Respiratory diseases of beef cattle under intensified systems

Extract

Under intensified management systems, the more common diseases of beef cattle include pasteurellosis or shipping fever, infectious bovine rhinotracheitis (IBR), enzootic or virus pneumonia, and bovine diphtheria. Other respiratory diseases that might be prevalent in the beef management systems of New Zealand include lungworm, atypical interstitial pneumonia, and allergic rhinitis. These will be discussed only in terms of differential diagnosis. No further mention will be made of the exotic diseases contagious bovine pleuropneumonia and haemorrhagic septicaemia or to the respiratory form of bovine tuberculosis which is uncommon in both Canada and New Zealand.     

如何搞好新形势下的肉牛疾病防制

近年来，随着我国农业经济结构的重大调整，我国的肉牛养殖业异军突起，发展迅速，牛群结构、饲养模式发生了根本性的变化。养牛业已经拓展到供种、养殖、加工、服务等多个生产环节，成为一个独立的产业，在农村经济中占有举足轻重的地位。　　与飞速发展的养牛业相比，作为重要保障体系的疾病防制工作却由于技术陈旧、手段落后，在生产中一直处于较为被动的局面。特别是近年来随着规模的扩大，肉牛发病率和死亡率一度呈上升趋势。据统计，我国每年因各种疾病死亡肉牛不低于100万头，发病不低于500万头，直接经济损失超过25亿元。因此，如何…     

Evaluation of veld potential in east griqualand using beef cattle under two grazing management systems

Abstract

Beef production from veld, in the short term, was found to be greater under a continuous grazing system than under a rotational grazing system. Average daily gains decreased from a maximum in late‐spring and the highest three‐year mean value was 0,5 kg/animal/day. Livemass gains/ha were highest at a stocking rate of 2,2 animals/ha and were 131,4 kg/ha under continuous grazing and 88,6 kg/ha under rotational grazing. Estimated mean maximum gains/ha were 0,78 kg/ha/day at a stocking rate of 2,5 animals/ha under continuous grazing and 0,55 kg/ha/day at a stocking rate of 1,7 animals/ha under rotational grazing. However, optimum economic stocking rates were estimated to occur below those where beef production/ha was maximum.     

Nutritional and dietary interrelationships with diseases of grazing beef cattle

This article describes current methods of controlling acute bovine pulmonary emphysema (ABPEE) and edema, lungworm and gastrointestinal nematodes, and bloat in grazing beef cattle. Success in handling outbreaks of these conditions and in their prevention depends on an understanding of their epidemiology and pathogenesis. Supplementation with ionophore antibiotics is effective in prevention of ABPEE and bloat and may also prevent other diseases of cattle that graze lush pastures.     

Identification of genes responsible for hereditary diseases in Japanese beef cattle

In the breeding of domestic animals, selection of economically desired traits has been the most important consideration for the improvement of animals, but excluding negative factors in animal production, such as causative genes for hereditary diseases, is also required for the genetic improvement of domestic animals. The incidence of various hereditary diseases has been reported in Japanese beef cattle and these diseases have caused serious problems in the breeding and raising of healthy beef cattle. This article reviews the identification of causative genes for the following three hereditary diseases in Japanese beef cattle: (i) Chediak–Higashi syndrome; (ii) renal tubular dysplasia; and (iii) bovine chondrodysplastic dwarfism. Chediak–Higashi syndrome is a hereditary bleeding disorder reported in Japanese black cattle. To identify the cause of this disease, we cloned and sequenced the bovine LYST gene, which has been found to be involved in Chediak–Higashi syndrome in humans, and found that an amino acid substitution of histidine to arginine at amino acid residue 2015 is the causative mutation in the cattle disease. Renal tubular dysplasia is a hereditary disease of Japanese black cattle showing renal failure and growth retardation. We mapped the locus for this disease to the 4 cM region of bovine chromosome 1 by linkage analysis and found a large deletion in this region. The deleted region contained the PCLN1 gene encoding a tight‐junction protein of renal epithelial cells, and we concluded that deletion of the PCLN1 gene is responsible for the disease. Bovine chondrodysplastic dwarfism is a hereditary disease of Japanese brown cattle, displayed by short limbs and joint abnormalities. We mapped the locus for the disease to a region of bovine chromosome 6 by linkage analysis. By constructing YAC and BAC contigs covering this region and sequence analysis, we identified a novel gene (LIMBIN), which plays an essential role in bone formation in this region, and found two mutations responsible for the disease. The identification of these mutations provided the basis for DNA‐based diagnostic systems for these three diseases, and after development of the diagnosis systems, the incidences of these hereditary diseases have dramatically decreased.     

山东省规模肥牛场疫病流行状况调查

1998年山东省牛出栏量居全国第一位,与1978年相比,全省牛出栏率增加了31个百分占,达到33％,是名符其实的养牛大省。为了摸清危害全省肉牛业发展的主要疫病,以采取针对性更强的防制措施控制其疫病的发生和传播,提高经济效益,我们课题组对山东省肉牛饲养比较集中的部分地区的规模育肥牛场牛群进行了疫病流行状况调查。     

Systems approaches to beef cattle production systems using modeling and simulation

Systems approach techniques have been applied to modeling production systems for beef cattle from the relatively micro‐level of tissues and organs to the macro‐level of farms and geographical regions. This paper reviews the various types of beef cattle production models already in operation in order to analyze beef cattle production systems and their components. It may be theoretically possible to construct system models which describe such complex production systems and can be generally used in various genetic, nutritional, management and economic situations as well as in training, extension and educational programs. Moreover, the systems approach can assist in the organization of information and identification of knowledge gaps and thereby open an avenue to multi‐disciplinary research projects.     

The reported use of drugs to prevent diseases in beef cattle in Tennessee

The National Animal Health Monitoring System (NAHMS) (Round 2) for Tennessee collected baseline data on the preventive (as opposed to therapeutic) use of drugs from 60 beef cow-calf herds selected by a random, stratified, two-stage sampling plan. Counties were selected randomly with replacement for three herd-size strata, and herds were selected within countries by an area-frame method. Data were collected during monthly interviews for 1 year (1987–1988).

Tennessee beef cattle were medicated with 31 drugs to prevent diseases. The drugs most frequently used were anthelmintics and insecticides. The diseases against which preventive drugs were most frequently used were external parasites, intestinal parasites, ‘pink eye’ (keratoconjunctivitis), anaplasmosis, and respiratory infections. Ivermectin was the most frequently used anthelmintic and the most frequently used drug. Levamisole, fenbendazole, and thiabendazole were also frequently used anthelmintics. The most frequently used insecticides were the organophosphates (including fenthion, dichlorvos, and stirofos). Antimicrobials seldom were used, suggesting that prophylactic antimicrobial use in Tennessee beef cattle may not be a major public-health concern.     

Cumulative discounted expressions of dairy and beef traits in cattle production systems

Gene-flow methodology was used to calculate the cumulative discounted expressions (CDE) for annual/lactation, replacement heifer, cull cow, birth, yearling, and slaughter traits in alternative cattle production systems. Generic equations were presented and parameters representing dairy-beef production systems in Ireland and Brazil were inputted. Cumulative discounted expressions using input parameters from a hypothetical purebred dairy production system with poor cow longevity were also calculated. Cumulative discounted expressions were calculated assuming either an initial purebred or crossbred mating within each production system. Absolute and relative differences in CDE existed among trait categories across the three alternative production systems investigated. For example, the CDE of beef-related traits accruing from an initial purebred mating ranged from 0.42 to 0.75 CDE of an annual/lactation trait across the three contrasting systems investigated which differed in various input parameters. Such variation may alter the relative emphasis of traits on overall profitability thereby contributing to genotype by environment interactions. The results of this study highlight the necessity to consider auxiliary traits in sire selection over and above those representing the principal intended use of the sire. This was particularly so for integrated dairy-beef cattle production systems.     

Backgrounding beef cattle.

Stocker operations differ significantly in management techniques and health programs. Critical control points should be identified for each farm and used to ascertain the biggest areas for potential improvement so as to allow proper allocation of resources. A customized wellness program couples medicine and management to minimize the negative impact of disease. A complete program involves animal selection, disease prevention, and management. Calves should be evaluated and classified into appropriate risk categories regarding treatment, management, and performance expectations. Disease prevention strategies should involve increasing immune responses while decreasing pathogen exposure and stress in cattle. Disease management includes the methods used to minimize the impact of illness on the population     

Economics of deworming beef cattle

From the practitioner level and for the producer, there is far too much confusion concerning internal parasites in cattle and the justification of control measures. By coordinating research efforts between parasitologists and other scientists, awareness of internal parasites will be raised and the total impact of parasitism can better be evaluated.     

牛短期育肥及牛肉分割测定试验研究

本文选择１６头１８月龄体重约３００ｋｇ的西杂牛（１０头）和夏杂牛（６头）公牛,进行为期３个月的育肥试验,结果表明两种杂交组合的牛日增重平均可达１．１ｋｇ,均适宜于高档牛肉生产。     

从肉牛到牛肉的经济指标分析

【目的】为了解现阶段肉牛到牛肉之间的联系现状和产出能力,掌握主要经济指标,确定计算肉牛产值的依据。 【方法】以张掖市肉牛与牛肉之间的联系现状为例,从中选取１个能够代表现阶段生产水平的随机样本（n=11777）,利用统计分析方法进行分类和分组,列出次数分布表与分布图,研究宰前重、胴体重、净肉重、屠宰率和净肉率5个变量的频率分布,并根据平均数() 和标准差（S）及其分布规律推算出总体平均数u的概率置信区间代表群体生产水平,作为计算肉牛产值的依据。【结果】现阶段进行肉牛生产的主要品种为西门塔尔、安格斯和荷斯坦,公牛育肥产肉占84.54%。其中西门塔尔占74.61%居主导地位,安格斯占16.08%,荷斯坦占9.31%。西门塔尔牛以宰前重在500~700kg的小架子牛育肥产肉占56.12%居主导地位,依次为大架子育肥占39.28%、小牛肉占2.57%和成年牛占2.03%。肉牛宰前重、胴体重、净肉重和屠宰率、净肉率5个指标样本分组频率与正态分布理论概率相关度高、绝对差值小,概率相近。 【结论】现阶段生产牛肉的主要品种有西门塔尔、安格斯和荷斯坦,以公牛育肥为主。主导品种西门塔尔牛生产周期有缩短趋势,小牛肉生产起步。 西门塔尔牛群的宰前重、胴体重、净肉重和屠宰率、净肉率均值为：684.94kg、385.16kg、316.85kg和56.47%、45.71%时,区间为：581.33≦x≦788.55、321.9≦x≦448.40、266.09≦x≦367.61、53.85≦x≦59.09、42.57≦x≦48.85。 大群体宰前重、胴体重和屠宰率的均值为：678.13kg、379.54kg和55.81%%,区间为572.63≦x≦783.63 、311.42≦x≦447.66、52.34≦x≦59.28 。 反映肉牛生产水平的5个经济指标的概率分布为正态分布,平均值（）一倍标准差左右取值概率为0.6827,可用概率密度函数公式进行相应的计算。根据正态分布特点,平均值左右一倍标准差范围内取值的概率最大为,平均值即为群体盈亏平衡点,且主导品种的宰前重、胴体重和屠宰率较大群体分别高6.81kg、5.62kg和0.66%。 祁连牧歌实业有限公司为张掖市规模最大肉牛屠宰加工企业,屠宰牛源为周边规模养殖场育肥牛,该结果能够代表张掖市域内肉牛大群体生产水平,指标平均值（）可以作为计算肉牛产值的统计依据。 生产中可以此为标准对经营情况进行分析,当个体牛只或经营单位的宰前重、胴体重、净肉重和屠宰率、净肉率高于平均值时说明该牛只育肥状况较好或该经营单位经营状态良好,大概率保持盈利。     

Hip dysplasia in beef cattle

A bilateral hip lameness has been found in young beef bulls of the Hereford, Aberdeen Angus, Galloway and Charolais breeds in the United Kingdom, North America and Australia. The incidence is usually small and sporadic, but up to half of the male animals on one farm may be affected clinically by the time they are one year old. Clinical lameness begins at three months to two years old, and very occasionally up to three years of age; some calves are obviously affected at birth. Aberdeen Angus cattle tend to be affected earlier than other breeds. Clinical evidence of the condition is almost entirely confined to the male.