生猪饲喂小麦饲粮

小麦是美国一种主要农作物,作为能量饲料其饲喂价值与玉米相当。当饲喂生猪时,小麦的能值相当于玉米能值的91%～97%。然而,小麦中标准回肠可消化(standardized ileal digestible,SID)氨基酸,特别是色氨酸、赖氨酸和苏氨酸含量比玉米中的含量更高。当可消化能和氨基酸平衡时,与饲喂玉米饲粮的生猪相比,饲喂小麦饲粮的生猪可以同样高效生长,并且肉品质与其相当。小麦中含有多种非淀粉多糖(NSP),主要是阿拉伯木聚糖,这可能会妨碍营养物质的消化。然而,小麦NSP对猪的影响好像比家禽要小。最近的报告表明不同种类小麦的消化能(DE)存在较大差异。因此,应该根据小麦的总化学成分和预测方程对其能量含量进行准确估算。生猪可以忍受的小麦粒度范围较大,但500～1 000微米的粒度更好。与玉米相比,生猪对小麦中磷的消化率更高,但如果饲粮中添加了植酸酶,磷的消化率会提高。检测小麦中的霉菌毒素如脱氧雪腐镰刀菌烯醇和玉米赤霉烯酮的浓度,并且测定损害粒和外壳破损粒的总量也应该作为评估猪饲料用小麦的一部分。     

Anaesthesia of pigs sensitive to malignant hyperthermia.

During general anaesthesia some pigs develop a hyperthermic response which is often fatal. The syndrome is most common in pigs which are susceptible to stress and have a low proportion of body fat. On the basis of an experimental investigation in Pietrain pigs recommendations are presented for the clinical management and treatment of susceptible animals.     

Blood serum characteristics of newborn pigs: comparison of unaffected pigs with pigs belonging to five mortality groups.

The blood serum levels of glucose, hemoglobin, insulin, cortisol, albumin, alpha-fetoprotein, alpha 2-macroglobulin f and s, alpha 2-antitrypsin inhibitor and alpha 1-protease inhibitor were determined at birth in 5 clinically and morphologically identified mortality groups of pigs. These were compared with the levels observed in unaffected, apparently normal newborn unsuckled pigs. The blood serum profile of the pigs in the stillborn intra partum, weak, splayleg and trauma groups, respectively, as well as that of clinically normal splayleg littermates, differed significantly from that of the unaffected pigs. This was especially true for the levels of hemoglobin and the two macroglobulins. The importance of placental insufficiency causing chronic episodes of hypoxia which ultimately lead to a disturbance in organ development in the etiology of the mortality groups is discussed.     

Miniature pigs.

Miniature pigs have become popular pets in North America, and veterinarians of a variety of clinical specialties may be called on for their care. Successful collection of blood from these animals requires familiarity with the location of sites for venipuncture and knowledge of adequate methods of restraint. In this article, restraint and techniques for venipuncture are described, as well as techniques for cerebrospinal fluid collection, semen collection, and vaginal cytologic examination. Interpretation of hematologic, serum biochemical, and urinalysis data are also discussed. Methods for diagnosis of skin diseases, gastrointestinal parasitism, and enteric infectious diseases are included in order to provide the practitioner with the essential knowledge and skills for a variety of clinical pathologic studies of this unique pet.     

Megacolon in pigs due to segmental colon aganglionosis.

Four pigs, each of about 8 weeks of age were submitted for pathological examination because of severe cachexia, combined with an enormous distension of the abdomen. In the herd, where these pigs originated from, these clinical signs were observed frequently for some period of time and stricture of the rectum was suspected. All pigs showed a severe cachexia, and most prominent in all pigs was a megacolon with large and distended colon and caecum and stenosis about 30 to 60 cm cranial of the anus. Tissue specimens were taken from the rectum, from the colon cranial and caudal of the stenosis and from the jejunum and examined histologically. Ganglia in the intestinal wall were examined immunohistochemically by using antibodies recognising neurofilament protein (kD 200). In all pigs submucosal and myenteric ganglia were absent in the post stenotic colon and rectum and in transverse section of the stenosis, whereas in the prestenotic colon of all pigs and also in the jejunum ganglia were present. Segmental aganglionosis of the colon is also known in humans (Hirschsprung disease) and other animal species and is considered as a congenital disorder. We also suggest a familiar background of the disease in these pigs.     

Experimental aerosol transmission of Actinobacillus pleuropneumoniae to pigs.

In order to demonstrate the possible role of aerosol in the transmission of Actinobacillus pleuropneumoniae, an experiment including 18 specific pathogen-free (SPF), 10-week-old piglets, randomly distributed into 2 adjacent units, was carried out. In these facilities, air was forced through absolute filters to prevent any contact with infectious agents. During the first 6 d post inoculation, the 2 units were connected by a rectangular opening and the air circulation was forced by the ventilation system from unit A (inoculated pigs) to unit B (non-inoculated pigs). The A. pleuropneumoniae strain (biovar 1 serovar 9) was isolated in France from an outbreak of porcine pleuropneumonia. Two different infecting doses, 10(7) cfu/animal and 10(8) cfu/animal, were inoculated by intranasal route in 6 pigs of unit A. The infection spread quickly from the inoculated pigs to the non-inoculated pigs. Clinical signs were acute during the 4 d post inoculation: hyperthermia, respiratory distress and, sometimes, death (6 pigs of the unit A and 2 pigs of the unit B). All pigs seroconverted against A. pleuropneumoniae serovar 9 within 2 weeks. Lung lesions were severe: fibrinous pleurisy and lung hemorrhages in the acute stage, pleural adherences and focal pulmonary necrosis in the chronic stage. Actinobacillus pleuropneumoniae was isolated from the tonsils and/or lungs in 16 animals. It could be also isolated from the air of the experimental unit. This study showed that A. pleuropneumoniae was readily transmitted through aerosol over a distance of at least 2.5 m.     

Electrocution of pigs.

Electrocution was considered to have caused 28 deaths in a house of 109 fat pigs. Post mortem examination showed haemorrhages at varying sites. Another 35, showing varying degrees of paralysis, were sent for slaughter. In most of these the pelvis was fractured and in some the vertebral column in the lumbosacral region. Twenty eight were condemned, 26 of them because of haemorrhages and because of spoilage associated with rupture of the urinary bladder.     

Polyserositis in pigs due to generalized Escherichia coli infection.

A fibrinous polyserositis syndrome due to generalized Escherichia coli infection in pigs was observed in 13 out of 17 systematically monitored herds. The mortality rate was approximately 0.1% among liveborn pigs. The occurrence was usually sporadic but a minor enzootic was observed in one herd. Most of the affected pigs succumbed during first or second week of life but cases were observed throughout the suckling period. The clinical signs included marked depression, anorexia, rough haircoat, laboured respiration and death in two to five days. Predominant gross pathological lesions were signs of septicaemia and a voluminous, gelatinous and fibrinous exudate in the pleural, the pericardial and the peritoneal cavities. Frequently also a firbinous polyarthritis and a fibrinous pneumonia were present. The majority of the isolated invasive E. coli strains were nonhaemolytic. Serologically 11 different E. coli O groups were encountered. O group most frequently represented was 020. None of the examined E. coli strains belonged to the serogroups which frequently are associated with enteropathogenicity in pigs.     

Colostral transfer of immunity to Haemophilus parahaemolyticus in pigs.

Complement fixating antibodies for Haemophilus parahaemolyticus were shown to be transferred from immune sows to their offspring. Colostrum-fed 4-day-old piglets from immune sows resisted intranasal inoculation whereas their littermates, fed on cows' milk, were fully susceptible to the infection. Piglets inoculated later in the suckling period (3 to 8 weeks after birth) when their serumtiters had declined to very low levels, showed some degree of resistance, but the infection was not eliminated from the mucous membranes of the respiratory tract. In chronically infected breeding herds piglets are usually affected during the later part of the suckling period and clinical symptoms are often vague. Though a positive titer is indicative of resistance the results presented above show that protection is usually not complete. Further studies are required to ascertain whether the results obtained here are applicable in a rational control.     

Resistance of Oesophagostomum spp. in pigs to pyrantel citrate

This study was undertaken to determine whether anthelmintic-resistant Oesophagostomum spp. populations occur in Danish swine herds. A controlled field trial on selected sow herds suggested resistance to pyrantel citrate in a herd where faecal egg count depression in response to treatment was only 28.3%. This was confirmed by subsequent experimental infection of pigs where the suspected resistant Oesophagostomum isolate was compared with a susceptible worm isolate. After treatment with the recommended dose of the drug, worm burdens of the suspected isolate were only reduced by 42.6% (p greater than 0.05) in contrast to the susceptible isolate, which was reduced by 94.6% (p less than 0.01). Differential counts of the resistant isolate suggested that O. dentatum might be more resistant than O. quadrispinulatum. The resistant isolate originated from a herd, where the anthelmintic had been administered four times a year over a period of 7 years. The potential for development of anthelmintic resistance in Oesophagostomum spp. under management practices in our country is discussed in the light of the current views on predisposing factors.     

Posterior paralysis due to fibrocartilaginous embolism in two weaner pigs.

Acute posterior paralysis in two weaner pigs was attributed to ischemic infarction of the lumbar spinal cord due to fibrocartilaginous emboli. These arterial and venous emboli were assumed to have originated from the nucleus pulposus of one or more intervertebral discs. There was no indication of an initiating factor in either instance, although some form of trauma may have been involved. Lesions were not grossly evident and were limited to one or two lumbar segments. Although it appears to be a rare occurrence, fibrocartilaginous embolism of the spinal cord should be considered in cases of acute paralysis in pigs particularly when gross lesions are absent.     

San Miguel sea lion virus fed to mink and pigs.

Mink became infected with San Miguel sea lion virus when fed ground meat from seal carcasses showing vesicular-like lesions in the skin. The mink also contracted the infection when they were fed San Miguel sea lion virus infected pig meat or cell culture propagated virus. San Miguel sea lion virus infection in mink was inapparent but the virus was isolated from blood and rectal swabs. Pigs treated similarly with the same virus preparations given to mink developed a severe vesicular disease syndrome similar to that produced by vesicular exanthema of swine. In a separate trial, pigs fed a large sample of commercial ground seal meat did not develop disease signs or antibodies. Further work is needed to assess the hazard of introducing San Miguel sea lion virus into swine on the same premises when potentially San Miguel sea lion virus infective seal meat is fed to mink.     

Staphylococcus hyicus virulence in relation to exudative epidermitis in pigs.

Staphylococcus hyicus strains with different phage types, plasmid profiles, and antibiotic resistance patterns were isolated from piglets with exudative epidermitis. The strains could be divided into virulent strains, producing exudative epidermitis, and avirulent strains, producing no dermal changes when injected in experimental piglets. The results showed that both virulent and avirulent strains were present simultaneously on diseased piglets. This constitutes a diagnostic problem. Concentrated culture supernatants from nine virulent strains injected in the skin of healthy piglets produced a crusting reaction in all piglets. Acanthosis was observed in the histopathological examination of the crustaceous skin. Concentrated culture supernatants from nine avirulent strains produced no macroscopic or microscopic skin changes. Protein profiles from all virulent strains and seven out of nine avirulent strains showed a high degree of protein band homology. An approximately 30 kDa protein present in all concentrated culture supernatants capable of producing skin changes, could not be detected in samples that did not produce skin changes. No other protein showed a similar association. It is concluded that crusting reaction of piglet skin is a suitable indicator of virulence in S. hyicus in relation to exudative epidermitis, and that virulent strains produce a 30 kDa protein, absent in concentrated culture supernatants from avirulent strains. This 30 kDa protein might be an exfoliative toxin.