牛肺疫的诊断与防控对策研究

牛肺疫是比较常见的一种牛接触性传染病症,严重危害着牛机体。随着近些年国内畜牧业的迅猛发展,牛养殖场规模与数量随之不断扩大,我国养殖业呈现繁荣发展局面。然而,牛养殖期间也会突发各种疫病,带给畜牧生产巨大的经济损失。所以,有效的牛肺疫诊断防控措施对我国养殖业的发展极具重要意义。     

The place of Sanga cattle in dairy production in Uganda

A survey was carried out on milk production and reproductive performance of dairy cattle: 24 farms, with a total of 900 animals and distributed in four agro-ecological zones, were visited every 15 days over 18 months. Cows were fed on natural pastures as the only source of feed, and animal performance was dependent on the season and exhibited a dramatic drop in dry spells. Numeric productivity indices integrating productive performance for settler’s, multipurpose, crop–livestock integrated and modern farms were 0.56, 0.74, 0.69 and 0.63, respectively. Milk productivity was higher on modern farms (6.7 L/cow per day) than in the other systems, and higher with Holstein-Friesian cows (7.7 L/cow per day) than with indigenous cattle (1.8 L/cow per day) or crossbred animals (3.7 L/cow per day). This paper speculates on the opportunity to improve the genetic potential of indigenous cattle, concomitantly with the efforts to adapt exotic cattle to a mountainous equatorial environment.     

Effect of blood metabolites, body condition and pasture management on milk yield and postpartum intervals in dual-purpose cattle farms in the tropics of the state of Veracruz, Mexico

Research was conducted on typical smallholder farms with dual-purpose cattle (DPC) (Bos indicus x B. taurus) in the coastal north-central area of Veracruz, Mexico. The study was divided into two phases. The aim of the first phase was to investigate the effect of blood metabolities, body condition and pasture management on milk yield and postpartum intervals, in order to investigate if the former are suitable indicators of the reproductive and nutritional status of DPC. One hundred and sixty-five calvings of crossbred cows were recorded from January 1992 to November 1994 on 12 small farms. Milk samples were collected twice a week for progesterone analysis. Blood samples and BCS were taken once a month. However, in Phase II emphasis was placed on the effect of pasture management upon reproductive and productive performance of DPC. Records of four farms were obtained from June 1995 to November 1996. Stocking rates were 0.40, 0.87, 0.35 and 1.5 cows/ha for farms A, B, C and D, respectively. Farms A and C used a slow rotation while B and D used a rapid rotation. In Phase I, the changes in BCS during the last month of pregnancy and first month postpartum did not correlate (p > 0.05) with milk yield or reproductive performance. Blood the metabolite profiles were not consistently related to productive or reproductive variables. The effect of farm and season was significant (p < 0.05) on most of the response variables and low productivity on overstocked farms lead to the conclusion that the low reproductive performance of DPC was linked to poor pasture management. During Phase II, farms A (FA) and D (FD) produce more milk than the others. Days to first service, days open, and calving interval were similar for farms B (FB) and C (FC), highest for Farm A, and lowest for Farm D. The forage availability mean was above the critical range of 6-8 kg of dry matter per 100 kg of liveweight (kg DM/100 kg LW) in all farms (range from 6.1 +/- 5.0 to 21.1 +/- 11.2 kg DM/100 kg LW). Farm D had the highest stocking rate (1.5 cows/ha), a rapid rotation (10 paddocks), a good forage availability (7.1 +/- 3.9 kg DM/100 kg LW) with a good quality for a tropical pasture (11.6 +/- 2.4% crude protein), and an economic energy supplementation. These results suggest this type of management could be more widely employed to improve the productivity of DPC on smallholder farms in the Mexican tropics.     

Prevalence of and risk factors for bovine respiratory syncytial virus (BRSV) infection in non-vaccinated dairy and dual-purpose cattle herds in Ecuador

A cross-sectional study was carried out to determine the seroprevalence and risk factors associated with bovine respiratory syncytial virus (BRSV) infection in non-vaccinated dairy and dual-purpose cattle herds from Ecuador. A total of 2,367 serum samples from 346 herds were collected from June 2008 to February 2009. A questionnaire, which included variables related to cattle, health, management measures, and the environment, was filled out in each herd. Presence of antibodies against BRSV was analyzed using a commercial indirect ELISA test. A logistic regression model was used to determine risk factors associated with BRSV at herd level. The individual seroprevalence against BRSV in non-vaccinated herds in Ecuador was 80.48% [1,905/2,367; 95% confidence interval (CI)?=?78.9-82.1]. The herd prevalence was 91.3% (316/346; 95% CI?=?88.3-94.3), and the intra-herd prevalence ranged between 25% and 100% (mean, 90.47%). The logistic regression model showed that the existence of bordering cattle farms, the dual-purpose farms, and the altitude of the farm (more than 2,338?m above sea level) were risk factors associated with BRSV infection. This is the first study about BRSV prevalence in Ecuador. It shows the wide spread of the BRSV infection in the country. The risk factors found will help to design effective control strategies.     

Seroprevalence of contagious bovine pleuropneumonia at export quarantine centers in and around Adama,Ethiopia

A cross sectional study was undertaken from October 2010 to March 2011 to determine the seroprevalence of contagious bovine pleuropneumonia (CBPP) and its related risk factors in export quarantine centers. A total of 3,111 cattle sera were collected from different export quarantine farms located in and around Adama, namely, Bekero, Jogo, Kedir, and Dera farms, and tested for the presence of Mycoplasma mycoides subsp. mycoides small colonies antibody using competitive enzyme-linked immunosorbant assay. Of the total 3,111 cattle sera examined, 124 (4 %) were found positive for CBPP. Among the potential predisposing factors assessed, origin, transportation condition, confinement level, and stay time of the animals in quarantine center were not found significantly (P?>?0.05) associated with the occurrence of the disease. Whereas age was found significantly (P?<?0.05) associated with the occurrence of the disease in which a high seroprevalence was recorded in aged (9.5 %) animals than young (3 %). Generally, this study showed that CBPP is a threat for Ethiopian livestock export market and a well established disease in Borana and Bale areas, where the animals originated.     

Anaplasma marginale: lack of cross-protection between strains that share MSP1a variable region and MSP4

In Mexico, there are no commercial alternatives for the immunoprophylaxis of bovine Anaplasmosis, a disease responsible for great economic losses. Blood derived Anaplasma marginale used for immunizing susceptible cattle has shown promising results for homologous protection and controversial results against unrelated strains. The present study examined, under controlled conditions, the cross-protective potential of an immunogen composed of blood derived A. marginale of three strains against challenge with strains not included in the immunogens. Groups 1 and 2 were immunized with blood derived Anaplasma from strains Mexico, Morelos and Yucatan, group 4 with strains Morelos, Veracruz and Yucatan, two more groups (2 and 5) of equal conditions were inoculated with an adjuvant alone. Groups 1, 4 and 5 were challenged with Mexico strain; groups 2 and 3 were challenge-inoculated with strain Veracruz; groups 3 and 5 with strains Veracruz and Mexico as controls. Only animals in group 1, immunized and challenged with strain Mexico showed adequate protection. Both groups challenged with strains not included in the immunogens developed poor protection, while all the controls had to be treated to prevent death.     

Prevalence of bovine herpesvirus 1 (BHV-1) infection in Hungarian cattle herds.

Hungarian cattle herds were surveyed for bovine herpesvirus 1 (BHV-1) infection by ELISA of milk and serum samples. In 1993, 75% of the large cattle herds (consisting of more than 50 cattle) and all small herds (small-scale producers' stocks), while in 1997 90% of the small herds were included in the survey. In the case of large herds, 79.3% of the herds and 64.1% of the samples tested were found to be positive. Of the small herds, 13.5% and 15.7% tested positive in 1993 and 1997, respectively. The majority of large herds were Holstein-Friesian dairy stocks. Small herds with an infection rate markedly exceeding the average were found in those counties where the small herds had been in close contact with the large-scale farms, or where new herds were established by using animals of uncontrolled infectious bovine rhinotracheitis (IBR) status originating from large farms. Attention is called to the importance of maintaining the IBR-free status of small herds that constitute one-third of the Hungarian cattle population.     

Economic analysis of alternative nutritional management of dual-purpose cow herds in central coastal Veracruz, Mexico

Market information was combined with predicted input-output relationships in an economic analysis of alternative nutritional management for dual-purpose member herds of the Genesis farmer organization of central coastal Veracruz, Mexico. Cow productivity outcomes for typical management and alternative feeding scenarios were obtained from structured sets of simulations in a companion study of productivity limitations and potentials using the Cornell Net Carbohydrate and Protein System model (Version 6.0). Partial budgeting methods and sensitivity analysis were used to identify economically viable alternatives based on expected change in milk income over feed cost (change in revenues from milk sales less change in feed costs). Herd owners in coastal Veracruz have large economic incentives, from $584 to $1,131 in predicted net margin, to increase milk sales by up to 74% across a three-lactation cow lifetime by improving diets based on good quality grass and legume forages. This increment is equal to, or exceeds, in value the total yield from at least one additional lactation per cow lifetime. Furthermore, marginal rates of return (change in milk income over feed costs divided by change in variable costs when alternative practices are used) of 3.3?±?0.8 indicate clear economic incentives to remove fundamental productivity vulnerabilities due to chronic energy deficits and impeded growth of immature cows under typical management. Sensitivity analyses indicate that the economic outcomes are robust for a variety of market conditions.     

A successful, sustainable and low cost control-programme for bovine hypodermosis in France

Bovine hypodermosis affecting livestock performance and the leather industry was still widespread in France up to the nineties despite successive directives from the Ministry of Agriculture since 1941, encouraging livestock owners to treat, on a voluntary basis. In 1969 the French Ministry of Agriculture, asked the national Farmers' Animal Health Organisation (FAHO), to plan a durable hypodermosis control programme and a working group including all the partners in cattle production was set up, under the coordination of the national FAHO. Improved systems of hypodermosis control, including new treatment and surveillance methods were developed. Among the main benefits obtained from this original work, were (i) the identification of scientific data which allowed inexpensive and accurate immuno-surveillance procedures, and a highly effective low-cost treatment, Ivomec, administered at the micro dose rate (2 microg/kg), which is environmentally non-threatening, and (ii) the development of a new strategy to manage the control programmes progressively, on a regional basis, in two to three concentric zones over three successive years at a maximum. The current programme, coordinated at the National level since 1998, has been implemented in each region of France. The compulsory systemic winter treatments directed against the endo-parasitic stage, carried out by technicians and veterinarians involved the entire bovine population in controlled zones. As each zone reached a hypodermosis herd prevalence of under 5%, usually after two years, the treatments were suspended. However treatments of the infected farms and contiguous farms were maintained. An immuno-survey was carried out, each winter, to evaluate the prevalence of the disease and detect any residual foci or re-infestations. Since 2002, bovine hypodermosis in France is under control with immuno-surveillance maintained at a very low cost. In 2006 hypodermosis became a notifiable disease.     

Evaluation of Metarhizium anisopliae (Hyphomycetes) for the control of Boophilus microplus (Acari: Ixodidae) on naturally infested cattle in the Mexican tropics

The efficacy of Metarhizium anisopliae on the control of Boophilus microplus in cattle infested naturally in the Mexican tropics was evaluated. The study was carried out on a ranch in Veracruz, Mexico. Twenty steers were randomly allocated into two groups of 10 cattle. Animals were naturally infested with B. microplus. Animals in the treated group were sprayed with M. anisopliae (strain Ma34) at a concentration of 1x10(8)conidia/ml every 15 days (four treatments). The other group remained as untreated control. Standard engorged female ticks were recorded on days 0, 1, 3, 5, 7 and 14 post-treatment. From the second application treatment (day 7) to the end of the experiment, animals in the treated group had lower tick infestation (P<0.05) with an efficacy of 40.0-91.2%. The results demonstrate the efficacy of repeated treatment with M. anisopiae (Ma34 strain) to control natural infestation of engorged female B. microplus on cattle in the Mexican tropics.     

Risk of babesiosis and anaplasmosis in different ecological zones of Santa Cruz Department, Bolivia

A cross-sectional study was done of seroprevalence of Babesia bigemina, B.bovis, and Anaplasma marginale in cattle from eastern Bolivia, to characterise the risk of tick-borne disease in three ecological zones. Nineteen farms were sampled in the subtropical humid zone, 13 in the dry subtropical zone and nine in the lower western valleys of the Andean massif. The enzyme-linked immunosorbent assay was used. All three pathogens were widespread. For B. bovis, seroprevalences were high (75-78%) in the two subtropical zones which thus had low risk of disease from this infection; but the western valleys were endemically unstable with higher risk. For B. bigemina, seroprevalences were lower (24-57%) in the two subtropical zones and thus these areas were endemically unstable for disease from this infection. However, the seroprevalence of B. bigemina in the western valleys was too low (13%) for risk of disease in susceptible cattle to be considered high. For A. marginale, the seroprevalences in the two subtropical zones were low (19-32%) and very low (6%) in the western valleys suggesting all these zones were endemically unstable for anaplasmosis. Data for individual farms were analysed for risk of both forms of babesiosis; this showed low risk of disease in the subtropical humid zone, higher risk in the dry subtropical zone and variable risk in the western valleys.     

Productivity in different cattle production systems in Kenya

Cattle are kept as an important source of livelihood in many Kenyan farming households whilst also having cultural and social value. A review was undertaken to estimate productivity in the three main Kenyan cattle production systems: small-scale dairy and meat; small-scale dairy; and large-scale dairy and meat. Data on production parameters were collected through a systematic literature search of electronic databases for peer reviewed and grey literature. The parameters included were reproductive rates, mortality rates and yields. Prices for livestock and livestock products were estimated from markets. The data were used to estimate net output from cattle using the Livestock Productivity Efficiency Calculator (LPEC), a deterministic steady state model which measures productivity as net output per megajoule (MJ) of metabolisable energy (ME). The estimated net outputs per livestock unit year^?1 were USD 146.6, USD 215.1 and USD 84.8 in the large-scale dairy and meat, small-scale dairy and meat and small-scale dairy systems, respectively. Milk production contributed significantly to net output in all systems and was 91.8 % of total output in small-scale dairy. Cattle sales had the highest contribution to net output in large-scale dairy and meat system (45.1 %). Sensitivity analysis indicated that output was most affected by milk yield, age and weight at maturity and parturition rate. The productivity differences between the production systems call for more detailed research on the constraints to the production systems such as diseases, and to describe the benefits that farmers and society would obtain from disease control and improved management.     

High prevalence of enterohemorrhagic Escherichia coli (EHEC) O157 from cattle in selected regions of Japan

The prevalence of enterohemorrhagic Escherichia coli (EHEC) O157 was examined in bovine faeces. EHEC O157 was isolated from the faeces of 42 (13.0%) of 324 cattle. Of the 4 farms and the facilities tested, the 3 farms and the facilities were found positive for EHEC O157. The highest isolation rate among the farms was 33.7%. The prevalence of EHEC O157 in heifers was higher than that in calves and other cattle. No cattle positive for EHEC O157 showed any clinical signs except 2 calves with diarrhea in a veterinary hospital. Almost all isolates possessed the stx gene, and Stx-positive strains carrying both stx(1) and stx(2) genes were predominant. These results indicate that EHEC O157 are distributed in bovine faeces, and that dairy and beef farms in selected regions of Japan are heavily contaminated with the organisms.     

Shiga toxin-producing Escherichia coli (STEC) isolated from healthy dairy cattle in southern Brazil

Over a period of 1 year, the production of verotoxin was investigated in 1127 Escherichia coli isolated from 243 dairy cattle from 60 small farms in southern Brazil. Vero cell assay was used to detect toxins in culture supernatants from E. coli isolated from bovine feces. Shiga toxin-producing E. coli (STEC) detection rates were 95% (57 of 60) for farms and 49% (119 of 243) for cattle. Prevalence of STEC-positive cattle in the farms ranged from 0 to 100%. Ninety-six percent (315 of 327) of the STEC isolates did not react in the panel of sera used for typing. Twelve isolates, all non-motile, belonged to serogroups previously associated with human diseases, and 67% (8 of 12) were of only two serotypes (O91:H- and sorbitol-fermenting O157:H-). These results indicate that dairy cattle from the region surveyed may be a source of STEC potentially pathogenic for humans.     

Seroprevalence of enzootic bovine leukosis in Trakya district (Marmara region) in Turkey

In this study, 481 cattle belonging to 77 farms from nine localities in Trakya district in the Marmara region of Turkey were blood sampled and serologically tested for enzootic bovine leukosis (EBL). Antibodies to bovine leukosis virus (BLV) were detected in 51 cattle sera (11%) belonging to nine farms in five localities. Cattle tested were mostly female Holstein or Brown Swiss of ages ranging between 18 months and 10 years. Analysis of the relationships between age, breed or sex and seropositivity to EBL in seropositive herds indicated no significant associations (p>0.05). The relationship between seropositivity and haematological changes was also studied, and seropositive cattle had higher lymphocyte percentage and lower neutrophil percentage than seronegative cattle (p<0.001).     

寻甸县肉牛主要疫病病原学监测和防控研究

2021年—2022年云南省寻甸县肉牛科技特派团成员对寻甸县肉牛主要疫病进行系统调查及疫病防治研究,2年来共完成了16个乡(镇)175个肉牛养殖场(户)的现场调查,并随机在全县16个乡镇71个肉牛养殖场(户)、1个屠宰场和1个大牲畜交易市场采集样品3267份,进行了口蹄疫、牛结节性皮肤病、牛蓝舌病、巴氏杆菌病、牛支原体、牛结核分枝杆菌、牛病毒性腹泻、牛传染性鼻气管炎、牛布鲁氏菌病、巴贝斯虫10个病的病原学检测,结果显示：牛结节性皮肤病、蓝舌病病毒、牛巴氏杆菌病、牛支原体、牛结核病、巴贝斯虫病6个病种的病原监测均为阴性;在73个养殖场(户)1394份棉拭子中检出牛病毒性腹泻阳性3份、牛传染性鼻气管炎阳性2份;在29个养殖场(户)899份全血样品中检出牛巴贝斯虫病12份,样品阳性率分别为0.22%,0.14%,1.33%;场阳性率分别为1.37%、1.37%,24.13%。通过2年持续地边监测边排查隐患,精准指导养牛户科学防控疫病、规范使用兽药、强化生物安全等措施,使养殖户掌握了科学养牛和科学防病技术,切实提高肉牛疫病防控和养殖水平,提高肉牛养殖效率和肉牛产品品质。     

Limitations and potentials of dual-purpose cow herds in Central Coastal Veracruz, Mexico

Feed chemical and kinetic composition and animal performance information was used to evaluate productivity limitations and potentials of dual-purpose member herds of the Genesis farmer organization of central coastal Veracruz, Mexico. The Cornell Net Carbohydrate and Protein System model (Version 6.0) was systematically applied to specific groups of cows in structured simulations to establish probable input-output relationships for typical management, and to estimate probable outcomes from alternative management based on forage-based dietary improvements. Key herd vulnerabilities were pinpointed: chronic energy deficits among dry cows of all ages in late gestation and impeded growth for immature cows. Regardless of the forage season of calving, most cows, if not all, incur energy deficits in the final trimester of gestation; thus reducing the pool of tissue energy and constraining milking performance. Under typical management, cows are smaller and underweight for their age, which limits feed intake capacity, milk production and the probability of early postpartum return to ovarian cyclicity. The substitution of good-quality harvested forage for grazing increased predicted yields by about one-third over typical scenarios for underweight cows. When diets from first parturition properly supported growth and tissue repletion, milk production in second and third lactations was predicted to improve about 60%. Judiciously supplemented diets based on good quality grass and legume forages from first calving were predicted to further increase productivity by about 80% across a three-lactation cow lifetime. These dual-purpose herd owners have large incentives to increase sales income by implementing nutritional strategies like those considered in this study.