The role of cultivated pastures in milk production in South Africa

A brief survey of existing methods of milk production in the Republic of South Africa is made, together with an appreciation of the role and importance of established pastures in relation to these. The cost of milk is discussed in relation to two roughage plans; the one being based on ordinarily accepted methods of roughage provision, and the other on roughage produced under intensive methods of grass farming where a high fertilizer regime is employed. High‐producing cows are more economic than low‐producing cows. So too, is a high‐level pasture fertilizing regime, except where cows have a very low inherent production.     

A consideration of veld condition assessment techniques for commercial livestock production in South Africa

Abstract

A number of procedures have been developed for the evaluation of veld condition in a variety of vegetation types in South Africa. These include both agronomic and ecologically based methods, about which there still remain a great deal of controversy. However, the urgent need for methods which can be applied in practice has recently prompted the recommendation of specific methods for the vegetation types representative of the major livestock producing areas of South Africa.     

Prevalence of mixed Trypanosoma congolense infections in livestock and tsetse in KwaZulu-Natal, South Africa

Trypanosoma congolense causes the most economically important animal trypanosomosis in Africa. In South Africa, a rinderpest pandemic of the 1890s removed many host animals, resulting in the near-eradication of most tsetse species. Further suppression was achieved through spraying with dichlorodiphenyltrichloroethane (DDT); however, residual populations of Glossina austeni and G. brevipalpis remained in isolated pockets. A total of 506 of these tsetse flies were captured in the Hluhluwe-iMfolozi Park, the St Lucia Wetland Park and Boomerang commercial farm. The polymerase chain reaction (PCR) was used to determine the infection rate and frequency of mixed infections of these flies. Additionally, 473 blood samples were collected from cattle at communal diptanks and a commercial farm in the area and each one examined by the haematocrit centrifugation technique (HCT). Furthermore, buffy coats from these blood samples were spotted onto FTA Elute cards and the DNA extracted from each one tested using 3 separate PCRs. The HCT revealed the presence of trypanosomes in only 6.6% of the blood samples; by contrast, species-specific PCR detected trypanosome DNA in 50% of the samples. The species-specific PCR detected trypanosome DNA in 17% of the tsetse flies, compared with the nested PCR targeting rDNA which detected trypanosome DNA in only 14% of the samples. Over time, the transmission of Savannah-type T. congolense and Kilifi-type T. congolense as mixed infections could have an impact on disease manifestation in different hosts in the area.     

The use of trees,shrubs and herbs in livestock production by communal farmers in northern KwaZulu-Natal,South Africa

A survey of the use of trees, shrubs and herbs for livestock production was conducted through questionnaires among 90 farmers in the communal areas of northern KwaZulu-Natal in South Africa. The areas surveyed were located at Mtubatuba, Hluhluwe, Kwadlangezwa and Jozini. All the farmers questioned were found to own some form of livestock, mostly the Nguni breed. The commonly perceived sources of constraints on livestock production were external and internal parasites. The well known plants reported to be consumed by the animals were Vitellariopsis arginata and Rhus gueinzii. Most of the farmers (27.7%) used Cissus quadrangularis and Gnidia kraussiana for treating worm infestations and coughs in livestock. Plants used for increasing milk production were Crinum macowanii and Sarcostemma viminale. The well known plant species detrimental to livestock was Moraea spathulata, which causes diarrhoea and death.     

The role of genetic engineering in livestock production

In this paper we discuss the use of genetic engineering in livestock production. We examine the main two different aspects of genetic engineering: cloning and transgenesis. After commenting what has been expected from both techniques in livestock production in the last 25 years, the practical difficulties for implementing cloning and transgenesis are examined. Apart from technical difficulties, problems derived from the detection of genetically superior animals and evaluation of the clones and the transgenic animals make these techniques less interesting than they appear to be. Most of the observed variability of the economically interesting traits is not genetic, genetic evaluation needs a large number of animals and cloning success will represent a serious loss of genetic variability and the loss of the flexibility needed for markets in constant evolution. There is a risk in transgenic animals of production of new intermediate biochemical products that may be toxic, allergenic or carcinogenic. The benefits produced by transgenic animals hitherto hardly justify this risk. The expectations that genetic engineering produced 25 years ago should be re-examined, considering the risks and the high investment required.     

Contacts between domestic livestock and wildlife at the Kruger National Park Interface of the Republic of South Africa

One of the most important transboundary animal diseases (TADs) in the southern African region is foot-and-mouth disease (FMD). In this region, a pathway for spread of FMD virus is contacts between cattle and certain species of wildlife. The objective of this study was to evaluate contacts between cattle and wildlife in the Kruger National Park (KNP) and the adjacent Limpopo province for the time periods October 2006 to March 2007 and April to September 2007. In this study, 87 livestock owners and 57 KNP field rangers were interviewed. Fifteen (17%) livestock owners reported contacts between wildlife and cattle. More livestock owners reported observing contacts between cattle and all wildlife species during October-March than April-September (p = 0.012). However, no difference was found between these periods for contacts between cattle and individual wildlife species. A total of 18 (32%) field rangers reported contacts between cattle and wildlife. The most common species-specific contacts were between cattle and buffalo (63/year), cattle and impala (17/year) and cattle and lion (10/year). There were no significant differences in rangers reporting observed contacts between cattle and wildlife during October-March versus April-September or between rangers reporting observed contacts outside versus within the KNP. Overall, there was no evidence of higher contact rates between cattle and wildlife in the study area during October-March compared to April-September. Contact data collected in this study can be used to better understand the transmission of FMD virus in this region.     

多胺在畜禽营养中的作用

本文就畜禽体内多胺的来源及代谢,多胺对畜禽小肠形态、功能以及畜禽生长性能的影响进行综述。     

Dealing with plant poisoning of livestock: the challenge in Queensland

The current and possible future situation of diagnosis, prevention and treatment of plant poisoning of livestock in Queensland is reviewed. Topics discussed are livestock producers' perceptions, field investigation, plant identification, veterinary laboratory techniques and prevention through knowledge of poisonous species and the circumstances of poisoning. Also considered are management strategies for prevention including the manipulation of rumen flora and epidemiological approaches, therapies including immunisation, plant control and sources of information on poisonous plants and poisoning.     

The role of female veterinarians in Africa

While the number of female veterinary students has reached figures as over 80% in the Netherlands and other European countries, the number of female veterinary students in Africa is also changing but still at a slower pace. Still nowadays, according to UNICEF, two-thirds of primary school age children, denied their right to basic education, are girls. In addition, especially in rural areas in Africa, there are only few secondary schools, so that children, either have to travel over large distances on a daily basis or have to live away from their families. As girls, already from an early age play an important role in the daily household routine, they are often not allowed to leave for schooling. There used to be less than 10 veterinary faculties in Africa during the first half of the 20th century. These faculties were located in South Africa, Sudan, Egypt and Nigeria. For many years, African veterinarians were also trained in western countries (UK, France, USA) or in former communist countries (Russia, Ukraine, Romania, Hungary Eastern Germany, Cuba) depending on the existence of historic or political links. A long stay abroad made it more difficult for female students, especially for those with children. Still nowadays, female veterinarians in Africa are mostly working for the veterinary departments mainly in the urban areas. Another area where many female veterinarians can be found are governmental diagnostic and research laboratories as well as training institutions such as veterinary faculties or agricultural colleges. Generally the salaries at these institutions are very low and therefore their male colleagues have gradually shifted to work in the private sector with more competitive salaries (private clinics, sector pharmaceutical companies, development projects, (agricultural) banks, etc). As still in most societies, women tend to follow their husbands, most female veterinarians are bound to find employment where their husbands are based. In addition, as most postgraduate training required a prolonged stay abroad, women encountered difficulties in leaving their families behind to improve their career perspectives. Gradually, there has been an increase of possibilities of post-graduate training in the African region as well as the introduction of a modular system and perspectives for training over the internet. These developments will clearly be beneficial for women, as it will enable them to follow post-graduate training without leaving their families for extended periods. Gradually, also female veterinarians in Africa are becoming empowered and recognise their capabilities. The understanding of the importance of gender aspects especially with regard to animal husbandry practices has opened up new opportunities for female veterinarians to work in extension services and as health promoters. The access to further education is the key to expanding their professional perspectives.     

Validation of the fluorescence polarization assay as a serological test for the presumptive diagnosis of porcine brucellosis.

Sera from Canadian pigs (brucellosis free, n = 14037) and sera from pigs infected with Brucella suis (n = 401) were tested by the buffered antigen plate agglutination test, the complement fixation test, an indirect and a competitive enzyme immunoassay and a fluorescence polarization assay. The results were analysed and assay sensitivity and specificity estimates were calculated. The sensitivity and specificity of the tests were as follows: the buffered antigen plate agglutination test, 77.1 and 96.9%; the complement fixation test (considering anticomplementary sera as negative), 93.3 and 95.5%; the complement fixation test (considering anticomplementary sera as positive), 58.1 and 99.9%; the indirect enzyme immunoassay, 94.0 and 97.9%; the competitive enzyme immunoassay, 90.8 and 96.6%; and the fluorescence polarization assay, 93.5 and 97.2%; respectively. It was concluded that the fluorescence polarization assay was a valuable asset to the diagnosis of porcine brucellosis because of its accuracy, ease of performance and relative cost.     

The Ecology of Patella From the Cape Peninsula South Africa

Forty-six species were recorded in association with Patella spp., but most of these are casual associates, seeking temporary shelter. The shell surface offers an important substrate for algae.

The amphipod Hyale grandicornis is often associated with Patella, particularly in the juvenile stages. It is a facultative inquiline which vacates its hosts at high tide. The isopods Dynamenella australis and D. scabricula are predominantly associated with limpets and complete their life cycles under limpets. Choice chamber experiments demonstrate their preference for sheltering under limpets. The copepod Scutellidium patellarum is similar, but the association is more marked.

Calliopiella michaelseni (Amphipoda) is commensal and show a preference for certain limpet species. Its colour changes in relation to the host species. Feeding occurs on limpet faeces and algal fragments. The life cycle is completed under the limpet, two reproductive peaks occurring each year. Adults usually occur in pairs and there is a positive correlation between host and amphipod size. Juveniles remain with their parents initially, and then disperse to other limpets. Adult pairs may defend their host, excluding other amphipods. Calliopiella is strongly photonegative and thigmotactic.

The turbellarian Notoplanapatellarum is preferentially commensal with Patella oculus. This can be experimentally demonstrated. It feeds on small Crustacea, including Scutellidium.     

A questionnaire-based evaluation of the veterinary cordon fence separating wildlife and livestock along the boundary of the Kruger National Park, South Africa

Veterinary cordon fences are used in Southern Africa to separate wildlife from domestic animals in order to prevent transmission of infectious diseases. Such fences are a control method recognized by the World Organization for Animal Health (OIE) for establishing disease-free zones in beef exporting countries. However, few studies have evaluated the ecological impact of these physical barriers or their effectiveness at a multispecies level. We examined the permeability of one such barrier, along 357 km of the western and southern boundary of the Kruger National Park (KNP) during 2007. Information was gathered using a semi-structured questionnaire implemented among 32 teams of fence maintenance workers. Data were analyzed to identify (a) the main causes of fence damage, (b) the seasonality, location and duration of fence repairs, (c) high permeability areas for elephant (Loxodonta africana), kudu (Tragelaphus strepsiceros), impala (Aepyceros melampus), buffalo (Syncerus caffer) and warthog (Phacochoerus africanus), and (d) the influence of fence electrification, rivers and elephant damage on the frequency of observation of wildlife species outside the KNP estimated during the year. Human and elephant damage were the most common reasons for fence repairs. Elephant and buffalo were the most and least common large mammal species reported observed outside the KNP (1076 and 162 reports/year), respectively. Cattle incursions into the KNP were also reported in 44% of the fence sections. Electrification of the fence was an important factor explaining differences in estimated wildlife species observations outside the KNP during the year. Correlations between estimations of observed species suggested that fence gaps created by elephants might be used by the other wildlife species. Estimated annual counts of kudu, impala and buffalo, but not warthog, were found to correlate with elephant observations. Negative binomial regression models were developed to explore the relationships between observed estimations of different wildlife species outside the KNP the fence, electrification of fence sections and the presence of watercourses, suggesting that kudu, impala and buffalo could use elephant induced fence damage to leave the KNP. The questionnaire was able to evaluate fence integrity and identify sections where integrity was sub-optimal for separating wildlife from domestic livestock species. If combined with more quantitative methods and applied on a routine basis, it could provide an efficient and cost-effective method for monitoring the effectiveness of physical barriers to contain wildlife within protected areas such as is the case with veterinary cordon fences in Southern Africa.     

The epidemiology of Parafilaria bovicola in the Transvaal Bushveld of South Africa

A total of 20 375 flies collected off cattle on 12 farms over 36 months were identified and examined for 3rd stage P. bovicola. The 3 vector species accounted for 64.1% of the flies collected and were the only fly species found to be infected. Musca lusoria was clearly the dominant vector fly, although large numbers of Musca sp. A appeared regularly between February and April each year. This phenomenon, coupled with high numbers of M. lusoria throughout most of the year, led to an increase in the numbers of vector flies from their lowest level in June to a peak in February-April. Of the 13 070 vector flies examined for 3rd stage larvae only 64 (0.52%) were positive; of these 41 were M. lusoria and 17 Musca sp. A. No positive male flies were found. Incubation of wild-caught flies for up to 13 days at 27 degrees C noticeably increased the larval recovery rate. Flies were found to be infected mainly from August-March. Infected M. lusoria were recorded from July-March and infected Musca sp. A from January-May. Only 6 infected M. xanthomelas were collected and this was during the period August-December, when most ovipositional blood spots occur on cattle. It is concluded that P. bovicola transmission in the Bushveld is not correlated with peak periods of bleeding but rather with high numbers of vector flies, the various species augmenting each other so that transmission may take place almost throughout the year.     

Environmental and economic impacts of livestock productivity increase in sub-Saharan Africa

Livestock production in sub-Saharan Africa (SSA) is not matching the annual 2.5?% growth of its population. Regional per capita meat and milk production corresponds, respectively, to about 13 and 8?% of developed countries indicators. Livestock performances in this region have decreased within the last 30?years. In fact, SSA, with a 12?% bovine extraction rate against a world average of 21?%, includes about 16?% of world cattle, only producing 6 and 2.6?% of global meat and milk, respectively. These low performances have economic and environmental consequences reflecting the necessity for upgrading livestock managing skills in the region. This effort includes various components such as sanitary prophylaxis, reproduction, nutrition, and in particular, substantial increase in livestock yield for human consumption. This will allow for an improved animal and pasture management and soil preservation, enhancing meat production and decreasing methane and nitrogen emissions from enteric fermentation and manure processing. These environmental gains due to increased livestock off-take rates can represent relevant credits in the global Environmental Carbon Market under the United Nations Framework Convention on Climate Change Kyoto protocol. These credits can be used for investments in livestock essential services and marketing facilities leading to improved productivity.     

必需微量元素在家畜胚胎和胎儿发育中的作用

多年前,人们就清楚地确认了营养与繁殖之间的重要联系。例如,Benetts和Chpman(1937)就确认了新生羔羊的地方性共济失调是由于母羊放牧于缺铜草场上所致。这些信息以及随后的一些研究都表明,给妊娠期的母羊补铜能防止该病的发生。自那时以来的研究都已表明,多种微量元素在支持多     

The role of essential trace elements in embryonic and fetal development in livestock

This review addresses the concept that essential trace minerals play a vital role in many enzymatic and metabolic pathways that are critical for conceptus development during pregnancy in livestock species. The conceptus relies entirely on the maternal system for a sufficient supply of trace minerals and other nutrients needed for normal development. If this supply is inadequate, growth and/or health of the conceptus can be affected adversely, and many of these effects carry over into the neonatal period. Information, accumulated in our laboratory and presented herein, indicates that zinc, copper and manganese are among the trace minerals that have the greatest impact on reproduction. For example, levels of zinc, copper and manganese were several fold greater in the conceptus than in other reproductive tissues, indicating that the conceptus preferentially accumulates these minerals, an action that may be important for conceptus development, growth and survival. Moreover, some recent results indicate that increasing the biological availability of zinc, copper and manganese, by attachment to short peptide chains (i.e., proteinated trace minerals) can enhance reproductive performance of swine. Mineral concentrations in conceptuses from female pigs consuming proteinated trace minerals were greater than those from females that consumed only inorganic mineral salts. Elucidating the mechanisms whereby conceptus development and survival are enhanced by essential trace minerals may lead to development of specific feeding programs to increase the number and health of offspring at parturition, thereby allowing for further improvements in production efficiency in animal agriculture.     

The helminths of ranch calves in the North-eastern Mountain Grassland of South Africa

The cumulative total helminth parasite burdens of ranch calves during their first seven months of life on the North-eastern Mountain Grassland of South Africa were determined during two consecutive years. Trichostrongylus axei was the most abundant nematode parasite followed by Cooperia spp. and Ostertagia ostertagi. Haemonchus spp. occurred in relatively low numbers and its development was significantly inhibited. The total helminth parasite burdens of the calves ranged from 681 to 7,269 with a mean of 4,405.