The small mammal community of a coastal site of south-west Mauritania

The small mammal community of a coastal site of south-western Mauritania was monitored using live trapping, owl pellet analysis and nocturnal visual censuses. Ten species of rodents and two shrews were recorded. Gerbillid rodents ( Gerbillus nanus, G. gerbillus, G. tarabuli, G. nigeriae and Taterillus arenarius ) were the most prevalent in traps, whereas a relatively large proportion of owl pellets were made up of a murid rodent, Mastomys huberti . The presence of two species of murids ( M. huberti and Arvicanthis niloticus ) in this presaharian environment is made possible by the presence of small patches of green vegetation associated with localized fresh water inputs. The contradiction of results from the sampling methods indicate potential biases in the determination of community composition and relative species abundance. Results are also discussed in estimating the potential role of predation and competition in this small mammal community.     

Hydrology and underwater climate of the Banc d'Arguin,Mauritania: a review

The northern coast of Mauritania between Cap Blanc and Cap Timiris is characterized by a large variety of hydrological situations. At the western slope of the Banc d'Arguin, at a depth of about 20 m, the underwater climate is essentially of a temperate character. This is a highly unstable area due to the occurrence of upwellings and the movements of the intertropical front. Close to the coast the isolation of water masses by the very shallow Banc d'Arguin results in an increase of temperature and salinity. These factors show a gradient towards the South from Cap, St. Anne to the islands. In this region the underwater climate is tropical, a feature which is most clearly expressed in land-locked bays such as the Baie d'Arguin, the area around the island of Tidra, and the Baie de St. Jean. In the latter bay the conditions are most extreme (salinity > 80). Due to the coastal topography the area of the islands around Tidra is highly isolated. This area receives no fertilization from the upwellings offshore.     

The functioning of the ecosystem of the Banc d'Arguin,Mauritania: a review

The Banc d'Arguin, Mauritania, is an area of over 10 000 km² of shallow water and tidal flats between the Sahara and the upwelling system off the Mauritanian coast. The results of the Dutch-Mauritanian project Banc d'Arguin 1988 as well as the relevant literature are reviewed in order to develop a preliminary conceptual model of the functioning of this ecosystem. Hydrographically the Banc d'Arguin can be characterized as a large-scale negative estuary with higher salinities near the shore. It is concluded that ultimately the Banc d'Arguin ecosystem is fueled by nutrients and organic matter derived from the upwelling area. The inner part of the Banc d'Arguin system is dominated by a detritus-based benthic foodweb in which seagrasses are the principal primary producers. Little of the seagrass production seems to be exported to other parts of the system or other areas. Zooplankton and zoobenthos biomasses are relatively low, but nevertheless support high densities of consumers. Aquatic birds are especially numerous. The study identifies many research topics for the future.     

The distribution and abundance of young fish in the Banc d'Arguin,Mauritania

The importance of the Banc d'Arguin (Mauritania) for juvenile fish has been investigated in September 1988. Fish have been sampled with a 2 m beam trawl at 50 locations in the coastal zone between Cap Sainte Anne and Cap Timiris. Water depth varied between 1 and 16 metres. Temperature and salinity at each station have been measured, as well as the weight of the catch and total length of the individual fish. The largest catches — in numbers as well as in weight — were obtained around the shallows of Tidra and Arel. This region has a large diversity in species, and contains large numbers of juvenile fish and cephalopods. The deeper areas seem to be much poorer in species, but average length and weight of the sampled fish are higher than around Tidra and Arel.     

Hydrographical observations west of the Banc d'Arguin,Mauritania, in May 1988

The present paper discusses the distribution of hydrographical parameters in Mauritanian waters between 19° 20 N and 20° 40 N. Data were collected during the first leg of the Dutch Mauritania Expedition in May 1988 with the R/V TYRO and comprise measurements of water temperature (T), salinity (S) and dissolved oxygen contents (O₂) in the area off the Banc d'Arguin. The time of investigation fell in the transitional period between the cold and warm season, which in this area is characterised by a peak in the trade wind speed and progressive heating of waters. Wind speed and sea surface temperature distribution in May 1988 were close to the seasonal averages which suggests that the observed hydrographical conditions were normal for this period as well. The highest spatial variability of T, S and O₂ was found near the southern end of the Banc d'Arguin, where the combined effect of coastal upwelling and seasonal heating made the thermocline upper limit rise towards the surface and upwelling waters reach the shallowest parts of the shelf. In the northern part of the study area upwelling phenomena were observed in the subsurface layers below 50 m depth; upwelling water did not reach beyond the outer edge of the shelf. The analysis of the TS diagram showed that water masses in the upper 300 m layer were mainly composed of South Atlantic Central Water with an admixture of warm, low-salinity surface water of Guinean origin. Traces of North Atlantic Central Water were found in the subsurface layer and at the deepest levels of measurements. Almost no traces of warm, saline water originating from the shallow Banc d'Arguin were registered during the survey.     

Determinants of short-run supply of small ruminants in Botswana

This study utilizes pooled agricultural region data for the 1982–1987 period to estimate the short-run supply of sheep and goats in Botswana. Elasticity estimates indicate that a 1% increase (decrease) in rainfall at year t leads to a 0.53% rise (fall) in goat marketing in year t+1, and that a 1% rise (fall) in goat population (inventory) leads to a 0.15% rise (fall) in goat sales. The sheep equation reveals that a 1% increase (decrease) in sheep inventory results in a 1.23% rise (fall) in the number of sheep marketed, and suggests that rainfall has no impact on sheep sales. It is argued that the inelastic response of goat sales to changes in goat inventory reinforces the general view that livestock in Botswana are treated as a store of wealth, rather than as primarily a commercial activity for generating cash incomes. This tendency seems to be reduced in the case of sheep, where an elastic response of sales to changes in sheep inventory is observed. Producer prices are found to have no impact on small ruminant sale. The lack of responsiveness of supply to prices may be revealing the existence of inadequate access by most producers to organized markets for small ruminants. It is further argued that without promoting the development of such markets, other developmental efforts, particularly those geared at improving farm-level productivity will yield no positive outcomes, as farmers lack the cash incentive to invest in improved management and husbandry practices.     

Sexual behavior in ewes and other domestic ruminants

Similarities as well as differences across species in the control of sexual behavior are helping to fully understand the subtle relations between physiology and eco-ethological constraints and how the brain integrates such information. We will illustrate this with sexual behavior in domestic ruminants and especially ewes. Females of these species like humans, but unlike rodents, have a long luteal phase. A prolonged exposure to progesterone (Pg) before the preovulatory estradiol rise is necessary for estrous behavior to be displayed. Estradiol action and receptor localization is very similar to that observed in other species. But not too surprisingly, the role of Pg is rather different with a priming effect not observed in rodents. However, as in rodents, Pg also has an inhibitory effect, is necessary for the display of proceptivity and is responsible for the timing of the different periovulatory events. These steroids act on the central nervous system in similar areas across mammalian species to regulate estrous behavior. Steroid fluctuations during the estrous cycle cause changes in catecholaminergic activity in the hypothalamus. Interestingly, these neurotransmitters seem to have very similar effects in ewes and rats as illustrated by the norepinephrine rise after male-female interactions observed in both species. Similar comparisons can be made regarding the action of some neuropeptides, including oxytocin and GnRH, and more integrative processes like sexual differentiation and modulation of reproduction by social interactions. Data on sheep, goats and cows will be compared with those of rodents.     

Tick-borne haemoparasitic diseases in small ruminants in Pakistan: Current knowledge and future perspectives

Livestock industry is an essential part of Pakistan’s economy, and a variety of ruminants (including sheep and goats) are reared for the increasing demand of milk, meat and hide products. Haemoparasitic illnesses such as theileriosis, anaplasmosis, and babesiosis are a significant health risk for small ruminants in our country. Information regarding distribution patterns, the tick species involved and effective strategies to control tick-borne diseases (TBD) in goats and sheep of Pakistan is limited. To this end, it is required to assess the present rank of TBDs in small ruminants of Pakistan with a note on their vector ticks in order to control and identify the gaps in the knowledge of TBDs. This will recommend areas for future research and will add to the understanding of these diseases and will draw attention to the need for better-quality tools for the diagnosis and control of TBDs in small ruminants of Pakistan.     

Molecular analysis of tick-borne protozoan and rickettsial pathogens in small ruminants from two South African provinces

Tick-borne protozoan and rickettsial diseases are a major threat to livestock in tropical and sub-tropical regions of Africa. In this study we investigated the presence and distribution of Theileria spp., Babesia ovis, Anaplasma ovis, Anaplasma phagocytophilum, Ehrlichia ruminantium and SFG Rickettsia in sheep and goats from Free State and KwaZulu-Natal provinces. A total of 91 blood samples were screened in this study, 61 from goats and 30 from sheep. PCR assay was conducted using primers based on Theileria spp. 18S rRNA, Babesia ovis (BoSSU rRNA), Anaplasma ovis (AoMSP4), Anaplasma phagocytophilum epank1, Ehrlichia ruminantium pCS20 and SFG Rickettsia OmpA. Overall infection rates of Theileria spp., Anaplasma ovis and Ehrlichia ruminantium were 18 (19.8%), 33 (36.3%) and 13 (14.3%), respectively. The co-infection of two pathogens were detected in 17/91 (18.7%) of all samples, goats having higher rates of co-infection compared to sheep. Phylogenetic tree analysis sequence of pCS20 gene of E. ruminantium of this study was found to be in the same clade with Kumm2 and Riverside strains both from South Africa. The phylogram of SSU rRNA of Theileria ovis had longer branch length compared to all other sequences most of which were from Asia and Middle East. This study provides important data for understanding the tick-borne diseases occurrence in the study area and it is expected to improve the approach for the diagnosis and control of these diseases.     

Wind,surface water temperature,surface salinity and pollution in the area of the Banc d'Arguin,Mauritania

Based on meteorological observations at Nouadhibou Airport, Mauritania, over the period 1953–1990 frequency distributions and averages are computed for wind speed and direction. Average wind speed reaches a maximum in May–June (9 m s^–1) and a minimum in November–December (6 m s^–1). About 85% of the time winds blow from northerly directions. Based on a data set collected since 1952 maps of surface water temperatures are constructed. Based on these maps and on observations on salinity an hypothetical current pattern for the shallow area between Nouadhibou and Cap Timiris, Mauritania, is proposed.     

The link between migration, the reproductive cycle and condition of Sardinella aurita off Mauritania, north-west Africa

The annual migration pattern of round sardinella Sardinella aurita up and down the north-western African coast between 12° N (Senegal) and 22° N (western Sahara) was shown to be associated with spawning activity and a distinct seasonality in fish condition, based on monthly sampling from commercial catches (2000–2003). Some S. aurita were found to spawn throughout the entire year, but a peak in spawning existed during the summer (June to September). The spawning cycle is apparent from seasonality in maturity stages, but is also demonstrated by the increase in gonad mass and fat content of the fish in springtime, the period preceding spawning. During the months after spawning, although feeding is maintained, the physical condition of the fish collapses, and fat content rapidly declines.     

Patterns in pelagic and benthic nanoflagellate densities in the coastal upwelling system along the Banc d'Arguin,Mauritania

We studied spatial variation in abundance of marine benthic and pelagic heterotrophic nanoflagellates in relation to abundances of autotrophic flagellates, bacteria and cyanobacteria in an upwelling area off the Banc d'Arguin, Mauritania.There was enormous spatial variation in densities. In the sediments these ranged from 8–219 × 10³ cm^–3 for heterotrophic flagellates. Maximum values are in the range of those for temperate shallow marine bottoms. Low densities (< 20 × 10³) were confined to the deep stations (> 1000 m). Over the shelf (10–100 m depth) densities were high but related to grain size rather than to concurrent upwelling phenomena or to the abundance of benthic macrofauna.Pelagic flagellate abundance appeared to be more indicative of contemporary hydrographic conditions, most obvious by an increase in the ratio heterotrophic/autotrophic nanoflagellates away from the area of most intense upwelling.     

Remote sensing of sea surface and coastal features in the area of the Golfe d'Arguin,Mauritania

The analysis of a series of NOAA AVHRR satellite data recorded between July and September 1986 shows the interaction between northerly and southerly water masses during summer as well as the northern limit of the northward advance of water masses originating from the South Equatorial Current. Two upwelling situations analysed by means of NOAA data show the intrusion of suspended matter from the ocean into the Golfe d'Arguin and illustrate the water circulation within the coastal zone. This circulation pattern is detailed by LANDSAT and SPOT data. A SPOT picture from October 1987 shows the structure of the intertidal and coastal geomorphology.     

Social cohesion in groups of sheep: Effect of activity level, sex composition and group size

We investigated the effects of activity, group size and sex composition on the cohesion of merino sheep (Ovis aries) groups. Mixed-sex (50% of each sex) and single-sex groups of 2, 4, 6 and 8 sheep were placed within 491-m² arenas located in natural pastures and were video recorded during 6 daily hours. The behaviour, orientation and location of each sheep were then extracted from the films at 1-s intervals. We analysed the polarisation of individual orientations, mean inter-individual and nearest neighbours’ distances, as well as the frequency of pairs of nearest neighbours according to their sex within mixed-sex groups. Sheep were more aggregated than predicted under the null hypothesis of random spatial distribution for all group compositions and sizes. Sheep were more spread out and less aligned in half-active than in all-active groups, showing that social cohesion was reduced by a lack of activity synchronisation. The highest proximity between individuals was found in resting groups, yet alignment was low. The polarisation peaked in all-active groups. Mean inter-individual distance did not vary and the nearest neighbour distance decreased as group size increased. When sheep were all-active or all-resting, mixed-sex groups were more spread out than single-sex ones, with a greater distance between opposite than between same-sex individuals. Nearest neighbours of the same sex were also more frequent than random. Our results show that social cohesion can be modulated by activity synchrony but also by social affinity.     

Characterization of progesterone profile,physiological responses,milk composition and blood biochemical and hematological indices at the early stage of lactation in goats

The aim of this research was to describe the progesterone profile, physiological response, milk composition, and blood chemistry at the early stage (DIM 30-90 days) of lactation (E₁:30-50; E₂:50-70; E₃:70-90 days) in Baladi goats under Egyptian conditions. The serum progesterone level was significantly reduced with the progress of the early lactation period to reach the least concentration (0.24 ng/ml) at the E₃ stage of lactation (P=0.001). The daily milk yield was significantly increased with the progress of the lactation to reach the peak at the E₂ stage of lactation (P=0.015). The percentage of milk fat was significantly decreased with the progress of the early lactation period (P=0.032). However, the percentages of total solids and SNF were significantly increased in E₂ and E₃ stages when compared with the E₁ stage (P=0.001 and 0.018, respectively). The serum glucose and total antioxidant capacity were considerably reduced with the progress of the lactation period (P=0.047 and 0.039, respectively). In conclusion, Baladi goats showed a decreased serum progesterone level with the progress of the early lactation period and produce milk with a relatively stable protein and lactose contents. Furthermore, Baladi does able to maintain the stability of most blood biochemical parameters during such period.     

Age and sex composition of family groups in shopping and recreational settings

The age and sex compositions of 3838 family groups exiting shopping malls and the zoo were recorded and analyzed for patterns in parental accompaniment of children. The findings included higher relative frequencies of both-parent groups at the zoo, greater likelihood of both parents accompanying young children, and greater likelihood of the mother than the father accompanying the single child, especially daughters at the shopping centers. The presence of more than one child increases the likelihood of both parents being present. Father involvement is seen as high in escorting children to public settings.     

Circular pools in the seagrass beds of the Banc d’Arguin,Mauritania, and their possible origin

The tidal flats of the Banc d’Arguin, Mauritania, are covered by vast beds of Zostera noltii. At low tide these seagrass beds appear to be interspersed with partly vegetated, circular pools of 5–25 m diameter. Between February and May 2001 we described these pools and studied their possible origin. Several hypotheses regarding the origin have been developed. The first group of hypotheses assumes that the pools result from erosion activity. Since human disturbance of seagrass beds at the Banc d’Arguin is virtually non-existent, causes should be found in natural bed disturbances and/or tide or wave action. Therefore, small gaps, simulating holes dug by the crab Callinectes marginatus, were made to see if they would further erode by tidal currents or waves. The experiments showed no erosion. Neither we found support for other hypotheses assuming erosion to be the cause of circular pools. The alternative group of hypotheses stated that sedimentation on the flats would be responsible. We conclude that accretion of creek remnants is the most likely process behind the development of the pools; this conclusion is based on both mapping of the pattern of pools, the sediment profile in and around the pools and the distribution of seagrass biomass. Also the disturbance experiments showed bed accretion rather than bed erosion and support this hypothesis.     

Age and size at maturity: sex, environmental variability and developmental thresholds

In most organisms, transitions between different life-history stages occur later and at smaller sizes as growth conditions deteriorate. Day and Rowe recently proposed that this pattern could be explained by the existence of developmental thresholds (minimum sizes or levels of condition below which transitions are unable to proceed). The developmental-threshold model predicts that the reaction norm of age and size at maturity will rotate in an anticlockwise manner from positive to a shallow negative slope if: (i) initial body size or condition is reduced; and/or (ii) some individuals encounter poor growth conditions at increasingly early developmental stages. We tested these predictions by rearing replicated populations of soil mites Sancassania berlesei (Michael) under different growth conditions. High-food environments produced a vertical relationship between age and size at maturity. The slope became increasingly shallow as food was reduced. By contrast, high food in the maternal environment reduced the slope of the reaction norm of age and size at maturity, whereas low food increased it. Overall, the reaction norm of age and size at maturity in S. berlesei was significantly nonlinear and differed for males and females. We describe how growth conditions, mother's environment and sex determine age and size at maturity in S. berlesei.     

Molecular characterization of Fasciola gigantica from Mauritania based on mitochondrial and nuclear ribosomal DNA sequences

Fasciolosis caused by Fasciola hepatica and Fasciola gigantica (Platyhelminthes: Trematoda: Digenea) is considered the most important helminth infection of ruminants in tropical countries, causing considerable socioeconomic problems. From Africa, F. gigantica has been previously characterized from Burkina Faso, Senegal, Kenya, Zambia and Mali, while F. hepatica has been reported from Morocco and Tunisia, and both species have been observed from Ethiopia and Egypt on the basis of morphometric differences, while the use of molecular markers is necessary to distinguish exactly between species. Samples identified morphologically as F. gigantica (n = 60) from sheep and cattle from different geographical localities of Mauritania were genetically characterized by sequences of the first (ITS-1), the 5.8S, and second (ITS-2) Internal Transcribed Spacers (ITS) of nuclear ribosomal DNA (rDNA) genes and the mitochondrial Cytochrome c Oxidase I (COI) gene.Comparison of the sequences of the Mauritanian samples with sequences of Fasciola spp. from GenBank confirmed that all samples belong to the species F. gigantica. The nucleotide sequencing of ITS rDNA of F. gigantica showed no nucleotide variation in the ITS-1, 5.8S, and ITS-2 rDNA sequences among all samples examined and those from Burkina Faso, Kenya, Egypt and Iran. The phylogenetic trees based on the ITS-1 and ITS-2 sequences showed a close relationship of the Mauritanian samples with isolates of F. gigantica from different localities of Africa and Asia. The COI genotypes of the Mauritanian specimens of F. gigantica had a high level of diversity, and they belonged to the F. gigantica phylogenically distinguishable clade. The present study is the first molecular characterization of F. gigantica in sheep and cattle from Mauritania, allowing a reliable approach for the genetic differentiation of Fasciola spp. and providing basis for further studies on liver flukes in the African countries.     

In vitro production of small ruminant embryos: Late improvements and further research

Beyond the potential use of in vitro production of embryos (IVP) in breeding schemes, embryos are also required for the establishment of new biotechnologies such as cloning and transgenesis. Additionally, the knowledge of oocyte and embryo physiology acquired through IVP techniques may stimulate the further development of other techniques such as marker assisted and genomic selection of preimplantation embryos, and also benefit assisted procreation in human beings. Efficient in vitro embryo production is currently a major objective for livestock industries, including small ruminants. The heterogeneity of oocytes collected from growing follicles by laparoscopic ovum pick up or in ovaries of slaughtered females, remains an enormous challenge for IVM success, and still limits the rate of embryo development. In addition, the lower quality of the IVP embryos, compared with their in vivo–derived counterparts, translates into poor cryosurvival, which restricts the wider use of this promising technology. Therefore, many studies have been reported in an attempt to determine the most suitable conditions for IVM, IVF, and in vitro development to maximize embryo production rate and quality. This review aims to present the current panorama of IVP production in small ruminants, describing important steps for its success, reporting the recent advances and also the main obstacles identified for its improvement and dissemination.