43 research outputs found

    Growth and reproductive traits of Friesian X Sanga crossbred cattle in the Accra plains of Ghana

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    The typical cattle production system in Ghana is predominantly pasture-based. Cattle are grazed all year round on natural pastures with minimal feed supplementation. The animals kept in this production system often experience inadequate nutrition and fluctuating nutrient supply affecting their productivity. There is presently limited information on the growth and reproductive performance of the Friesian x Sanga crossbred cattle (Plate 1) and factors influencing these performance traits. The growth and reproductive performance records of 150 Friesian x Sanga crossbred cattle, kept at the Animal Research Institute station in the Accra Plains of Ghana from April 1993 to October 2009 were evaluated to determine the effect of parity of cow, season of calving and sex of calf on birth weight, weaning weight, growth rate, age at first calving and calving interval. The birth weight and weaning weights of the calves averaged 21.8 ± 0.5 kg and 94.2 ± 3.8 kg, respectively, and were not (P > 0.05) affected by sex of calf, parity of cow or season of calving. Parity of cow affected (P < 0.05) weight of calf at 12 months. Calf weight at 12 and 18 months averaged 128.0 ± 3.4 kg and 159.9 ± 4.5 kg, respectively. Pre-weaning and post-weaning average daily gains were 0.33 ± 0.02 kg/day and 0.23 ± 0.03 kg/day, respectively, and were not significantly (P > 0.05) affected by sex of calf, parity of cow or season of calving. The mean age at first calving was 41.2 ± 1.2 months. Calving interval was prolonged averaging 441.6 ± 10.3 days and was significantly (P < 0.05) affected by parity of cow. Calving interval decreased with increasing parity of cow. The age at first calving and calving interval were not (P > 0.05) affected by either sex of calf or season of calving. The growth and reproductive performance of the Friesian x Sanga crossbred cattle was less than optimum. Improving their nutrition could impact, positively, on their productivity through fast growth, increased milk yield and early resumption of ovarian cycles after calving. Thus, results from this study should guide the development of appropriate strategies for increased meat and milk production in Friesian x Sanga crossbred cattle.Keywords: Cattle, grazing, growth, pasture, reproductionAfrican Journal of Food, Agriculture, Nutrition and Development, Volume 13 No 2, April 201

    The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

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    Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015

    Haplotype analyses of haemoglobin C and haemoglobin S and the dynamics of the evolutionary response to malaria in Kassena-Nankana District of Ghana.

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    BACKGROUND: Haemoglobin S (HbS) and C (HbC) are variants of the HBB gene which both protect against malaria. It is not clear, however, how these two alleles have evolved in the West African countries where they co-exist at high frequencies. Here we use haplotypic signatures of selection to investigate the evolutionary history of the malaria-protective alleles HbS and HbC in the Kassena-Nankana District (KND) of Ghana. METHODOLOGY/PRINCIPAL FINDINGS: The haplotypic structure of HbS and HbC alleles was investigated, by genotyping 56 SNPs around the HBB locus. We found that, in the KND population, both alleles reside on extended haplotypes (approximately 1.5 Mb for HbS and 650 Kb for HbC) that are significantly less diverse than those of the ancestral HbA allele. The extended haplotypes span a recombination hotspot that is known to exist in this region of the genome SIGNIFICANCE: Our findings show strong support for recent positive selection of both the HbS and HbC alleles and provide insights into how these two alleles have both evolved in the population of northern Ghana
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