The genetic polymorphism of the blood proteins in RID-positive reacting cows]

Cattle herd of Black-and-White, Red and Simmental breeds having positive or negative RID-reaction to leucosis was studied as to the polymorphism of serum blood proteins in three loci: Tf, Am and Cp. One system of polymorphic proteins has been determined as having a higher concentration of homozygotes (Tf) and another one as having a higher concentration of heterozygotes (Am) within one and the same herd among animals with the positive RID-reaction.     

Towards welfare biology: Evolutionary economics of animal consciousness and suffering

Welfare biology is the study of living things and their environment with respect to their welfare (defined as net happiness, or enjoyment minus suffering). Despite difficulties of ascertaining and measuring welfare and relevancy to normative issues, welfare biology is a positive science. Evolutionary economics and population dynamics are used to help answer basic questions in welfare biology: Which species are affective sentients capable of welfare? Do they enjoy positive or negative welfare? Can their welfare be dramatically increased? Under plausible axioms, all conscious species are plastic and all plastic species are conscious (and, with a stronger axiom, capable of welfare). More complex niches favour the evolution of more rational species. Evolutionary economics also supports the common-sense view that individual sentients failing to survive to mate suffer negative welfare. A kind of God-made (or evolution-created) fairness between species is also unexpectedly found. The contrast between growth maximization (as may be favoured by natural selection), average welfare, and total welfare maximization is discussed. It is shown that welfare could be increased without even sacrificing numbers (at equilibrium). Since the long-term reduction in animal suffering depends on scientific advances, strict restrictions on animal experimentation may be counter-productive to animal welfare.     

Prevalence and clonal nature of Escherichia coli O157:H7 on dairy farms in Wisconsin.

A survey was conducted between March and October of 1994 to determine the prevalence and identify the sources of serotype O157:H7 isolates of Escherichia coli in Wisconsin dairy herds. A stratified sample of 400 farms was identified, and 70 farms with weaned calves less than 4 months old were included in the study. During the prevalence study, 5 of the 70 farms (herd prevalence, 7.1 +/- 4.5%) and fecal samples from 10 of 560 calves (animal prevalence, 1.8%) tested positive for serotype O157:H7. In a follow-up study, the five O157:H7-positive farms and seven of the O157:H7-negative farms identified in the prevalence study were visited again. An additional 517 fecal samples from cattle of various ages were tested, and a total of 15 animals from four of the five herds that were previously positive and 4 animals from two of seven herds that were previously negative tested positive for E. coli O157:H7. Observations made during the follow-up study suggested that horizontal transmission was an important means of E. coli O157:H7 dissemination on the farms. A total of 302 environmental samples, were examined, and 2 animal drinking water samples from one previously negative farm and 1 animal drinking water sample from a previously positive farm contained E. coli O157:H7. Analyses by the pulsed-field gel electrophoresis technique of contour-clamped homogeneous electric field electrophoresis revealed that isolates from the same farm displayed identical or very similar XbaI restriction endonuclease digestion profiles (REDP), whereas isolates from different farms typically displayed different REDP. However, more than one REDP was usually observed for a given herd over the 8-month sampling period. Analyses of multiple isolates from an animal revealed that some animals harbored O157:H7 strains that had different REDP, although the REDP of isolates obtained from the same fecal sample were very similar. Collectively, 160 bovine isolates obtained from 29 different animals and three water isolates displayed 20 distinct XbaI REDP. Our data revealed that there are several clonal types of serotype O157:H7 isolates in Wisconsin and indicated that there is probably more than one source of this pathogen on the dairy farms studied. However, animal drinking water was identified as one source of E. coli O157:H7 on one farm.     

Patch choice under predation hazard

In this paper we study optimal animal movement in heterogeneous environments consisting of several food patches in which animals trade-off energy gain versus predation risk. We derive a myopic optimization rule describing optimal animal movements by fitness maximization assuming an animal state is described by a single quantity (such as weight, size, or energy reserves). This rule predicts a critical state at which an animal should switch from a more dangerous and more profitable patch to a less dangerous and less profitable patch. Qualitatively, there are two types of behavior: either the animal switches from one patch to another and stays in the new patch for some time before it switches again, or the animal switches between two patches instantaneously. The former case happens if animal state growth is positive in all patches, while the latter case happens if animal state growth is negative in one patch. In particular, this happens if one patch is a refuge. We consider in detail two special cases. The first one assumes a linear animal state growth while the second assumes a saturating animal state growth described by the von Bertalanffy curve. For the first model the proportion of time spent in the more profitable and more risky patch increases with profitability of this patch when state growth is positive in both patches. On contrary, if state growth is negative in the less profitable and safer patch, animals spend proportionally less time in the more profitable and more risky patch as its profitability increases. As a function of the predation risk in the more profitable patch the time spent there proportionally decreases. When animal state growth is described by the saturating curve, time spent in the more risky patch is a hump-shaped curve if state growth is positive in both patches. Our results extend the mu/f rule, which predicts that animals should behave in such a way as to minimize mortality risk to resource intake ratio.     

Estimation of the relative sensitivity of the comparative tuberculin skin test in tuberculous cattle herds subjected to depopulation

Bovine tuberculosis (bTB) is one of the most serious economic animal health problems affecting the cattle industry in Great Britain (GB), with incidence in cattle herds increasing since the mid-1980s. The single intradermal comparative cervical tuberculin (SICCT) test is the primary screening test in the bTB surveillance and control programme in GB and Ireland. The sensitivity (ability to detect infected cattle) of this test is central to the efficacy of the current testing regime, but most previous studies that have estimated test sensitivity (relative to the number of slaughtered cattle with visible lesions [VL] and/or positive culture results) lacked post-mortem data for SICCT test-negative cattle. The slaughter of entire herds ("whole herd slaughters" or "depopulations") that are infected by bTB are occasionally conducted in GB as a last-resort control measure to resolve intractable bTB herd breakdowns. These provide additional post-mortem data for SICCT test-negative cattle, allowing a rare opportunity to calculate the animal-level sensitivity of the test relative to the total number of SICCT test-positive and negative VL animals identified post-mortem (rSe). In this study, data were analysed from 16 whole herd slaughters (748 SICCT test-positive and 1031 SICCT test-negative cattle) conducted in GB between 1988 and 2010, using a Bayesian hierarchical model. The overall rSe estimate of the SICCT test at the severe interpretation was 85% (95% credible interval [CI]: 78-91%), and at standard interpretation was 81% (95% CI: 70-89%). These estimates are more robust than those previously reported in GB due to inclusion of post-mortem data from SICCT test-negative cattle.     

The Role of Hemispheric Functional Specialization in the Analysis of the Relationship between Signal and Nonsignal Information during Image-Shape Classification

The effect of additional information on image shape classification was studied in seven-year-old children. The classified images were either dissimilar in the axis ratio of the basic oval (F) or had an additional element (F + E). In one series of experiments, the additional element was oriented towards a longer axis of the oval, which was a discriminative sign (situation 1, matching); in another series it was rotated by 90° (situation 2, mismatching). The analysis of the successful image classification in series 1 and 2 showed that images with an additional element that mismatches a discriminative sign were classified as being significantly worse than those with matching information. The analysis of the event-related potentials (ERP) from different cortical areas revealed a specific role of the frontal and temporo-parieto-occipital cortical areas in the classification of additional sensory information. The analysis of additional matching information (series 1) was associated with the right hemisphere and evidenced by an increase in N200 wave amplitude in the frontal area and by a negative shift during the development of a late positive complex (250–550 ms) in the temporo-parieto-occipital area. The analysis of additional information mismatching a discriminative sign (series 2) was associated with the left hemisphere and evidenced by an early positive component (P100) in the frontal area, negative components N200–N250, and a further negative shift during the development of late positive complex in the temporo-parieto-occipital area.     

Higher non-return rate associated with Mycobacterium avium subspecies paratuberculosis infection at early stage in Holstein dairy cows

The effects of infection by Mycobacterium avium paratuberculosis (Map) on dairy cows are poorly documented and quite controversial. This retrospective study aimed at quantifying the variation in non-return to service of Holstein dairy cows according to their Map-infection status. Three different statuses were defined based on both individual and herd tests results: ELISA positive cow, all tests negative cow in a negative herd and all tests negative cow in a positive herd. Whatever the age at Map testing, the status was attributed to a cow from its first lactation onwards. Non-return to service was determined at 200 days after first and second services. The study was performed from 1999 to 2007 on 185,950 AI from 48,914 cows in early stage of the infection in 1069 herds by logistic regression controlling for known factors influencing non-return rate. Non-return rate was higher for infected cows compared to negative cows from negative herds (RR of 1.10 or +3.9 points of % of non-return rate). The effect was significant for parities 1 and 2 (RR of 1.11 and 1.12, respectively) but not for higher ones. This effect was lower when comparing positive cows to negative cows in the same herds but relative risks were still above 1. The hypothesis that the effect of Map on non-return depends upon the stage of infection is formulated.     

The herd,a source of flexibility for livestock farming systems faced with uncertainties?

'Adapt to endure' has become a necessity in agriculture, but the means to do so remain largely undefined. The aim of this literature review is to analyse how the herd contributes to a livestock farming system's capacity to adapt to a changing world and evolve when the future is uncertain. We identify six categories of elements linked to the herd, called 'sources of flexibility', that are used to manage perturbation. The first three are: using the animal's adaptive capacities, using the diversity of species and breeds and combining the diversity of animal products. The last three are: organising the mobility of animals and livestock farmers, juggling the herd numbers and mastering the balance between productivity and herd survival. These sources of flexibility are described in the literature by studying the different ways in which they are used. For example, the 'juggle herd numbers' source is described by volume, categories of animals, type of transfer, such as births, purchases or gifts, and timing of use, especially linked to the timing of the perturbation. Identified studies also compare or rank sources and analyse the connections between them. The flexibility framework (management science) is used for this analysis according to the levels of organisation of a livestock farming system: a strategic level referring to long-term options and to the capacity to modify the system structure, and an operational level referring to adjustment decisions during the productive cycle, the presence or absence of intervention by the livestock farmer, and the time scales involved. We conclude that the decision to use one or another source (in terms of modalities, alternatives, scheduling and combinations) is made according to the production objectives, the structural means, the type/frequency/intensity of perturbations and the context/environment. Consequently, the flexibility of a livestock farming system cannot be assessed in absolute terms. Enhancing flexibility needs management of all elements and scales involved (and not only the herd), and requires diversity to be organised at different scales.     

Attachment kinetics of the adult tick Amblyomma variegatum to cattle

At the beginning of the 1999 rainy season, three traditional cattle herds were monitored for 48 days while grazing in the bushy savannah of southwestern Burkina Faso. Cattle in each herd were caught on several occasions each day and the attached ticks were counted. This confirmed that Amblyomma variegatum Fabricius (Acari: Ixodidae) adults picked up in the pastures mainly attach to the interdigital areas (87% of the 791 ticks captured), and reach the predilection sites later (chest and udder/inguinal area) when the animals lie down. As many females as males attached to the hosts, but the seasonal distribution was very heterogeneous, with only a few females attaching as long as the humidity rate remained low. It is suggested that this prevents eggs from being laid when conditions are not optimal for their survival and that of the larvae. Ticks attached all day but the number picked up hourly and daily varied greatly according to their density on the pasture. As a general trend, confirmed by another study carried out in 2005, the number of ticks picked up daily increased from less than one tick/animal/day, before the onset of the rainy season, to 6.5 (+/- 1.5) ticks/animal/day on average during the infestation peak, which lasted 6-8 weeks, until early or mid-July. The number then decreased to less than one tick/animal/day from the end of July onwards. The infestation on the predilection sites followed the same trend, with a daily tick burden increase of three to five A. variegatum adults, depending on herd and year, during the infestation peak.     

Using an in vivo phagemid system to identify non-compatible loxP sequences

The site-specific recombination system of bacteriophage P1 is composed of the Cre recombinase that recognizes a 34-bp loxP site. The Cre/loxP system has been extensively used to manipulate eukaryotic genomes for functional genomic investigations. The creation of additional heterologous loxP sequences potentially expands the utility of this system, but only if these loxP sequences do not recombine with one another. We have developed a stringent in vivo assay to examine the degree of recombination between all combinations of each previously published heterologous loxP sequence. As expected, homologous loxP sequences efficiently underwent Cre-mediated recombination. However, many of the heterologous loxP pairs were able to support recombination with rates varying from 5 to 100%. Some of these loxP sequences have previously been reported to be non-compatible with one another. Our study also confirmed other heterologous loxP pairs that had previously been shown to be non-compatible, as well as defined additional combinations that could be used in designing new recombination vectors.     

Using an in vivo phagemid system to identify non-compatible loxP sequences.

The site-specific recombination system of bacteriophage P1 is composed of the Cre recombinase that recognizes a 34-bp loxP site. The Cre/loxP system has been extensively used to manipulate eukaryotic genomes for functional genomic investigations. The creation of additional heterologous loxP sequences potentially expands the utility of this system, but only if these loxP sequences do not recombine with one another. We have developed a stringent in vivo assay to examine the degree of recombination between all combinations of each previously published heterologous loxP sequence. As expected, homologous loxP sequences efficiently underwent Cre-mediated recombination. However, many of the heterologous loxP pairs were able to support recombination with rates varying from 5 to 100%. Some of these loxP sequences have previously been reported to be non-compatible with one another. Our study also confirmed other heterologous loxP pairs that had previously been shown to be non-compatible, as well as defined additional combinations that could be used in designing new recombination vectors.     

Pastoral Herding Strategies and Governmental Management Objectives: Predation Compensation as a Risk Buffering Strategy in the Saami Reindeer Husbandry

Previously it has been found that an important risk buffering strategy in the Saami reindeer husbandry in Norway is the accumulation of large herds of reindeer as this increases long-term household viability. Nevertheless, few studies have investigated how official policies, such as economic compensation for livestock losses, can influence pastoral strategies. This study investigated the effect of received predation compensation on individual husbandry units’ future herd size. The main finding in this study is that predation compensation had a positive effect on husbandry units’ future herd size. The effect of predation compensation, however, was nonlinear in some years, indicating that predation compensation had a positive effect on future herd size only up to a certain threshold whereby adding additional predation compensation had little effect on future herd size. More importantly, the effect of predation compensation was positive after controlling for reindeer density, indicating that for a given reindeer density husbandry units receiving more predation compensation performed better (measured as the size of future herds) compared to husbandry units receiving less compensation.     

中缅树鼩自然感染六种病毒的血清流行病学

中缅树鼩作为一种新型实验动物,在医学生物学上,尤其是病毒学方面的应用受到越来越多的重视.实验动物自身病毒感染会影响动物健康和干扰实验结果,甚至危害实验人员生命安全.所以,实验动物病毒检测一直是动物质量控制的重要部分.中缅树鼩研究迄今缺乏清晰的病毒自然感染资料.为调查中缅树鼩的病毒感染状况,采集野生俘获和人工繁殖的中缅树鼩血清样本272份,全部血清样本通过ELISA方法对乙型肝炎病毒(HBV)表面抗原,丙型肝炎病毒(HCV)总抗体,以及戊型肝炎病毒(HEV)、腺病毒(ADV)、单纯疱疹病毒1型(HSV-1)和2型(HSV-2)的IgG抗体进行了检测.结果表明,ELISA初筛HBV表面抗原有3份阳性样本,但通过乙型肝炎两对半定量检测进一步确认为阴性:抗HCV抗体和抗HEV、ADV、HSV-1 IgO抗体检测均为阴性;抗HSV-2 IgG检测有1份阳性样本.提示仪抗原或抗体血清学指标检测树鼩肝炎结果并不能反应个体携带病毒的状态,应该再进行病毒学指标确认.同时建议中缅树嗣繁殖群应进行HSV-2的筛选,以便杜绝和控制该病毒的感染.     

Epidemiological relatedness and clonal types of natural populations of Escherichia coli strains producing Shiga toxins in separate populations of cattle and sheep.

Two separate animal populations consisting of a herd of cattle (19 animals) and a flock of sheep (25 animals) were investigated for strains of Escherichia coli producing Shiga toxins (STEC) over a time period of 6 months. Thirty-three STEC were isolated from 63.2% of cattle and grouped into 11 serotypes and eight electrophoretic types (ETs) by multilocus enzyme analysis. In sheep, 88% of the animals excreted STEC (n = 67 isolates) belonging to 17 different serotypes and 12 different ETs. STEC from cattle and sheep differed with respect to serotype, and only 4 of the 16 ETs occurred in both animal populations. In cattle, ET14 (O116:H21) strains predominated, whereas other STEC serotypes occurred only sporadically. The predominating STEC types in sheep were ET4 (O125 strains), ET11 (O128:H2 and others), and ET14 (O146:H21). In contrast to their diversity, STEC originating from the same animal population were similar with respect to Shiga toxin (stxy genes. Almost all STEC isolated from cattle were positive for stx2 and stx2c; only one was positive for stx1. In sheep, almost all STEC isolated were positive for stx1 and stx2, whereas stx2c was not found. XbaI-digested DNAs of genetically closely related O146:H21 strains have different restriction profiles which were associated with size alterations in XbaI fragments hybridizing with stx1- and stx2-specific DNA probes. Our results indicate that stx-encoding bacteriophages might be the origin of the genetic heterogeneity in STEC from animals.     

Opportunities for reintroducing British mammals

There is good evidence that die three rarer British predatory mammals, the Polecat, Pine Marten and Wild Cat, owe their present restricted distribution to intense human persecution. Since this persecution has now diminished considerably, it would be feasible to attempt to reintroduce them to parts of Britain where they were exterminated last century. More important, however, would be attempts to reintroduce mammals which became totally extinct in historic times, including Aurochs, Boar, Brown Bear, Beaver and Wolf. The last of these survived the longest, and is a prime candidate for consideration. There are good ecological reasons for attempting to reintroduce it to Rhum, where the large herd of Red Deer has to be culled by one sixth each year in an attempt to reduce overgrazing and starvation. Evidence of studies in North America suggests that Wolf predation would be a far more efficient way of controlling the Red Deer; and it would be more in keeping with the management objectives of a National Nature Reserve. Similarly an attempt should be made to use genetically 'reconstituted' Tarpan and Aurochs to diversify the grazing, rather than domestic ponies and cattle.     

Economic Aspects of Disease Monitoring with Special Reference to Bovine Paratuberculosis

Monte Carlo simulation models were used to evaluate the feasibility and potential results of a proposed national survey of the prevalence of bovine paratuberculosis (PTB) in dairy herds in Norway. The expected herd prevalence was assumed to be 0.2% in the simulations. Infected herds were classified as detected if 1 animal was sero-positive. With a sample size of 6000 herds at least 1 truly infected herd was detected in 99% of the iterations. The low sensitivity of the ELISA test, the assumed low herd prevalence, the typical low within-herd prevalence of PTB and the small herd sizes in Norway all present problems in detection of the disease. The results showed that the ratio between false-positive herds and true positive herds detected had a median of 70:1. At the assumed herd prevalence of 0.2% and a cost/test of 70 NOK the median cost of detecting 1 infected herd was approximately 900,000 NOK. If 2 positive reactors were needed to classify a herd "infected" the median cost of detecting 1 infected herd was 5,055,000 NOK. Our results suggest that a randomized national prevalence survey would not be feasible, due to the low probability of detecting infected herds and because of the high number of false-positive reactions that would be expected.

     

Economic Aspects of Disease Monitoring with Special Reference to Bovine Paratuberculosis

Monte Carlo simulation models were used to evaluate the feasibility and potential results of a proposed national survey of the prevalence of bovine paratuberculosis (PTB) in dairy herds in Norway. The expected herd prevalence was assumed to be 0.2% in the simulations. Infected herds were classified as detected if 1 animal was sero-positive. With a sample size of 6000 herds at least 1 truly infected herd was detected in 99% of the iterations. The low sensitivity of the ELISA test, the assumed low herd prevalence, the typical low within-herd prevalence of PTB and the small herd sizes in Norway all present problems in detection of the disease. The results showed that the ratio between false-positive herds and true positive herds detected had a median of 70:1. At the assumed herd prevalence of 0.2% and a cost/test of 70 NOK the median cost of detecting 1 infected herd was approximately 900,000 NOK. If 2 positive reactors were needed to classify a herd "infected" the median cost of detecting 1 infected herd was 5,055,000 NOK. Our results suggest that a randomized national prevalence survey would not be feasible, due to the low probability of detecting infected herds and because of the high number of false-positive reactions that would be expected.     

An Integrated Approach to Modeling Grazing Pressure in Pastoral Systems: The Case of the Logone Floodplain (Cameroon)

The discussion about the impact of pastoral systems on ecosystems has been profoundly shaped by Hardin’s “tragedy of the commons” argument that held pastoralists responsible for overgrazing the range. Recent studies have shown that grazing ecosystems are much more complex and dynamic than was previously assumed and that pastoralists adaptively manage these systems. However, we still have little understanding how everyday herding affects ecosystems at the landscape level. We conducted a study of daily herd movements and grazing strategies in a mobile pastoral system in the Logone floodplain, Cameroon. We integrated GPS/GIS technology, video recordings of animal behavior, and ethnographic methods to develop a more accurate measurement of grazing pressure that takes into account both livestock densities and grazing behavior. We used the resulting grazing pressure data to evaluate existing conceptual models of grazing pressure at a landscape level. We found that models that predict that grazing pressure is skewed towards the direction of water most accurately reflect the situation in the Logone floodplain in the dry season. However, we found that the higher grazing pressure is not only the result of a higher density of cattle but also a change in the grazing behavior of animals after watering. Finally, we caution that the models of grazing pressure in the dry season cannot simply be extrapolated to the landscape level because mobile pastoralists do not remain in one central place.     

Relationship between dairy cow genetic merit and profit on commercial spring calving dairy farms

Because not all animal factors influencing profitability can be included in total merit breeding indices for profitability, the association between animal total merit index and true profitability, taking cognisance of all factors associated with costs and revenues, is generally not known. One method to estimate such associations is at the herd level, associating herd average genetic merit with herd profitability. The objective of this study was to primarily relate herd average genetic merit for a range of traits, including the Irish total merit index, with indicators of performance, including profitability, using correlation and multiple regression analyses. Physical, genetic and financial performance data from 1131 Irish seasonal calving pasture-based dairy farms were available following edits; data on some herds were available for more than 1 year of the 3-year study period (2007 to 2009). Herd average economic breeding index (EBI) was associated with reduced herd average phenotypic milk yield but with greater milk composition, resulting in higher milk prices. Moderate positive correlations (0.26 to 0.61) existed between genetic merit for an individual trait and average herd performance for that trait (e.g. genetic merit for milk yield and average per cow milk yield). Following adjustment for year, stocking rate, herd size and quantity of purchased feed in the multiple regression analysis, average herd EBI was positively and linearly associated with net margin per cow and per litre as well as gross revenue output per cow and per litre. The change in net margin per cow per unit change in the total merit index was €1.94 (s.e. = 0.42), which was not different from the expectation of €2. This study, based on a large data set of commercial herds with accurate information on profitability and genetic merit, confirms that, after accounting for confounding factors, the change in herd profitability per unit change in herd genetic merit for the total merit index is within expectations.     

The presence of black vultures at the calving sites and its effects on cows’ and calves’ behaviour immediately following parturition

Black vultures (Coragyps atratus) are often present near calving sites, and under this situation they may play a positive role by removing animal carcasses and afterbirth or a negative role by attacking neonate calves or disturbing cow–calf behaviours following parturition. Cow–calf behaviour was recorded over a 4-year study period from a total of 300 births involving 200 Nellore, 54 Guzerat, 20 Gyr and 26 Caracu cows. The calving site in relation to the location of the herd, considering cow–calf pairs within, close or distant to the herd, the presence of vultures and the behaviour of cows and calves were recorded instantaneously, at 5-min interval. On average, vultures were present at 80% of the calving sites. The frequency of vultures present at calving sites was dependent on the years for the Nellore herd, increasing from 1998 to 2003. When vultures were present, the time that the cow was in contact with its calf decreased, and the percentage of time that the cow was standing still increased. Vultures were observed pecking cows and their neonates during 34.1% of all recordings. However, in only two cases pecking injuries were actually observed on calves that were noted to be very weak. The preliminary results suggest that although black vultures cannot be characterized as a predator of neonate calves, they sometimes attack neonate calves and their presence near the calving sites alter the behaviours of cows and calves.