后备母猪的引进与管理

对于一个需要进行连续繁殖生产的猪场来说,引进后备母猪是一项必不可少的工作。本人曾在《当代畜禽养殖业》2003年第11期上发表了“引进种猪的方法”一文,主要对引进种猪的注意事项进行了简单总结。根据目前刚刚开始从事养猪业的个体饲养场(户)比较多(猪价低谷时投资)的特点,以     

后备母猪的营养与繁殖

后备母猪的繁殖能力关系到整个猪场的经济效益,其中营养水平和采食量在繁殖方面的影响不容忽视。本文简要叙述了有关营养在后备母猪各个阶段繁殖性能上的影响,以期为我国的养猪生产实践提供一定的帮助。     

Evidence that oxidative stress is higher in replacement gilts than in multiparous sows

The recent success obtained in term of increasing the litter size of sows has not correlated with a reduction of replacement rate. There is thus an increased economic demand for gilts with optimal reproductive potential and longevity. Unfortunately, replacement gilts are known to be more susceptible to diseases and less productive than multiparous sows. Interestingly, reproductive performance, resistance to diseases and longevity could all be largely affected by oxidative stress. To investigate whether oxidative stress conditions could account for the poor longevity of gilts, three distinct groups of conventional Yorkshire × Landrace sows were formed based on their similar age and parity (gilts, second parity sows as well as fourth to fifth parity sows). All animals were slaughtered during the post‐ovulatory period, and blood as well as tissue samples were collected. Biomarkers of oxidative damage to proteins (carbonyls) and DNA (8‐OHdG) were analysed in samples. Specific mRNA expression of major antioxidants such as glutathione peroxidases 1, 3 and 4 (GPx1, GPx3, GPx4) as well as superoxide dismutases 1 and 2 (Sod1, Sod2) were monitored in liver and kidney samples by quantitative RT‐PCR. Specific enzymatic activities of both GPx and SOD were measured by spectrophotometric assays. The plasma concentration of protein carbonyls was significantly different between the three groups with the highest concentration being observed in gilts (p ≤ 0.001). The mRNA expression levels of GPx1 and GPx4 were also significantly increased in the liver of gilts when compared to multiparous sows (p ≤ 0.05). SOD2 enzymatic activity was found to be higher in the liver of gilts than multiparous sows (p ≤ 0.05). Taken together, these results indicate that replacement gilts sustain significantly higher oxidative conditions than multiparous sows. Current findings may contribute to the design of nutritional regimens that will increase the productivity of gilts by counteracting oxidative stress.     

Coccidiosis in swine

It is clear that although the clinical history, pathologic lesions, and endogenous stage life cycle of I. suis are well understood, the epidemiology of this parasite is not understood or is misunderstood. Consequently, treatment of individual piglets and prophylactic use of coccidiostats in sows have not been consistently rewarding. The best control at present is achieved through use of extensive sanitation, particularly steam cleaning. The incidence of clinical coccidiosis in piglets continues to be a major component (approximately 20 per cent) in the differential etiology of scours in baby pigs.     

鸡球虫病的防控

本文描述了在孵化场进行球虫病免疫接种的四个不同方面,以及有助于提高日后鸡群生产性能的方法。球虫病是全球流行最普遍的家禽疾病,据估算,养禽业每年防治此病的投入相当于30亿美元。1鸡球虫病概述球虫病是一种消化道传染病,常导致肠道表层细胞的损伤,从而抑制营养物质和水分的消化吸收。其后果是鸡的采食量下降、脱水和血液流失,即使能存活下来,也会导致日后的生产性能下降。     

家兔球虫病的调查与防治

经对宁夏５３５只家兔的球虫种类调查，共查出１４种艾美尔属球虫，并对各种球虫的感染率，感染种数和年龄的分布进行了统计，经２０４５只家兔球虫发病的调查，阐述了自然发病的症状，剖检变化以及发病与年龄、季节，饲养方式的关系，通过２０例发病兔的治疗试验，表明氯苯胍和磺胺药交替用药，其效果尤于单用氯苯胍，应用上述药物防治１３６０００多只家兔，取得了显著的经济效益。     

Luteinizing hormone secretion in ovariectomized gilts: effects of age, reproductive state and estrogen replacement

Crossbred gilts were ovariectomized (OVX) at 120, 150, 180 and 210 d of age to determine whether various characteristics of luteinizing hormone (LH) concentrations are influenced by age and reproductive state (prepuberal vs postpuberal). All 120-d-old gilts were prepuberal and all 210-d-old animals were postpuberal, whereas gilts 150 and 180 d old included both prepuberal and postpuberal animals. Blood was collected at 15-min intervals for 2 h, 2 d before OVX (d -2), and 2 (d +2), 8 (d +8) and 14 (d +14) d after OVX. Mean LH concentrations for prepuberal gilts were similar among age groups (P greater than .05) on d -2 and +2; however, LH increased (P greater than .05) from d -2 to +2. No change in LH secretion was found in postpuberal gilts during these two periods. After OVX, LH increased from d +2 to +14 in both prepuberal and postpuberal gilts in all age groups. In postpuberal gilts, LH increased linearly (P less than .05) between d +2 and +14; rate of increase accelerated with advancing age (P less than .01). In prepuberal gilts, LH increased in a nonlinear manner, but it did not increase between d +2 and +8. The increase observed in prepuberal and postpuberal gilts after OVX resulted primarily from an increase in magnitude of peak concentrations of LH. Implants of estradiol-17 beta (E2) were used to determine whether the postovariectomy increase in LH is affected differently by E2 in prepuberal and postpuberal gilts during advancing ages.(ABSTRACT TRUNCATED AT 250 WORDS)     

Porcine Neonatal Coccidiosis

Coccidia were identified in intestinal sections from 82 piglets comprising 37 consignments from 34 farms, and represented a yearly increasing incidence in the three years 1978 to 1980. Piglets were primarily from medium to large farms with intensive, continuous-farrowing, confinement-rearing programs. Piglets, usually five days to 15 days old, had yellow, fluid diarrhea, became unthrifty and sometimes died. In six piglets from two farms, a green, adherent, fibrinonecrotic membrane was seen throughout most of the jejunum and ileum. Significant gross lesions were not observed in the other 76 piglets. Moderate to severe villous atrophy of jejunum and ileum was seen histologically. Various asexual and sexual stages of coccidia were seen within parasitophorous vacuoles of villar epithelial cells. Multifocal erosions with necrosis of villar tips and occasionally more diffuse mucosal necrosis with fibrinocellular exudate were seen. Isospora suis oocysts were identified in feces from several weaners from one farm. Amprolium and decoquinate mixed in the sow ration at 1 kg/tonne for three weeks prior to and postfarrowing was moderately successful in stopping outbreaks of neonatal diarrhea associated with coccidiosis.