A Case–Control Study of Risk Factors for Bovine Cysticercosis in Danish Cattle Herds

Bovine cysticercosis (BC) is a zoonotic, parasitic infection in cattle. Under the current EU meat inspection regulation, every single carcass from all bovines above 6 weeks of age is examined for BC. This method is costly and makes more sense in countries with higher number of BC‐infected animals than in countries with few lightly infected cases per year. The aim of the present case–control study was to quantify associations between potential herd‐level risk factors and BC in Danish cattle herds. Risk factors can be used in the design of a risk‐based meat inspection system targeted towards the animals with the highest risk of BC. Cases (n = 77) included herds that hosted at least one animal diagnosed with BC at meat inspection, from 2006 to 2010. Control herds (n = 231) consisted of randomly selected herds that had not hosted any animals diagnosed with BC between 2004 and 2010. The answers from a questionnaire and register data from the Danish Cattle Database were grouped into meaningful variables and used to investigate the risk factors for BC using a multivariable logistic regression model. Case herds were almost three times more likely than control herds to let all or most animals out grazing. Case herds were more than five times more likely than control herds to allow their animals access to risky water sources with sewage treatment plant effluent in proximity. Case herds were also more likely to share machinery or hire contractors than control herds. The risk decreased with increasing herd size probably because the larger herds generally tend to keep cattle indoors in Denmark. The results are useful to guide future data recording that can be supplied by the farmer as food chain information and then be used for differentiated meat inspection in low‐ and high‐risk groups, enabling development of risk‐based meat inspection systems.     

A Comparison of the Prevalence and Burdens of Helminth Infections in Growers and Adult Free-Range Chickens

Matched samples of 100 chickens of each of growers and adult rural free-range chickens in Morogoro, Tanzania, were purchased from the beginning to the end of the long rainy season. At necropsy, the trachea, the gastrointestinal tract and the oviduct were examined for helminth infections. The helminth species isolated comprised 18 nematodes and 8 cestodes but no trematodes. Tetrameres fissispina is a new record in Tanzania. All the chickens harboured at least three different helminth species. Growers contained 4–14 and adults 3–12 helminth species. The number of species isolated per chicken increased as the rainy season advanced. The prevalence of the following species were significantly higher in growers than in adults (p<0.05); Ascaridia galli (69% of growers, 29% of adults); Syngamus trachea (14%, 3%); Tetrameres americana (94%, 82%); Trichostrongylus tenuis (43%, 7%); Choanotaenia infundibulum (15%, 6%); Davainea proglottina (9%, 2%); and Raillietina tetragona (36%, 21%). Allodapa suctoria (3%, 20%) and Capillaria annulata (1%, 10%) had a significantly lower prevalence in growers than in adults (p<0.05). There were significantly higher worm burdens (p<0.05) in growers than in adults for A. galli, Capillaria caudinflata, R. tetragona, S. trachea, T. americana, T. fissispina and T. tenuis. Conversely, A. suctoria and C. annulata showed significantly higher worm burdens in adults (p<0.05). The sex of the chickens influenced the burdens of Heterakis brevispiculum (p<0.05). There was an interaction effect such that growing males and adult females had statistically higher (p<0.05) burdens of T. tenuis and A. suctoria, respectively.     

Prevalence of the Proventricular Nematode Tetrameres americana Cram (1927) in Different Age Groups of Chickens in the Morogoro Region,Tanzania

Tropical Animal Health and Production -     

Prevalence and Risk Factors for Bacterial Food‐Borne Zoonotic Hazards in Slaughter Pigs: A Review

The Hygiene Package and Regulation EC‐2160/2003 require information flow from farm to slaughterhouse to enhance European consumers protection in a ‘farm to fork’ approach. This obligation especially concerns food‐borne zoonotic hazards transmitted to humans through pork consumption, such as thermophilic Campylobacter spp., Listeria monocytogenes, Salmonella enterica and Yersinia enterocolitica. Prevalence estimates of these four hazards are affected by the sampling strategy and diagnostic procedure. Individual prevalence estimates for pig carriage (from digestive contents or lymph nodes collected at slaughterhouse) were higher than individual prevalence estimates for pig shedding (from faeces). Among risk factors described in the literature, poor pen cleaning and disinfection after pig departure to slaughterhouse and poor bio‐security measures are of major significance. Moreover, whereas wet feed increases the risk of pig infection by L. monocytogenes, dry feed is a risk factor for Salm. enterica. Mixing batches of pigs, notably in fattening herds, represents a risk for the transmission of Salm. enterica and Y. enterocolitica. Whereas small herds are more infected by thermophilic campylobacters and Y. enterocolitica, higher prevalence of Salmonella is observed in large herds due to a more frequent mixing of batches. Antibiotic treatment during the finishing period increases the risk of transmission of Salm. enterica. The forenamed elements should be taken into account to characterize farms in a risk assessment approach and to improve zoonotic hazard management in the pork food chain.     

我国畜禽饲料资源中微量元素铁含量分布的调查研究

本调查旨在研究我国不同地区间各种饲料原料中铁含量分布情况,以及我国畜禽基础饲粮中铁含量,从而为饲粮中合理添补铁提供科学依据。采集全国31个省、直辖市和自治区的37种共3 719个主要畜禽饲料原料,经微波消解后,用IRIS IntrepidⅡ等离子体发射光谱仪测定其中铁含量。结果表明:这37种饲料原料的平均铁含量为21.3~2 472.0 mg/kg,而各类饲料原料铁含量平均值分布规律为:矿物质饲料(1 178 mg/kg)>动物性蛋白质饲料(1 030 mg/kg)>牧草饲料(433 mg/kg)>秸秆饲料(404 mg/kg)>谷物籽实加工副产品(260 mg/kg)>植物性蛋白质饲料(181 mg/kg)>谷物籽实饲料(71.2 mg/kg)。通过比较不同省(自治区)的玉米、小麦和豆粕的铁含量发现,不同省(自治区)同一种饲料原料的铁含量均存在显著差异(P<0.05)。根据全国各地猪、鸡常用的142个饲料配方所计算出的基础饲粮中铁含量为70.6~86.1 mg/kg,如按我国猪、鸡饲养标准(2004)或NRC(1994)畜禽铁营养需要量的要求,基础饲粮中总铁含量可提供猪、鸡生长前期约4/5的铁营养需要量,可提供猪、鸡生长后期的铁营养需要量,但上述估算尚未考虑不同饲料原料中铁的利用率。由此可见,不同种类和不同地区饲料原料中铁含量差异较大;全国各地猪、鸡常用的基础饲料配方中总铁含量可提供猪、鸡整个生长期大部分的铁营养需要量。因此,在实际生产中,应充分考虑不同地区基础饲粮中的总铁含量及其利用率,精准配制饲粮,以满足畜禽高效生产的需要,同时减少铁的添加及其排放对环境的污染。     

Seroprevalence Estimation and Risk Factors for <Emphasis Type="Italic">A. marginale</Emphasis> on Smallholder Dairy Farms in Tanzania

A cross-sectional serological survey of A. marginale was conducted on 200 randomly selected smallholder farms in each of the Tanga and Iringa Regions of Tanzania between January and April 1999. Sera, from dairy cattle of all ages, sexes and breeds were tested for antibodies against A. marginale using an indirect enzyme-linked immunosorbent assay. Antibodies to A. marginale were present in cattle throughout the study areas and the overall prevalence was 20% for Tanga and 37% for Iringa. The forces of infection based on the age seroprevalence profile were estimated at 8 for Tanga and 15 for Iringa per 100 cattle years-risk, respectively. In both regions, seroprevalence increased with age (β = 0.01 and 0.017 per year of age, p < 0.005, in Tanga and Iringa, respectively). Older animals in Iringa were significantly and negatively associated with decreased seropositivity (β = −0.002, p = 0.0029). Further results of logistic regression models reveal that geographic location of animals in Tanga was associated with seropositivity (odds ratio (OR) = 2.94, p = 0.005, for Tanga Rural and OR = 2.38, p = 0.066, for Muheza). Animals acquired as a gift in Iringa had higher odds for seropositivity than brought-in cattle (OR = 2.44, p = 0.005). Our study has identified and quantified some key risk factors that can guide planners devising disease control strategies.     

云南北亚热带夏秋牧草混播组合试验研究

总结了在云南北亚热带昆明小哨开展两年的夏秋饲草豆禾混播试验,提出在云南北亚热带气候条件下适宜的刈割型豆禾混播组合为非洲狗尾草＋三得利紫花苜蓿。