Occurrence of PSE and DFD meat in swine slaughtered under emergency conditions

The occurrence of qualitative changes in meat was studied in a set of 1008 pigs slaughtered in four sanitation slaughter houses for the period of 12 months. PSE meat was found in 206 pigs (20.43 per cent) and DFD meat only in 9 pigs (0.89 percent) of the total number of pigs examined. The rule was applied that the defect should be demonstrated by two of three commonly used parameters (the pH value, colour and water loss by dripping). The highest occurrence of qualitative changes in meat of PSE type was registered in the group of animals with a defect of the respiratory organs (32.53 per cent) and the lowest in animals with diseases of sexual organs, including parturition complications (5.00 per cent). A similar trend was recorder even in the DFD meat occurrence. As to the seasons, the highest percentage of occurrence of PSE defects was in July and August (35.41 and 29.06 per cent) and the lowest (8.64 and 10.97 per cent) in March and January. The actual disease is proved to be only one of the secondary stress to induce the PSE meat formation.     

Glycolytic potential of red, soft, exudative pork longissimus muscle

Red, soft, exudative (RSE) pork is red as "normal" pork and exudative as PSE pork. The origin of RSE quality is unknown. In the present study, we determined whether the occurrence of RSE pork is related to the presence of the RN (Rendement Napole) gene. A glycolytic potential [= 2 x (glucose + glycogen + glucose-6-phosphate) + lactate] of > 180 micromol lactate/g of meat was used as indicator for presence of the RN gene. At 1 d postmortem, pork loin samples were collected at a commercial slaughter plant, and meat quality characteristics and glycolytic potential were determined. Glycolytic potential of RSE pork (n = 42) was higher (P < .01) than that of RFN (red, firm, nonexudative) pork (n = 25): 137 vs 110 micromol lactate/g of muscle. The glycolytic potential of PSE pork (n = 28) was 161 micromol lactate/g of muscle, which was higher (P < .01) than the glycolytic potential of RFN or RSE pork. Using a glycolytic potential of 180 micromol lactate/g of muscle as suggestive for the presence of the RN gene, four (10%) of the RSE samples were from RN carriers. By the same criterion, the PSE group contained nine (32%) RN gene carriers. These results suggest that the occurrence of RSE quality is not related to the presence of the RN gene.     

Effect of stunning on pork muscle quality]

The following methods of insensitisation were tested for their effects on muscle pork quality: Electrocoma, 75 V, 15 sec; Electrocoma following intensive electrical stimulation and irritation of various parts of the animals's body, using the insensitising forceps; Dart gun insensitisation. Also tested was the action of muscle relaxants on pork quality. Minor deviation from proper practice of electrical insensitisation was found to cause no significant deterioration in cutlet muscle and ham muscle quality. However, intensive irritation immediately before insensitisation caused higher percentages of PSE (16.7 per cent) and DFD (16.7 per cent). Dart gun insensitisation was quite often followed by poorer quality in the form of watery and bright pork (25.0 per cent). This had detrimental consequences for boiled ham processing (higher loss rates). Sensorial assessment of boiled ham obtained from animals in various categories did not reveal any significant discrepancy between the above techniques. When muscle relaxants were used, muscle pork quality of pigs relaxed by means of succicholine dichloride was much better than that in animals to which electrical insensitisation had been applied. Characteristics of such better quality included slower decline in pH over 45 minutes after death and lower drip loss.     

Slaughter value, meat quality, creatine kinase activity and cortisol levels in the blood serum of growing-finishing pigs slaughtered immediately after transport and after a rest period

The experimental materials comprised 44 hybrid [female (Polish Large White x Polish Landrace) x male Duroc] growing-finishing pigs. The animals were randomly divided into two groups: 24 pigs were slaughtered immediately after transport and 20 pigs were slaughtered after a 24-hour rest period in the lairage. The meat content of pork carcasses, carcass dressing percentage, the proximate chemical composition, physicochemical and sensory properties of meat and shear force values were determined. Serum creatine kinase activity and cortisol levels were determined in blood samples collected before transport and during carcass bleeding. Pigs slaughtered immediately after transport, compared with those slaughtered after a 24-hour rest period, were characterized by a higher meat content of the carcass and a higher carcass dressing percentage. Pre-slaughter handling had no effect on pork quality. The incidence of normal-quality meat, partially PSE (pale, soft, exudative) meat and PSE meat was similar in both groups. Chemical analysis showed that the content of dry matter, total protein, fat and minerals in meat was comparable in both groups. As regards the functional properties of the pork, samples from the carcasses of pigs that had rested before slaughter had a higher contribution of the red color component. Meat from pigs slaughtered immediately after transport had more desirable sensory properties. Pre-slaughter resting had a significant effect on those analyzed physiological parameters which were found to be good indicators of pre-slaughter stress. Serum creatine kinase activity and cortisol levels were higher in blood samples collected after transport (during carcass bleeding) than in samples collected before transport, pointing to a strong stress response of animals to pre-slaughter treatment. The decrease in serum cortisol levels in blood samples collected during bleeding from the carcasses of pigs slaughtered after a 24-hour rest period, compared with samples collected from animals slaughtered immediately after transport, suggests that rest before slaughter alleviated stress induced by pre-slaughter handling operations.     

Hemoglobin, hematocrit, lactates and glucose in blood of fattening pigs in the course of slaughering and snout loop fixation

Blood was sampled from fattening pigs fixed with the snout loop in the pen as well as during slaughter after control or container transport. Assays were made of haemoglobin (Hb), haematocrit (Hk), glucose concentration (PG), and lactic acid (MS) in the plasma. The mean values and standard deviations of Hb and Hk were 13.97 +/- 1.14 g/100 ml, 48.36 +/- 3.67 per cent, 15.24 +/- 1.12 g/100 ml, 49.83 +/- 4.04 per cent, 15.32 +/- 1.23 g of 100 ml, and 51.08 +/- 3.73 per cent. The means values of PG were between 51 and 101 mg of 100 ml and those of MS between 8 and 16 mMol/l.     

Behavioural and physiological responses of pigs to being transported for up to 24 hours followed by six hours recovery in lairage

Ninety-six pure-bred Large White pigs weighing 80 to 100 kg were either not transported or transported for eight, 16 or 24 hours, and then either slaughtered immediately on arrival at the abattoir or kept in lairage for six hours before being slaughtered. The pigs travelling for eight, 16 or 24 hours lost 2.2, 2.0 and 4.3 per cent of liveweight, respectively, and the pigs travelling for 24 hours lost 2.6 per cent of hot carcase weight Both liveweight and hot carcase weight recovered during the lairage period although there was a net liveweight loss in comparison with the control animals. Only transport for 24 hours led to losses in carcase weight The concentration of non-esterified fatty acids increased with the time spent travelling. The concentrations of cortisol, creatine phosphokinase and lactate were all low in comparison with the levels found in commercially slaughtered animals. Plasma albumin and protein concentrations indicated that the animals were becoming dehydrated during the longer journeys. The animals lay down for most of the journey and appeared to be asleep. During the period in lairage, the animals transported for eight hours had two distinct periods of feeding and drinking but spent most of the time lying down, but those transported for 16 and 24 hours showed far more eating and drinking activity. All the groups appeared tired, but the urge to eat of the groups transported for 16 hours, and especially 24 hours appeared to be more important. There were behavioural and the physiological differences between the transported groups and the controls. Six hours in lairage with access to food and water allowed most of the physiological parameters to return to pretransport levels.     

Thyroid function in the cat: assessment by the TRH response test and the thyrotrophin stimulation test

Changes in total thyroxine (T4), free T4 and total tri-iodothyronine (T3) were measured in 13 cats after the intravenous injection of varying doses of thyrotrophin stimulating hormone (TSH) (0–5 U/cat n = 6; 1 U/cat n = 8; 1 U/kg bodyweight, n = 7) or thyrotrophin releasing hormone (TRH) (100 ug/cat, n = 10). All three doses of TSH resulted in a significant (P < 0–05) rise in T4, free T4 and T3 levels, with the mean peak in hormone concentrations occurring six to eight hours after injection. The three doses of TSH all appeared to produce maximal stimulation of thyroid hormone secretion. The mean percentage increase in hormone concentrations at seven hours following the three doses of TSH ranged from 167 to 198 per cent for T4, 240 to 365 per cent for free T4, and 73 to 116 per cent for T3. Following administration of TRH there was also a significant (P < 0–05) rise in T4, and free T4. The mean peak in T4 and free T4 levels occurred at four hours, and mean increases in hormone levels at this time were 92 per cent for T4, and 198 per cent for free T4. The administration of TRH produced little change in T3 levels. TSH administration resulted in a significantly higher (P < 0–05) percentage peak increase in T4, free T4 and T3 levels at all three dosages than did TRH.     

Effect of wavelength on spatial measurements of light scattering for the measurement of pork quality.

White light from a xenon arc was focused onto the upper surface of 25-mm-thick transverse sections of pork longissimus muscle. A servo motor moved an optical fiber across the lower surface of the muscle to collect transmitted light, which then was passed through a grating monochromator and onto a photomultiplier for spatial measurements of scattering (SMS) and transmittance spectra. The SMS were calculated as the slope of the logarithm of transmittance relative to path length through the sample (which was calculated trigonometrically). Pale, soft, exudative (PSE) pork was measured with an index that included a subjective evaluation of meat color and objective measurements of reflectance, drip loss, and centrifugation fluid loss. The strongest correlation of SMS with PSE was at 610 nm (r = .86, P less than .005) and the strongest correlation of transmittance with PSE was at 650 nm (r = -.95, P less than .005). This supports the use of a red laser at 633 nm for the detection of PSE pork.     

Investigation of a simplified artificial lighting programme to improve the fertility of sows in commercial piggeries

Two artificial lighting regimens were studied in a commercial unit of 800 sows. The aim was to develop a simplified lighting regimen to overdrive the effects of season on reproduction. A long-day group had a constant 16 hours light and eight hours dark photoperiod in all units during a production cycle. A short-day group had eight hours of light and 16 hours darkness in a farrowing unit for four weeks and in a mating unit for four weeks. After one month of pregnancy the short-day group was transferred to 16 hours light and eight hours dark for the rest of the dry-sow period. Production data were collected for eight months, and the farrowing rate, weaning to oestrus interval, culling rate for fertility problems and the number of live-born piglets were analysed. Seasonal infertility, which had previously affected the herd, was not detected in either group during the follow-up period. The farrowing rate was 90 per cent for both groups. The median weaning to oestrus interval was five days in both lighting regimens with ranges from four to 74 days in the short-day group and three to 55 days in the long-day group. The long-day programme had a positive effect on the weaning to oestrus interval. When the sows were classified as either "normal", with a weaning to oestrus interval of up to 10 days, or "problem" animals, with a weaning to oestrus interval of over 10 days, the short-day programme also had a positive effect. The culling rate for fertility problems was 2.4 per cent for the short-day group and 3.2 per cent for the long-day group (P=0.027). The only significant predictor for the number of live-born piglets was parity (P=0.027).     

Fluid distribution in pork, measured by x-ray diffraction, interference microscopy and centrifugation compared to paleness measured by fiber optics

Moderately PSE (pale, soft, exudative) and moderately DFD (dark, firm, dry) pork was examined by x-ray diffraction for interfilament separation, by differential interference contrast microscopy for interfiber area, and was centrifuged to measure water holding capacity (WHC). Internal reflectance spectra were measured by fiber optics. For PSE to DFD pork, filament separation ranged from 39 to 48 nm, interfiber area from 42 to 3%, and WHC from 49 to 64%, respectively. The correlation of reflectance with interfilament separation varied considerably with wavelength (reaching r = -.83 at 680 nm, P less than .005). The correlation of reflectance with interfiber area was more uniform across the spectrum (reaching r = .90 at 450 nm, P less than .005), as was the correlation of reflectance with WHC (reaching r = -.80 at 400 nm, P less than .005). At 24 h postmortem, fiber-optic spectrophotometry may be used as a rapid, nondestructive method to predict WHC and potential fluid losses from commercial pork with a moderate range from PSE to DFD. Interfiber area was correlated negatively with filament lattice area and WHC, but no significant correlation was found between filament lattice area and WHC. Filament separation was decreased only slightly by centrifugation. These results indicate that at 24 h postmortem the extra fluid released from PSE pork already has been lost from the myofilament lattice and is awaiting release from compartments downstream such as interfiber and interfascicular spaces.     

Optimal lairage times and conditions for slaughter pigs: a review

Keeping pigs in lairage provides a buffer to supply the slaughter line and allows the pigs to recover from the stress of transport. It has implications for the pigs' welfare by influencing their behaviour and ease of handling. In terms of pork quality, optimal lairage times for most pigs in the UK are probably one to three hours. Shorter lairage times are associated with more pale, soft, exudative (PSE) meat and longer times are associated with more dark, firm, dry (DFD) meat, more skin blemishes caused by fighting, and a lower carcase yield. However, when pigs have not been previously stressed by handling procedures, resting them in lairage may have no beneficial effects on the pigs' welfare or meat quality. At very high environmental temperatures there is evidence that a holding period of less than one hour may help to reduce the number of PSE carcases. At temperatures above 10 degrees C showering the pigs with water is beneficial. Fasting times need to be controlled to minimise the potential loss of carcase yield while reducing the volume of gut contents to reduce the risk of carcase contamination. Lairages can act as reservoirs of infection by pathogenic bacteria and there is evidence that longer holding times increase the risk of cross-contamination.     

Effects of misoprostol and omeprazole on basal gastric pH and free acid content in horses

The basal gastric pH and free acid contents from five young adult healthy horses were determined at one hour intervals for eight hours. The basal gastric pH and free acid contents varied from 1.63 +/- 0.06 to 1.97 +/- 0.11 and 26.42 +/- 4.14 to 17.92 +/- 5.28 mmol litre-1, respectively. Misoprostol, a methylester analogue of prostaglandin (5 micrograms kg-1, orally) produced a time-dependent increase in the basal gastric pH to above 3.5 (P less than 0.05) at three, four and five hours after administration with a concomitant reduction of 80 to 90 per cent in the basal gastric free acid contents throughout the eight hour period monitored. Omeprazole, a benzimidazole derivative (0.5 mg kg-1, intravenously) increased the basal gastric pH to above 3.5 at two and three hours after administration with a concomitant reduction of 65 to 90 per cent in the basal gastric free acid contents for seven of the eight hour periods monitored. These results confirm that the horse is a basal acid secretor, and both misoprostol and omeprazole are effective inhibitors of the basal gastric acid secretion, thus establishing that both prostaglandins and H+/K+-ATPase play an important role in controlling parietal cell function of the equine gastric mucosa.     

Effects of periparturient events on subsequent culling and fertility in eight UK dairy herds

The occurrence of five periparturient events and their effects on subsequent culling and fertility was recorded in eight herds in the UK. Combining data from all 2105 calvings, the proportion affected by assisted calving, dead calf, retained fetal membranes (RFM), milk fever or twins was 5.9, 8.2, 5.3, 5.0 or 3.3 per cent, respectively. Compared with unaffected herdmates, cows with an assisted calving or a dead calf had higher early (but not late) culling rates, (assisted calving: 8.8 per cent being culled before 100 days after calving compared with 5.7 per cent; P=0.05; dead calf: 12.2 per cent culled compared with 5.3 per cent; P=0.001). Compared with unaffected animals, cows with milk fever were four times more likely to be culled before 100 days after calving (16.2 per cent compared with 5.3 per cent; P=0.001), whereas those with RFM were twice as likely to be culled between 100 and 200 days (14.3 per cent compared with 7.6 per cent; P=0.003), and both groups were twice as likely to not be pregnant by 200 days. Cows with RFM or milk fever also had markedly reduced subsequent fertility: both conditions extended calving to pregnancy intervals (by 20 days; P=0.001, or by 13 days; P=0.03, respectively), lowered 100-day in-calf rates (by 24.5 per cent; P=0.001, or by 17.8 per cent; P=0.008, respectively) and lowered 200-day in-calf rates (by 20 per cent; P=0.001, or by 15 per cent; P=0.002, respectively). The birth of twins had no effect on subsequent culling or fertility.     

The response of pigs to being loaded or unloaded onto commercial animal transporters using three systems

Groups of pigs were subjected to three different systems of loading and unloading to and from commercial animal transporters. The systems under trial were: the use of a hydraulic tail-lift, a tail board ramp at an angle of 18 degrees and a modular system. The module was a container 2 m x 2.4 m x 1 m high into which the pigs were loaded. The module could then be lifted on and off the lorry with a fork lift truck. Non-invasive monitoring techniques were used to study the responses of the pigs. A subjective handling score, time taken to load and unload, skin temperature, heart rate and salivary cortisol were recorded. Loading and unloading were subjectively assessed as being easiest and quickest using the modular system, which also appeared to be less physically demanding for the animals, as evidenced by lower heart rate and a reduced maximum heart rate. However, with the modular system, elevated cortisol was found during the loading, unloading and resting periods. This could be interpreted as indicating that the pigs were unable to settle in the module and suffered some small degree of stress, which might become more of a problem during prolonged transport. Of the other two systems, there appeared to be little difference between the hydraulic tail-lift and the ramp.     

Herd-specific and age-specific seroprevalence of Neospora caninum in 14 British dairy herds.

All the cattle in 14 dairy herds in England were tested for Neospora caninum-specific antibodies with a commercial ELISA. Three of the herds had had sporadic abortions, eight had had endemic abortions and three had had epidemic abortions associated with N caninum before the study. Of 4295 cattle tested, 17.1 per cent were seropositive and the herd-specific prevalence ranged from 7.3 per cent to 44.8 per cent. No significant effect of either herd size (P = 0.988), endemic (P = 0.869) or epidemic (P = 0.138) patterns of abortion on herd-specific prevalence was found by using logistic regression analysis. There was no evidence in any herd of a significant increase in prevalence with age; the prevalence in seven-to 12-month-old cattle was not significantly different (P > 0.400) from the prevalence in older cattle, except that there was a significantly lower prevalence (P = 0.017) in 13-to 24-month-old cattle. The results of this study are consistent with vertical transmission being the major route of N caninum transmission in these herds.     

Comparison of methods for the sampling and isolation of toxigenic Pasteurella multocida from the nasal cavity of pigs

The efficacy of detecting toxigenic Pasteurella multocida from nasal swabs of slaughtered and live pigs was assessed. The isolation of toxigenic P multocida from nasal cavities of slaughtered bacon pigs from two herds with atrophic rhinitis was reduced by immersion in the hot water tank by 25 per cent and 75 per cent. Individual sows from one of the infected herds were repeatedly swabbed to find the best method of isolating toxigenic P multocida. Toxigenic P multocida were isolated from 50 per cent of cotton swabs inoculated on to selective medium the same day. After 24 hours in the post, 45 per cent of cotton swabs placed in transport medium, 38 per cent of alginate swabs dissolved in transport medium and inoculated into mice, and 36 per cent of the dissolved swabs inoculated directly on to selective medium yielded toxigenic P multocida. These bacteria were isolated from only 25 per cent of cotton swabs held in transport medium at 10 degrees C for 48 hours to simulate prolonged postage times; from slaughtered pigs a similar reduction in isolation was seen with swabs kept for 24 or 48 hours. The reduced isolation caused by a delay before culture was associated with an overgrowth of other flora. The development of this flora was prevented by storage of swabs at 4 degrees C in the laboratory or by the use of cool boxes for postage.     

Improving transport container design to reduce broiler chicken PSE (pale,soft, exudative) meat in Brazil

Throughout the chicken production chain, transport from farm to the commercial abattoir is one of the most critical sources of stress, particularly heat stress. The aim of this work was to describe the performance of a new prototype truck container designed to improve the microenvironment and reduce the incidence of pale, soft and exudative (PSE) meat and dead on arrival (DOA) occurrences. Experiments were carried out for four different conditions: regular and prototype truck, both with and without wetting loaded cages at the farm (for bird thermal stress relief) just before transporting. While there was no difference in the DOA index (P ≥ 0.05), the prototype truck caused a reduction (P < 0.05) in the occurrence of PSE meat by 66.3% and 49.6% with and without wetting, respectively. The results of this experiment clearly revealed a low‐cost solution for transporting chickens that yields better animal welfare conditions and improves meat quality.     

Experimental rapid infection in market swine following exposure to a Salmonella contaminated environment

The objective of these experiments was to evaluate the possibility of swine becoming infected with Salmonella Typhimurium after a short time interval in a contaminated environment. Two experiments were conducted. Experiment 1 consisted of five trials with eight market weight swine. Pigs were necropsied at 2 (n = 10), 3 (n = 10) and 6 (n = 5) hours after continuous exposure to an environment contaminated with feces shed by swine intranasally inoculated with nalidixic acid-resistant Salmonella Typhimurium (chi 4232). In Experiment 2, pigs were necropsied after 30 minutes (n = 6), 60 minutes (n = 6), 2 hours (n = 6), and 6 hours (n = 3). In addition, control animals with no exposure were also necropsied in both experiments. At necropsy, the superficial inguinal, ileocecal, and mandibular lymph nodes, as well as cecal contents, distal ileum portion, and feces were evaluated. All samples were cultured for the presence of the nalidixic acid-resistant Salmonella. Feces deposited on the floor by intranasally inoculated swine were mixed with water to form slurry with a resulting load of 10(3)-10(5) Salmonella Typhimurium CFU per gram. In Experiment 1, 80% percent of animals with a 2-hour, 60% of animals with a 3-hour, and 100% of animals with a 6-hour exposure to this slurry had at least one sample test positive for the marked Salmonella Typhimurium strain. In Experiment 2, 50% of the 30 minute, 50% of the 60 minute, and 33% of the 2-hour exposed pigs had at least one sample test positive. These experiments show that market swine can become infected during routine resting or holding periods when exposed to relatively low levels (10(3) CFU) of Salmonella in the simulated pre-slaughter environment, and that exposure times as short as 30 minutes are sufficient to produce contaminated gastrointestinal tracts. They also demonstrate the high risk of holding pigs longer than six hours. Intervention at this step in the swine production process may have a significant impact on the safety of pork products.     

The Duration of Farrowing in Relation to the Reproductive Performance of Yorkshire Sows

Records for 212 attended farrowings by 38 Yorkshire sows were examined. Eighty per cent of the farrowings were less than six hours, 18 per cent between six and 12 hours and two per cent between 12 and 17 hours duration. There appeared to be no marked relationship between the duration of farrowing and the size of litter.

In spite of a higher stillbirth rate in males, there were more male (52.3 per cent) than female piglets born alive. As the time taken to farrow increased from within 1-3 hours to more than eight hours, the percentage of stillborn piglets and the percentage of litters with stillbirths increased to 10.5 from 2.4 and to 61.1 from 18.2 per cent respectively.

Twenty-nine per cent of the litters were farrowed on the 114th day of gestation. As the gestation period lengthened to 117 days or more, from 113 days or less, there were corresponding increases in the duration of farrowing and the incidence of stillbirths, and a decrease in litter size.

A need to investigate the use of hormones to control parturition in sows was suggested.

     

Studies in epidemiology of maedi/visna in sheep.

Lambs born to ewes from flocks with a high incidence of maedi/visna were separated from their dams at birth (group 1), or after 10 h (group 2), six weeks (group 3) or one year (group 4) and were observed for periods of up to eight years. Group 1 lambs remained free of infection while 28 per cent, 76 per cent and 81 per cent respectively of lambs in the other groups developed clinical, serological or histopathological evidence of infection during the observation period. It is therefore concluded that vertical transmission, if it occurs at all, is of little significance in the epidemiology of the disease. The number of serologically, virologically and histopathologically maedi/visna positive sheep, the time of onset of disease and the severity of lesions were related to the duration of exposure to the parent flock. In a separate trial no evidence was obtained for the transmission of maedi/visna by Muellerius capillaris larvae.