The pig performance testing scheme in Zimbabwe

Commercial pig production in Zimbabwe largely involves the use of exotic pig breeds numbering approximately 104 thousand out of a total of 295 thousand pigs (CSO 1999a, 1999b). In pig production there are many traits of economic importance and improving these traits requires improvement of the environment together with genetic improvement. The genotype of an animal sets a ceiling to which the animal can be improved through manipulation of the environment. It is, therefore, important to complement advances made in management practices by improving the pigs genetically. Genetic improvement within breeds can only be achieved by means of selection. Selection is the act of choosing those animals which will be the parents of the next generation and which have the highest breeding value. Information on the breeding value of an animal can be obtained by testing its relatives, e.g. sibs and progeny, or by evaluating the animal’s own performance. In Zimbabwe genetic evaluation of pigs is done only for the large-scale commercial pig production sector

Genetic analysis of somatic cell score and udder type traits in South African Holstein cows

Selection accuracy for resistance to mastitis may be increased by combining somatic cell score (SCS) and udder type into an udder health index, using genetic parameter estimates among them. A multi-trait animal model was used to estimate genetic parameters among lactation average SCS and udder type traits in South African Holstein cattle, through REML procedures. Data comprised records on 22 999 Holstein cows in 722 herds, collected through the National Milk Recording Scheme from 1996 to 2002. Average SCS in the first three lactations (SCS1, SCS2, SCS3) were considered as different traits and the udder type traits were fore udder attachment (FUA), rear udder height (RUH), udder cleft (UC), udder depth (UD), fore teat length (FTL) and fore teat placement (FTP). Heritability estimates for SCS were 0.19 ± 0.02, 0.17 ± 0.02 and 0.19 ± 0.02, respectively for SCS1, SCS2 and SCS3. Udder type traits had heritability estimates ranging from 0.13 ± 0.01 for UC to 0.34 ± 0.01 for FTL. The genetic correlations between lactation SCS ranged from 0.82 ± 0.04 to 0.99 ± 0.03 for correlations of SCS3 with SCS1 and SCS2, respectively. Genetic correlations between SCS and udder type traits were in the range -0.01 ± 0.07 between FUA and SCS3 to -0.38 ± 0.04 between UD and SCS1 and SCS2. Slow genetic progress is expected when selection is applied independently on SCS and udder type traits, due to the generally low heritability estimates. Low, shallow udders with narrowly placed teats are associated with low SCS in the South African Holstein population. Keywords: Genetic parameters, mastitis, selection accuracy, udder healthSouth African Journal of Animal Science Vol. 38 (1) 2008: pp. 1-1

Evaluation of female fertility in dairy cattle enterprises – A review

The aim of this article was to review the state of fertility of female dairy cattle in South Africa and to compare it with international efforts at improving fertility. Fertility in dairy cows is defined as the ability to conceive from first insemination soon after calving and to carry the calf full term to calving. It is one of the main profit drivers in the dairy industry and is a complex trait that is influenced by the environment, genetics, and their interaction. Generally, there has been a decline in dairy cow fertility across breeds worldwide because of intense selection for milk yield, milk components, and body conformation traits. In addition, most fertility traits are negatively correlated to milk production traits. Milk production has been the focal point of selection programmes as it is linked directly to the profitability of the dairy enterprise. The low heritability of fertility traits is one of the factors that discouraged efforts to include fertility in genetic evaluations. However, owing to its economic importance, female fertility was later included in the breeding objectives for dairy cattle in several countries. Although most fertility traits are heritable to a low degree, some additive genetic variability can be exploited

Short communication Sex of calf and age of dam adjustment factors for birth and weaning weight in Tswana and Composite beef cattle breeds in Botswana

________________________________________________________________________________ Abstract Records on 2 257 Composite and 5 923 Tswana calves born between the period of 1988 and 2006 in Botswana were used to calculate additive correction factors for the effects of sex of calf and age of dam on birth weight and weaning weight. The mature age group in both breeds for the two growth characteristics was 5 -12 year old dams. Male calves were heavier than their female contemporaries throughout the preweaning growth period. The sex of calf adjustments for birth and weaning weights were 2.75 and 8.21 kg in the Tswana while the corresponding values for the Composite were 2.84 and 10.11 kg. Both birth and weaning weights increased with advancing age of dam, reaching a peak in mature dams and declined when dams reached an old age. Age of dam adjustment factors for birth weight in the 3, 4 and 13+ year age groups were, respectively, 1.74, 0.96 and 1.87 kg in the Tswana. Corresponding values for the Composite were 2.28, 0.94 and 2.06 kg, respectively. Age of dam adjustment factors for WW were respectively 10.36 and 5.46 kg for age groups 3 -4 and 13+ years in the Tswana. Adjustment factors for weaning weight in the Composite breed were 13.84, 3.20 and 9.58 kg for age groups 3, 4 and 13+ years, respectively. These results indicate that adjustment factors for birth and weaning weights should be considered separately for sex of calf and age of dam in these breeds, and also, that these adjustments need to be applied within the breed from which they were derived. _______________________________________________________________________________

A review of artisanal cheese making: An african perspective

Artisanal cheeses and other fermented milk products have long been part of the diet of African rural communities. Cheese is a source of nutrients that are essential to the development and growth of children in rural areas, where intake of amino acids, vitamin A, vitamin B12, calcium, phosphate, and polyunsaturated fatty acids may be limited. Wara, Karish, Ayib, Takammart, Wagashi, Domiati, and Ras are prominent cheeses of African origin. Artisanal cheese making should be expanded to improve people’s nutritional status at low cost, stimulate the local economy, and empower small-scale farmers. This review firstly gives an overview of artisanal cheese production and consumption, and evaluates opportunities and challenges, while focusing on an African perspective. Secondly, it provides an insight into strategies that could improve cheese making at small-scale level. Possible areas of research and knowledge gaps are highlighted, particularly ways of improving cheese quality and safety

A review of artisanal cheese making: An African perspective

Artisanal cheeses and other fermented milk products have long been part of the diet of African rural communities. Cheese is a source of nutrients that are essential to the development and growth of children in rural areas, where intake of amino acids, vitamin A, vitamin B12, calcium, phosphate, and polyunsaturated fatty acids may be limited. Wara, Karish, Ayib, Takammart, Wagashi, Domiati, and Ras are prominent cheeses of African origin. Artisanal cheese making should be expanded to improve people’s nutritional status at low cost, stimulate the local economy, and empower small-scale farmers. This review firstly gives an overview of artisanal cheese production and consumption, and evaluates opportunities and challenges, while focusing on an African perspective. Secondly, it provides an insight into strategies that could improve cheese making at small-scale level. Possible areas of research and knowledge gaps are highlighted, particularly ways of improving cheese quality and safety

Some insights into the phenotypic and genetic diversity of indigenous pigs in southern Africa

Indigenous pigs in southern Africa are mainly owned by economically vulnerable groups in marginal areas where they are used as a source food, income and security. A study was carried out to achieve three objectives: to describe pig production systems, get a phenotypic description of the pigs and to characterize them genetically. A survey of 199 farmers in three districts in South Africa, (Vhembe, OR Tambo and Alfred Nzo) and one district in Zimbabwe (Chirumhnazu) was carried out. Additional farmers in Malawi (Dedza, Mchinji and Salima) and Zimbabwe (Mutoko) were sampled in order to meet the other two objectives. Most of the pigs (69.7%) were owned by women, with men owning 20.5% and children the remainder. Production of the pigs was constrained by several factors including disease, inadequate feeds, poor housing and lack of knowledge. The majority of the pigs were small and black with characteristics that are probably suited for thermoregulation in arid environments. The third objective was achieved through genotyping 111 pigs using 22 microsatellites. Preliminary results indicate very little differences across populations with an overall inbreeding coefficient of the subpopulation relative to the total population (FST) of 0.071. The results indicate that the indigenous pigs in southern Africa are relatively homogenous.Keywords: Conservation, Kolbroek, microsatellites, smallholder pig production, Windsnye

Index selection of beef cattle for growth and milk production using computer simulation modelling

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 the dam. The incorporation of genetic concepts into the model allowed for the introduction of variation between individuals and generations. This was achieved by interfacing the original model with stochastic genetic subroutines including a restricted selection index for desired genetic change. The index included birth weight and yearling weight. In addition, a function for estimating dystocia was also added. The model was used to simulate selection strategies for a small-to-moderate size breed of cattle and a large-size breed using a restricted selection index. There was an increase in both birth and yearling weight after 20 years of selection in the small-to-moderate size breed, and there was also an increase in dystocia. Antagonistic selection to decrease birth weight and increase yearling weight was simulated for the large breed. Birth weight and dystocia problems declined while yearling weight increased for all classes of animals. In both experiments correlated responses were recorded for mature size and milk production. It was concluded that the modified TAMU Beef Cattle Production model offers breeders an opportunity to compare different selection strategies and evaluate different breeding plans. (South African Journal of Animal Science, 2001, 31(2): 65-76

Socio-economic aspects in draught animal-crop linkages: a diagnostic study of Tsholotsho, Chinyika and Mutoko smallholder farming areas of Zimbabwe

A research paper on Zimbabwe's small-holder farmers' constraints in crop production due to shortages of draught animal power during the 1994/95 agricultural season.A survey was conducted on 451 households in Tsholotsho, Chinyika and Mutoko smallholder areas to understand farmers’ crop production constraints in relation to draught animal power (DAP) during the 1994/95 agricultural season. Farmers without DAP constituted 48.6 percent in the three districts. Of these, 54.5 percent had access to neighbours’ or relatives’ animals. The rest hired or worked in others’ fields in exchange for draught animals. Animal diseases and shortage of grazing land were noted as the major constraints in animal production. Both farmer education and experience as well as household head were found to be associated with district (p<0.001). Tsholotsho had the largest number of farmers (52.8 percent) with more than 10 years experience while Mutoko had the largest proportion (43.3 percent) of Master farmers. Farmer education and experience were found to be independent of sex. The average land holdings per farmer for Tsholotsho, Chinyika and Mutoko were 6.21 ha, 4.22 ha and 1.62 ha, respectively. Tsholotsho is a dryland communal area whilst Chinyika is a relatively wet area. Mutoko is a typical communal area with a high population pressure. Maize is the main crop in Chinyika and Mutoko whilst millet is the most common in Tsholotsho