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Effects of two pellet diameters for piglets pre and post weaning on feed intake, BW, and feed-related behaviour were studied in 3 experiments. In experiment 1, 19 litters were provided with pellets of 2 and 12-mm in diameter in a choice-feeding setup from d 4 of lactation onward. From d 4 to 18, piglets preferred the 12-mm diameter pellet over the 2-mm diameter pellet (519 vs. 168 g/pen; P

Two experiments were conducted to develop a simplified dose-response technique to estimate the Lys requirement of individual, meal-fed growing pigs. In Exp. 1, we studied adaptation processes that occur during such a dose-response study in meal-fed pigs, and in Exp. 2, we studied the accuracy of this simplified technique to estimate changes in Lys requirement estimates of pigs following changes in energy intake. In Exp. 1, the effect of the Lys supply strategy on the Lys requirement was assessed in 14 barrows fed an increasing [low to high (LH)] or decreasing [high to low (HL)] total Lys supply, with total Lys levels varying from 0.36 to 1.06 g/MJ DE in 7 equidistant steps of 4 d each. Urinary urea and ammonia excretion and whole body N turnover were measured. In Exp. 2, the accuracy of the dose-response technique to determine a shift in Lys requirement was assessed in 20 barrows fed at either 2.2 [low energy (LE)] or 2.7 [high energy (HE)] times the energy requirements for maintenance, with total Lys supply decreasing from 1.10 to 0.37 g Lys/MJ DE in 9 equidistant steps of 3 d each. In Exp. 1, a lower increment in protein synthesis, breakdown, and whole body N turnover with increasing dietary Lys supply was observed in LH pigs than HL pigs (P

It is recognized that mycotoxins can cause a variety of adverse health effects in animals, including altered gastrointestinal barrier function. It is the aim of the present study to determine whether mycotoxin-contaminated diets can alter the oral bioavailability of the antibiotics doxycycline and paromomycin in pigs, and whether a mycotoxin adsorbing agent included into diets interacts with those antibiotics. Experiments were conducted with pigs utilizing diets that contained blank feed, mycotoxin-contaminated feed (T-2 toxin or deoxynivalenol), mycotoxin-contaminated feed supplemented with a glucomannan mycotoxin binder, or blank feed supplemented with mycotoxin binder. Diets with T-2 toxin and binder or deoxynivalenol and binder induced increased plasma concentrations of doxycycline administered as single bolus in pigs compared to diets containing blank feed. These results suggest that complex interactions may occur between mycotoxins, mycotoxin binders, and antibiotics which could alter antibiotic bioavailability. This could have consequences for animal toxicity, withdrawal time for oral antibiotics, or public health.

This study investigated the effects of different environmental treatments and personality types on aggression at mixing of newly weaned domestic piglets. From birth to weaning, 16 litters were housed with their dams in either barren (B) or larger, substrate-enriched (E) environments. At 15 days old, piglets were classified as 'high' (HR) or low resistant' (LR) in a manual restraint test (backtest), which is thought to identify proactive (HR) and reactive (LR) stress coping strategies that may reflect different personality types. At 30 days old, 128 piglets were weaned, relocated and mixed into 32 pens comprising two HR and two LR unfamiliar pigs, balanced for sex and weaning weight. Eight B and eight E groups changed environmental condition whereas the others remained in the same type of environment. Number and duration of fights. fight outcomes and unilateral fighting were scored for 5 h post-mixing and skin lesions were counted before and 5 h, 1 day and 2 days after mixing. On the day following weaning, fighting and also exploratory and oral manipulative behaviours were measured for 6 h. Generalized Linear Mixed Model analyses suggested interactions between pre-weaning environment, post-weaning environment and personality type. Overall, pre-weaning E pigs had longer fights at weaning and mixing (P=0.01) and fought for longer on the next day (P=0.02) than pre-weaning B pigs, and inflicted more skin lesions (P=0.02). Post-weaning enrichment did not affect fighting at mixing but reduced the time spent fighting the next day (P=0.03). Personality had subtle and environment-dependent effects on fighting, and influenced the "structure" rather than the amount of aggressive behaviour. HR pigs, for instance, bullied (i.e. chased surrendering pigs) more often (P=0.009) and their fighting behaviour was less affected by their relative body weight than that of LR pigs. Post-weaning E pigs showed relatively higher levels of exploratory behaviour (P=0.02) and less oral manipulative behaviour (P=0.04) than post-weaning B pigs. In particular, switching from a good quality environment (E) to a worse quality one (B) at weaning decreased exploratory behaviour on the next day, especially for LR pigs, who also tended to fight with and orally manipulate their pen mates more in that condition, and seemed to be more affected by a deterioration of the environment. Overall, pre-weaning enrichment increased aggression after weaning whereas post-weaning enrichment reduced it, and personality type related to some aspects of fighting behaviour. (C) 2011 Elsevier B.V. All rights reserved.

It has become common practice in pig fattening production systems to castrate young boar piglets without the use of anaesthesia. In this study, we examined whether or not CO2 gas is capable of inducing an acceptable anaesthetic state during which castration can be performed. The first step was to identify the most promising CO2/O2 mixture. Based on the results from this first experiment, a mixture of 70% CO2 + 30% O2 was chosen for further investigation as a potential anaesthetic during the castration of young piglets. Thereby, it was established whether the duration and depth of anaesthesia were acceptable for castration where the animal has to be insensible and unconscious. Physiological effects were assessed based on electroencephalogram (EEG) and electrocardiogram (ECG) measurements, blood gas values and behavioural responses. During the induction phase, the only typical behaviour the piglets exhibited when exposed to the 70/30 gas mixture was heavy breathing. All piglets (n = 25) lost consciousness after approximately 30 s according to the EEG. Heart rate decreased slowly during the induction phase, a serious drop occurred when piglets lost their posture. Immediately after this drop, the heart rate neared zero or showed a very irregular pattern. Shortly after loss of posture, most animals showed a few convulsions. None of the animals showed any reaction to castration in behaviour and/or on the EEG and ECG. On average, the piglets recovered within 59 s, i.e. EEG returned to its pre-induction pattern and piglets were able to regain a standing position. After 120 s, heart rate returned to pre-induction levels. In order to explore the usage range of CO2 concentration, 24 piglets were exposed to 60% CO2 + 20% O2 + 20% N2 for up to 30 s after loss of consciousness (as registered on EEG), and castrated after removal from the chamber. Sixteen of the 24 animals showed a reaction to the castration on the EEG. To establish the maximum time piglets survive in 70% CO2 + 30% O2, five piglets were placed in this mixture for 3 min. Two of them died. After that, four piglets were placed in this mixture for 2 min after unconsciousness, one died after 2 min. It was concluded from this study that it is possible to anaesthetise piglets with a mixture of 70% CO2 + 30% O2, but that there are limits to its safety in terms of CO2 concentration and duration of exposure. Before implementation for practical use, further research is essential to assess the limits of gas concentration and exposure times.

The objective of the study was to estimate Leu requirement for weaned piglets to balance indispensable AA in reduced CP diets. A dose-response experiment was conducted to estimate the standardized ileal digestible (SID) Leu to Lys ratio required for the maximum growth of young pigs after weaning. In this study, 96 female pigs (initial BW of 8 kg) were allotted to 1 of 6 dietary treatments with 16 individually penned pigs per treatment. Graded levels of crystalline l-Leu were added to a basal diet to provide diets containing 0.70, 0.80, 0.90, 1.00, 1.10, and 1.20 SID Leu: Lys. Lysine was limiting and fulfilled 90% of the current recommendations. The ADFI, ADG, and G: F were determined during a 2 wk experimental period. Blood and urine samples were taken at the end of each wk. The ADFI increased linearly (P

An experiment with 224 weaner pigs (initial BW of 7.8 kg) was conducted to determine the effect of dose of dietary phytase supplementation on apparent fecal digestibility of minerals (P, Ca, Mg, Na, K, and Cu) and on performance. Four blocks, each with 8 pens of 7 pigs, were formed. Eight dietary treatments were applied to each block in the 43-d experiment: supplementation of 0 (basal diet), 100, 250, 500, 750, 1,500, or 15,000 phytase units (FTU) or of 1.5 g of digestible P (dP; monocalcium phosphate; positive control) per kilogram of feed. The basal diet, with corn, barley, soybean meal, and sunflower seed meal as the main components, contained 1.2 g of dP per kilogram of feed. Fresh fecal grab samples were collected in wk 4 and 5 of the experiment. Average daily feed intake, ADG, G:F, and digestibility of all of the minerals increased (P

Two metabolism experiments were carried out, to determine the effect of microbial phytase addition to barley-canola meal and barley-soybean meal diets on P and Ca balance in growing. pigs; In experiment 1, six barrows (29.6kg: initial LW) were fed a barley-canola meal diet, without or. with phytase (500 units.kg(-1) ring 24 days, according to a crossover design. The diet provided suboptimal levels. of P. In experiment 2, twelve barrows (53.4kg initial LW) were fed four barley-soybean meal diets, according to a two-period changeover design; Diet 1 was supplemented with inorganic P and Ca to meet requirements,. diets, 2, 3 and 4 contained suboptimal levels of P, diet 3 being supplemented with phytase; diet 4 was supplemented with both phytase and a mixture of xylanase and beta-glucanase. The supplementation of phytase to the barley-canola meal and the barley-soybean meal diets increased (P0.05) values far P retention and P and Ca digestibilities as for diets 1 and 3. In conclusion; phytase supplementation to the barley-canola meal and barley-soybean meal diets improved the utilization of P and digestibility of Ca; but no further effect was observed with the supplementation with the mixture of xylanase and beta-glucanase.

Mixing of unfamiliar pigs is common practice in intensive pig husbandry. Since pigs maintain a dominance hierarchy, mixing often leads to vigorous fighting. Apart from the negative impact that fighting has on welfare, there is evidence that the social stress associated with fighting suppresses immune function. In the present experiment, we investigated the impact of mixing on specific long-term immune responses and protection against challenge infection after vaccination with pseudorabies virus (PRV). Specific pathogen-free (SPF) pigs were mixed pairwise with an unfamiliar same-gender conspecific or left undisturbed with a same-gender littermate at 3 days after vaccination with PRV. Half of the pigs were females (gilts) and half were castrated males (barrows). Mixing increased agonistic behavior to the same degree in gilts and barrows. Cortisol concentrations in saliva and catecholamine excretion in urine were increased in mixed pigs, and these effects were independent of dominance status and gender. Subsequently, the effects of mixing, gender, dominance status and interactions between these factors on immune response parameters were studied. The main result was that mixed barrows showed suppressed immune responses after vaccination and increased clinical symptoms after challenge infection compared to control barrows. Mixed gilts however did not differ from control gilts. It also appeared that mixed dominants were more seriously affected than mixed subordinates were. We conclude that, in some pigs, social stress after mixing suppresses the immune response to a viral vaccine and consequently impairs protection against challenge infection. (C) 2001 Elsevier Science Inc. All rights reserved.

Endocrine, behavioural and immunologic processes, together with body growth, were evaluated in gilts that were defeated at 10 weeks of age in resident-intruder tests. Immediately after defeat, gilts were either separated from or reunited with a familiar conspecific (litter-mate; always a barrow). Gilts were assigned to one of four treatments: (a) DI: defeat, followed by isolation (separation from original litter-mate; n = 8); (b) I: no defeat, isolation (control group; n = 9); (c) DP; defeat, followed by pair-housing (reunion with original litter-mate; n = 8); and (d) P: no defeat, pair-housing (control group; n = 8). The following general conclusions were derived: (1) social defeat caused pronounced short-term elevations in hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal medullary activities, and of prolactin levels. Moreover, as soon as Ih after defeat, percentages of blued lymphocytes and neutrophilic granulocytes were, respectively, decreased and increased; (2) social defeat had some long-lasting influence on behaviour and physiology, but isolation predominantly determined responses in the longer term. Defeat, as well as isolation, resulted in increased cardiovascular activities compared to P controls, as observed in a novel object test (NOT: +7 days) and an aversion test (AVT: + 14 days). Moreover, defeated as well as isolated gilts did not habituate to a repeated novel environment test (NET: -7, +2 and +7 days) in terms of frequencies of vocalising, whereas P controls did. Isolation, through the separation from any other pig, was responsible for the other observed long-term characteristics. which developed progressively. Isolated gilts showed high mobilities and high cortisol responses in the repeated NET (+7 days), not being habituated. This contrasted the reactions of pair-housed gilts, which were much reduced. In addition to their high cardiovascular activities in the NOT and the AVT, isolated gilts also displayed higher heart rates in the repeated NET and during human presence following the NOT, compared to pair-housed gilts. Finally, isolated gilts were more inhibited to approach a novel object (in the NOT) than pair-housed pigs; and (3) stress responses of defeated gilts were modulated by the subsequent social environment. Stimulation of the HPA-axis (plasma- and salivary cortisol) was prolonged in those defeated gilts which were isolated (observed in the first hour). Changes in leucocyte subsets were still observed after 3 days in DI, but were 'normalised' within 1 day in DP gilts. Two days after defeat, habituation to the repeated NET in terms of mobility and salivary cortisol responses occurred in control and DP gilts, but not in DI gilts. We argue that these effects of the social environment shortly after defeat were related to a stress-reducing effect of a stable social relationship, i.e. social support. (C) 2001 Elsevier Science B.V. All rights reserved.

Effects of two pellet diameters for piglets pre and post weaning on feed intake, BW, and feed-related behaviour were studied in 3 experiments. In experiment 1, 19 litters were provided with pellets of 2 and 12-mm in diameter in a choice-feeding setup from d 4 of lactation onward. From d 4 to 18, piglets preferred the 12-mm diameter pellet over the 2-mm diameter pellet (519 vs. 168 g/pen; P

Two experiments were conducted to develop a simplified dose-response technique to estimate the Lys requirement of individual, meal-fed growing pigs. In Exp. 1, we studied adaptation processes that occur during such a dose-response study in meal-fed pigs, and in Exp. 2, we studied the accuracy of this simplified technique to estimate changes in Lys requirement estimates of pigs following changes in energy intake. In Exp. 1, the effect of the Lys supply strategy on the Lys requirement was assessed in 14 barrows fed an increasing [low to high (LH)] or decreasing [high to low (HL)] total Lys supply, with total Lys levels varying from 0.36 to 1.06 g/MJ DE in 7 equidistant steps of 4 d each. Urinary urea and ammonia excretion and whole body N turnover were measured. In Exp. 2, the accuracy of the dose-response technique to determine a shift in Lys requirement was assessed in 20 barrows fed at either 2.2 [low energy (LE)] or 2.7 [high energy (HE)] times the energy requirements for maintenance, with total Lys supply decreasing from 1.10 to 0.37 g Lys/MJ DE in 9 equidistant steps of 3 d each. In Exp. 1, a lower increment in protein synthesis, breakdown, and whole body N turnover with increasing dietary Lys supply was observed in LH pigs than HL pigs (P

The present study addresses the questions whether on-farm use of local anaesthesia with lidocaine leads to a reduction in pain responses during castration, and whether the non-steroidal anti-inflammatory drug meloxicam improves technical performance after castration of piglets. Five treatments were included in the study: (1) castration without anaesthesia or analgesia (CAST), (2) castration after local anaesthesia with lidocaine (LIDO), (3) castration after administration of meloxicam (MELO), (4) castration after lidocaine and meloxicam (L + M) and (5) sham castration (SHAM). To reduce litter influences, each treatment was present in each of the 32 litters (n = 32 per treatment). During castration, vocalizations were recorded continuously. Blood samples were collected 15 min before and 20 min after castration for determination of plasma levels of total cortisol, glucose, lactate and creatine kinase (CK). Mortality was registered and piglets were weighed several times to calculate growth. Several aspects of vocalizations during castration showed consistent and significantly different levels in CAST compared with LIDO, L + M and SHAM. CAST piglets squealed longer, louder and higher. Vocalizations of MELO piglets most resembled those of CAST. An increase in cortisol was seen in all treatments. However, in SHAM piglets this increase was significantly lower than in the other treatments. LIDO piglets showed a significantly smaller increase in plasma cortisol levels compared with CAST and MELO. L + M piglets differed significantly only from the SHAM group. Lactate levels differed significantly between LIDO and MELO, the level in LIDO being decreased after castration. In the other treatments an increase was measured. No treatment effects were found in plasma glucose and CK levels, nor in growth and mortality of the piglets. In conclusion, on the basis of vocalizations and plasma cortisol, local anaesthesia with lidocaine reduces pain responses in piglets during castration. A positive effect of meloxicam on technical performance was not found.

Stress occurs in intensive pig farming when piglets are weaned and mixed. In this study, we investigated whether this stress might be reduced with elevated dietary levels of Trp. The effects of supplemental dietary Trp (5 g/kg of feed, as-fed basis) were tested on the neuroendocrine system, intestinal integrity, behavior, and growth performance in nursery pigs, both before and after mixing. Mixing occurred 5 d after weaning and diet introduction. On d 4, 5, and 6, Trp-fed pigs vs. control pigs showed approximately a 2-fold elevation in plasma Trp concentrations (68 ± 7 vs. 32 ± 2 µmol/L; P 0.10). In conclusion, supplemental dietary Trp (5 g/kg) to piglets increased hypothalamic serotonergic activity, reduced the salivary cortisol response to mixing, improved intestinal morphology, and reduced physical activity 10 d after diet introduction. Consequently, diets containing high Trp levels improved neuroendocrine components of stress and increased gastrointestinal robustness but did not affect behavioral reactivity in nursery pigs during weaning and mixing.

An experiment with 224 weaner pigs (initial BW of 7.8 kg) was conducted to determine the effect of dose of dietary phytase supplementation on apparent fecal digestibility of minerals (P, Ca, Mg, Na, K, and Cu) and on performance. Four blocks, each with 8 pens of 7 pigs, were formed. Eight dietary treatments were applied to each block in the 43-d experiment: supplementation of 0 (basal diet), 100, 250, 500, 750, 1,500, or 15,000 phytase units (FTU) or of 1.5 g of digestible P (dP; monocalcium phosphate; positive control) per kilogram of feed. The basal diet, with corn, barley, soybean meal, and sunflower seed meal as the main components, contained 1.2 g of dP per kilogram of feed. Fresh fecal grab samples were collected in wk 4 and 5 of the experiment. Average daily feed intake, ADG, G:F, and digestibility of all of the minerals increased (P

Individual pigs, Sus scrofa, differ considerably in how aggressive they are during encounters with unfamiliar conspecifics. We examined whether individual coping characteristics of pigs were predictive of aggression during social encounters and the resulting social status. Piglets were subjected to the Backtest during the suckling period, as their behavioural response in this test seems to be predictive of their coping style. Each piglet was restrained in a supine position for 1 min and the resistance (i.e. number of escape attempts) was scored. After weaning, 30 `high-resisting¿ (HR) and 30 `low-resisting¿ (LR) pigs were regrouped with unfamiliar pigs of similar weight and we recorded their aggressive behaviour for 180 min. In addition, we assessed the social rank of each pig. HR pigs showed more aggressive behaviour than LR pigs: they initiated more fights, started fighting earlier and spent more time fighting during the observation period. HR and LR pigs did not differ, however, in achieved social rank. Level of self-initiated fighting was positively correlated with social rank in LR pigs, but this relation was not found in HR pigs. In conclusion, the coping style of pigs is related to their aggressive behaviour and the establishment of dominance relationships after mixing. Our results indicate that LR pigs are flexible in using aggression, whereas the high level of aggression of HR pigs regardless of their success in encounters suggests that these animals are more rigid in their aggressive behaviour.

Phosphorus in most diets for breeding sows is digested from 20% to 40%, thus leading to a relatively high amount of P in the manure. To enhance the P digestibility in diets for both lactating and gestating sows, two separate experiments were carried out to study the efficacy of phytase derived from Peniophora lycii. Thirty crossbred lactating sows and 24 gestating sows were used in the studies. Five treatments were imposed on the lactating sows: (1) the negative control, a low-P diet without added feed phosphate and microbial phytase. Treatments 2, 3 and 4 were the same as the negative control diet, except that an amount of 750, 1000 and 10,000 U of phytase kg−1 of diet, respectively, was added. Treatment 5 was the positive control diet, being treatment 1 with 1.5 g of digestible P added kg−1 of diet from monocalcium phosphate. The gestating sows received the same first three treatments and a positive control diet supplemented with 1.0 g of digestible P kg−1. The negative control diets were different in feedstuff composition. The ratio between Ca and digestible P was kept constant at 2.9:1 and 3.3:1 for the lactating and gestating diets, respectively. Feeding level of the sows was according to Dutch recommendations. Six sows per treatment were used. The lactating sows received the diets from 2 weeks before farrowing until weaning of piglets at 4 weeks of lactation and the gestating sows from day 49 to day 100 of pregnancy. Sampling of the faeces of the sows was done by rectal stimulation, and carried out at days 15 and 21 post-farrowing, and at days 70 and 99 of pregnancy. Digestibility coefficients of dry matter (DM), organic matter (OM), ash and the minerals under investigation were calculated using Cr2O3 as an indigestible marker. In addition, several performance characteristics were observed. Phosphorus digestibility was clearly enhanced by the addition of microbial phytase to the sow diets, as was the digestibility of ash, Ca, Mg, Na, K, Cu and Zn. There was a positive relationship between dose of phytase and the amount of liberated digestible phosphorus in lactating sows. The difference in liberated amount of digestible P between 1000 and 10,000 U kg−1 was 0.34 g/kg of lactating diet. An amount of 0.77 and 0.42 g digestible P kg−1 was liberated by 750 U/kg in the lactation and gestating diets, respectively. No signs of any adverse effect of phytase was observed on sow or piglet health and performance, even at a dose of 10,000 U kg−1. The performance of piglets and sows at 10,000 U phytase kg−1 was comparable to or better than the positive control diet. If feed phosphates are (partly) replaced by 750 U phytase kg−1 of diet, then P excretion can be reduced by 0.75–0.90 kg per breeding sow per year.

Two metabolism experiments were carried out, to determine the effect of microbial phytase addition to barley-canola meal and barley-soybean meal diets on P and Ca balance in growing. pigs; In experiment 1, six barrows (29.6kg: initial LW) were fed a barley-canola meal diet, without or. with phytase (500 units.kg(-1) ring 24 days, according to a crossover design. The diet provided suboptimal levels. of P. In experiment 2, twelve barrows (53.4kg initial LW) were fed four barley-soybean meal diets, according to a two-period changeover design; Diet 1 was supplemented with inorganic P and Ca to meet requirements,. diets, 2, 3 and 4 contained suboptimal levels of P, diet 3 being supplemented with phytase; diet 4 was supplemented with both phytase and a mixture of xylanase and beta-glucanase. The supplementation of phytase to the barley-canola meal and the barley-soybean meal diets increased (P0.05) values far P retention and P and Ca digestibilities as for diets 1 and 3. In conclusion; phytase supplementation to the barley-canola meal and barley-soybean meal diets improved the utilization of P and digestibility of Ca; but no further effect was observed with the supplementation with the mixture of xylanase and beta-glucanase.