Domestic Piglets Research Articles

Risky behaviour by piglets: a trade off between feeding and risk of mortality by maternal crushing?

Accidental crushing by the sow is a major cause of death among domestic piglets. Piglets risk being crushed if they are underneath the sow as she lies down, but they may benefit from staying close to the sow by improving their access to teats during nursings and by increasing milk production. The prediction was tested that piglets with relatively low weight gains, and thus in greatest need of energy or nutrients, would spend more time in close proximity to the sow and therefore assume a higher mortality risk from crushing. Piglets ( N=138 from 17 litters) were highly variable in birth weight, weight gain, and the amount of time they spent in the risky area underneath a standing or sitting sow. As predicted, piglets that had gained less weight spent more time in this risky area. The relationship held both within and between litters, and was largely because poor-gaining piglets spent more time actively nuzzling the sow's udder, an activity that may increase milk production of a teat.

Haemodynamic effects of arteriovenous and venovenous haemofiltration in piglets.

The aim of this study was to compare the early haemodynamic effects of continuous arteriovenous haemofiltration (CAVH) with those of continuous venovenous haemofiltration (CVVH) in normal and endotoxic piglets, within the framework of a two-period cross-over trial. Sixteen domestic piglets (weight 6-18 kg) underwent 1 h of CAVH followed by 1 h of CVVH or 1 h of CVVH followed by 1 h of CAVH. Six were pre-treated with a graded endotoxin infusion to simulate clinical sepsis. The main measurements included: heart rate; mean arterial (MAP), pulmonary artery, central venous and pulmonary artery occlusion pressures; thermodilution cardiac output; and calculated systemic (SVRI) and pulmonary vascular resistance indexes. Each measurement was performed immediately before and 30 min after commencement of each technique of filtration. Commencement of haemofiltration in normal piglets caused minimal haemodynamic effects. In endotoxic piglets, commencement of filtration, whether CAVH or CVVH, caused a haemodynamic change which was significantly more pronounced in the first filter (SVRI -39%, MAP -32%) than the second filter (SVRI +22%, MAP +0.9%) (SVRI, P=0.01, first filter vs. second) (MAP, P=0.009 first filter vs. second). In conclusion, there were no significant differences between the early haemodynamic effects of CAVH and CVVH in normal or endotoxic piglets. The haemodynamic effects of either technique may become more significant in the presence of sepsis.

Individual differences in suckling and solid food intake by piglets

Domestic piglets' individual differences in the use of solid food in relation to weight and suckling behaviour has been studied. Piglets ( n 115) from 11 litters were kept with their mothers from birth to 9 weeks of age. From week four, the intake of solid food of each individual piglet was measured for one period of 24 h each week. All periods of suckling during a 4 h period were recorded once per week on video. For each such suckling the participation of each piglet in the pre-massage, milk ejection and post-massage phase was noted. The suckling position and consistancy of teat occupation was determined for each piglet. Weekly weights, weekly participation in post-massage and weekly solid food consumption were included in a factor analysis. Consistent individual traits were found in each of these variables. There was a high correlation between a weight factor and a food intake factor, indicating that large pigs consumed more food and also occupied more productive teats. No correlation was observed in the tendency to participate in post massage with weight or food intake. Piglets occupying front teats scored lower on the post-massage factor. Individual piglets thus varied in their early feeding strategies in that some were inclined to engage in energy consuming teat stimulation and some were more inclined to start feeding on solids sooner. However, these behavioural traits did not relate to each other in any systematic manner.

Calling by domestic piglets: reliable signals of need?

Two manipulations were performed on domestic piglets to determine whether differences in calling during periods of separation from the mother can indicate differences in need. In both cases, the aim was to manipulate the piglet's need for the sow's attention. In the first manipulation a ‘thriving’ piglet (i.e. the piglet with the heaviest weight and most rapid weight gain) and a ‘non-thriving’ one (lightest and slowest weight gain) were selected from each of 15 litters. The two piglets were removed from the sow and litter and recorded for 13 min in separate isolated enclosures. For the second manipulation, two piglets of intermediate weight and weight gain were selected from each of the same 15 litters and were removed from the sow during nursing under one of two conditions. The ‘unfed’ piglet was removed just before the milk ejection and the ‘fed’ one just after receiving milk. Both were recorded as in the first manipulation. ‘Non-thriving’ and ‘unfed’ piglets called more and used more high-frequency calls, longer calls, and calls that rose more in frequency than their ‘thriving’ and ‘fed’ litter-mates. By means of a playback experiment, the assumption that sows respond to these piglet calls was tested. Sows were more likely to vocalize and approach the loudspeaker during playback of the piglet isolation calls than during playback of white noise. It is argued that if a piglet's calls provide reliable information about its need for the sow's resources, then this calling can be used as a measure of its welfare. These results are consistent with theoretical models of honst signalling.

A Comparison of Solute Clearance During Continuous Hemofiltration, Hemodiafiltration, and Hemodialysis Using a Polysulfone Hemofilter

The clearance of urea, creatinine, amino acids, vancomycin, and phenytoin was measured in vivo in a small animal model during continuous venovenous (CVV) hemofiltration, CVV hemodiafiltration, and CVV hemodialysis using a 0.25 m2 polysulfone hemofilter. Six domestic piglets (weighing 6-11.8 kg) each received 1 hr of all three techniques in random order. Blood flow was 50 ml/min. During CVV hemofiltration, filtrate production was 500 ml/hr and dialysate flow was zero. During CVV hemodiafiltration, filtrate production was 250 ml/hr and dialysate flow was 250 ml/hr. During CVV hemodialysis, net filtrate production was zero and dialysate flow was 500 ml/hr. The ratio of concentration of solute in filter effluent to concentration in whole plasma was derived for each solute during each of the three techniques. Mean (SD) effluent:plasma ratio for urea during CVV hemofiltration was 0.957 (0.038), CVV hemodiafiltration 0.876 (0.109), and CVV hemodialysis 0.754 (0.123); creatinine 0.942 (0.05), 0.934 (0.056), and 0.814 (0.057); amino acids 0.996 (0.344), 0.904 (0.196), and 0.778 (0.18). For small unbound solutes, there is a decrease in clearance of 6% from CVV hemofiltration to CVV hemodiafiltration and a further decrease of 14% from hemodiafiltration to hemodialysis. The effluent:plasma ratio for vancomycin during CVV hemofiltration was 0.739 (0.082), CVV hemodiafiltration 0.643(0.063), and CVV hemodialysis 0.509 (0.081), corresponding to a decrease of 30% from CVV hemofiltration to CVV hemodialysis. The effluent:plasma ratio for phenytoin was 0.302 (0.028) during CVV hemofiltration and was not significantly different during CVV hemodiafiltration or CVV hemodialysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of a piglet model of status epilepticus: preliminary results.

Ventilation frequently is impaired during prolonged clinical seizures and their treatment. In a pilot study, respiratory, metabolic, and hemodynamic variables were studied during induced seizures in a lightly anesthetized, spontaneously breathing piglet model. Weanling, mixed-breed domestic piglets. Piglets were instrumented with a tracheostomy, arterial catheter, and epidural electrodes. Conditions included hyperoxia, normothermia, and ketamine maintenance infusion throughout recordings. After baseline recordings, 2 mg/kg IV bicuculline was administered. For further model validation, piglets were randomized to infusions of diazepam (three), lorazepam (two), or saline (control; five) groups after ten minutes of untreated seizures. Integrated tidal volume, respiratory rate, PaCO2, pH, arterial pressure, rectal temperature, heart rate, and bipolar EEG waveforms were recorded and compared at intervals for 60 minutes. Vigorous tonic-clonic seizures occurred in all piglets, confirmed by sudden synchronization and large-amplitude EEG waveforms. Increases in heart rate, arterial pressure, tidal volume, respiratory rate, PaCO2, minute ventilation, and base deficit occurred in all piglets during seizures as compared with baseline. Five minutes after bicuculline was administered, increases in minute ventilation (4.5 +/- 0.4 L/min at baseline to 13 +/- 2.1 L/min) were accounted for by increases in both tidal volume and respiratory rate. More abrupt decreases in respiratory rate were observed in anticonvulsant-treated piglets as compared with controls. The duration of continuous seizure activity (12 +/- 1.0 minutes versus 21 +/- 3.3 minutes; P < .05) was reduced in anticonvulsant-treated piglets. Significant increases in ventilation occur during generalized seizures in tracheostomized piglets given bicuculline. Diazepam and lorazepam infusions ameliorate seizure activity and suppress increases in respiratory rate but not minute ventilation as compared with controls. Problems with this model included baseline variability, temperature instability, and that direct respiratory stimulation from the convulsant agent may have occurred.

Sequential analysis of infarcted and normal myocardium in piglets using in vivo gadolinium-enhanced MR images

Gadolinium-enhanced magnetic resonance (MR) imaging was performed before, and 1 and 3 wk after coronary occlusion in domestic piglets. After administration of the contrast agent gadopentetate dimeglumine, two different enhancement patterns within the infarcted region were observed. The first pattern, showing peripheral enhancement of the infarcted region with absence of contrast in the center, was seen at 1 wk after occlusion at 5 min after administration of the contrast agent. The second pattern showed signal enhancement of the center of the infarcted region and was observed at 1 wk after occlusion, 30 min following contrast administration, and at 3 wk after occlusion, both 5 and 30 min following contrast administration. Infarct size and left ventricular (LV) mass by MR imaging, measured 3 wk after infarction, corresponded well with pathologic assessment. LV mass, measured by static and dynamic MR imaging, increased during the period of investigation. It is concluded that gadoliniumenhanced MR imaging clearly identifies infarcted myocardium early and late after coronary occlusion in the piglet. Combined results of infarct size and LV mass can be obtained simultaneously during one imaging procedure.

A Surgical Model for Normotensive Chronic Renal Failure in the Growing Piglet

Studying the effects of chronic uremia in children has been hindered by the lack of a suitable large mammalian animal model with normotensive renal failure. We performed nephrectomy with simultaneous contralateral partial nephrectomy using a stapling device and absorbable staples in 22 domestic piglets. Up to 93% of the total renal mass could be excised by this method. A chronic uremic state was reproducibly developed and correlated with the percentage of renal mass excised. There were no associated postoperative complications with the stapled partial nephrectomy. Pigs with moderate renal failure had a significant decrease in growth compared to those with mild renal failure, which represents the successful development of a normotensive large mammalian animal model that could be used to study the effects of chronic renal failure and hyperfiltration during a state of rapid growth. In addition, this study confirms the successful use of a stapling device to perform partial nephrectomy.

Trypanosome infections in warthogs ( Phacochoerus aethiopicus) in The Gambia

The prevalence of trypanosome infections in warthogs ( Phacochoerus aethiopicus) in The Gambia was found to be 11% of a sample of 62 animals. All isolates were identified as Trypanasoma simiae. Serological evidence indicated a higher level of exposure to T. simiae, but results were inconclusive for the presence of Trypanosoma congolense. The course of T. simiae infection in warthog piglets showed a rapidly rising parasitaemia, with a concomitant fall in packed cell volume, and resulted in a prolonged period of low-level parasitaemia. The same infections killed domestic piglets.

The seeking of novelty and its relation to play

Inquisitive exploration, in which an animal acts so as to initiate a change in its environment rather than responding to a stimulus, was studied in six litters of domestic piglets, Sus scrofa, aged 5–6 weeks. During 16 tests each of 5 min the piglets were allowed to enter two side pens adjacent to their home pen and with either a novel or a familiar object hidden in it. No object had any biological value to the piglets, and in each test a different novel object was used. They were placed in the same side pen over all sessions with each litter, and all litters showed a significant preference for the pen with the novel object in it first. Exploration directed towards the novel objects lasted 2·3–92 times, longer than towards the familiar objects. However, the interest in the novel objects declined rapidly and significantly over the 5 min of each session. During the same time, play, i.e. scampering and sparring, increased significantly. The function of this could be to direct the attention of litter-mates towards the novel stimulus and to make them participate in the exploration. The ability of the piglets to learn to enter first the pen with the novel object and consequently to examine it is considered clear evidence for the presence of inquisitive exploration. Therefore pigs seem to possess a high level of curiosity, and the results underline the need to do away with monotonous environments if the welfare of piglets is to be considered seriously.

Nutritive and nonnutritive sucking and the temporal organization of the suckling behavior of domestic piglets.

Detailed video recordings of the suckling behavior of one piglet from each of four litters were analyzed to determine how the components of piglet suckling behavior are organized in relation to the time of milk ejection and the temporal pattern of grunting by the sow. Early in the suckling episode, most piglets massaged the udder with their snouts, and then changed gradually to sucking the teats with slow mouth movements (1-2/sec). The piglets then had a distinct phase of sucking with rapid mouth movements (4-5/sec) which began suddenly and lasted about 5 to 15 sec. The weight gains of piglets removed at different times showed that piglets consumed milk during the fast sucking but not during the preceding slow sucking, regardless of how much slow sucking had occurred. Three of the four sows showed a characteristic increase in rate of grunting about 20 to 25 sec before fast sucking began. The piglets' change from massaging to slow sucking often coincided with the increase in grunt rate, but the timing of the transition varied greatly. This suggests that the change in grunting is one but not the only cue used by the piglets to time their suckling behavior. During the slow, nonnutritive sucking, mouth movements were highly variable in duration, with occasional short bursts of rapid mouth movements. This contrasted with the more uniform duration of fast sucking movements. Evidently, in piglets, nutritive and nonnutritive sucking differ in both rate and temporal patterning.

Biological effects of biliary shock wave lithotripsy in swine.

Extracorporeal shock waves generated with an electromagnetic lithotriptor of the second generation were administered to the gallbladder or bile ducts of 24 domestic piglets. In six animals, fresh human cholesterol gallstones were implanted into the gallbladder two weeks before shock wave administration. Treatment with 3,000 shock waves resulted in fragmentation of the majority of the gallstones in all six animals. In the other animals, 3,000 shock waves (n = 12) or 6,000 shock waves (n = 6) were directed at the gallbladder or the bile ducts without previous stone implantation. Twelve of all 24 animals were killed immediately after shock wave treatment, the other 12 after one week. Autopsy in all 24 animals revealed no gross traumatic changes; the peritoneal fluid was clear in all 24 animals. Microscopically, acute hemorrhage was found in the gallbladder wall (3/12 animals) or in the portal fissure and right lung base (1/12 animals) in those animals who were killed immediately. After one week, resolving hemorrhage with scar formation was found in the right or left lung base in 2/12 animals.

Playful behaviour of piglets

Domestic piglets living in multi-litter groups with their dams and other pigs in a large, socially and ecologically rich outdoor enclosure were observed, to obtain a quantitative description of the frequencies and sequences of behaviour patterns performed during play. Focal animal sampling was used to collect data on the playful behaviour of 14 male and 21 female piglets from birth to 14 weeks of age. The “play markers” hop, scamper, pivot, toss head, shake object and carry object were used to identify playful behaviour sequences. The variety of different behaviour patterns performed in first order transitions with play markers was highest in the first 6 weeks and declined thereafter with increasing age. Behaviour patterns occurring in transitions with play markers significantly more often than expected included stand, walk, trot, gallop, freeze, shove and circle. The overall frequency of play markers was significantly affected by age, with a peak frequency occurring between 2 and 6 weeks of age. Male and female piglets performed play markers at similar rates. Results are discussed with reference to the welfare of piglets kept in housing systems which limit playful behaviour.

An optimal morphometric method for quantitating wound epithelization

A new, inexpensive method for quantitative evaluation of reepithelization of shallow split thickness wounds in piglets is described. Wounds, 2.2 × 2.2 cm and 0.4 mm depth are inflicted by an electro-keratome knife in domestic piglets. At a specific time after wounding, the wound area is excised and processed for histology. A computer simulation, based on a randomized systematic sectioning of an entire wound, was used to conclude that only eight sections from the 2.2 × 2.2 cm wound are needed for the final evaluation. The results showed that the above method allows for determination of the epithelization magnitude within ± 5% at a 95% confidence limit. It was found that in 15 kg piglets 50% epithelization of the above wounds was achieved in 65 hr; however, there exists a great interindividual variability. The rate of epithelization is age dependent and significantly faster in 7 kg body weight piglets than in those weighing 40 kg. The epithelization rate was the same at both the wound edge and the center of the wound, stressing the importance of hair follicles as a source of epithelization.

Development of some behaviour patterns in piglets under semi-natural conditions

ABSTRACTA study was made of the behavioural development of domestic piglets living in a spacious, ecologically and socially diverse environment. The effects of age and sex of piglet on the frequencies of 30 behaviour patterns over the period from birth to 14 weeks of age were examined through focal animal sampling of 35 piglets from six litters. It was found that the frequencies of lying and standing in contact with other pigs declined significantly with age while walking, wagging the tail, sniffing the ground and the biting of objects increased with age (P &lt; 0·05). Trotting, scampering and circling with other piglets were most frequent between 2 and 6 weeks of age. The frequencies of shaking the head, ‘quacking’, rooting, shovelling, and chewing at, and shoving, other pigs also varied significantly with age. Females wagged their tails more frequently than males whereas males circled, shoved and mounted more frequently than females (P &lt; 0·05). Results are discussed with reference to the behaviour of young pigs kept under intensive housing conditions.

Gastrointestinal food allergy and its role in large domestic animals.

The significance of food allergy as a primary cause for gastrointestinal disturbances in domestic animals, especially calves and piglets, is discussed. The immunological backgrounds and pathogenesis are described in some detail. The clinical and pathological manifestations in animals are related to those in man. Diagnostic possibilities, therapy and prevention, as far as known in animals, are mentioned and, based on human experiences, further extensions are proposed.

Social relationships of piglets in a semi-natural environment

The social relationships of domestic piglets ( Sus scrofa) kept with adult and juvenile pigs in a large outsid enclosure were examined. Focal and scan sampling techniques were used to collect data on five measures of social behaviour: resting, social facilitation, nearest neighbours, butting and sniffing. Cluster analysis indicated that, between birth and 13 weeks of age, piglets had stronger social relationships with littermates than with non-littermates, their dam, other adults or juveniles but social preferences were not found between particular pairs of littermates. Litters were born in separate farrowing nests but nonlittermates came into contact within 15 days of birth. Fostering occurred when two piglets switched dams spontaneously, and these piglets subsequently exhibited stronger relationships with their foster than with their natural littermates. Results are discussed with reference to intensive housing systems and evolutionary pressures.

A comparison of intragastric and intrajejunal feedings in neonatal piglets

Intrajejunal feedings by continuous infusion of nutrients into the proximal jejunum have been advocated for premature and low-birthweight infants. This technique eliminates the risks of gastric distention and aspiration associated with intragastric feedings. However, intrajejunal feedings disregard the normal physiologic responses to gastric feedings and completely bypass the stomach and duodenum, thus eliminating the important contributions to intestinal function of salivary enzymes, pancreatic secretions, and duodenal osmoregulation and absorption. The objective of this investigation is the comparison in neonatal piglets of differences in nutritional status and intestinal absorption between animals administered intrajejunal nutrients with those given intragastric formula. A total of 14 three- to five-day-old 1.5 to 2.5 kg domestic strain piglets were studied for two weeks. Seven animals underwent operative insertion of a jejunostomy tube into the proximal jejunum, while seven animals had a gastrostomy tube inserted. Intravenous antibiotics and fluids were given for two days postoperatively, then Premature Enfamil (24 kcal/oz) was administered continuously through the feeding tube. The animals were maintained on 115 kcal/kg/d for 10 to 14 days with daily measurements of weight, height, length, stool volume, and weekly determinations of electrolytes, blood counts, and fecal fat analysis. Student's unpaired t-test analysis of the data reveals significantly greater weight gain in the gastrostomy animals (2.5% weight gain/d +/- 0.3% v 1.5% +/- 0.3%, P less than 0.05). These animals also had less diarrhea (14% v 71%), and less fat malabsorption (0.15g/48 hr v 0.9g/48 hr).(ABSTRACT TRUNCATED AT 250 WORDS)

Description of collared peccary (Tayassu tajacu) milk composition

AbstractComposition of collared peccary (Tayassu tajacu) milk was described for samples obtained from a group of four captive females maintained on a high quality diet and four wild‐caught females inhabiting semiarid rangelands in southern Texas. The gross composition of peccary and porcine milks are fairly similar, with some differences in mineral composition. Results suggest that bottle formulations developed for domestic swine piglets would provide adequate nutrition for hand‐rearing nursling peccaries.

Investigations on the eliminative behaviour of piglets

To describe eliminative behaviour of domestic piglets, 17 litters were observed from the first until the 15th day of life. The first urination took place 44 min post partum and the first defaecation 187 min post partum. From 4.9 days old, the litter kept the lying area clean. After that day, only 2.7% of all eliminations happened in the lying area. From 8.1 days, the piglets had a special dunging area. A significant difference was recorded between the sexes. The urinating and defaecating postures of domestic and European wild piglets have been described. Some environmental influences on eliminative behaviour were investigated. In the first days of life, light has an influence on the choice of the dunging place. However, the same could not been ascertained for warmth. Straw-bedding was preferred for eliminations to a solid floor. Draught did not have an influence on the choice of the dunging place. With increasing age, the piglets urinated and defaecated more often in the same dunging area as the sow. From 7 days of age, that area was chosen in more than 50% of the cases. A large number of the eliminations took place near the walls of the pen. Males showed this behaviour more often than females. Most eliminations occurred after suckling and before playing; only a few after sleeping and before suckling. Social facilitation in eliminations was observed several times. Defaecation due to excitation happened only in fright and in excitement but not in intraspecific conflicts.