The role of host management in tick population changes on Rusinga Island,Kenya

Contrary to patterns described elsewhere, tick numbers on Rusinga Island cattle drop markedly after the onset of the rainy season. One possible explanation is that this is related to seasonal differences in host behaviour since cattle grazing on the island are restricted during the crop-growing season (the rainy season) and free grazing afterwards. In a field experiment, cattle were divided into two groups, free grazing and restricted, for 2 months each during the rainy season and during the dry season, and the number of ticks infesting each group was compared. In both seasons, the free-grazing group carried more ticks than the restricted group. Not only did the restricted group come into less contact with ticks, they were also exposed to tick-predating chickens for longer periods each day than the free-grazing group. Management practices that affect host behaviour should, therefore, be taken into consideration in tick population studies.     

Numbers of fecal streptococci and Escherichia coli in fresh and dry cattle, horse, and sheep manure

Livestock are known contributors to stream pollution. Numbers of fecal streptococci and Escherichia coli in manure naturally deposited by livestock in the field are needed for activities related to bacterial source tracking and determining maximum daily bacterial loading of streams. We measured populations of fecal streptococci and E. coli in fresh and dry manure from cattle (Bos taurus L.), horses (Equus caballus L.), and sheep (Ovis aires L.) on farms in southern Idaho. Populations of indicator bacteria in dry manure were often as high as that in fresh manure from horse and sheep. There was a 2 log10 drop in the population of fecal coliform numbers in dry cattle manure from cattle in pastures but not from cattle in pens. Bacterial isolates used in source tracking should include isolates from both fresh and dry manure to better represent the bacterial source loading of streams.     

Thelazia rhodesii (Desmarest, 1828) in cattle of Central Province, Zambia

Sanga cattle from Central Zambia were examined during the dry and the rainy seasons for the presence of the adult stage of eyeworm Thelazia rhodesii. Prevalences were recorded according to age/sex groups. The occurrence of ocular diseases was also noted. Differences between the total prevalences of infection with the parasite in the dry and rainy seasons were observed: respectively 3.1% and 26.6% of all cattle examined (p less than 0.001), which numbered 223 head in the dry season and 248 in the rainy season. In both seasons, adult males showed the highest prevalence and calves the lowest. In the dry season the parasite was found in two of the 23 males (8.7%) but in none of the 24 calves. During the rains, eight of the 22 adult males (36.4%), and two of 53 calves (3.8%) were parasitized (p less than 0.001). A comparison of the prevalences in the latter season between a group of cows sprayed weekly with a synthetic pyrethroid and an untreated group showed no significant difference between the two groups (p greater than 0.1). No correlation was found between T. rhodesii infection and the occurrence of eye lesions (p greater than 0.1). It is concluded that in traditionally managed Zambian cattle the infection is seasonal, is more frequent in adult male animals and is not associated with eye infections (i.e., pink-eye).     

Changes in composition and structure of a tropical dry forest following intermittent cattle grazing

In northwestern Costa Rica, cattle are being used as a "management tool" to reduce the amount of combustible material, mainly dominated by Hyparrhenia rufa, an African grass. This project is being developed within Parque Nacional Palo Verde and Reserva Biológica Lomas Barbudal, both of which form part of the only remaining tropical dry forests in Mesoamerica. To determine the short-term effects of cattle grazing on the natural vegetation, we compared the floristic composition within Palo Verde in an area under intermittent cattle grazing with an area that has not been grazed. There were significantly fewer plant species in the area with intermittent cattle grazing compared to the area with no grazing. Floristic composition of these two habitats was different as reflected by both Fisher's alpha values and the Shannon index of diversity, both of which were significantly higher in the ungrazed site. The ungrazed area contained more plant species and was more similar to mature forest. The structure of the vegetation was significantly different between the intermittently grazed and ungrazed sites with more small stems (1-5 cm dbh) and fewer large stems (> 5 cm dbh) in the intermittently grazed habitat. These results indicate that cattle grazing has an impact on the dry forest by reducing the relative abundance and density of larger tree species and by changing the species composition and structure of the community. The current management plan implemented in Palo Verde and Lomas Barbudal is not appropriate because of the impact that cattle have on the structure of the natural vegetation and should not be considered a viable alternative in other protected areas of dry forest in the Neotropics. We suggest that alternative fire prevention measures be evaluated including hand-cutting H. rufa, the creation of more frequent and larger fire breaks, and the development of green breaks.     

Removal of cattle accelerates tropical dry forest succession in Northwestern Mexico

Domestic livestock influence patterns of secondary succession across forest ecosystems. However, the effects of cattle on the regeneration of tropical dry forests (TDF) in Mexico are poorly understood, largely because it is difficult to locate forests that are not grazed by cattle or other livestock. We describe changes in forest composition and structure along a successional chronosequence of TDF stands with and without cattle (chronic grazing or exclusion from grazing for ~ 8 year). Forest stands were grouped into five successional stages, ranging from recently abandoned to mature forest, for a total of 2.7 ha of the sampled area. The absence of cattle increased woody plant (tree and shrub) density and species richness, particularly in mid-successional and mature forest stands. Species diversity and evenness were generally greater in sites where cattle were removed and cattle grazing in early successional stands reduced establishment and/or recruitment of new individuals and species. Removal of cattle from forest stands undergoing succession appears to facilitate a progressive and non-linear change of forest structure and compositional attributes associated with rapid recovery, while cattle browsing acts as a chronic disturbance factor that compromises the resilience and structural and functional integrity of the TDF in northwestern Mexico. These results are important for the conservation, management, and restoration of Neotropical dry forests.     

Cattle select African savanna termite mound patches less when sharing habitat with wild herbivores

African savanna termite mounds function as nutrient‐rich foraging hotspots for different herbivore species, but little is known about their effects on the interaction between domestic and wild herbivores. Understanding such effects is important for better management of these herbivore guilds in landscapes where they share habitats. Working in a central Kenyan savanna ecosystem, we compared selection of termite mound patches by cattle between areas cattle accessed exclusively and areas they shared with wild herbivores. Termite mound selection index was significantly lower in the shared areas than in areas cattle accessed exclusively. Furthermore, cattle used termite mounds in proportion to their availability when they were the only herbivores present, but used them less than their availability when they shared foraging areas with wild herbivores. These patterns were associated with reduced herbage cover on termite mounds in the shared foraging areas, partly indicating that cattle and wild herbivores compete for termite mound forage. However, reduced selection of termite mound patches was also reinforced by higher leafiness of Brachiaria lachnantha (the principal cattle diet forage species) off termite mounds in shared than in unshared areas. Taken together, these findings suggest that during wet periods, cattle can overcome competition for termite mounds by taking advantage of wildlife‐mediated increased forage leafiness in the matrix surrounding termite mounds. However, this advantage is likely to dissipate during dry periods when forage conditions deteriorate across the landscape and the importance of termite mounds as nutrient hotspots increases for both cattle and wild herbivores. Therefore, we suggest that those managing for both livestock production and wildlife conservation in such savanna landscapes should adopt grazing strategies that could lessen competition for forage on termite mounds, such as strategically decreasing stock numbers during dry periods.     

Plant functional traits under cattle grazing and fallow age scenarios in a tropical dry forest of Northwestern Mexico

Evaluating plant functional traits helps to understand how plants respond to changing environmental conditions and resource availability associated with disturbance events. Livestock production is one of the primary drivers of tropical forest loss and degradation. Livestock alter environmental conditions within the forest by grazing, trampling and nutrient inputs, which in turn can influence species composition and functional traits of species. Understanding how livestock influence functional traits along a successional gradient is poorly understood. Here, we studied the effect of cattle grazing and fallow age on plant functional traits and soil nutrients in secondary and old-growth tropical dry forests. We analyzed plant functional traits of the most important species in successional and old-growth forest communities in both cattle present and cattle excluded plots. Our results showed the effects of cattle grazing and fallow age on plant functional traits, with fallow age explaining more variation than cattle grazing. In early succession, functional traits were associated with water conservation (thicker leaves, lower specific leaf area), and in later successional they were linked with sunlight conservation (larger height, higher specific leaf area). The presence of large fruits and seeds in advanced successional sites suggests high resource availability, which may help plants to successfully reproduce. Moreover, under cattle grazing some functional traits are associated with herbivory defense (high foliar dry weight and thick leaves). Even though N and C increased as succession advanced, the sites with cattle grazing had higher NH4 and NO3 concentrations as a result of fecal deposition. Plant functional traits responded to fallow age than to cattle grazing. Our study showed that cattle exclusion, as a management and biodiversity conservation strategy, contributes positively to soil nutrition. Thus, fallow age and cattle exclusion facilitate soil recovery and allows establishing species with suitable functional attributes for overcoming environmental filters in abandoned cattle fields.     

Use of Tropical Dry Forests and Agricultural Areas by Neotropical Bird Communities

Agricultural activities represent a global threat to biodiversity, yet little is known about the relative importance of different agricultural land uses in relation to their wildlife communities. We explored bird community structure, diversity, and composition in a landscape dominated by primary tropical dry forest, and in three agricultural systems (i.e., tree orchards, herbaceous cropfields, cattle pastures) to evaluate the way in which birds use different habitats within the landscape. Tropical dry forests had the highest species richness and community evenness, although the bird community in tree orchards was also relatively species rich and even. Cattle pastures had more bird species than cropfields but both habitats were comparatively species poor with low evenness. Our results are related to habitat structure and the spatial location of sites within the landscape matrix. Based on our observations, we recommend including native tree species within agricultural systems and surrounding areas to provide additional resources for birds. Finally, we suggest promoting natural recruitment of native trees and shrubs within cattle pastures to provide suitable habitat for species that use tropical dry forest plants. Abstract in Spanish is available at http://www.blackwell‐synergy.com/loi/btp .     

Anaerobic fermentation of sheep droppings for biogas production

Production of biogas in batch digesters at 30°C from sheep droppings produced 93 l gas/kg dry matter whereas cattle dung yielded 234 l/kg dry matter. When the sheep droppings and cattle dung were used at 25:75 (w/w), gas production per kg dry matter was equal to that of cattle dung only. The methane content of the biogas obtained from sheep droppings was 70 to 72% as compared to 56 to 60% from cattle dung.     

Identifying targets of selection in mosaic genomes with machine learning: applications in Anopheles gambiae for detecting sites within locally adapted chromosomal inversions

Chromosomal inversions are important structural changes that may facilitate divergent selection when they capture co‐adaptive loci in the face of gene flow. However, identifying selection targets within inversions can be challenging. The high degrees of differentiation between heterokaryotypes, as well as the differences in demographic histories of collinear regions compared with inverted ones, reduce the power of traditional outlier analyses for detecting selected loci. Here, we develop a new approach that uses discriminant functions informed from inversion‐specific expectations to classify loci that are under selection (or drift). Analysis of RAD sequencing data we collected in a classic dipteran species with polymorphic inversion clines—Anopheles gambiae, a malaria vector species from sub‐Saharan Africa—demonstrates the benefits of the approach compared with traditional outlier analyses. We focus specifically on two polymorphic inversions, the 2La and 2Rb arrangements that predominate in dry habitats and the 2L+^a and 2R+^b arrangements in wet habitats, which contrast with the minimal geographic structure of SNPs from collinear regions. With our approach, we identify two strongly selected regions within 2La associated with dry habitat. Moreover, we also show that the prevalence of selection is greater in the arrangement 2L+^a that is associated with wet habitat (unlike presumed importance of selective divergence associated with the shift of the mosquitoes into dry habitats). We discuss the implications of these results with respect to studies of rapid adaptation in these malaria vectors, and in particular, the insights our newly developed approach offers for identifying not only potential targets of selection, but also the population that has undergone adaptive change.     

Mapping of quantitative trait loci controlling tick [Riphicephalus (Boophilus) microplus] resistance on bovine chromosomes 5, 7 and 14

Differences in domestication and selection processes have contributed to considerable phenotypic and genotypic differences between Bos taurus and Bos indicus cattle breeds. Of particular interest in tropical and subtropical production environments are those genetic differences between subspecies that underlie the phenotypic extremes in tolerance and susceptibility to parasite infection. In general, B. taurus cattle are more susceptible to ectoparasites than B. indicus cattle in tropical environments, and much of this difference is under genetic control. To identify genomic regions involved in tick resistance, we developed a B. taurus x B. indicus F(2) experimental population to map quantitative trait loci (QTL) for resistance to the Riphicephalus (Boophilus) microplus tick. About 300 individuals were measured for parasite load in two seasons (rainy and dry) and genotyped for 23 microsatellite markers covering chromosomes 5, 7 and 14. We mapped a suggestive chromosome-wide QTL for tick load in the rainy season (P < 0.05) on chromosome 5. For the dry season, suggestive (P < 0.10) chromosome-wide QTL were mapped on chromosomes 7 and 14. The additive effect of the QTL on chromosome 14 corresponds to 3.18% of the total observed phenotypic variance. Our QTL-mapping study has identified different genomic regions controlling tick resistance; these QTL were dependent upon the season in which the ticks were counted, suggesting that the QTL in question may depend on environmental factors.     

Behavioural responses of cattle to shared foraging with wild herbivores in an East African rangeland

We assessed whether prior foraging by wild herbivores affected foraging behaviour of cattle in Laikipia rangeland, Kenya, during February 2001, August 2001 and February 2002. The study compared cattle bite rate, step rate and bites per step in plots exclusively accessible to cattle and those accessible to cattle and large wild herbivores. During February 2001 when conditions were dry, cattle bite rate was 18–19% lower, step rate 25–26% higher, and bites per step 36% lower in plots shared by cattle and wildlife compared to those exclusively accessible to cattle. Differences in these measured foraging behaviour parameters were strongly correlated with reductions in herbage cover in plots accessible to wild herbivores. Plot differences in herbage cover and the measured foraging behaviour parameters were not significant in the subsequent trials when conditions were wet, suggesting that wild herbivore impacts reported here are short-term within season and dependent on weather conditions (and plant productivity). With reduced herbaceous plant cover in wildlife grazed realms in the dry season, cattle respond with increased travel and reductions in bite rate and bites per step, suggesting that wild herbivores can seasonally affect foraging behaviour of cattle. It remains to be demonstrated whether or not these altered behaviours of cattle affect weight gains or other measures of performance.     

Coprophagy by wild ring-tailed lemurs (Lemur catta) in human-disturbed locations adjacent to the Beza Mahafaly Special Reserve, Madagascar

Coprophagy occurs in a number of animal species, including nonhuman primates. During the 2003-2004 dry seasons at the Beza Mahafaly Special Reserve, Madagascar, we observed wild ring-tailed lemurs (Lemur catta) consuming dried fecal matter from three different species. Ring-tailed lemurs consumed human feces on 12 occasions, cattle feces twice, and feral dog feces once. Coprophagy in this population may be a behavioral adaptation that provides animals access to energy and nutrients and may be an important nutritional source for older, and/or dentally impaired individuals during the dry season.     

Genetic relationships of Austrian cattle breeds

Methods of phylogenetic analysis were used to study the relationships of ten Central European cattle breeds using gene frequencies at eleven blood group and protein polymorphism loci. The results show remarkable agreement with historical and geographical relationships, but are different from the relationships postulated earlier in the century from studies of skull shape. Lowland cattle of Northern Germany are distinct from the West Alpine breeds, but the Pustertaler and Pinzgauer breeds from the Eastern Alps are more closely related to those lowland breeds than to the other Alpine breeds, suggesting they were brought from the North by Germanic settlers in the early Middle Ages. Thus, a sharp distinction between lowland cattle and all Alpine breeds seems unwarranted. Moreover, we find no evidence to justify a unique taxonomic position for Pustertaler, nor do we find any evidence that Spanish cattle might have influenced the Pinzgau. We find a close genetic relationship of the Murbodner breed to the Fleckvieh (Simmenthal) breeds that is not supported by any known historical relationship; it may indicate a little-known human migration.     

The sound of the illegal: Applying bioacoustics for long-term monitoring of illegal cattle in protected areas

Passive acoustic monitoring coupled with automated signal recognition software has been widely used in recent years as an effective and affordable tool for wildlife monitoring and to combat illegal activities within protected areas. Here, we evaluate this technique to monitor the patterns of illegal cattle occurrence in the Brazilian Pantanal over a complete annual cycle. We aim to provide one of the first assessments of the performance of automated signal recognition software to detect ungulates. Cattle occurrences reached their maximum during the end of the dry season when lowland areas provide excellent pastures for cattle. In contrast, cattle occurrences were very low during the rainy season when the study area was seasonally inundated. Automated software was an efficient tool that was able to detect approximately three-quarters of cow calls within the recordings. Passive acoustic monitoring can be used to direct patrols to areas where illegal activities, such as cattle and poaching or logging, have been confirmed, which could be a method that would be especially well suited for remote areas, such as tropical forests. Future studies should evaluate whether there is a relationship between cattle grazing intensity and its associated impacts on wildlife and flora. Rapid advances in automated recognition and the recent development of low-cost recorders foresee a new era of acoustic ecology for improved conservation in the short term.     

Omasal ciliated protozoa in cattle, bison, and sheep.

Omasal contents were collected from slaughtered cattle (n = 54), bison (n = 15), and sheep (n = 40) to determine numbers and generic distribution of ciliated protozoa. Total protozoan numbers were significantly lower in omasal contents than in ruminal contents of all three species, but the percent composition of all protozoan genera was similar between omasal and ruminal populations. The highest numbers of omasal protozoa found were 7.61 X 10(5)/g in cattle, 7.01 X 10(5)/g in bison, and 1.29 X 10(6)/g in sheep. Omasal dry matter was significantly higher than ruminal dry matter in all species and ranged up to 51.5% in cattle fed high-concentrate diets. The omasal pH was similar to the ruminal pH in all species. The number of omasal laminae averaged 149, 145, and 74 for cattle, bison, and sheep, respectively. Although protozoan concentrations in omasal contents were approximately 80% lower than those in ruminal contents, the omasum harbored relatively high numbers of ciliated protozoa. The resident omasal protozoa are extremely difficult to remove, particularly in cattle, and apparently are responsible for reinoculating transiently defaunated rumens.     

Omasal ciliated protozoa in cattle, bison, and sheep

Omasal contents were collected from slaughtered cattle (n = 54), bison (n = 15), and sheep (n = 40) to determine numbers and generic distribution of ciliated protozoa. Total protozoan numbers were significantly lower in omasal contents than in ruminal contents of all three species, but the percent composition of all protozoan genera was similar between omasal and ruminal populations. The highest numbers of omasal protozoa found were 7.61 X 10(5)/g in cattle, 7.01 X 10(5)/g in bison, and 1.29 X 10(6)/g in sheep. Omasal dry matter was significantly higher than ruminal dry matter in all species and ranged up to 51.5% in cattle fed high-concentrate diets. The omasal pH was similar to the ruminal pH in all species. The number of omasal laminae averaged 149, 145, and 74 for cattle, bison, and sheep, respectively. Although protozoan concentrations in omasal contents were approximately 80% lower than those in ruminal contents, the omasum harbored relatively high numbers of ciliated protozoa. The resident omasal protozoa are extremely difficult to remove, particularly in cattle, and apparently are responsible for reinoculating transiently defaunated rumens.     

Sources of normal variation of plasma l-aspartate:2-oxoglutarate aminotransferase in Hereford range cattle

1. Plasma levels of L-aspartate:2-oxoglutarate aminotransferase (AST) were estimated in Hereford cattle, 1 month to 12 years of age, kept under range conditions and in a group of Hereford x Angus cows kept on the same range. 2. Plasma levels of AST were estimated in a group of Crossbred cows and their calves fed a constant diet and kept in individual pens in the same geographic area as the Herefords. 3. Seasonal changes in mean plasma AST were observed in the Herefords corresponding with the change from dry winter grasses/hay and well water to fresh spring and summer grasses and slough water. No seasonal changes were observed in the Crossbreds given a constant dry diet and city water. 4. Plasma AST increased with age in calves 1 to 12 months of age in the Herefords but not in the Crossbreds. Mean plasma AST did not change with age in any of the adult cattle studied. 5. Small increases in plasma AST corresponding to increases in ambient temperature above - 12 degrees C were observed in the Crossbreds. 6. An increase in plasma AST was observed near the time of first ovulation in the confined cows. 7. No relationship could be demonstrated between plasma AST and sex, breed or time to parturition in the range cattle. Breed differences were observed in the Crossbred cows.     

Relationships between livestock grazing intensity and mammal predator-prey: A study case in Copo National Park in the dry Chaco forests

Extensive livestock ranching is one of the main drivers of habitat degradation in terrestrial communities in the dry Chaco forest (Argentina). Grazing intensity could differentially affect native mammals and their interactions, which could impact both, native mammal communities and livestock production systems. Here, we determined how the activity index of grey foxes Lycalopex gymnocercus and capture abundance and richness of small mammals vary along a grazing intensity gradient in a particular region of the dry Chaco forest (Copo National Park, Argentina). Track plots were used to estimate the activity index of foxes and cattle, and Sherman traps for small mammals. Fresh scats were collected to analyse the diet of foxes and to assess possible changes in predator-prey dynamics. Fruit availability and shrub density were measured in 6 plots of 2 m × 50 m. We used generalized linear mixed models, Spearman’s nonparametric rank correlation, Chi-squared test, and Spearman’s partial correlation coefficient to analyse the potential effects of grazing intensity. We found that the activity index of foxes increased (0.06 ± 0.018) while small mammal abundance (-0.08 ± 0.024) and species richness decreased (r_s = -0.94) with increasing grazing intensity. However, the proportion of scats with mammalian remains decreased with increasing grazing intensity. Also, we did not find a strong partial correlation between foxes and small mammals when we controlled for grazing intensity. This suggests that the abundance and diversity of small mammals in the study area are determined more by grazing intensity than by predator-prey interactions. Grazing intensity could negatively affect small mammals, but not through changes in fruit availability or shrub density, but possibly by affecting grass cover. Consequently, foxes’ activity could increase to meet caloric intake requirements. Our results suggest that specific cattle management recommendations depend on the wildlife species that serves as a conservation target. We recommend testing whether reducing cattle load can make this productive activity compatible with wildlife conservation in dry Chaco forests.     

Resource use efficiency in urban and peri-urban sheep, goat and cattle enterprises

Urban livestock husbandry receives growing attention given the increasing urban demand for livestock products. At the same time, little is known about the resource use efficiency in urban livestock enterprises and eventual negative externalities. In livestock production, feeds are an important resource whose nutrients are transformed into products (meat and milk) to generate financial return to the producer. The lack of knowledge on nutrient supply through feed might lead to oversupply with severe environmental impacts. In Niamey, a typical West African city and capital of the Republic of Niger, urban livestock production is constrained by feed scarcity, especially during the dry season. Here, the issue of resource use efficiency was studied in 13 representative and differently managed sheep/goat and cattle enterprises characterized by high and low feed inputs, respectively, during a period of 28 months. Nitrogen (N), phosphorus (P) and potassium (K) inflows into each farm through livestock feeds and outflows through manure were determined using a semi-structured questionnaire; interviews were accompanied by regular weighing of feed supplied and dung produced. Live weight gain (LWG) and efficiency of conversion of total feed dry matter offered (kg TDMO/kg LWG) were computed along with nutrient balances (NBs) per metabolic body mass (kg0.75). NBs (per kg0.75/day) in the high-input (HI) sheep/goat enterprises were +1762.4 mg N, +127.2 mg P and +1363.5 mg K and were significantly greater (P < 0.05) than those in low-input (LI) units (+69.1 mg N, -98.3 mg P and +16.5 mg K). In HI cattle enterprises, daily balances averaged +454.1 mg N, +40.1 mg P and +341.8 mg K compared to +34.4 mg N, -9.0 mg P and +68.3 mg K (P > 0.05) in LI cattle systems. All systems were characterized by poor conversion efficiencies of offered feed, which ranged from 13.5 to 46.1 kg TDMO/kg LWG in cattle and from 15.7 to 43.4 kg TDMO/kg LWG in sheep/goats. LWG in HI sheep/goats was 53 g/day in the rainy season, 86 g/day in the hot dry season and 104 g/day in the cool dry season, while HI cattle lost 79 g/day in the hot dry season and gained 121 g/day and 92 g/day in the cool dry and rainy seasons, respectively. The data indicate that there is nutrient wasting and scope for improvement of feeding strategies in Niamey's livestock enterprises, which might also decrease nutrient losses to the urban environment.