Morphological differences and molecular phylogenetic relationship of two tapeworm species,Moniezia expansa and Moniezia benedeni,collected from domestic ruminants in northern Vietnam

Moniezia expansa and M. benedeni are two common tapeworm species of domestic ruminants over the world. However, their morphological and molecular data are available for limited specimens from a few countries. In the present study, we compared morphological characteristics of these two species collected from goats and cattle in northern Vietnam and analyzed their phylogenetic relationship based on the 5.8S and second internal transcribed spacer (ITS2) of nuclear ribosomal DNA and the mitochondrial cytochrome c oxidase subunit I gene (cox1). The two species are clearly distinguishable from one another not only in the morphological appearance of the interproglottidal glands but also in the gross appearance of mature and gravid proglottids. Molecular analyses revealed that the 5.8S-ITS2 sequences of Vietnamese M. expansa were highly similar (99.7%) to the sequences from Japan and India, and made a common clade, which was clearly distinct from M. benedeni of Vietnam. For cox1 sequences, Vietnamese M. expansa showed a high similarity to and were grouped with the sequences from Ethiopia and some sequences from Senegal and China to make a common clade, which was separated from the remaining clades of Senegal and China. The cox1 sequences of M. benedeni from China, Vietnam, and Senegal were far distant (10.0–15.9%) from each other. The results of this study suggest that more sequence data of Moniezia species with details of morphological features from various geographical locations should be obtained to clarify the taxonomic status of Moniezia species.     

Conservation genetics of cattle, sheep, and goats

Cattle, sheep and goats were domesticated about 10,000 years ago, spread out of the domestication centers in Europe, Asia, and Africa during the next few thousands years, and gave many populations locally adapted. After a very long period of soft selection, the situation changed dramatically 200 years ago with the emergence of the breed concept. The selection pressure strongly increased, and the reproduction among breeds was seriously reduced, leading to the fragmentation of the initial gene pool. More recently, the selection pressure was increased again via the use of artificial insemination, leading to a few industrial breeds with very high performances, but with low effective population sizes. Beside this performance improvement of industrial breeds, genetic resources are being lost, because of the replacement of traditional breeds by high performance industrial breeds at the worldwide level, and because of the loss of genetic diversity in these industrial breeds. Many breeds are already extinct, and genetic resources in cattle, sheep, and goats are thus highly endangered, particularly in developed countries. The recent development of next generation sequencing technologies opens new avenues for properly characterizing the genetic resources, not only in the very diverse domestic breeds, but also in their wild relatives. Based on sound genetic characterization, urgent conservation measures must be taken to avoid an irremediable loss of farm animal genetic resources, integrating economical, sociological, and political parameters.     

Molecular survey and genetic identification of Anaplasma species in goats from central and southern China

Anaplasma species are obligate intracellular rickettsial pathogens that impact the health of humans and animals. Few studies have been carried out on Anaplasma infections in central and southern China. This study was conducted to determine the coinfection rates of Anaplasma ovis, A. bovis, and A. phagocytophilum from 262 field blood samples of goats in these regions. The average prevalences of single infection of A. ovis, A. bovis, and A. phagocytophilum were 15.3, 16.0, and 6.1%, respectively. Coinfection of A. ovis and A. bovis was dominant, with an infection rate of 27.1%. Coinfection of A. ovis and A. phagocytophilum was 1.9% and that of A. bovis and A. phagocytophilum was 4.2%. Three-pathogen coinfection was found in three of four investigated provinces with a prevalence between 0 and 5.3%. The accuracy of the PCR results was corroborated by sequencing. Analysis of the 16S rRNA gene sequences of A. bovis and A. phagocytophilum confirmed the presence of these pathogens at the investigated sites and indicated the possible genetic diversity of A. phagocytophilum. Field blood inoculation of experimental animals led to successful identification and observation of the morphological shapes of A. bovis in the infected monocytes of sheep. Phylogenetic study with msp4 sequences of A. ovis indicated that the A. ovis genotypes from sheep in the north differed from the genotypes of goats in the investigated sites.     

Comparison of RBG-banded karyotypes of cattle, sheep, and goats

The karyotypes of the three main domestic Bovidae species. Bos taurus, Ovis aries, and Capra hircus, have been investigated by RBG-banding. Primary fibroblast cells were cultured from fetal lung or muscle tissue and collected for chromosome preparation after double thymidine synchronization. Depending on the culture and species, BrdU and FdU were added for 8-11 h or 7-10 h, respectively, before harvest. The chromosomes of the three species were classified and numbered according to standard conventions (ISCNDA, 1989) and compared at different stages of condensation. Within the resolving power of the images obtained, the RBG-banding patterns appear to be very similar, with only minor differences existing between chromosome 9 and the sex chromosomes of cattle and the same chromosomes in the domestic sheep and the goat.     

The significance of water absorption and fibre digestion in the omasum of sheep, goats and cattle

1. The omasal dry matter contents constituted 0.6, 1.2 and 3.3% of the body weight in the sheep, goats and cows, respectively. 2. A large part of the fluid leaving the reticulo-rumen passed quickly through or along the omasum to the abomasum in sheep (43%). The proportion was much less in goats (17%). 3. The absorption of water from the fluid delayed in the omasum was low: 15, 18 and 19% in sheep, goats and cows, respectively. 4. Little or no acid detergent fibre was degraded in the omasum.     

Purification and characterisation of a novel cysteine conjugate beta-lyase from the tapeworm Moniezia expansa

The paper presents the first report of the purification of an invertebrate cysteine conjugate beta-lyase (CCBL). CCBL activity was shown to predominate within the cytosolic fraction of tissue from the tapeworm Moniezia expansa. The monomeric cytosolic enzyme was isolated with a M(r) of 72 kDa and co-purified with transaminase activity towards L-aspartate. The substrate profile for M. expansa CCBL is different from that of mammalian CCBLs. Exploiting the differences in mammalian and parasite substrate profiles will facilitate the development of helminth targeted conjugates which will not be activated by host (mammalian) CCBLs.     

Behaviour of goats,sheep and cattle and their selection of browse species on natural pasture in a Sahelian area

A study was conducted in the Sahelian zone of Burkina Faso of the behaviour of cattle, sheep and goats on natural pasture and their preference for browse species. Concurrently, a survey was undertaken on a sample of farmers (herders, women and livestock owners) in the study area to estimate the indigenous knowledge of browse species and their utilisation by ruminants. A herd of cattle and flocks of sheep and goats belonging to farmers were followed on pasture, each species during three consecutive days each month, from May 2003 to April 2004, and their activities were recorded regularly every 15 min, as well as the browse species selected and the height reached while browsing. The farmers had good knowledge of the browse species present in the area and their preferential classification depended on the availability of the species, their nutritive value and also other ways of utilising the species concerned. However, some divergence existed in the knowledge of farmers compared to the result from the behaviour study, e.g. some species were mentioned by farmers but not found in the inventory. There was a decline in the feeding activities of all animal species from rainy to dry season, while resting and ruminating activities were increasing at the same time. This decline in time spent feeding was more important for cattle (from 72 to 39% of total time) as they relied on the herbaceous biomass for feeding, while sheep and goats made a shift in the feeding activities from grazing to browsing when the herbaceous biomass decreased. Cattle browsed (leaves and litter) during all the study period for around 4.5% of the time spent on pasture. Sheep and goats showed a peak in browsing activity in the dry season, 28 and 52% of the time, respectively. During the whole observation period, cattle browsed 10 species, with Guiera senegalensis most often selected, with 59, 54 and 84% of browsing time, respectively, in the rainy, post rainy and dry season. G. senegalensis, Combretum micranthum and Balanites aegyptiaca were the most important species browsed by sheep among the 20 browse species selected. Goats browsed more than 20 species daily but the most preferred species were Acacia senegal, B. aegyptiaca and Pterocarpus lucens. The mean height reached by goats when browsing was higher (1.65 m) than that of cattle (1.47 m) and sheep (0.87 m). The result from this study can be used to select species for regeneration and to advice farmers on the importance of herd composition.     

Antral follicle growth and endocrine changes in prepubertal cattle,sheep and goats

In the growing heifer calve, there is an early post-natal, gonadotrophin driven increase in ovarian antral follicle growth. The endocrine regulation of and reason for this initial stimulation of ovarian follicular development are not fully understood. This initial endocrine activity appears to be later held in check by negative feedback suppression mechanisms until the heifer is of a sufficient body size to initiate oestrous cycles and to reproduce. There is increasing evidence from recent ultrasonographic studies, performed in the same groups of prepubertal heifer calves, that the development of ovarian antral follicles and tubular genitalia occur in parallel. There appear to be two distinct periods of enhanced development of the reproductive organs, from 2 to 14 weeks of age and again from 34 to 60 weeks of age, or just prior to puberty. First ovulation in heifers is preceded by a gradual increase in pulsed LH secretion, which results in enhanced antral follicle development and oestrogen production. It was demonstrated that prepubertal heifers produced recurrent antral follicular waves; maximum sizes and life span of the dominant follicles of waves, as well as periodicity and FSH dependency of wave emergence were similar to those in adult cattle. In does, no Graafian follicles are seen at birth and total follicle numbers increase to 2 months of age, and then decline to 5 months of age. In ewe lambs, studies using transrectal ovarian ultrasonography showed that antral follicle recruitment and growth increased after the first 2 months of age and just before puberty. This bi-phasic pattern of changes in ovarian follicle recruitment and growth is strikingly similar to that in heifer calves, but it contrasts with earlier post-mortem examinations of ovaries in ewe lambs. Unlike in cattle and adult ewes, the rhythmic pattern of follicular wave emergence was not established in pre- and peripubertal ewe lambs. The early increase in antral follicle numbers and size in ewe lambs may be, at least in part, due to changes in FSH release and potency, and enhanced follicle production prior to first ovulation is probably caused by an increase in the frequency of LH pulses.     

Effect of lead in water on the absorption of copper, iron, manganese and zinc by sheep (Ovis aries) infected with sheep tapeworm (Moniezia expansa)

The sheep tapeworm (Moniezia expansa) and its host Ovis aries were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) for their copper, iron, manganese, zinc and lead levels. Element concentrations in cestode parasites were compared to those in various organs (liver, kidney, and muscle) of sheep. Tapeworms in the small intestine of sheep that were administered 2g of Pb(CH(3)COO)(2) per os daily (7 days) had significantly higher lead concentrations than sheep tissues. Cu levels significantly increased after Pb administration in sheep muscle and sheep tapeworms. Contrarily, Zn content significantly decreased in sheep muscle, but significantly increased in sheep tapeworms. However, Mn content significantly decreased after Pb administration in sheep tapeworms. Furthermore, Fe content significantly decreased after Pb administration in sheep liver and kidneys.     

Seroprevalence of Toxoplasma gondii in pigs, sheep, goats, and cattle from Grenada and Carriacou, West Indies

Prevalence of Toxoplasma gondii infection in pregnant women in Grenada is considered high. Little is known of the epidemiology of T. gondii infection in Caribbean Islands. Serum samples of 750 food animals in Grenada and Carriacou were tested for antibodies to T. gondii by the modified agglutination test (MAT). Antibodies to T. gondii (MAT, 1∶25 or higher) were found in 23.1% of 247 pigs, 44.1% of 204 sheep, 42.8% of 180 goats, and 8.4% of 119 cattle. Seroprevalence increased with age, indicating postnatal acquisition of T. gondii. Antibody titers of 1∶200 or higher were present in 65 of 90 seropositive sheep, 61 of 77 seropositive goats, and 23 of 57 seropositive pigs. However, none of the cattle had a MAT titer of 1∶200, suggesting that bovines are a poor host for T. gondii. Results indicate that pigs, sheep, and goats could be important sources of T. gondii infection if their meat is consumed undercooked.     

Effective population sizes in cattle,sheep, horses,pigs and goats estimated from census and herdbook data

Accurate measures of effective population sizes (N_e) in livestock require good quality data and specialized skills for their computation and analysis. N_e can be estimated by Wright’s equation N_e=4MF/(M+ F) (M, F being sires and dams, respectively), but this requires assumptions which are often not met. Total census sizes N_c of livestock breeds are collated globally. This paper investigates whether estimates of N_e can be made from N_c; this would facilitate conservation monitoring. Some N_e methodologies avoid the assumptions of Wright’s equation and permit measurement, rather than estimation, of N_e. Those considered here employ, respectively, linkage disequilibrium (LD) of single-nucleotide polymorphisms (yielding N_e(LD)), and genealogical analysis (rate of increase of inbreeding, DF), yielding N_e(DF). Considering breeds of cattle, sheep, horses, pigs and goats for which N_c and either N_e(LD) or N_e(DF) are known (totals of 203 breeds and 321 breeds, respectively), proportionality has been investigated between N_c and these measures of N_e. N_e(LD) was found to increase with N_c, significantly in sheep and horses, less so in cattle, but not at all in pigs. N_e(DF) was correlated with log₁₀(N_c) in cattle, sheep and horses (53, 56, 43 breeds, respectively). N_e(LD) was correlated in cattle (73 breeds) and pigs (31 breeds) with the log₁₀ transformation of N_e as calculated by Wright’s equation. Further verification and refinement are needed, particularly of census data, but credible predictions of N_e are obtainable by applying the following multipliers to log₁₀(N_c): cattle 17.61, sheep 97.72, horse 70.78. For cattle and pigs, multiplying log₁₀(N_e(Wright)) by, respectively, 40.69 and 60.09, also gives credible predictions. Such census-based estimates of N_e could in principle be generated by non-specialists and are likely to be suited to audits of conservation activity when financial resources or availability of data are limiting. The ratio N_e/N_c varied among species with an overall median value of 0.03, less than a tenth of that typically observed in wild mammals. Characteristics were also investigated of a distinct herdbook-based methodology, namely the development of Wright’s equation to take into account variances of progeny numbers to yield what has been termed here N_e (Hill). Comparison of these values with N_e (Wright) could help to identify breeds with breeding structures conducive or inimical to genetic conservation. However, N_e(Hill) requires breed-specific values for these variances, and this restricts its applicability.     

The establishment and reversibility of species affinities in domestic sheep and goats

The establishment and reversibility of cross-species attachments were studied in sheep and goats taken from their mothers at birth and reared in same- or cross-species pairs until 12 months of age. Species affinities were determined at eight to nine months of age by time spent proximate to stimulus herds of sheep and goats housed in separate enclosures within a larger pasture. Sheep reared with goats spent significantly more time with the stimulus goats than did controls (sheep reared with sheep). Likewise, goats reared with sheep spent a significantly greater percentage of time with the stimulus sheep than did control goats. At approximately 13 months of age the sheep were segregated from the goats in separate pastures and were retested, as before, for species affinities after 34 to 90 days of exposure to conspecifics. Experimental subjects demonstrated a significant reversal of species preferences. However, the reversal was more complete for subjects housed for 57 to 90 days in same-species groups than for those tested after 34 to 56 days of exposure to conspecifics. It was concluded that species affinities of sheep and goats are basically learned and that relatively long-standing cross-species social attachments can be reversed by approximately 60 to 90 days of same-species cohabitation.     

Nutritional requirements of sheep,goats and cattle in warm climates: a meta-analysis

The objective of the study was to update energy and protein requirements of growing sheep, goats and cattle in warm areas through a meta-analysis study of 590 publications. Requirements were expressed on metabolic live weight (MLW=LW^0.75) and LW¹ basis. The maintenance requirements for energy were 542.64 and 631.26 kJ ME/kg LW^0.75 for small ruminants and cattle, respectively, and the difference was significant (P<0.01). The corresponding requirement for 1 g gain was 24.3 kJ ME without any significant effect of species. Relative to LW^0.75, there was no difference among genotypes intra-species in terms of ME requirement for maintenance and gain. However, small ruminants of warm and tropical climate appeared to have higher ME requirements for maintenance relative to live weight (LW) compared with temperate climate ones and cattle. Maintenance requirements for protein were estimated via two approaches. For these two methods, the data in which retained nitrogen (RN) was used cover the same range of variability of observations. The regression of digestible CP intake (DCPI, g/kg LW^0.75) against RN (g/kg LW^0.75) indicated that DCP requirements are significantly higher in sheep (3.36 g/kg LW^0.75) than in goats (2.38 g/kg LW^0.75), with cattle intermediate (2.81 g/kg LW^0.75), without any significant difference in the quantity of DCPI/g retained CP (RCP) (40.43). Regressing metabolisable protein (MP) or minimal digestible protein in the intestine (PDI_min) against RCP showed that there was no difference between species and genotypes, neither for the intercept (maintenance=3.51 g/kg LW^0.75 for sheep and goat v. 4.35 for cattle) nor for the slope (growth=0.60 g MP/g RCP). The regression of DCP against ADG showed that DCP requirements did not differ among species or genotypes. These new feeding standards are derived from a wider range of nutritional conditions compared with existing feeding standards as they are based on a larger database. The standards seem to be more appropriate for ruminants in warm and tropical climates around the world.     

Subtilase cytotoxin-coding genes in verotoxin-producing Escherichia coli strains from sheep and goats differ from those from cattle

Subtilase cytotoxin (SubAB) from verotoxin (VT)-producing Escherichia coli (VTEC) strains was first described in the 98NK2 strain and has been associated with human disease. However, SubAB has recently been found in two VT-negative E. coli strains (ED 591 and ED 32). SubAB is encoded by two closely linked, cotranscribed genes (subA and subB). In this study, we investigated the presence of subAB genes in 52 VTEC strains isolated from cattle and 209 strains from small ruminants, using PCR. Most (91.9%) VTEC strains from sheep and goats and 25% of the strains from healthy cattle possessed subAB genes. The presence of subAB in a high percentage of the VTEC strains from small ruminants might increase the pathogenicity of these strains for human beings. Some differences in the results of PCRs and in the association with some virulence genes suggested the existence of different variants of subAB. We therefore sequenced the subA gene in 12 strains and showed that the subA gene in most of the subAB-positive VTEC strains from cattle was almost identical (about 99%) to that in the 98NK2 strain, while the subA gene in most of the subAB-positive VTEC strains from small ruminants was almost identical to that in the ED 591 strain. We propose the terms subAB1 to describe the SubAB-coding genes resembling that in the 98NK2 strain and subAB2 to describe those resembling that in the ED 591 strain.     

Genetic characterisation by isoenzyme markers of North American and Australasian isolates of species of Sarcocystis (Protozoa: Apicomplexa) from mice,sheep, goats and cattle

The technique of isoenzyme (enzyme isotype) electrophoresis was used to compare genetic profiles of extracts of zoites of sarcocysts from North America and Australasia. The species examined were Sarcocystis muris (Railliet, 1886) from mice, S. gigantea (Railliet, 1886) (syn. S. ovifelis Heydorn et al., 1975) from sheep, S. capracanis Fischer, 1979 from goats and S. cruzi (Hasselmann, 1923) (syn. S. bovicanis Heydorn et al., 1975) from cattle. Sarcocysts from the four host animals had different alleles at almost all loci studied. This was not affected by having a common definitive host. Extracts of two cat-borne Sarcocystis species shared alleles at only 3 out of 16 loci, while two dog-borne Sarcocystis species had different alleles at 8 out of 16 loci. The extent of genetic divergence among sarcocysts confirmed the existance of distinct species in each host sampled. By contrast, the isolates from the United States of America and Australasia for any particular host were essentially identical, sharing at least one allele at every locus tested. ac]19860908