Medullary bone of piglets.

The bone marrow is commonly present in the medullary cavity of long bones in most mammals at birth. In the present study, the persistence of the osseous tissue was examined in the medullary cavities of piglet bones at and after birth. Immediately after birth, medullary cavities of long bones were almost completely filled with the spongy bone. The persisted spongy bone, i.e., medullary bone was prominent in younger pigs but decreased with advance in age. By 90 days of age, the medullary bone almost disappeared to form the extended medullary cavity. During the disappearing process of the medullary bone, osteoclasts showed significant increase in size and number (p less than 0.05). In irregular and flat bones, osseous trabeculae of the medullary bone became slender with age. The extramedullary hematopoiesis in the liver and spleen was very active till 30 days of age. This may suggest that the persistence of the medullary bone narrows the medullary cavity to cause poor medullary hematopoiesis and is compensated by extramedullary hematopoiesis. The relationship among the medullary bone, extramedullary hematopoiesis and piglet anemia was discussed.     

Campylobacter infections in calves, piglets, lambs and kids in Trinidad.

Faeces or rectal swabs from 689 diarrhoeic and non-diarrhoeic animals were cultured for thermophilic campylobacters and their antibiograms were determined. Three hundred and fifteen (45.7%) samples were positive for Campylobacter. Piglets had the highest prevalence, 79.3% (233/294) and lambs, the lowest with 17.9% (15/84) being positive. The difference was statistically significant (P < or = 0.01; chi 2). In calves, 20.5% (60/293) and in kids 38.9% (7/18) were positive for campylobacters. The prevalence of infection was not significantly (P > or = 0.05; chi 2) different between diarrhoeic (46.1%) and non-diarrhoeic (45.1%) animals nor between male (47.5%) and female (43.8%). The frequency of isolation of campylobacters harvested from semi-intensively managed animals (75.4%) was, however, significantly higher (P < or = 0.001; chi 2) than from intensively or extensively managed animals. Overall, C. coli strains (32.8%) were more frequently isolated than C. jejuni strains (12.9%) and the difference was significant (P < or = 0.001; chi 2). Biotype I accounted for 67.3% (152/226) of C. coli and 64.0% (57/89) of C. jejuni strains isolated. A total of 245 (77.8%) strains of Campylobacter exhibited resistance to one or more antibiotics and was highest to streptomycin (76.5%), kanamycin (28.6%) and neomycin (26.7%). It was concluded that Campylobacter infections were widespread in livestock in Trinidad, particularly C. coli in piglets.     

Studies on the tryptophan requirement of piglets.

Three experiments were conducted to determine the requirement of tryptophan for piglets. In the first two experiments dose-response relationships between the dietary tryptophan concentration and performance criteria of piglets were examined in order to determine the dietary tryptophan concentration required for maximum performance. In the first experiment dietary tryptophan levels ranged from 1.09 to 2.32 g per kg, in the second experiment they ranged from 1.70 to 2.60 g per kg. In both experiments a close correlation was observed between the dietary tryptophan concentration and piglet performance criteria (feed intake, daily gains, feed efficiency). In the first experiment, regression analysis using a non-linear model revealed that the optima, defined as 95% of the asymptotic response in the model used, for feed intake and daily gains were achieved at tryptophan levels in excess of the highest concentration of 2.32 g per kg feed. The performance level of the piglets in this experiment was generally very low, however. In the second experiment feed intake, the optimum tryptophan concentration, defined as 95% of the asymptotic response, for daily gains and feed efficiency were achieved within a small range between 2.07 and 2.14 g tryptophan per kg feed, corresponding to 1.84 to 1.91 g precaecal digestible tryptophan per kg feed or 0.153 to 0.159 g tryptophan per MJ ME. These results suggest that the tryptophan concentration for maximum performance of piglets is probably higher than has been implied in numerous studies to date. The third experiment was set up to investigate the effect of the reduced feed intake and the effect of an inadequate tryptophan supply per se on the animals' growth. Here a two-factorial experimental design was used also by varying the energy density of the diet (13 vs. 14 MJ ME per kg feed). In addition to tryptophan deficient groups (1.5 g tryptophan per kg feed), this experiment contained conventional control groups (2.6 g tryptophan per kg feed, ad libitum feeding) and pair-fed control groups (2.6 g tryptophan per kg feed, feed intake identical to that of the tryptophan deficient group). The energy density had no significant effect on the animals' performance and increasing the energy density of the diet did not significantly affect feed and energy intake or daily gains of the tryptophan deficient animals. Feed intake, daily gains and feed efficiency of the tryptophan deficient groups were markedly poorer (by 30, 35 and 10%) than in the ad libitum control groups. When compared with the pair-fed control groups, on the other hand, the performance of the tryptophan deficient groups in terms of daily gains, feed conversion and energy efficiency was only slightly and not significant lower by 1, 4 and 3%, respectively. These results demonstrate conclusively that the growth depression in tryptophan deficiency is almost entirely due to the marked reduction in feed intake rather than to a direct limitation of protein accretion caused by an inadequate tryptophan supply.     

Transfer of lactic acid bacterial strains from the feed to the sow, the environment, and the piglets.

The spread of lactic acid bacterial strains to the environment and to newborn piglets was investigated after feeding of such strains to sows. Rifampicin resistant bacterial strains were fed to sows, 10(10) c.f.u. per day, during the period from 1 week before expected farrowing until 1 week after farrowing. Fecal samples from the sows and samples of litter were collected for bacteriological examination together with swabs from the pens, the skin of the sows, and from the rectum of the piglets. The test strains were only excreted in relatively low amounts in the feces of the sows, approximately 10(3)-10(6) c.f.u. per gram. They were not able to displace the normal lactic acid bacterial flora in the sows nor were they transmitted to the intestinal tract of the piglets to any significant extent. After the last administration the test strains disappeared from both feces, skin, and environment, indicating that no permanent colonization had taken place, although considerable differences in duration of persistence were noticed between test strains.     

Swine fever. Immunisation of piglets

Vaccination against Swine Fever using the CL Chinese strain can be done in 7-day-old piglets if they are born of non-immune sows. The simultaneous weaning and vaccination emphasises the safety of this strain. The excellent immunity observed confirms the immunocompetence of 7-day-old piglets. In piglets born of immune sows and also weaned at 7 days, passive protection can extend beyond the age of 2 months if the sow is vaccinated several months prior to gestation. The immune level of the piglets would seem to depend on the interval between vaccination of the sow and farrowing and can be attributed to the quality of the antibodies transmitted by the colostrum. Piglets born of sows vaccinated 10 months prior to farrowing can be vaccinated as early as 5 weeks; the protection percentage observed at the age of about 6 months is over 80%. A booster injection at this age then confers immunity to future breeders throughout their economic life, i.e. 4 years in the reported experiment.     

The concentrations of copper, zinc, manganese and selenium in the hair of newborn piglets and their dams.

Instrumental neutron activation analysis was employed to determine the levels of certain trace elements in the hair of newborn piglets and their dams. The mean concentrations (mumoles/mg) of copper, zinc, manganese and selenium in the neonatal piglet hair samples were 222 +/- 55, 4940 +/- 1728, 12.7 +/- 17.1 and 8.9 +/- 5.5, respectively, and in sow hair samples the mean concentrations (mumoles/mg) were 156 +/- 22, 5124 +/- 1927, 31.7 +/- 22.2 and 6.5 +/- 3.7, respectively. The mean copper level was higher (p less than 0.05) in piglet hair compared with sow hair. However the mean concentration of manganese was lower (p less than 0.05) in piglet hair. There was no relationship between the trace mineral levels found in the piglets' hair and the dams' hair. The levels of copper, zinc, manganese and selenium found in piglet hair were shown to be unrelated to the piglet body weight. The feasibility of using porcine hair as a practical biopsy material for trace element analysis is discussed.     

Morphological changes in the lungs of meconium-stained piglets.

Meconium staining of the skin is a common event associated with fetal hypoxia, stillbirths, weak-born piglets, and neonatal mortality. Aspiration of meconium leads to meconium aspiration syndrome (MAS). This study was undertaken to assess the relationship between the degree of meconium staining of the skin at birth, meconium aspiration, and pulmonary changes in porcine neonates. A total of 353 farrowing sows and 3,693 born piglets were monitored during parturition and for 15 days after delivery. Umbilical cords were classified as normal or ruptured. Meconium staining in the skin was graded as nonstained, mildly, moderately, and severely stained. Mortality from birth to 15 days of age was 8.4%. The lungs from 60 meconium-stained piglets and 60 lungs from nonstained piglets were collected and microscopically examined for meconium aspiration and inflammation. Rupture of the umbilical cord was significantly higher (P < 0.01) in meconium-stained piglets. Microscopically, 32% and 40% of the lungs had evidence of meconium for the stained and nonstained groups, respectively. The microscopic grade of meconium aspiration and inflammatory cells was not different between nonstained and meconium-stained piglets. Aspiration of meconium induced a granulomatous response in the lungs. It was concluded that the grade of meconium staining is a good indicator of fetal hypoxia, but not a good predictor for meconium aspiration and MAS in piglets.     

Socializing piglets before weaning: effects on behavior of lactating sows, pre- and postweaning behavior, and performance of piglets

This study evaluated how socializing piglets before weaning affects behavior of lactating sows and the pre- and postweaning behavior and performance of piglets. Two farrowing rooms, each with 6 pens, and 1 nursery with 4 pens were used. In total, data were obtained from 24 sows and their litters. In each farrowing room, the solid barriers between 3 farrowing pens were removed on d 12 after farrowing, and the sows remained confined in their crates (experimental group). In the other 3 farrowing pens of each farrowing room, sows and their litters were kept under conventional conditions until weaning (control group). All piglets were weaned 28 d after birth. After weaning, piglets from each group remained together in 1 pen of the nursery. The behavior of sows (lying, standing, sitting, nursing) and piglets (lying, active, suckling) in the farrowing rooms was observed for 24 h before and for 48 h after removal of the barriers between the pens. In addition, behavior (active, lying, feeding, agonistic behavior) of piglets was observed in the nursery during the initial 48-h period after weaning. Each piglet was weighed on d 5, 12, and 28 after birth and thereafter weekly until the fifth week of rearing. In the farrowing room, mixing of litters did not influence behavior of piglets and sows. Preweaning weight gain of the piglets did not differ (P = 0.60) between the treatments. In the initial 48 h after weaning, less agonistic behavior (P < 0.001) was observed in piglets belonging to the experimental group. During 5 wk of rearing, piglets in the experimental group gained more weight compared with the control group (P = 0.05). The advantage shown by the experimental group became especially conspicuous in the first week after weaning (P = 0.05). By socializing unfamiliar piglets before weaning, stress due to mixing could at least be distanced in time from the other burdens of weaning, thereby improving performance.     

The content of ascorbic acids in different tissues of cattle, normally developed piglets, splay-legged piglets, adult swine and dogs

The following ascorbic acid levels were recorded from different organs of cattle, with all values quoted being related to mg/100 g fresh matter: 150 +/- 20 in pituitary gland, 170 +/- 40 in left adrenal gland, 45.5 +/- 12.5 in spleen, 38.1 +/- 7.3 in liver, 30.0 +/- 8.5 in cerebrum, 23.2 +/- 7.2 in cerebellum, 16.4 +/- 6.1 in kidney, 11.0 +/- 2.9 in heart, and 9.1 +/- 2.1 in M. longissimus dorsi. The ascorbic acid level in blood plasma of normally developed piglets was 6.5 +/- 2.7 mg/dl and was thus higher with significance (p less than 0.01) than that recorded from splayleg piglets which was 2.3 +/- 0.96 mg/dl. The levels in the M. semimembranosus and M. semitendinosus in piglets of moderate birth weight were higher, as well (p less than 0.05). The liver level in pigs for slaughter was 30.8 +/- 9.0 mg/100 g lower than that in piglets. Piglets exhibited genetically founded differences in their capability of biosynthesis of ascorbic acid. The highest ascorbic acid level in dog was recorded from the pituitary and adrenal glands, values being 135.5 +/- 7.5 mg/100 g fresh matter or 90.3 +/- 37.8 mg/100 g. Their liver level was 27.9 +/- 11.9 mg/100 g.     

Sleep and activity of piglets weaned into cages.

The duration and type of sleep and activity were monitored in a group of 9 Duroc piglets weaned at 7 weeks of age and placed into a cage of 1.2 x 1.2 m. Average air temperature in the cage ranged between 20 and 23 degrees C and relative humidity was around 70%. The piglets were fed and watered ad libitum. The measurements were performed one week after the pigs had been transferred to the cages, in the period between 8 a.m. and 1 p.m. Approximately half of the 5-hour period of observation was occupied by sleep. There were, however, marked individual differences (ranges: 66 and 24%). Non-REM sleep occupied 79% while REM sleep 21% of the whole sleep time. REM episodes lasted, on the average, 3.8 + 0.58 min. The other half of the period studied was occupied by wakefulness which was devoted to movement, lying and, also, massaging and sucking each other. In some animals this activity was high and was the cause of unrest in the whole group. Differences in respiratory rate between non-REM and REM sleep recorded in heavier animals were the result of their heat load.     

Effect of metabolic disorders accompanying gastroenteritis on the pancreatic exocrine function in piglets. C. Histopathological and immunohistochemical changes in the pancreas of piglets with gastroenteritis

The study was performed on 20 piglets of both sexes. The control group consisted of 10 healthy piglets, the experimental, group included 10 piglets with symptoms of gastroenteritis. All the animals were subjected to euthanasia at the age of 21 or 35 days (weaning), or 7 days after weaning, and immunohistochemical and histopathological examinations were performed on all of them. Immunohistochemical examinations of the experimental piglets included additional tests made on five piglets with gastroenteritis, characterized by poor general condition. Histopathological examinations of the pancreas revealed retrogressive changes, which might result from hemodynamic disorders. Changes in the localization of SOM and VIP found in the pancreas suggested inhibition of pancreatic enzyme synthesis in piglets with diarrhea. The co-localization of GAL and dopamine beta-hydroxylase (D beta H--a key enzyme of the noradrenaline synthesis pathway) in perivascular nerve fibers could lead to considerable vasospasms in the pancreas, resulting in deeper hypoxia of the organ. Immunohistochemical and histopathological examinations confirmed the results of biochemical analyses, indicating failure of the pancreatic exocrine function in piglets with gastroenteritis.     

Effect of metabolic disorders accompanying gastroenteritis on the pancreatic exocrine function in piglets. A. Metabolic disturbances in piglets with gastroenteritis

The study were performed on 90 piglets of both sexes, divided into two groups, i.e. control, consisting of 30 healthy animals, and experimental, including 60 piglets with symptoms of gastroenteritis. Clinical, hematological and biochemical tests were performed in all the animals at the age of 21 and 35 days, and 7 days after weaning. Hematological investigations included the determination of Hb, Ht, Erys, Lkcs, MCHC and MCV. Biochemical analyses allowed to determine the serum activity of ALT, ALP, LDH and its isoenzymes, the serum level of Na+, K+ and Cl-, as well as the serum content of glucose, cholesterol and total protein. Indices of the acid-base equilibrium were determined in whole blood. The results obtained show that anemia and a tendency towards metabolic acidosis observed in healthy piglets may have a negative effect on homeostasis. Hypotonic dehydration, metabolic acidosis and energy deficits found in piglets with gastroenteritis may cause damage of some organs including the liver and pancreas. It was also found that isoenzymatic separation of LDH together with indices of the so called hepatic profile may be helpful to diagnose hepatocellular damage.     

Experimental transmission of intestinal coccidiosis to piglets: clinical, parasitological and pathological findings.

Twenty-eight piglets coming from a "specific pathogen free" herd were inoculated at three days of age with 50 000 or 100 000 sporulated oocysts of Isospora suis. Fecal samples were examined for oocyst shedding daily and several clinical parameters were recorded. Ten piglets were used as normal controls. Groups of piglets were euthanized from three days to 12 days postinoculation and routine necropsies were performed. Bacteriological, virological, parasitological and histopathological examinations were made on the intestinal tracts. The incubation period was four to five days. Clinical signs and microscopic intestinal lesions observed in the experimentally infected animals were similar to those reported in spontaneous cases of porcine neonatal coccidiosis. Lesions of villous atrophy in the small intestine seemed to result from the destruction of villous epithelial cells mainly during the peak of asexual reproduction which occurred around four to five days postinoculation. Intracellular coccidial organisms were difficult to find during the late atrophic and villous regrowth stages of the intestinal lesions. The prepatent period varied from four to seven days and the most common was five days. Eighty percent of the piglets kept alive more than four days postinoculation have shed oocysts. Piglets dosed with old sporulated oocysts (ten months old) shed many more oocysts than those infected with a fresh inoculum (less than two months old). The patent period was not determined precisely with the design of the experiment but some of the infected piglets shed oocysts for at least five days.     

仔猪大肠杆菌病的病原分离鉴定

仔猪大肠杆菌病是危害仔猪较严重的传染性疾病之一 ,特别是仔猪黄痢和白痢常引起仔猪发育不良 ,饲养成本增高 ,严重时导致大量死亡[1,2 ] 。目前在一些大型和个体养猪场中 ,由于饲养管理不良 ,卫生条件差 ,消毒不严 ,常暴发大肠杆菌病。在临床上由于缺乏化验条件 ,加之生产上盲目滥用药物 ,导致大肠杆菌的耐药菌株不断产生 ,致使该病的控制越来越难 ,给养猪业带来严重经济损失。生产实践中 ,我们接触到许多疑为该病的病猪 ,为了进一步确诊 ,并给该病防治上提供可靠依据 ,从而指导生产 ,减少该病带来的经济损失 ,因此进行了以下试验 ,报告如…     

Pathogenesis of intestinal cryptosporidiosis in conventional and gnotobiotic piglets.

The pathogenesis of intestinal cryptosporidiosis was studied in 52 conventionally reared and 20 gnotobiotically reared piglets by inoculation with different doses of Cryptosporidium parvum oocysts. The prepatent period of C. parvum in both groups of animals were variable, depending on the number of oocysts administered. The patent period of C. parvum in conventionally reared piglets was 8 or 9 days; in gnotobiotic piglets cryptosporidia were found in feces until Day post infection (DPI) 16, when the last piglet was necropsied. Cryptosporidiosis in conventionally reared piglets is a self-limited diarrheal disease associated with morphological changes within the intestine. The most severe lesion was seen in the posterior jejunum and ileum from DPI 3 to DPI 7, and consisted of villous atrophy, crypt hyperplasia and inflammatory infiltration in the lamina propria. In gnotobiotic piglets cryptosporidia induced severe enterocolitis which occurred at least until DPI 16. The characteristics of enteric lesions were similar to those found in conventionally reared piglets. Intestinal cryptosporidiosis in both groups of animals shifted in the course of infection in the caudal direction and terminated in the large intestine. Examination by scanning electron microscope showed that infected absorptive cells had thicker and longer microvilli than those on non-infected cells; neighboring non-infected cells were hypertrophic, bulbously protuberant with minute microvilli with no distinct intercellular borders. Numerous cryptosporidia in the heterotopic glandular epithelium in the submucosa of cecum and colon on DPI 9 and 10 were found. No differences in the location and degree of cryptosporidial infection between colostrum-fed and colostrum-deprived conventionally reared piglets were found. Sow's colostrum does not appear to protect piglets from C. parvum infection. The role of intestinal microflora in the pathogenesis of cryptosporidiosis in piglets is discussed.     

中草药添加剂仔猪健

由白头翁、苦参等8味中草药及增效剂配伍组成添加剂"仔猪健”,按每头每天100g的剂量分2次添加于母猪的饲料中,观察其对吮乳仔猪黄白痢的预防作用及对仔猪育成率和增重作用的影响.试验结果表明哺乳母猪添加"仔猪健”后能有效预防仔猪的黄白痢,并能显著降低仔猪的死亡率,显著提高仔猪的育成率、增加窝重.