牛粪堆积对草地影响的研究

初步研究了松嫩草地牛粪堆积对草地的影响。结果表明,草地牛粪堆积能提高土壤水分、有机质、全氮、全磷、全钾含量,降低土壤pH值,因而改善土壤理化性质,利于其周围植物生长,但只能延及到牛粪堆外围3~5 cm处,牛粪堆积造成其影响范围内的草地生产力下降11.2%。在草地牛粪中共调查到大型节肢动物3目8科15种,粪食性型种类10种,直蜉金龟在4,5,6和9月为优势种,而肖秋家蝇和东方角蝇幼虫在7,8月为优势种。牛粪中种子种类较少,数量较多,主要为稗草种子,其发芽率较低。牛粪中植物种子对碱斑地植被建植有重要意义。     

Examination of potential methods to predict pulmonary arterial pressure score in yearling beef cattle

Susceptibility of beef cattle to high altitude disease (HAD) is of major importance to economic and genetic selection on high elevation ranches. However, currently the best indicator of HAD susceptibility is the pulmonary arterial pressure (PAP) test, a test with high cost and invasive nature. Therefore, 2 experiments were undertaken to determine whether emerging technologies that predict blood components could be used to predict the PAP score in yearling Angus cattle. In Exp. 1, 39 yearling Angus bulls were used to determine if a relationship existed between PAP score and 10 blood components provided by a hemogram using whole blood or oxygen saturation as predicted by pulse oximetry in nonanesthetized cattle measured rectally or orally. Three of the hemogram values (packed cell volume, hemoglobin concentration, and red cell distribution width) were correlated (P < 0.10) with the PAP score. Prediction equations for PAP score were generated using the hemogram values and resulted in R2 values of 0.375 and 0.305 for the regression model using all of values and the best 2-variable model, respectively. Pulse oximetry was able to provide oxygen saturation predictions rectally or orally; however, the predicted values were not correlated with the PAP score (P > 0.10) or with each other (P > 0.10). In Exp. 2, 84 yearling Angus cattle (62 bulls, 22 heifers) were used to evaluate the ability of a portable clinical analyzer to predict the PAP score using 11 blood components from a sample of whole blood evaluated at the processing chute. The portable clinical analyzer was able to provide values for all of the 11 blood components; however, none of the predicted values were correlated with the PAP score (P > 0.10). In these preliminary experiments, 3 blood component values provided via the hemogram were the only variables both correlated with the PAP score and able to contribute to the development of a useful PAP prediction equation that could reduce the cost of traditional measures of HAD susceptibility. Future research is needed to determine whether additional blood components or emerging blood analysis technologies are able to accurately predict the PAP score in beef cattle.     

Absence of endothermy in flightless dung beetles from southern Africa

Body temperatures of the large, flightless dung beetle Circellium bacchus have been measured during walking, ball making and ball rolling, but were not significantly different from black bulb temperatures. Circellium is thus strictly ectothermic, unlike winged dung beetles, which are endothermic during terrestrial activity as well as in flight.     

Use of the brucellosis card test for screening cattle in Saskatchewan.

One group of 28,714 bovine sera were tested by both the brucellosis tube serum agglutination test and the brucellosis card test. The tube serum agglutination test confirmed 99.8% of the negative brucellosis card test results. The brucellosis card test identified 63% of the tube serum agglutination test reactors. In a second group of 496 sera reacting to either the tube serum agglutination test, complement fixation test, plate serum agglutination test or acid antigen serum agglutination test the brucellosis card test identified 99.1% of the complement fixation test positive sera and 91.3% of the sera reacting to any of the other serological tests. The brucellosis card test showed satisfactory agreement with both the complement fixation test and tube serum agglutination test. It appears to be a useful screening test in operations involving large numbers of animals since under these conditions the reactors can be quickly identified and isolated.     

A review of the potential impact of increased use of housing on the health and welfare of dairy cattle in New Zealand

AIM: To assess the likely impact on the health and welfare of dairy cattle in New Zealand of increased use of housing. METHODS: Published data on the effect of housing on the welfare of dairy cattle were reviewed to determine whether, under New Zealand conditions, housing was likely to increase or reduce welfare. The focus of this review was on permanent housing, and the welfare outcomes assessed were primarily those associated with biological function rather than behaviour. The five areas of focus were shelter, feeding, calving, lameness, and other diseases, and were based on the welfare concerns expressed by dairy farmers of large herds. RESULTS: The shelter provided by housing dairy cattle would appreciably improve welfare under a relatively small range of conditions. For feeding and calving, both advantages and disadvantages of housing were identified. For lameness and mastitis, published research and comparisons of disease levels in New Zealand with those in other developed dairying countries strongly suggest that increased use of housing will increase the risk of these diseases. CONCLUSIONS: Under New Zealand conditions, housing dairy cattle is likely to have both significant welfare benefits (protection from environmental conditions) and drawbacks (increased risk of mastitis and lameness). New Zealand-based research suggests that in most areas of the country the benefits of protection from extremes of temperature and wind and rain are likely to be apparent on only a few days a year, insufficient to justify the costs associated with housing cattle. Thus, dairy cattle are likely to be housed for longer than required for shelter purposes, increasing the risk of deleterious effects without a balancing welfare advantage from environmental protection. CLINICAL RELEVANCE: Increases in lameness and mastitis are likely to be associated with the increased use of housing and are likely to be accompanied by changes in the aetiology and presentation of these diseases, requiring better detection techniques, such as measurement of comfort or locomotion score, and new preventive regimes, such as pre-milking teat spray and routine corrective hoof-trimming.     

Secondary seed dispersal by dung beetles in an Amazonian forest fragment of Colombia: influence of dung type and edge effect

Seeds of many plant species are secondarily dispersed by dung beetles, but the outcome of this interaction is highly context‐specific. Little is known about how certain anthropogenic disturbances affect this plant–animal interaction. The aims of this study were to assess the effect of dung type on secondary dispersal by dung beetles in a forest fragment, and to determine whether this interaction is affected by edge effects. Using pitfall traps, we captured dung beetles attracted to dung of 2 frugivorous mammals: woolly monkeys and howler monkeys. We found differences between both dung beetle assemblages, but these differences were not consistent in time. Using seeds surrounded by both dung types, we carried out a field experiment using seeds of 2 plant species. We found that the probability of secondary dispersal by dung beetles was higher for seeds placed in woolly monkey dung. Finally, we carried out a field experiment using plastic beads as seed mimics to assess edge effects. We found that secondary seed dispersal by dung beetles was negatively affected by edges. The disruption of plant–animal interactions along anthropogenic forest edges could have long‐term negative effects on forest dynamics by affecting processes of regeneration.     

苜蓿草饲喂肥育肉牛效果试验

苜蓿草以其产量高、对土地适应性强、蛋白质含量高、营养丰富、饲用价值高等优点而被称为牧草之王。目前苜蓿草在奶牛业中已被广泛应用。在肉牛业中 ,由于苜蓿草市场售价较高 ,利用不当会增加饲养成本 ,因而在肥育牛中很少使用。本试验的目的就是通过肉牛肥育试验 ,筛选出苜蓿草饲喂肉牛的最佳给量 ,使苜蓿草在肉牛肥育中得以有效利用 ,为促进草畜结合 ,推进牧草产业化进程提供科学依据。1　材料与方法选择 1 8月龄左右 ,体重在 3 5 0千克左右的西门塔尔杂交公牛 1 2头 ,随机分成三组 ,每组 4头 ,其中一组为对照组 ,饲料中不加苜蓿草 ,其他…     

Model based on weather variables to predict seroconversion to bluetongue virus in Alabama cattle

A model for the prediction of bluetongue virus seroconversion was developed using weather variables and results from serum samples collected from a research herd of Hereford, Angus, Holstein and mixed breed beef cows at 12 different times over 2 years. The six weather variables analyzed were: mean daily air temperature; mean daily soil temperature at a depth of 10 cm; mean daily hours of wet vegetation; total days of rainfall ≥ 0.13 cm; total rainfall for each 7 day period; mean daily solar energy (W m⁻²). A maximum R² multiple linear regression technique was applied to meteorological data collected during the four weekly intervals prior to each sample collection date (48 sets of weekly meteorological data). The best predictors for seroconversion were mean daily hours of wet vegetation and total rain days during the second weekly period prior to sample collection. The bluetongue virus seroconversion was related to mean daily hours of wet vegetation, total rain days, and total precipitation as expressed by the equation: Seroconversion=7.1+4.0 (mean daily hours of wet vegetation)−1.3 (total precipitation) (R²=0.62, P<0.0001).     

封育和添加牛粪对退化亚高山草甸土壤恢复的影响

为了解封育和添加牛粪措施对退化草地土壤恢复的影响,本研究以滇西北部亚高山草甸为研究对象,进行了延续4年的试验。结果表明,封育、添加牛粪均显著提高了退化亚高山草甸土壤有机质含量(P0.05),且封育下有机质含量高于添加牛粪处理;二者对土壤容重、含水量均无显著影响(P0.05)。封育、添加牛粪对土壤氮磷钾含量的作用有所不同,封育显著提高了0-10cm土层中全氮、全磷、速效钾的含量(P0.05),降低了全钾的含量(P0.05);牛粪处理则显著降低了0-10cm土壤全氮和速效磷的含量(P0.05),对全磷、速效钾的含量没有明显影响(P0.05)。封育和添加牛粪措施之间存在互作效应,共同作用时对0-10cm的全氮、全磷、速效磷的影响最大,对0-30cm土壤的有机质含量则存在累积效应。另外,全氮、全磷、全钾、速效磷、速效钾在土壤中的分布以0-10cm为主,在0-30cm土层中从上往下呈递减趋势。可见,封育和添加牛粪均改善了土壤的养分状况,有利于退化亚高山草甸土壤的恢复。     

Development of a model to predict forage intake by grazing cattle

A mathematical model to predict daily DMI and account for effects of energy supplementation on forage intake has been developed in several stages. A previously evaluated dynamic rumen model for sheep was adopted as the fermentation component of the intake model. Intake was adjusted to reach a given level of DM fill, which is the sum of the concentrations of each of the dietary fractions within the rumen. Differential equations described the rate of change of each nutrient fraction. Genetic size scaling rules based on mature body size relationships were used to adjust rate and fill parameters of the intake model from sheep to beef cattle. Nutrient fractions were partitioned into those that flow at the particulate passage rate vs the fluid passage rate. Forty-two data points representing perennial ryegrass, wheat pasture and range grasses were used to parameterize and evaluate the model. The model was relatively sensitive to the coefficient relating DMI to particulate rate of passage, the rate constant for the use of the potentially degraded fiber fraction of the forage, and to the composition constants for the amount of carbohydrate and nitrogen in the microbial mass. Relative insensitivity was observed for starch and protein nutrient use rate constants, for the coefficient relating DMI to fluid passage rate, and for constants relating to the growth of the microbial mass in the rumen. Feed intake of grazing cattle may be predicted by mechanistic models describing various nutrients' contribution to ruminal fill.     

The ecology of nematode-trapping hyphomycetes in cattle dung from three plateau pastures

This paper investigated the influence of season and altitude on the occurrence of nematode-trapping fungi in cattle faeces. Six hundred and sixty samples of cattle faeces deposited on three plateau pastures with different altitudes in the west of Yunnan Province, China, were examined in 2004. A total of 17 species of nematode-trapping hyphomycetes were isolated from these samples. The predominant species from all three plateau pastures were Arthrobotrys oligospora, A. musiformis, Monacrosporium ellipsosporum, and M. thaumasium. Species with adhesive networks were the most frequently isolated. Overall, species diversity index was negatively correlated with altitude and was different among seasons within the same site. Levels of diversity were highest in the summer, followed by autumn, spring, and winter. The conidia of the hyphomycetes isolated here germinated normally on medium containing cattle faeces, with species developing adhesive networks having the highest rate of germination. However, the rate of conidial trap (CT) formation was lower in species with adhesive networks than those in other species.     

Application of the glutaraldehyde test in cattle

In a cohort study involving 62 cows from an experimental farm, the kinetics of the glutaraldehyde test (GAT) according to Sandholm (1974) was examined by testing samples of EDTA blood, lithium heparinate blood, serum, and plasma taken at various intervals. Total protein was measured in serum, and fibrinogen was determined in plasma. Gamma globulin was measured by electrophoresis. All glutaraldehyde tests were performed in duplicates, and the relation of the two results was used as measurement of precision. Optimal cut-off of the GAT time was determined as the zenith of the sum of sensitivity and specificity of various intervals for detecting combinations of gamma globulin and fibrinogen levels above 32 g/l. Precision was the best in EDTA blood. The relation between coagulation time and gamma globulin plus fibrinogen is best described by an exponential curve. The maximum value for the sum of sensitivity and specificity was found at 7 and 8 min. Seven days was the shortest interval observed between a negative test result (>15 min) and a strongly positive test result (<3 min). Twenty-one days was the shortest interval observed between a strongly positive test result and a negative test result. EDTA blood should be used for the GAT. A cut-off of 8 min yields the highest efficiency. Test results must be viewed in light of clinical findings.     

Effects of farm management practices on cattle grazing behaviour and the potential for transmission of bovine tuberculosis from badgers to cattle

Despite the large body of circumstantial evidence to suggest a link, the means by which bovine tuberculosis is passed from badgers to cattle remains unclear; pasture contamination with the urine, faeces and/or sputum of infectious badgers is believed to be the main route of transmission. Therefore the behaviour of grazing cattle was studied to determine whether they avoided investigating and/or grazing pasture contaminated with badger excreta, and whether different farm management practices enhanced the potential for disease transmission. Active latrines were avoided by most cattle until the sward length in the rest of the field was reduced, after which there was an increasing likelihood that active badger latrines would be grazed. Most of the cattle grazed active badger latrines, but cattle of low rank within the herd grazed latrines more heavily. Farm management practices that reduced the availability of long swards shortened the period of investigative behaviour and greatly enhanced the risk that cattle would graze active badger latrines. Cattle were more likely to graze pasture away from latrines that was contaminated either with badger urine or single faeces. Because bacilli remain viable in the soil for up to 2 years, there is the potential for bacilli to accumulate at active badger latrines, and these could pose a significant risk to cattle, even when the latrine is no longer being used by badgers. Cattle readily grazed the lush sward at disused latrines, during which they could ingest contaminated soil; the amount of soil ingested increases as sward length decreases.