A field study on feed supplementation, body weight and selected blood parameters in local pigs in Laos

The aim of the present study was to investigate feed allowances, body weight (BW), haematocrit, haemoglobin, plasma ionised calcium (iCa), sodium, potassium, pH and glucose concentration and faecal K/Na ratio in local growing pigs, sows and piglets kept by small-holder farmers in Laos. Starting hypotheses were that (1) local pigs are under fed, (2) BW is higher in pigs receiving supplementary feed and (3) the blood profile of pigs subjected to very poor nutrition is outside the normal range. On 54 pig-keeping smallholdings in Borikhamxay province, Lao PDR, daily feed allowances were weighed and BW recorded for 27 lactating sows, 54 piglets and 27 growing pigs. Blood samples were collected from the vena jugularis in all pigs. Feed supplementation did not affect BW, but plasma iCa concentration was outside the normal range for all pigs. There was a tendency for lower faecal K/Na ratio in Na-supplemented sows. The results confirm that local pigs in small-scale production systems in Laos suffer from poor nutrition. The most important challenge for farmers appears to be provision of more feed, particularly feed with a high Ca content.     

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.     

Assessment of the use of gross lesions at post-mortem to detect outbreaks of classical swine fever

The performance of pathological findings as a diagnostic tool for the detection of classical swine fever (CSF) outbreaks during the 1997/1998 CSF-epidemic in The Netherlands was evaluated by constructing and analysing receiver operating characteristic (ROC) curves. This was done at the individual pig level and at the submission level (a group of pigs from the same herd submitted together for post-mortem investigation). At post-mortem examination, the tonsils, spleen, ileo-caecal valve and renal pelvis were sampled, sent to the reference laboratory, and tested by means of a CSF-specific fluorescent antibody test in combination with a confirmatory test. This resulted in an infection status at the individual pig level. The infection status and pathological findings of 1072 individual pigs from a total of 230 infected herds were included in this analysis. We also included submissions of pigs from herds that were sent to post-mortem examination because of a clinically CSF-suspect situation but afterwards were concluded to be from non-infected herds. Infection status and pathological findings of 1224 individual pigs from a total of 241 non-infected herds were included in the analysis. Pneumonia, pleuritis, chronic bronchitis, pulmonary oedema, chronic gastric ulceration, dry faecal contents in the colon, conjunctivitis, haemorrhages in the renal pelvis, renal haemorrhages, splenic enlargement, haemorrhages in the urinary bladder, haemorrhagic and enlarged lymph nodes were the most frequently recorded pathological findings during a post-mortem examination of pigs submitted in a CSF-suspect clinical situation. However, some of these pathological findings (e.g. pneumonia, pleuritis) were almost evenly distributed in infected and in non-infected pigs, resulting in a high sensitivity combined with a low specificity. The area under the ROC curve of pathological findings at the individual pig level and at the submission level was 0.720 and 0.782, respectively, which was significantly (P<0.0001) larger than the area under the random ROC curve. It was concluded that, although gross pathology is a legitimate test, its quantitative contribution to the detection of CSF is limited.     

Effect of creep feeding on structural and functional changes of the gut of early weaned pigs

Dose-dependent hypersensitivity responses mounted against antigenic constituents of creep feeds have been previously implicated in intestinal damage, digestive disorders and impaired performance of early weaned pigs. In the present study biochemical and histological investigations of the small intestine were undertaken to determine the putative relationship between creep feed level and hypersensitivity response in pigs weaned at 14 days. Creep feed was administered by gastric intubation and weaned pigs received the same diet by gastric intubation for five days. Mucosal structure and function at weaning were not affected by creep feeding regimen. Villus height decreased and crypt depth increased in weaned compared to suckled pigs, but morphology was unaffected by prior exposure to creep. Xylose absorption was not influenced by either creep feed level or weaning. Intraepithelial lymphocyte numbers increased during weaning but were not affected by the creep feeding regimen. Mucosal carbohydrase activity in weaned pigs was not significantly affected by preweaning treatment. The results do not support the hypothesis that post weaning changes in structure and function of the gut are related to creep feed level or to immune responses to dietary antigens.     

Field evaluation of a live vaccine against porcine reproductive and respiratory syndrome in fattening pigs

A live vaccine based on a European isolate of porcine reproductive and respiratory syndrome virus (Porcilis PRRS) was tested in this study in order to determine the protection of fattening pigs against the respiratory form of the syndrome under field conditions. Ten thousand pigs in an infected farm were vaccinated against PRRS virus at the age of 6 weeks and were compared with non-vaccinated pigs with respect to their health status, mortality, performance parameters (average daily gain, average daily feed intake, feed conversion ratio) and the presence of certain pathogens in their lungs. The results showed that treated pigs became ill less frequently and demonstrated reduced mortality compared with untreated ones. As compared with non-vaccinated animals, PRRS-vaccinated pigs also performed in a better way with respect to the feed conversion ratio (P < 0.05) and average daily gain (P < 0.05), while feed intake was similar for both groups (P > 0.05). Bacteriological examinations of the lungs revealed increased incidence of respiratory bacterial infection in untreated pigs compared with treated ones. A tendency for a faster antibody response was also detected in the vaccinees. The results of the present study show that immunization with a live vaccine does protect fattening pigs against the respiratory manifestations of PRRS.     

A cost-benefit analysis of Salmonella-control strategies in Danish pork production

In Denmark, it was agreed to lower the Salmonella prevalence in pork to 1.2% before the end of 2006. The current control did not seem to be sufficient to attain this goal. Therefore, four alternatives to the existing Danish control strategy for Salmonella in pork were compared in a cost-benefit analysis: (1) hot-water decontamination of all pigs at slaughter, (2) sanitary slaughter of pigs from herds with high levels of Salmonella, (3) use of home-mixed feed in herds with slaughter pigs and (4) use of acidified feed for slaughter pigs. The data originated from official statistics, published papers as well as expert opinion. The partial cost-benefit analysis was restricted to slaughterhouses affiliated with the Danish Meat Association and Danish human cases ascribable to pork from these slaughterhouses. Only hot-water decontamination was socio-economically profitable. Hot-water decontamination had a net present value over 15 years of 3.5 million euros. For sanitary slaughter the net present value was - 43.6 million euros, for home-mixed feed it was - 262.3 million euros and for acidified feed it was - 79.9 million euros. For all alternatives the costs were born solely by the pig sector, whereas primarily the consumers and public authorities received the benefits. The conclusions were robust in sensitivity analyses.     

Secondary effects caused by feed medication in swine

Giving medical feed to weanling pigs it is possible to produce a vitamin K-deficiency as a side effect, which is caused by destruction of the intestinal flora. In this investigation the effect of different drugs in a vitamin K-deficient diet on blood coagulation of weanling pigs was examined. In a first trial clinical symptoms of a vitamin K-dependent coagulation disorder could be seen in five from six animals after feeding a combination of sulfadimidine, tylosin, furazolidone and arsanilic acid. Animals showed haemorrhages, when they were housed on flatdecks as well as on concrete floor. This indicated that coprophagy plays no role in pigs for supply of vitamin K. Feeding these drugs in other combinations or one of the drugs alone caused no clinical signs in a second trial. Significant differences to untreated control pigs were found only in one group (sulfadimidine/arsanilic acid) for activities of coagulation factors. Other groups demonstrated only prolongation of clotting times in single animals. Pigs, which received sulfadimidine within their ration, were more often affected than other animals. In a third trial suckling pigs were treated over a period of three weeks with a drug combination used in the first trial to allow an adaptation of the intestinal flora. Same treatment after weaning was unable to produce any clinical symptoms, but led to distinct coagulation disorders in pigs treated before as well as in untreated animals. It is supposed that the development of a vitamin K-deficiency depends on faecal bacterial count and on the specific resistance of intestinal flora in individuals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Herd-level risk factors for subclinical Salmonella infection in European finishing-pig herds

Our objective was to find herd factors associated with pigs testing seropositive for Salmonella. Data were collected from 359 finishing-pig herds in Germany, Denmark, Greece, The Netherlands and Sweden, between 1996 and 1998. Pigs fed non-pelleted feed (dry or wet) had 2- and 2.5-times lower odds of seropositivity, compared to pigs fed pelleted feed. The protective effect of non-pelleted feed over pelleted feed may be ascribed to the structure and composition. Also, pigs that were given whey (to drink or as the liquid part of the diet) had 2.6-times lower odds to test seropositive than pigs not getting whey. Pigs produced in batches in herds with hygienic-lock facilities had >3-times lower odds for testing seropositive compared to pigs in herds where only one or neither factor was present. In herds where the caretaker(s) washed hands consistently before tending to the animals, pigs had 1.5-times lower odds of seropositivity than pigs in herds where the caretaker did not. Pigs which were able to have snout contact with pigs in neighbouring pens (because pen separations were either open or too low) had 1.7-times higher odds to test seropositive compared to pigs for which such contact was prevented. Pigs in herds recruiting from more than three supplier herds had three-times higher odds to test seropositive than pigs in herds which breed their own replacement stock or recruit from a maximum of three supplier herds.     

Listeria spp. contamination in piggeries: comparison of three sites of environmental swabbing for detection and risk factor hypothesis

Listeria monocytogenes is a foodborne pathogen of major concern for public health in industrialized countries. Listeria carriage by pigs at the herd level could be a primary source for carcass contamination. Forty-seven finishing pig facilities were involved in the present study designed to compare three environmental swabbing sites in order to detect Listeria spp. in piggeries. Swabs were taken from the pen walls, the perianal regions of the pigs and the trough/feeder of the piggery premises. Listeria contamination of wet or dry feed given to the pigs was also investigated. The capacity of the various sampling sites for Listeria spp. detection were compared with a maximum likelihood estimation method. Listeria spp. were recovered in 74% of the pens studied and L. monocytogenes was detected in 15% of pens. With a specificity of 99%, sensitivity estimates (and 95% CI) of the Listeria spp. detection method were 93.4% (72.7-98.7) for pen walls, 73.1% (54.9-85.9) for pigs and 66.6% (48.6-80.7) for the trough/feeder. Listeria spp. were isolated from 84% of wet feed samples and 5% of dry feed samples. Listeria monocytogenes was found in 13% of wet feed samples. The type of feeding (wet versus dry) was associated (P < 0.001) with Listeria spp. contamination of both the pen and the feed. The results of this study confirm that Listeria spp., including L. monocytogenes, are present in pig facilities. Pen wall swabbing appears to be an effective way to assess Listeria spp. status of finishing pigs. The type of feeding (wet versus dry) could play a role in pig contamination.     

Effect of fermented feed on shedding of Enterobacteriaceae by fattening pigs

Epidemiological studies showed that the use of fermented feed could significantly reduce Salmonella prevalence in pigs compared to the use of normal feed. Experimental challenge experiments with Salmonella have however never been conducted to reveal the efficacy of fermented feed in reducing Salmonella shedding and/or reducing the number of Salmonella-positive pigs. A longitudinal study was conducted to measure the effect of fermented feed, in particular of its components lactic acid and Lactobacillus plantarum, on gastrointestinal bacterial ecology (Salmonella, Enterobacteriaceae, lactobacilli, volatile fatty acids (VFAs), pH). Seeder pigs were used as a mode for Salmonella transmission within a pig herd. Bacteriological measurements were performed in faeces of the pigs. The results showed that fermented feed affected/reduced the Enterobacteriaceae population in faeces of the pigs. No differences were found in the number of positive pigs infected or in the number of shedding with Salmonella serovar Typhimurium fed fermented feed and between the normal feed group. S. serovar Goldcoast could not establish an infection in the seeder pigs in the fermented feed group as well as in the normal feed group. The pH of the faeces in the fermented feed groups was significantly higher than the pH of the faeces of the normal feed groups. The role of the undissociated form of the faecal VFAs on the significantly lower Enterobacteriaceae number in faeces of the pigs of the fermented feed groups could not be demonstrated because of the significant higher pH in the faeces of the pigs fed fermented feed.     

全自动供料系统在生猪养殖中的应用效果分析

为了分析全自动供料系统在生猪养殖中的应用效果,选用80头25日龄断奶仔猪,按体重、性别及血统无差异分为2组(试验组和对照组),每组4个重复,每个重复10头猪,试验期为180 d。其中,试验组采用全自动供料系统进行饲养,对照组采用传统饲养模式进行饲养。试验结果表明,全自动供料系统能提高生猪的日增重,提前出栏日龄,提高均匀度;全自动供料系统可以降低饲料浪费,提高饲料报酬率;全自动供料系统能显著降低人力,提高人力利用率。     

Effect of transportation and feed withdrawal on shedding of Salmonella typhimurium among experimentally infected pigs.

OBJECTIVE: To determine whether stress associated with transportation or feed withdrawal increased fecal shedding of Salmonella Typhimurium among pigs experimentally infected with the organism. ANIMALS: 86 healthy pigs. PROCEDURE: Pigs were challenge exposed with Salmonella Typhimurium at 4 weeks old and reared conventionally. When pigs reached market weight, they were assigned to groups and subjected to various combinations of transportation and feed withdrawal. Ileocecal contents were collected after slaughter and tested for Salmonella Typhimurium. RESULTS: Salmonella Typhimurium was not detected in feces collected from pigs just prior to slaughter. When feed was withheld for 24 hours prior to slaughter, the proportion of transported pigs with Salmonella Typhimurium in ileocecal contents at the time of slaughter was not significantly different from the proportion of nontransported pigs. However, when feed was not withheld prior to slaughter, the proportion of transported pigs with Salmonella Typhimurium in ileocecal contents at the time of slaughter was significantly higher than the proportion of nontransported pigs. CONCLUSIONS AND CLINICAL RELEVANCE: When carrier pigs remained on feed, transportation stress increased the proportion positive for Salmonella sp. On the basis of results reported here, it is suggested that producers withhold feed from pigs for 24 hours prior to transportation to a slaughter plant.     

Acute toxicosis in swine associated with excessive dietary intake of vitamin D

Acute toxicosis developed in a group (n = 35) of fattening hogs and replacement gilts that had excessive vitamin D3 inadvertently added to their feed. All of the pigs were lethargic, and emesis was evident in about half of the pigs 1 to 2 days after they consumed the feed. On the 2nd day, 3 of the pigs died. The remaining pigs were given a different ration. Five additional pigs died during the next 2 weeks. Clinical toxicosis also was observed in 1 of 2 feeder pigs fed the suspect feed in the laboratory and in 2 of 2 pigs fed the suspect feed by the company that had mixed the feed. Gross necropsy findings consistently observed were hemorrhagic gastritis and diffuse interstitial pneumonia. Myocardial degeneration and nephrosis were seen in, respectively, 1 of 6 and 4 of 6 pigs necropsied. Histologically, necrosis and mineralization of variable severity were observed in the fundic gastric mucosa, lungs, kidneys, bone, heart, and small blood vessels of the lungs and heart. Less necrosis and more mineralization were observed in pigs that survived longer than 6 days. The 2 pigs fed the suspect feed in the laboratory had increased concentrations of serum calcium from the 3rd to the 9th days or the 1st to the 3rd days, after feeding the suspect feed. Serum phosphorus concentrations were increased from the 1st until the 2nd or 3rd day, and serum magnesium concentrations were increased from the 1st or 2nd to the 3rd day after feeding the suspect feed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Physiologic and body composition changes in feeder pigs under simulated marketing conditions

Two experiments were conducted to determine changes in body composition and various physiologic variables in feeder pigs under simulated marketing conditions. In the first experiment, pigs were assigned to 1 of 4 treatment groups for 48 hours: (1) no water and feed; (2) water ad libitum, no feed; (3) no water, feed ad libitum; or (4) water and feed ad libitum. During a 48-hour recovery period, all pigs were allowed feed and water ad libitum. Plasma triiodothyronine decreased (P less than 0.01) within the first 24 hours in groups-1 and -2 pigs, but increased (P less than 0.01) within the first 6 hours of the recovery period. The circadian rhythm of plasma cortisol was disrupted in groups-1 and -3 pigs and during recovery in group-1 pigs. Packed cell volume increased (P less than 0.05) in groups-1 and -3 pigs and returned to initial values within the first 24 hours of the recovery period. In the second experiment, body composition was estimated by the 40K technique for fat-free body mass, percentage of nitrogen, and percentage of fat. Body composition was determined before and after pigs were allotted to 1 of 2 groups for 48 hours: group-1 pigs were given feed and water ad libitum and group-2 pigs were not given feed and water. Group-1 pigs gained 2.2 kg of body weight (P less than 0.01), 0.6% fat (P less than 0.01), 0.7 kg of fat-free body mass, and 0.02% nitrogen (P greater than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Fermented and nonfermented liquid feed to growing pigs: effect on aspects of gastrointestinal ecology and growth performance

The effect of feeding dry feed (DF), nonfermented liquid feed (NFLF), and fermented liquid feed (FLF) to growing pigs on aspects of gastrointestinal ecology and on performance was investigated. Nonfermented liquid feed was prepared by mixing feed and water at a ratio of 1:2.5 immediately before feeding. Fermented liquid feed was prepared by mixing feed and water in the same ratio as NFLF, and stored in a tank at 20 degrees C for 4 d, after which half the volume was removed twice daily at each feeding and replaced with the same volume of feed and water mixture. A total of 60 pigs (initial BW of 30.7 kg) from 20 litters was used. Twenty pigs, housed individually, were allotted to each of the diets and fed restrictively. Five pigs from each diet were sacrificed at an average BW of 112 kg and digesta from the gastrointestinal tract (GI-tract) was obtained to examine variables describing some aspects of the gastrointestinal ecology. Fermented liquid feed contained high levels of lactic acid bacteria (9.4 log cfu/g) and lactic acid (approximately 169 mmol/kg), low levels of enterobacteria (<3.2 log cfu/g), and had a low pH (4.4). Nonfermented liquid feed contained 7.2 log cfu/g of lactic acid bacteria, and 6.2 log cfu/g of enterobacteria, which indicated that fermentation had started in the feed. The pigs fed FLF had the lowest levels of enterobacteria along the GI-tract (<3.2 to 5.0 log cfu/g), and those fed NFLF the highest levels (5.7 to 6.6 log cfu/g; P < or = 0.02). Fermented liquid feed caused a decrease in gastric pH from 4.4 and 4.6 for DF and NLF, to 4.0 (P = 0.003), and increased numerically the gastric concentration of lactic acid (P = 0.17) from 50 to 60 mmol/kg in the DF and NFLF treatments to 113 mmol/kg in the FLF treatment. The animals fed NFLF showed the highest weight gain (995 g/d) and feed intake (2.14 kg/d), and those fed FLF the lowest values (weight gain, 931 g/d; feed intake, 1.96 kg/d; P = 0.003 for weight gain, and P < 0.001 for feed intake). The results from the present study indicate that feeding FLF as prepared here may be a valid feeding strategy to decrease the levels of enterobacteria in the GI-tract of growing pigs, whereas feeding liquid feed that has started to ferment (high levels of enterobacteria and high pH as with NFLF) increases the presence of these undesirable bacteria. Nonetheless, higher daily feed intake and body weight gain are obtained when feeding NFLF compared with feeding FLF or DF.     

Nutritional value of quality protein maize and food corn for starter and growth pigs

Growth traits with starter and grower pigs and a digestion trial were conducted to compare the nutritional value of Quality Protein Maize (QPM), food corn and conventional feed corn. The QPM, food and feed corn contained .45, .31 and .29% lysine, respectively. The growth trials evaluated a QPM-soybean meal diet formulated on a lysine basis (.96% in starter and .7% in grower diets) and four diets arranged in a 2 (food corn vs feed corn) X 2 (low vs high soybean meal) factorial. Soybean meal was either added in the same amount as in the QPM diet or was added to provide the lysine content of the QPM diet. Performance was similar for pigs fed food corn and feed corn in both trials. The QPM diets resulted in greater performance than food and feed corn diets containing the same level of soybean meal supplementation; starter pigs were more (P less than .10) efficient and grower pigs had a higher (P less than .01) rate and efficiency of gain. However, performance of pigs fed the QPM diets was not equal to that of pigs fed isolysinic food and feed corn diets; growth rate was lower (P less than .05) in starter pigs and gain:feed was lower (P less than .05) in grower pigs. Diets in the digestion trial consisted of the corns plus 3.25% casein. Energy digestibility was similar for all diets. Ileal N and amino acid digestibilities were highest for QPM, intermediate for food corn and lowest for feed corn. In most instances, these differences were significant (P less than .05). Apparent biological value was highest (P less than .05) for QPM. These trials indicate that food corn and feed corn have similar nutritional value, and that starter and grower pigs can benefit from the higher protein quality of QPM.     

3-Acetyl-4'-isovaleryl tylosin for prevention of swine dysentery

The 21 field isolates of Treponema hyodysenteriae which were tested were sensitive to 3-acetyl-4'-isovaleryl tylosin (AIV); the minimal inhibitory concentration was 0.25 to 16 micrograms/ml. 3-Acetyl-4'-isovaleryl tylosin administered prophylactically to pigs at concentrations of 5 to 100 mg/kg of feed and tylosin at 110 mg/kg of feed for 28 or 31 days prevented swine dysentery induced by tylosin-sensitive T hyodysenteriae strain SQ2; 15 nonmedicated, inoculated control pigs had bloody diarrhea, and 9 pigs died. In 2 additional trials, AIV administered prophylactically for 28 days at 55 or 110 mg/kg of feed prevented swine dysentery induced by tylosin-insensitive T hyodysenteriae strain B204. All of the inoculated principal pigs medicated with AIV at 55 or 110 mg/kg of feed or carbadox at 55 mg/kg of feed and the noninoculated sentinel pigs for each group had solid feces throughout the 56-day trial. In the nonmedicated, inoculated control groups, bloody diarrhea began at 4 to 5 days after inoculation was done, and 9 of 10 principal pigs and 6 of 9 sentinel pigs had dysentery; 2 pigs died. In the groups medicated with AIV at 27.5 or 5.5 mg/kg of feed, all 5 principal pigs and 3 or 4 sentinel pigs in each group had dysentery; 3 or 4 pigs in each group died. In the group medicated with tylosin at 110 mg/kg of feed, 7 of 10 principal pigs and all 9 sentinel pigs had dysentery; 1 pig died.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of the antimicrobial growth promoter tylosin on subclinical infection of pigs with Salmonella enterica serotype Typhimurium

OBJECTIVE: To determine whether feeding tylosin, an antimicrobial growth promoter, to pigs was associated with increased risk of infection with and excretion of Salmonella enterica serotype Typhimurium. ANIMALS: 17 healthy pigs. PROCEDURE: A commercial pelleted dry feed was given in 2 feeding trials. In trial A, 11 pigs were given feed with tylosin, 11 pigs were given feed without tylosin, and 11 pigs were given feed with tylosin before and feed without tylosin after inoculation with S Typhimurium. In trial B, 44 pigs were given feed that contained tylosin, and 44 pigs were given feed without tylosin. Three weeks after the start of each trial, pigs were orally inoculated with approximately 5 x 10(6) colony-forming units of S Typhimurium. Feces were examined for S Typhimurium, using semiquantitative microbiologic techniques before and for 5 or 6 weeks after inoculation. Serum antibody titers against S enterica were measured by use of ELISA. RESULTS: None of the pigs developed clinical signs of salmonellosis. However, after inoculation, S Typhimurium was isolated from feces of most pigs, and all but 2 pigs developed serum antibodies against S enterica. Significant differences were not detected between experimental and control groups in either trial. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that tylosin fed as an antimicrobial growth promoter to pigs may not be an important factor in promoting infection with or excretion of S enterica serotype Typhimurium.     

Increasing daily feeding occasions in restricted feeding strategies does not improve performance or well being of fattening pigs

Background

The natural feeding behaviour of the pig is searching for feed by rooting activities throughout the day; self-feeding pigs randomly space their eating and drinking periods throughout the day consuming ten to twelve meals per day. Pigs in conventional fattening pig production are normally fed 2–3 times daily with the feed consumed within 15 minutes. The aim of this study was to determine if more frequent feedings could improve the performance of conventionally kept fattening pigs.

Methods

The experiment was carried out on 360 fattening pigs (27–112 kg live weight), weighed and assigned to pens stratified by weight and sex. Each treatment group consisted of 180 pigs, allocated to 20 pens with nine pigs in each pen. To evaluate how more feeding occasions affects performance and well-being the pigs were divided into two groups and fed three (control group) or nine (treatment group) times daily. The same total amount of liquid feed was fed to each group and the feed ration was correlated to the live weight of the pigs. All weight and slaughter recordings were made individually and recordings of feed consumption were made pen-wise. At slaughter the stomach of each pig was examined for lesions in the pars oesophagea and scored on a scale from 1–6.

Results

Frequent feeding occasions influenced both performance and status of gastric lesions of the pigs adversely. Pigs in the treatment group grew slower compared to pigs in the control group; 697 g/day (± 6.76) versus 804 g/day (± 6.78) (P < 0.001) with no difference in within-pen variation. There was also a lower prevalence of gastric lesions within pigs in the control group (2.4 (± 0.12) compared to 3.0 (± 0.12) (P < 0.01)). There was a positive correlation between gastric lesions in the treatment group and daily weight gain (r = 0.19; P < 0.01).

Conclusion

Increased daily feeding occasions among group housed pigs resulted in a poorer daily weight gain and increased mean gastric lesion score as compared with pigs fed three times daily. This may be a consequence of more frequently occurring competition for feed in the treatment group. The present study does not support increased daily feeding occasions in fattening pigs.     

Effects of administration of antimicrobials in feed on growth rate and feed efficiency of pigs in multisite production systems

OBJECTIVE: To evaluate effect of various regimens for administration of antimicrobials in feed on growth rate and feed efficiency (feed/gain) of pigs in multisite production systems. DESIGN: Controlled trial. ANIMALS: 24,099 growing pigs in 3 multisite production systems. PROCEDURE: 10 trials involving various regimens for administration of antimicrobials in feed were evaluated. Trial 1 compared effects of 2 antimicrobial regimens on finishing pig performance. Trials 2 through 10 compared growth rate and feed efficiency of nursery and finishing pigs given antimicrobials in feed with values for control pigs not given antimicrobials. RESULTS: In trial 1, no significant differences were observed between the 2 antimicrobial regimens. In the remaining trials, growth rate of nursery pigs fed antimicrobials was significantly improved, compared with growth rate of control pigs. However, growth rate of finishing pigs and feed efficiency of nursery and finishing pigs were not significantly improved by adding antimicrobials to the feed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that use of antimicrobials in the feed to promote growth should be limited to the nursery phase in multisite pig production systems. Use of antimicrobials in the feed of finishing pigs should be limited to therapeutic applications in which a diagnosis of bacterial infection susceptible to the antimicrobial to be used has been confirmed.