would be of little value to present the mineral composition of wood ash in feed composition tables. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the potential of macadamia oil cake meal (MOCM) and wood ash as feed ingredients for poultry under subsistence farming conditions. In this article, the effect of these ingredients on bone characteristics is reported. Two hundred and eighty eight day-old New Hampshire chickens were used in the study. The research was conducted as a 3 x 2 factorial design, and 48 chicks were randomly allocated per treatment. Three basic diets were formulated: one without MOCM and the other two containing 10% and 50% MOCM. The MOCM contained 132 g/kg of crude protein, 228 g/kg crude fat and 365 g/kg crude fibre on an ‘as-fed’ basis. Each of these three treatments was split into two: one receiving feed lime (CaCO3) as the main source of calcium; and the other wood ash, which contained 257 g Ca/kg. All diets contained a Ca level of ca. 10 g/kg. The chickens received the experimental diets from 2 to 15 weeks of age. After week 15, eight chickens per treatment were killed and their right legs removed at the femorotibial articulation and frozen for later evaluation. Between Ca sources there were no significant differences in tibia weight, diameter, volume, density and breaking strength. The ash content and Ca, P and Mg concentrations in bone ash between Ca sources were similar. However, in the two Ca diets containing 50% MOCM the Ca and P concentrations of the tibiae were significantly lower than in the diets containing lower levels of MOCM. It was concluded that wood ash was as effective as feed lime in supplying Ca to chickens. However, some practical problems in the feeding of wood ash became apparent, such as that wood ash is a fine powder and does not mix well with other ingredients, except when the oil content of the diet is high, as with the treatments containing MOCM. [ABSTRACT FROM AUTHOR]

The general perception that livestock is a major contributor to global warming resulted mainly from the FAO publication, Livestock's Long Shadow, in 2006, which indicated that livestock is responsible for 18% of the world's greenhouse gas (GHG) emissions. This figure has since been proved to be an overestimation, since it includes deforestation and other indirect contributions. The most recent figure is in the order of 5% - 10%. Although only ruminants can convert the world's high-fibre vegetation into high- quality protein sources for human consumption, ruminant production systems are targeted as they are perceived to produce large quantities of GHG. Livestock is also accused of using large quantities of water, an allegation that is based on questionable assumptions and the perception that all sources of food production require a similar and equal quantity and quality of water. In the case of ruminants, extensive systems are usually found to have a lower per-area carbon footprint than grain-fed systems, but a higher footprint if expressed in terms of kg product. Feedlots maximize efficiency of meat production, resulting in a lower carbon footprint, whereas organic production systems consume more energy and have a bigger carbon footprint than conventional production systems. Cows on pastures produce more methane than cows on high concentrate diets. In South Africa, as in most of the countries in the sub-tropics, livestock production is the only option on about 70% of the agricultural land, since the marginal soils and rainfall do not allow for crop production and the utilization of green water. An effective way to reduce the carbon and water footprint of livestock is to decrease livestock numbers and increase production per animal, thereby improving their efficiency. [ABSTRACT FROM AUTHOR]

A total of 896 maize grain samples were obtained from all the maize silos throughout South Africa (231 silos) and analysed for selenium (Se) content. This information was used to compile a regional distribution map of the Se content of maize grain in South Africa. Of the samples analysed, 94% contained below 50 µg selenium/kg DM and can thus be classified as deficient from an animal and human nutritional point of view. Maize grain in South Africa is therefore a poor source of Se for animals and humans. The geographical distribution of Se values of maize grain is consistent with that of previous studies on the Se status of herbivores in South Africa, suggesting that plants growing in most of the maize-producing areas of the country contain low concentrations of Se. However, these findings contradict those of the soil Se status in the country as reported by the Agricultural Research Council's Institute for Soil, Water and Climate, which states that the eastern part of the maize-producing areas of the country tends to have adequate to high soil Se levels and the western areas to have low levels. These contradictory results can be explained to a large extent by the varying soil pH throughout the country. Soil pH plays a primary role in the availability of selenium to plants. Although the eastern parts of the country tend to have high Se concentration in the soil, it is not available to the maize plant owing to a low soil pH, while in the western parts of the country, where soil pH may be suitable for Se uptake by plants, there seems to be an inadequate concentration of available Se in the soil. [ABSTRACT FROM AUTHOR]

Samples of kikuyu foggage (standing hay) were collected in northern KwaZulu-Natal from five adjoining paddocks to measure the changes in nutrient composition of the foggage as winter progressed. Leaves and stems were separated. The first samples collected on the 18th of May contained green to dry material at a ratio of 3 : 1 and that was reduced to practically no green material in July. Although the proportion of leaf decreased from 64.6% to 56.8% as winter progressed, differences were not significant. Crude protein (CP) levels and effective dry matter degradation decreased significantly with time while neutral and acid detergent fibre levels increased. The calcium (Ca) and phosphorus (P) concentrations in the leaves decreased significantly between the first collection and later collections, while these changes were less pronounced in the stems. At all stages the stems contained significantly lower concentrations of Ca than the leaves, while P concentrations between leaves and stems did not differ. Consequently, the Ca : P ratios in the leaves varied between 2.08 and 1.60 and that of the stems between 0.74 and 1.10. These results suggest that the significantly lower Ca levels in kikuyu stems compared to leaves could make a significant contribution to the variation in Ca : P ratios reported for kikuyu. The concentrations of the other elements measured did not differ between the leaves and stems. Concentrations of CP, potassium, magnesium, copper and selenium in the kikuyu foggage decreased rapidly from the first collection that contained a relatively high proportion of green material to later collections when the foggage was dry. [ABSTRACT FROM AUTHOR]

A study was conducted to test whether supplementation of trace elements would have any beneficial effect on year-old ewes receiving a submaintenance level of nutrition. The ewes were fed a poor quality hay. The control group received no supplementation (Treatment 1). A solution containing copper (Cu, 5 mg/d), selenium (Se, 1.6 mg/d) and zinc (Zn, 48.2 mg/d) was dosed twice a day to sheep in Treatment 2 while the ewes in Treatment 3 received a double dose of the three elements. Tissue analyses at the end of the 93-day experimental period suggested that the lambs in the control group suffered from a marginal Se deficiency, while the intake of the other elements seemed to be sufficient. Within treatments, weight changes varied tremendously. Therefore, even though differences were not significant, the unsupplemented control group lost weight, while the sheep in the other two treatments maintained their initial body weights during the study. Likewise, the control group tended to have a lower immune response against an injected foreign protein than the supplemented treatments, though differences were not significant. Plasma in the control group showed significantly higher activities of creatine phosphatase and aspartate transaminase than the supplemented groups. This suggested that the supplemented elements protected the body against tissue damage. Although it is traditionally considered that deficiencies in energy and protein, as first limiting nutrients with the highest priority in nutrition, should be overcome before any response to trace element supplementation could be expected, many of the micronutrients are involved in antioxidant activities in the body. Results from this study suggested that positive responses to micronutrient supplementation could be possible if the body is subjected to oxidative stress during submaintenance levels of energy and/or protein nutrition. [ABSTRACT FROM AUTHOR]

The aim of this experiment was to determine the site and extent of digestion of nutrients in sheep fed broiler litter alone (100% litter treatment), broiler litter plus 7.5% sugarcane molasses (92.5% litter treatment) and broiler litter plus 15% molasses (85% litter treatment). Voluntary intake was increased by molasses, apparently due to an increased rate of passage of digesta through the digestive tract. This resulted in a shift in the site of disappearance of organic matter (OM) from the rumen towards the lower digestive tract. For the 100 and 92.5% litter treatments, 0.37 and 0.46 of dietary OM disappeared in the rumen respectively, compared to 0.21 for the 85% litter treatment, while 0.16, 0.08 and 0.35 of dietary OM disappeared in the small intestine for the 100, 92.5 and 85% litter diets respectively. In the case of the 85% litter treatment, 0.26 of dietary nitrogen (N) disappeared in the rumen and 0.45 in the small intestine, compared to 0.55 and 0.62 in the rumen and 0.18 and 0.11 in the small intestine for the 100 and 92.5% litter diets respectively. There were no differences between treatments for total tract apparent digestibility of N (0.73) and OM (0.65-0.73), rumen degradability of N (71-87%) or concentration of ammonia-N in rumen fluid (53 mg/100 ml). It was concluded that the addition of molasses might be advantageous when the intake of litter is restricted or when voluntary intake of litter is unacceptably low. [ABSTRACT FROM AUTHOR]

Available information on the selenium (Se) status of grazing herbivores in South Africa is reviewed and collated in the form of a geographical distribution map. Marginal to acute Se deficiencies have been reported to occur in the Midlands region and in mountainous areas of the KwaZulu-Natal province and in the southern coastal region of the Western Cape province. These areas receive a high annual rainfall and the soils are predominantly acid. The Se status of livestock in the highland sourveld areas of the Gauteng, northern Free State and Mpumalanga provinces is varied. Selenium intake appears to be adequate in most areas although localised cases of deficiencies occur. Substantial air and water pollution occurs in some of these areas, and the presence of Se antagonists could increase the incidence of Se deficiency in future. Limited data indicates that vegetation in the arid regions of South Africa provides Se sufficient to meet the requirements of grazing herbivores. Subterranean water from a number of locations contains Se at concentrations higher than the norm for safe drinking water, the impact of which has not yet been established. There are large areas of South Africa for which little or no information on the Se status of grazing animals exist, and further investigations are required. [ABSTRACT FROM AUTHOR]

In this study the mineral composition of ash from fireplaces at rural homesteads was determined to establish if such ash could be a source of minerals to goats. The mineral composition of ash collected from homesteads in six different communal farming regions of South Africa was determined. The ash samples collected in the three northern regions of the country contained between 180 and 248 g Ca/kg dry ash, while those from the Eastern Cape Province contained low concentrations (8-45 g Ca/kg ash) and high concentrations of Si. It is concluded that wood was probably used as fire making material in the northern regions, while cattle manure was probably used in the Eastern Cape regions, though soil contamination could have contributed to the high Si concentrations. The concentration of the Fe and Zn in ash was high while that of the other elements in ash was relatively low and would probably contribute little to a goat's diet, considering the proportion of ash in a total diet. It is concluded that in some regions of the country goats would be able to ingest a substantial proportion of Ca when scavenging on ash heaps or receiving ash as a dietary supplement, while in other regions this will not be the case. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the nutritional status of scavenging chickens by assessing the composition of their crop contents. The study was conducted on 288 free-ranging indigenous chickens from six adjacent rural villages in Venda region of South Africa over three seasons (autumn, winter and spring). The chickens consumed grains, kitchen waste, seeds from the environment, plant materials, worms and insects, and some undistinguishable materials. Household waste accounted for 78.6%, 91.1% and 75.8% and materials of animal origin, including insects and worms, accounted for 7.4%, 10.4% and 16% of the crop content in autumn, winter and spring, respectively. Grains and kitchen waste consumption and macro- and micro-nutrient concentrations varied with season. The crude protein (CP) level of the crop contents of adult chickens in all seasons and the calcium and phosphorus levels in winter corresponded with the requirements of poultry for maintenance and growth, but not egg production. Supplementation of CP to young birds in all seasons and calcium and phosphorus in autumn and spring might be necessary to improve their growth. Concentrations of copper, manganese, zinc and cobalt were above the requirements of poultry, but below their maximum tolerance levels (MTL). Iron concentrations ranged from 2907 mg/kg DM to 6424 mg/kg DM, which are well above MTL, suggesting potential detrimental effects on the birds if the iron in the crop contents is bioavailable. Aluminium concentrations ranged from 2256 mg/kg DM to 4192 mg/kg DM, though aluminium is considered non-toxic. It was concluded that the birds would not suffer from micro-mineral deficiencies, and that a risk of toxicity would depend on the bioavailability of the consumed element. [ABSTRACT FROM AUTHOR]

The in vitro affinity and adsorption capacity of a humic acid, oxihumate, for aflatoxin B1 (AFB1) was evaluated, utilizing Langmuir and Freundlich adsorption isotherms. Oxihumate showed a high in vitro affinity for AFB1. The Freundlich isotherm fitted the data better than the Langmuir isotherm, and binding capacities of 10.3, 7.4, and 11.9 mg of AFB1/g of oxihumate at pH 3, 5, and 7, respectively, were calculated. The in vivo efficacy of oxthumate as an aflatoxin binder in male broiler chickens exposed to aflatoxin-contaminated feed from 7 to 42 d of age was also assessed. The efficacy of oxihumate was compared with a commercially available product with a brewers dried yeast (BDY) and brewers fermentation solubles as main active ingredients. A total of 420 birds were assigned to 28 pens, with 15 birds per pen. The following treatments were applied: 1) 0 mg of AFB1 + 0 additives, 2) 1 mg of AFB1/kg of feed + 0 additives, 3) 1 mg of AFB1/kg of feed + 3.5 g of oxihumate/kg of feed, 4) 1 mg of AFB1/kg of feed + 3.5 g of BDY/kg of feed, 5) 2 mg of AFB1/kg of feed + 0 additives, 6) 2 mg of AFB1/kg of feed + 3.5 g of oxihumate/kg of feed, and 7) 2 mg of AFB1/kg of feed + 3.5 g of BDY/kg of feed. Each treatment consisted of 4 replicates. Oxihumate was effective in diminishing the adverse effects caused by aflatoxin on BW of broilers (P < 0.05). Oxthumate also showed protective effects against liver damage, stomach and heart enlargement, as well as some of the hematological and serum biochemical changes associated with aflatoxin toxicity (P < 0.05). Results indicated that oxthumate, but not BDY, could alleviate some of the toxic effects of aflatoxin in growing broilers. Oxthumate might, therefore, prove to be beneficial in the management of aflatoxin-contaminated feedstuffs for poultry when used in combination with other mycotoxin management practices. Additional studies are warranted to assess its efficacy under a wide variety of circumstances. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of method of sample preparation on the degradation kinetics of herbage when applying the in situ technique. Ryegrass (Lolium multiflorum cv. Midmar) was harvested at three and four weeks after cutting and fertilizing with 200 kg nitrogen (N)/ha. Freshly cut herbage was used to investigate the following four sample preparation methods. In trial 1, herbage was (1) chopped with a paper-cutting guillotine into 5-10 mm lengths, representing fresh (FR) herbage; (2) chopped and stored frozen at -20 °C in a chest freezer, representing frozen (FN) herbage; (3) chopped, stored frozen at -20 °C for 12 h followed by freeze drying for 48 h and thereafter milled through a 2 mm screen, representing freeze dried (FD) herbage and (4) chopped and oven dried at 65 °C for 48 h and thereafter milled through a 2 mm screen, representing oven dried (OD) herbage. Prepared samples were incubated in three rumen cannulated, lactating Holstein-Friesian cows. The dry matter (DM) and N loss (%) of the FR, FN, FD and OD herbage differed significantly at 0 and 5 hours incubation but not at 24 or 48 hours. Sample characteristics (particle size, wet or dry sample) clearly influenced the degradability of herbage DM and N. Frozen herbage showed similar degradation characteristics to fresh herbage. In trial 2, ryegrass samples were prepared by the same four methods, but at a standardized particle size, namely, chopped into 5-10 mm lengths. The treatments were: chopped fresh, chopped frozen, chopped freeze dried and chopped oven dried. The N losses differed significantly between treatments for the 0, 5 and 10 hour incubations, but not at the 22 and 46 hour incubation periods. Although the a, b and c fractions differed significantly between treatments, the effective degradability did not differ for fresh, frozen and freeze dried chopped samples. Oven dried chopped samples had reduced effective degradability and are not recommended for determining effective degradability. It is proposed that fresh chopped herbage be used in degradability studies. [ABSTRACT FROM AUTHOR]

The effect of high levels of broiler litter in the diets of sheep on sensory characteristics and composition of fat in mutton was evaluated. Thirty-six South African Mutton Merino wethers weighing ca. 41 kg were randomly allocated to four treatment diets containing 0, 28, 56 or 85% broiler litter. All wethers were slaughtered at a target body mass of 55 kg. Dressing percentage was calculated and the composition of fatty acids in the subcutaneous fat was analysed. An analytical sensory panel evaluated sensory characteristics of carcass samples and loin sample characteristics. High sensory scores (7 out of 10) were obtained for all dietary treatments. Compared to the other treatments, a high inclusion level (85%) of broiler litter in the diet reduced (p < 0.05) the flavour and overall acceptability of sensory samples, decreased concentrations of myristic acid (C 14:0) and margaric acid (C 17:0) in subcutaneous fat and increased linolenic acid (C 18:3) concentrations. It was concluded that the inclusion of broiler litter in diets for sheep at levels of up to 56% should not adversely affect the sensory characteristics of the meat, but higher inclusion levels might have a slight adverse affect on subcutaneous fat composition and sensory characteristics. [ABSTRACT FROM AUTHOR]