降低优质肉鸡制种成本的基本策略

我国优质肉鸡的育种研究已取得了相当大的成绩,但相对于国际著名的商用品种而言还有一定的差距,突出表现在占市场主导地位的品种或配套系制种成本居高不下。因此,降低优质肉鸡制种成本是育种者所应追求的目标。     

种鸡场如何减少饲料浪费

当前,畜禽养殖行业的发展环境发生了较大的变化,居民消费增长有所放缓,市场需求不旺,产品价格下滑,企业的经营成本也随着玉米等大宗饲料原料价格的持续上涨而长期处于高     

Effectiveness of simulated interventions in reducing the estimated prevalence of E. coli O157:H7 in lactating cows in dairy herds

A transmission model developed to investigate the dynamics of Escherichia coli O157:H7 bacteria in a typical Dutch dairy herd was used to assess the effectiveness of vaccination, diet modification, probiotics (colicin) and hygienic measures as to water troughs and bedding, when they are applied single or in combination, in reducing the prevalence of infected animals. The aim was to rank interventions based on their effectiveness in reducing the baseline prevalence of infected animals in the lactating group. The baseline prevalence of the lactating group and the within-herd prevalence were estimated by the model to be 5.02% and 13.96% respectively. The results show that all four interventions, if applied to all four animal groups or only to young stock, are the most effective and will reduce the baseline prevalence by 84% to 99%. In general, combinations of hygiene (applied in all groups) and one other intervention had the highest effectiveness in reducing prevalence in the lactating group. Vaccination and diet modification show a slightly higher effectiveness than colicin and hygiene.     

Anesthetic waste gases in veterinary medicine: analysis of the problem and suggested guidelines for reducing personnel exposures

Anesthetic waste gases are a concern to veterinarians and their personnel. Investigations have shown that many of the anesthetic units used in veterinary medicine have leaks that contribute to operating room contamination. Many others do not have appropriate scavanging attachments to remove escaping gases. Personnel were frequently observed carelessly using equipment or handling anesthetic agents in a manner contributing to excessive exposure. Proper maintenance of equipment and careful use of gaseous anesthetic agents can significantly reduce waste gas levels and exposure of personnel.     

Effectiveness of GnRH plus prostaglandin F2alpha for estrus synchronization in cattle of Bos indicus breeding

Postpartum and lactating crossbred cows containing a percentage of Bos indicus breeding at three locations were studied to determine the efficacy of GnRH + PGF2alpha combinations for synchronization of estrus and(or) ovulation. Cows were equally distributed to each of three treatments by body condition score at the start of the experiment (d 0). All cows received 100 microg of GnRH on d 0 and 25 mg of PGF2alpha 7 d later. The three insemination protocols included 1) AI 12 h after exhibiting estrus during d 7 to 12 of the experiment (Select-Synch; n = 197); 2) timed-AI + 100 microg of GnRH on d 9 of the experiment (CO-Synch; n = 193); 3) AI 12 h after exhibiting estrus during d 7 to 10 of the experiment. Cows not exhibiting estrus by d 10 were timed-AI and injected with 100 microg of GnRH on d 10 of the experiment (Hybrid-Synch; n = 200). The percentage of cows exhibiting estrus during d 7 to 12 of the experiment was lower (P < 0.05) for CO-Synch (17.6%) cows than for Select-Synch or Hybrid-Synch (45.2 and 33.0%, respectively) cows, which did not differ (P > 0.05). For the Select-Synch and Hybrid-Synch cows that exhibited estrus during d 7 to 10 of the experiment and were artificially inseminated, conception rates were similar across treatments (50.5%). Pregnancy rates were greater (P < 0.01) for CO-Synch and Hybrid-Synch (31.0 and 35.5%, respectively) cows than for Select-Synch (20.8%) cows. A greater (P < 0.01) percentage of cycling cows became pregnant (34.5%) than noncycling cows (25.9%) across all treatments. The CO-Synch and Hybrid-Synch synchronization protocols resulted in greater pregnancy rates compared with the Select-Synch protocol in postpartum and lactating crossbred cows containing a percentage of Bos indicus breeding.     

减抗、限抗、禁抗及其替代方案对生猪养殖的影响

药物添加剂作为饲料添加剂应用于畜牧业生产,在促进动物生长和提高其抗病力等方面发挥了重要作用。但随着时间的推移,抗生素的滥用也引发了诸如药物残留、细菌耐药性及环境污染等问题,减抗、限抗乃至禁抗已刻不容缓。文章综述了药物饲料添加剂发展历程、种类、作用以及减抗、限抗、禁抗及其替代方案对生猪养殖的影响。     

Influence of selective breeding on the prevalence of chorioretinal dysplasia and coloboma in the rough collie in Sweden

A total of 8204 rough collies, representing 76 per cent of all collies registered by the Swedish Kennel Club between 1989 and 1997, were examined before 10 weeks of age for collie eye anomaly (CEA). All dogs were permanently identified and examination results were registered and computerised. The policy of breeders during the study period was to select against coloboma in breeding stock, but to allow breeding of chorioretinal dysplasia (CRD) affected animals. The prevalence of CRD increased significantly from 54.2 per cent to 68.1 per cent (P < 0.001) from 1989 to 1997, while the prevalence of coloboma did not (8.3 per cent to 8.5 per cent, P = 0.4). These results are not compatible with a simple, recessive, autosomal inheritance for the entire CEA complex.     

Survey of Salmonella prevalence on commercial turkey breeding and fattening farms in the UK in 2006 to 2007

A total of 29 breeding turkey holdings and 317 fattening turkey holdings were sampled between October 2006 and September 2007 in order to establish the baseline prevalence of Salmonella in turkeys in the UK. The weighted holding level Salmonella prevalence was found to be 20.1 per cent (95 per cent confidence interval [CI] 8.6 to 40.3 per cent) in breeding turkeys and 37.7 per cent (95 per cent CI 33.4 to 42.3 per cent) in fattening turkeys. For breeding turkeys, a weighted flock-level prevalence, as more than one flock per holding was sampled, was estimated at 7.1 per cent (95 per cent CI 3.2 to 14.8 per cent). A total of 13 different serovars were identified in the survey. The most frequent serovar in both turkey flock classes was Salmonella Kottbus, which was found on two breeding holdings and 63 of the fattening holdings giving weighted prevalences of 10.4 per cent (95 per cent CI 2.6 to 34.1 per cent) and 23.0 per cent (95 per cent CI 19.3 to 27.3 per cent), respectively. On breeding holdings, a single isolate of Salmonella Typhimurium, identified as DT12 (weighted prevalence 3.5 per cent [95 per cent CI 0.7 to 15.8 per cent] [holding], 0.7 per cent [95 per cent CI 0.1 to 3.7 per cent] [flock)], was found. On fattening holdings, there were 55 isolates of S Typhimurium from 16 holdings, giving a weighted prevalence of this serovar of 5.4 per cent (95 per cent CI 3.6 to 8.0 per cent). There were no isolates of Salmonella serovars Enteritidis, Hadar, Infantis or Virchow.     

ASVCP guidelines: allowable total error guidelines for biochemistry

As all laboratory equipment ages and contains components that may degrade with time, initial and periodically scheduled performance assessment is required to verify accurate and precise results over the life of the instrument. As veterinary patients may present to general practitioners and then to referral hospitals (both of which may each perform in‐clinic laboratory analyses using different instruments), and given that general practitioners may send samples to reference laboratories, there is a need for comparability of results across instruments and methods. Allowable total error (TE_a) is a simple comparative quality concept used to define acceptable analytical performance. These guidelines are recommendations for determination and interpretation of TE_a for commonly measured biochemical analytes in cats, dogs, and horses for equipment commonly used in veterinary diagnostic medicine. TE_a values recommended herein are aimed at all veterinary settings, both private in‐clinic laboratories using point‐of‐care analyzers and larger reference laboratories using more complex equipment. They represent the largest TEa possible without generating laboratory variation that would impact clinical decision making. TE_a can be used for (1) assessment of an individual instrument's analytical performance, which is of benefit if one uses this information during instrument selection or assessment of in‐clinic instrument performance, (2) Quality Control validation, and (3) as a measure of agreement or comparability of results from different laboratories (eg, between the in‐clinic analyzer and the reference laboratory). These guidelines define a straightforward approach to assessment of instrument analytical performance.     

Evaluation of the stallion for breeding soundness.

The breeding soundness evaluation of a stallion is a thorough investigation of a stallion's libido, mating ability, and semen quality. The evaluation should include historical data about the medical aspects of the horse's performance and breeding career, observations and breeding behavior characteristics, collection and evaluation of semen, tests to determine freedom from infectious or contagious disease, and production of foals free of genetic defects. This information should allow the examiner to anticipate the impact of the stallion on the reproductive efficiency of a group of mares. The breeding soundness evaluation should also assist farm management in optimizing stallion, mare, veterinary, and management influences on total herd breeding performance.