40 research outputs found

    Origin and phylogenetic status of the local Ashanti Dwarf pig (ADP) of Ghana based on genetic analysis.

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    BACKGROUND: The Ashanti Dwarf Pig (ADP) of Ghana is an endangered pig breed with hardy and disease resistant traits. Characterisation of animal genetic resources provides relevant data for their conservation and sustainable use for food security and economic development. We investigated the origin and phylogenetic status of the local ADP of Ghana and their crosses with modern commercial breeds based on mtDNA, MC1R, Y-chromosome sequence polymorphisms, and genome-wide SNP genotyping. RESULTS: The study involved 164 local pigs sampled from the three agro-ecological zones of Ghana. Analyses of the mitochondrial D-loop region and Y-chromosome sequences revealed both European and Asian genetic signatures, with differences between the geographical zones. Black coat colour is the most predominant within the breed, with black MC1R alleles of both Asian and European origin. European alleles for spotting are present at a low frequency in the sample set, and may account for the occurrence of spotted piglets in some APD litters. PCA analysis of SNP data revealed a strong location and breed effect on clustering of local Ghanaian pigs. On a global level, Ghanaian local pigs cluster closely with European pigs of commercial origin, but we identified intervals via FST analyses that may elucidate loci for ADP specific traits. CONCLUSIONS: The presence of both European and Asian contributions, with differences between geographical zones probably reflects trading and colonial influences. Understanding the effects of admixture on important adaptive and economic traits of the ADP and other local breeds in Africa is critical for developing sustainable conservation programmes to prevent the decline of these genetic resources.The authors are grateful to Cambridge in Africa Research Excellence (CAPREx) for the award of Post-doctoral Fellowship to ROA, and the Alborada Trust for supporting the Research. G.L is supported by the European Research Council (337574-UNDEAD), and BMS is supported by BBSRC grant number BB/N000129/1. CAS is funded by the Department of Pathology and Hughes Hall, Cambridge

    Impact of heat stress on ruminant livestock production and meat quality, and strategies for amelioration

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    Climate change will continue to accentuate the negative impact of heat stress (HS) on ruminant livestock production, compromising animal welfare and meat quality. Mitigation strategies, including providing shade on farms, modifications of animal housing (heat extractors, fans, water sprinklers, and cool drinking water), and nutritional interventions, are important short-Term measures to reduce the negative effects of HS. Climate-smart breeding for thermotolerance and matching of adapted ruminant breeds to appropriate production systems should be considered for more sustainable livestock production systems

    Domesticated animals as hosts of henipaviruses and filoviruses: A systematic review

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    Bat-borne viruses carry undeniable risks to the health of human beings and animals, and there is growing recognition of the need for a 'One Health' approach to understand their frequently complex spill-over routes. While domesticated animals can play central roles in major spill- over events of zoonotic bat-borne viruses, for example during the pig- amplified Malaysian Nipah virus outbreak of 1998-1999, the extent of their potential to act as bridging or amplifying species for these viruses has not been characterised systematically. This review aims to compile current knowledge on the role of domesticated animals as hosts of two types of bat-borne viruses, henipaviruses and filoviruses. A systematic literature search of these virus-host interactions in domesticated animals identified 72 relevant studies, which were categorised by year, location, design and type of evidence generated. The review then focusses on Africa as a case study, comparing research efforts in domesticated animals and bats with the distributions of documented human cases. Major gaps remain in our knowledge of the potential ability of domesticated animals to contract or spread these zoonoses. Closing these gaps will be necessary to fully evaluate and mitigate spill-over risks of these viruses, especially with global agricultural intensification

    Comparative Assessment of Thermotolerance in Dorper and Second-Cross (Poll Dorset/Merino × Border Leicester) Lambs

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    The objective of this study was to compare the thermotolerance of second-cross (SC; Poll Dorset × Merino × Border Leicester) and Dorper lambs. Dorper and SC lambs (4–5 months of age) were subjected to cyclic heat stress (HS) (28–40 °C). The temperature was increased to 38–40 °C between 800 and 1700 h daily and maintained at 28 °C for the remainder of the day (30–60% relative humidity (RH)) in climatic chambers for 2 weeks (n = 12/group), with controls maintained in a thermoneutral (TN) (18–21 °C, 40–50% RH) environment (n = 12/group). Basal respiration rate (RR), rectal temperature (RT) and skin temperature (ST) were higher (p < 0.01) in SC lambs than in Dorpers. HS increased RR, RT and ST (p < 0.01) in both genotypes, but the levels reached during HS were lower (p < 0.01) in Dorpers. HS increased (p < 0.01) water intake to a greater extent in SC lambs, while feed intake was reduced (p < 0.05) by HS in SC lambs but not in Dorpers. HS increased (p < 0.01) blood urea nitrogen and creatinine in SC lambs only. Plasma non-esterified fatty acid concentrations were reduced (p < 0.05) by HS in SC lambs but increased (p < 0.05) in Dorpers. There was no effect of HS on pO2, cHCO3− and cSO2, but higher (p < 0.01) blood pH and lower (p < 0.01) pCO2 were recorded under HS in both genotypes. Blood electrolytes and base excess were reduced (p < 0.01) under HS, while a genotype difference (p < 0.05) was only observed in blood K+ and hemoglobin concentrations. Basal plasma prolactin concentrations were lower (p < 0.01) in Dorpers but were elevated at a similar level during HS (p < 0.01) in both genotypes. Dorper lambs are more resilient to HS than SC lambs. Future research should focus on confirming whether the better heat tolerance of Dorpers is translated to better returns in terms of growth performance and carcass traits over the summer months

    Morphological characterization of local pigs in Ghana

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    Characterization is essential for conservation and sustainable utilization of farm animal genetic resources, especially local breeds that are often less fancied due to their relatively low production potential. A total of 163 local Ashanti Dwarf pigs (ADP) and their crossbreds with exotic breeds, sampled from six regions of Ghana were characterized morphologically following FAO’s methodology on phenotypic characterization of Animal Genetic Resources (AnGR). Results indicated no significant (p &gt; 0.05) effect of type of breed and sex on linear body measurements. There was a significant (p &lt; 0.05) effect of location on linear body measurements. Local pigs presented concave head profile (85.89%), black coat colour type (67.48%), plain coat colour pattern, erect ear type (84.66%), projecting backwards (52.15%) and a short and cylindrical snout type (62.58%). A greater number of the local pigs (70.55%) showed aggressive temperament. The data gathered from this study should contribute to the development of sustainable conservation schemes for local pig genetic resources and prevent their extinction.Keywords; characterization, morphological, ADP, conservatio

    A critical review of sustainable conservation options for animal genetic resources in indigenous production systems in the African region

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    The African continent is made up of a land mass of 30.1 million km2 covering a wide variety of geo-ecological zones. This and other anthropological activities have given rise to a variety of cultures and production systems after centuries of evolution under human and natural selection pressures. Currently the continent harbours about 101 regional transboundary breeds and 2055 local breeds even though the actual figures may be higher. The size and genetic composition of these breeds can only be static under static conditions that are merely hypothetical. Animal genetic resources are subjected to change due to multiple factors such as environmental changes, socio-economic or policy drivers including market trends of livestock products. Current trends indicate a reduction in livestock breeds and species in Africa and thus the most appropriate intervention is conservation. Conservation of Animal Genetic Resources can be achieved by any of the methods including in situ conservation, ex situ in vivo conservation and cryoconservation. However the species and breed of interest, conservation objectives and goals, available financial, human and technical infrastructure are key factors one considers in selecting a conservation method. Considering the current state of characterisation and capacities for conservation it is clear that in situ conservation involving indigenous systems have great potential for African countries such as Ghana. However there are challenges associated with over dependence on dynamic production systems in the continent. Therefore it is important to consider other conservation methods to avoid a big gap between the developed and the developing world in implementing the third strategic priority area of the Global Plan of Action on animal genetic resources. This review evaluates the conservation methods in African context and discusses the interventions needed and innovations available to get the best out of indigenous knowledge and production systems for in situ conservation in Sub Saharan Africa for multiple stakeholders in African countries.Keywords: Africa; germplasm; in situ conservation; ex situ conservation; cryoconservatio

    Association of Phenotypic Markers of Heat Tolerance with Australian Genomic Estimated Breeding Values and Dairy Cattle Selection Indices

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    Dairy cattle predicted by genomic breeding values to be heat tolerant are known to have less milk production decline and lower core body temperature increases in response to elevated temperatures. In a study conducted at the University of Melbourne’s Dookie Robotic Dairy Farm during summer, we identified the 20 most heat-susceptible and heat-tolerant cows in a herd of 150 Holstein Friesian lactating cows based on their phenotypic responses (changes in respiration rate, surface body temperature, panting score, and milk production). Hair samples were collected from the tip of the cows’ tails following standard genotyping protocols. The results indicated variation in feed saved and HT genomic estimated breeding values (GEBVs) (p ≤ 0.05) across age, indicating a potential for their selection. As expected, the thermotolerant group had higher GEBVs for HT and feed saved but lower values for milk production. In general, younger cows had superior GEBVs for the Balanced Performance Index (BPI) and Australian Selection Index (ASI), whilst older cows were superior in fertility, feed saved (FS), and HT. This study demonstrated highly significant (p ≤ 0.001) negative correlations (−0.28 to −0.74) between HT and GEBVs for current Australian dairy cattle selection indices (BPI, ASI, HWI) and significant (p ≤ 0.05) positive correlations between HT and GEBVs for traits like FS (0.45) and fertility (0.25). Genomic selection for HT will help improve cow efficiency and sustainability of dairy production under hot summer conditions. However, a more extensive study involving more lactating cows across multiple farms is recommended to confirm the associations between the phenotypic predictors of HT and GEBVs

    Phenotypic characterization of local Ghanaian chickens: egg-laying performance under improved management conditions

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    Impacts of heat stress on meat quality and strategies for amelioration: a review

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    During the summer, high ambient temperature and humidity cause economic loss to the global livestock industry via reduced livestock productivity and increased mortality. The problem of heat stress (HS) is likely to be exacerbated by global warming and climate change. Recent research has shown that HS not only leads to physiological and metabolic perturbations in live animals but can also affect carcass and meat quality characteristics plausibly by altering the rate and extent of postmortem muscle glycolysis and resultant pH. However, these impacts of HS are not consistent across species. Higher incidence of pale soft and exudative (PSE) meat has been reported in poultry. On the contrary, higher incidence of high ultimate pH and dark firm and dry (DFD) meat or no impacts of HS have been reported in sheep and cattle. With the limited data on HS impacts on meat quality of ruminants, it is difficult to explain the exact mechanisms driving these variable impacts. However, it is hypothesized that the severity and duration of HS may lead to variable impacts due to lack of opportunity to adapdate to acute heat exposure. Longer HS exposure may allow ruminants to adapdate to heat and may not record any negative impacts on meat quality. This paper reviews the recent research on impacts of HS on meat quality characteristics and identify the key areas of further research required to better understand these negative impacts to develop strategies for amelioration. In addition, some mitigation strategies of HS have also been discussed which include both managemental and nutritional interventions
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