Pen Mates Research Articles

Effects of grow-finish group size on stress responses at loading and unloading and the effect on transport losses from market-weight pigs

<h2>ABSTRACT</h2> The objective of this study was to determine the effects of grow-finish group sizes on stress response and transport losses from the market-weight pig. A total of 4,522 pigs (122.0 ± 10.6 kg; n=26 trailer loads of pigs) were used in a randomized complete block design. In the grow-finish barn, the small group size (SG) treatment had 36 pigs per pen, whereas the large group size (LG) treatment had 324 pigs per pen. Floor space and feeder space were standardized across treatments. Market-weight pigs were sorted from pen mates at loading and mixed with unfamiliar pigs during transport. Treatments were assigned to trailer decks in an alternating manner. Loading time, physical signs of stress, and transport losses were monitored by treatment. Loading time was analyzed using mixed model procedures, and stress responses were analyzed using generalized linear mixed model methodology. Loading time differed (P < 0.01) between treatments, with LG taking longer to load than SG. The SG size had lower incidences of (P < 0.01) open-mouth breathing and skin discoloration during loading, but there were no differences (P < 0.05) in incidence of muscle tremors or nonambulatory pigs at loading. At the slaughter facility, LG had a lower incidence of skin discoloration (P < 0.01); however, there were no differences (P > 0.05) for open-mouth breathing or muscle tremors. There were no differences for dead on arrival, nonambulatory pigs, or total losses. In summary, group size does not appear to affect the incidence of transport losses.

Peat as environmental enrichment for piglets: The effect on behaviour, skin lesions and production results

The aim of this study was to examine whether the provision of small amounts of peat to piglets would influence behaviour and production. At approximately 5 days of age, nine litters received a tray of peat as enrichment, while nine others did not. All piglets had access to solid feed, which was used to compare substrate-directed behaviour. Piglets were weaned at week 4, and half of the pens in the nursery again received peat. The other half did not. This resulted in the following experimental design: peat/peat (PP), peat/no peat (PN), no peat/peat (NP) and no peat/no peat (NN). Each pen was observed for 4 × 1 min in the morning and also in the afternoon. During every minute the behaviour of each piglet was recorded continuously. The main behavioural categories were: foraging, exploration, playing, locomotion, resting, sleeping, biting and fighting. At 9 weeks of age the pigs were moved to the fattening unit, where no peat was provided. However, observations continued until the pigs reached slaughter age, i.e. until about week 24. Production results (weight, weight gain) and skin lesions were recorded from start to end. Piglets with access to peat performed foraging behaviour significantly more often than piglets without peat ( P < 0.0001). After weaning, the results suggested a greater influence of present enrichment than previous experience in the farrowing pen. NP and PP piglets showed significantly less manipulation of pen mates ( P < 0.005), less fighting ( P < 0.001) and less inactivity ( P < 0.0001). No effect on fighting or manipulation of pen mates was found in the fattening phase. Sleeping was observed more in the NP and PP groups ( P < 0.05). Lying was seen less in the NN group than in the other treatment groups ( P < 0.0001). No treatment effect was found on the frequency and severity of skin lesions. Weaning weight of P piglets did not differ from that of the control piglets (N). At the end of the weaning phase, PP piglets had a higher weight than NN piglets ( P < 0.05). PP piglets also had a higher weight gain during weaning than NN and NP piglets ( P < 0.05). The results suggest that providing small amounts of peat to suckling and weaner pigs could be an effective enrichment strategy to increase explorative behaviour and possibly reduce aggression time post weaning. It also had a beneficial effect on weight and weight gain of piglets. The removal of the peat during fattening led to more inactive behaviour, and differences in aggressive behaviour were no longer significant. Hence, a long term effect of peat supply was not observed.

Differences in the Spacing Behaviour of Two Breeds of Domestic Sheep (Ovis aries) - Influence of Artificial Selection?

The aim of this experiment was to investigate differences in spacing behaviour, measured by the individual distance when resting and feeding, between two breeds of sheep with a different selection history. Eight groups of four pregnant ewes from the Nor-X breed (a heavy, composite breed mainly selected for growth and meat quality) and eight groups of four pregnant ewes of the coloured Spael breed (a light breed, mainly selected for wool quality) were placed in oblong experimental pens for 7 days. The distance between animals was measured from digital video recordings. The heavy Nor-X ewes kept a significantly larger individual distance to their pen mates when resting but not when feeding compared to the lighter Spael ewes. Spael ewes also kept a significantly smaller individual distance during resting than during feeding, but this difference was not found in Nor-X ewes. Our results indicate that selection for growth and meat quality might influence spacing behaviour in sheep. Looking at the selection history of these two breeds we discovered differences in how long they had coexisted with large carnivores. The possible effects of previous exposure to carnivores and the role of domestication in modifying spacing behaviour are also discussed.

Effects of previous housing system on agonistic behaviors of growing pigs at mixing

Previous studies indicated that rearing environment in early life affects behavioral development, which consequently modifies behavioral response of pigs to stressful environments in later stages of the production. A study was conducted to investigate effects of group-farrowing system on behavior of growing pigs at mixing. A total of 216 pigs at 8 weeks of age from one farrowing batch were used, with equal number of pigs that were born and reared in a group-farrowing system and in a confinement system. In the group-farrowing system, pigs were farrowed in bedded individual pens, and mingled into a group of eight litters at about 10 days of age. Pigs were weaned at 5 weeks, and remained in groups of 81 (±2.6) in the group-farrowing barn until 8 weeks of age. In the confinement system, pigs were born in farrowing crates, mixed and moved to pens of nine pigs in a confinement nursery at weaning (5 weeks of age). At 8 weeks of age, all pigs were allocated into 24 pens of nine pigs in a confinement grow-finish barn, with 12 pens from each previous housing system. The familiarity among pigs within a pen was maintained the same between the two housing systems. Aggressive interactions among pigs in six pens of each housing system were video-recorded for 24 h immediately after mixing. The videos were viewed continuously to register all fighting events. The total duration and the frequency of fighting, fighting among familiar and unfamiliar pigs, and fighting occurring at feeders, the drinker, and in the open area of the pen were registered. Data were analyzed by using the Glimmix procedure of the SAS with pen as the experimental unit. The total duration (19 versus 120 s/h, P = 0.001) and the frequency (1.5 versus 3.8 fights/h, P = 0.002) of fighting was less among pigs originated from the group-farrowing system, compared with pigs from the confinement system during the 24 h period after mixing. The majority of fighting was observed in the open area and at feeders, with pigs reared in the group-farrowing system fighting less than pigs reared in the confinement systems in these locations. Only 5% of total fighting time occurred among familiar pigs, regardless of previous housing system. These results suggest that pigs reared in the group-farrowing system maintained the ability to discriminate between pen mates and non-pen mates, and were more tolerant of unfamiliar pigs when mixed in small groups compared to pigs reared in the confinement system.

Autonomic reactions indicating positive affect during acoustic reward learning in domestic pigs

Cognitive processes, such as stimulus appraisal, are important in generating emotional states and successful coping with cognitive challenges is thought to induce positive emotions. We investigated learning behaviour and autonomic reactions, including heart rate (HR) and its variability (standard deviation (SDNN) and root mean square of successive differences (RMSSD) of a time series of interbeat intervals). Twenty-four domestic pigs, Sus scrofa, housed in six groups of four, were confronted with a cognitive challenge integrated into their familiar housing environment. Pigs were rewarded with food after they mastered the discrimination of an individual acoustic signal followed by an operant task. All pigs quickly learned the tasks, while baseline SDNN and RMSSD increased significantly throughout the experiment. In reaction to the signals, pigs showed a sudden increase in HR, SDNN and RMSSD, and a decrease in the RMSSD/SDNN ratio. Immediately after this reaction, the HR and SDNN decreased, and the RMSSD/SDNN ratio increased. During feeding, the HR and the RMSSD/SDNN ratio stayed elevated. The pigs showed no cardiac reaction to the sound signals for other pigs or their feeding pen mates. We concluded that the level of cognitive challenge was adequate and that the observed changes in the autonomic tone, which are related to different dimensions of the affective response (e.g. arousal and valence), indicated arousal and positive affective appraisal by the pigs. These findings provide valuable insight into the assessment of positive emotions in animals and support the use of an adequate cognitive enrichment to improve animal welfare.

Effects of Presorting on Stress Responses at Loading and Unloading and the Impact on Transport Losses from Market-Weight Pigs

The objective of this study was to determine the effects of presorting before loading on stress responses and transport losses at the slaughter facility in the market-weight pig. A total of 5,802 pigs (n = 33 loads) were used in a randomized complete block design with 2 treatments. The presorted (PRE) and not presorted (NON) treatments each had 292 pigs/pen (0.65 m2/pig). For the PRE treatment, internal swing gates were used to presort pigs manually 18 h before loading, whereas pigs in the NON treatment were sorted from pen mates at the time of marketing. Treatments were assigned to trailer decks in an alternating manner. Data were analyzed using generalized linear mixed model methodology, and loading time was analyzed using mixed model procedures. Loading time differed (P 0.05) different. There were no (P > 0.05) differences between treatments for total losses at the slaughter facility. Two pigs in the PRE treatment and zero pigs in the NON treatment were classified as dead on arrival. In conclusion, presorting market-weight pigs reduced loading time and some stress responses on farm; however, no treatment differences were observed for stress responses or transport losses at the slaughter facility.

Cryptosporidium andersoniin Western Australian feedlot cattle

Cryptosporidium andersoni has not been previously reported in feedlot beef cattle in Western Australia. Faecal samples were collected from 10 groups of cattle ranging in age from 11 to 36 months in five different feedlots in Western Australia. The incidence of C. andersoni ranged from 0% to 26%. There were no clinical signs associated with C. andersoni infection, but there was a significant reduction in rate of gain of 0.44 kg in infected animals compared with negative pen mates. Cryptosporidium andersoni is characterised by large oocysts (7.4 x 5.5 μm) and was confirmed by 18S sequencing.

The behaviour of male fattening pigs following either surgical castration or vaccination with a GnRF vaccine

Vaccination of male fattening pigs with a gonadotropin releasing factor (GnRF) vaccine is regarded as a possible solution to solve the welfare problem associated with surgical castration, which causes pain and stress even when performed under local or general anaesthesia. The objective of the present study was to compare the behaviour of male fattening pigs either surgically castrated without anaesthesia (T1) or vaccinated twice with a GnRF vaccine (T2). Data collection took place in a commercial German fattening unit. Each treatment comprised 8 groups of 12 pigs, housed in fattening pens with partially slatted floor and liquid feed provided three times a day. Data on postures were scored from 24-h videos recorded in every week of the fattening period (16 weeks) using scan sampling with 5 min intervals. Social behaviour was analysed in weeks 2, 4, 6, 8, 10, 12, 14, 15 and 16 by continuous behaviour recording of focus animals in four blocks of 2 h phased evenly during the day. Overall, during the whole fattening period, vaccinates (T2) were more active than surgical castrates (T1), indicated by a higher proportion of pigs standing (T1: 9.3%; T2: 10.74%; P < 0.023). T2 animals showed a significant decrease in standing and an increase of sitting and lying after the second vaccination of Improvac. No significant effects of treatment on the total number of agonistic interactions ( P = 0.064) and on biting and fighting ( P = 0.151) were found. In T2 the prevalence of aggressive behaviours decreased after the second vaccination ( P < 0.001), which was not found in T1 during the same period. T2 animals showed a higher level of mounting behaviour compared with T1 animals, but on a very low level. Treatment had no effect on the prevalence of play behaviour and manipulating of pen mates. It is concluded that housing of male pigs vaccinated against GnRF in single sex groups of 12 individuals does not increase behavioural problems in the fattening period compared with surgically castrated males.

Effects of fermentable starch on behaviour of growing pigs in barren or enriched housing

Fermentation of resistant starch might prolong satiety, and, therefore, positively affect behaviour and welfare of restrictedly-fed pigs. The impact of a potentially satiating diet likely depends on housing conditions, such as the availability of rooting material which may serve as a substrate for foraging behaviour. We investigated effects of resistant starch on behaviour of growing pigs in barren housing (B) or on straw bedding (S) in a 2 × 2 factorial arrangement. Thirty-two groups of eight pigs (approximately 25 kg) were assigned to either B- or S-housing, and to native, resistant (NS) or highly digestible pregelatinised starch (PS) in the diet. Pigs were fed at 2.5 times energy requirements for maintenance in two daily meals. Behaviour was recorded in week 3 for five 1-h periods using 2-min instantaneous scan sampling. On day 23, six pigs per group were relocated to respiration chambers. Activity over the 24-h cycle was scored in week 5 using 9-min instantaneous scan sampling. S-housed pigs on the PS-diet were more active over the 24-h cycle than S-housed pigs on the NS-diet, whereas effects of starch type on activity patterns were less obvious in B-housing (starch type × housing interaction, P = 0.05). In the morning, when fresh straw was supplied, behaviour was strongly affected by housing, whereas effects of dietary starch were most obvious around the second, afternoon, meal. S-housed pigs were more active, showed more exploration and less oral manipulation of pen mates and fixtures than B-housed pigs. The PS-diet resulted in more aggression over the day than the NS-diet in B-housed pigs, whereas levels of aggression were similar for S-housed pigs on both diets (starch type × housing interaction, P < 0.10). Before their second meal, NS-fed pigs showed less locomotion, aggression ( P < 0.05) and manipulation of pen mates ( P < 0.10) than PS-fed pigs, which likely reflects reduced restlessness due to enhanced inter-meal satiety in the NS-fed pigs. After the afternoon meal, NS-fed pigs showed less activity, exploration and manipulation of pen fixtures ( P < 0.05) than PS-fed pigs. In conclusion, dietary resistant starch affected behaviour patterns of restrictedly-fed growing pigs. The decreased activity and reduced preprandial restlessness suggest that fermentable starch enhances interprandial satiety in pigs, and therefore may improve their welfare. Even though effects of resistant starch on activity levels were more obvious in enriched housing, the welfare benefits of fermentable starch may be more pronounced in barren housed pigs as these animals lack an outlet for their increased foraging motivation.

The effect of type of rooting material and space allowance on exploration and abnormal behaviour in growing pigs

The experiment aimed to investigate the effect of type of rooting material and space allowance on explorative and abnormal behaviour in growing pigs. Thirty-six pens with partly slatted concrete floor were allocated to one of four treatments: (1) low space allowance and maize silage as rooting material, (2) high space allowance and maize silage as rooting material, (3) low space allowance and straw as rooting material, and (4) high space allowance and straw as rooting material. Pens with low space allowance had 17 pigs (0.64 m 2/pig), while pens with high space allowance had 11 pigs (1.0 m 2/pig). Behaviour was recorded by instantaneous sampling during 1 h before and 1 h after the daily allocation of rooting material at 10.00 h, as well as during 1 h in the afternoon starting at 13.00 h. Observations were conducted at 13 and 20 weeks of age. Pigs offered maize silage manipulated rooting material more (23% vs. 19% of the pigs; P < 0.001) and manipulated pen components less (3.3% vs. 4.5% of pigs; P < 0.01) than pigs offered straw. Pigs housed at a high space allowance manipulated rooting material more (22% vs. 19% of pigs; P < 0.05) than pigs at a low space allowance. At 13 weeks of age, pigs manipulated rooting material more (23% vs. 18% of pigs; P < 0.001), pen components more (4.8% vs. 3.1% of pigs; P < 0.01) and pen mates less (2.2% vs. 3.0% of the pigs; P < 0.05) than at 20 weeks of age. Manipulation of rooting material was lower before the daily allocation of rooting material than after (15%, 40% and 7% of pigs at 09.00, 10.00 and 13.00 h, respectively; P < 0.001), while manipulation of pen components (6.4%, 3.5% and 1.9% of pigs at 09.00, 10.00 and 13.00 h, respectively; P < 0.001) and pen mates (4.1%, 2.1% and 1.5% of the pigs at 09.00, 10.00 and 13.00 h, respectively; P < 0.001) were higher before allocation of rooting material than after. In conclusion, pigs manipulated maize silage more than chopped straw and the level of explorative behaviour redirected towards pen components was lower when maize silage was offered as a rooting material. Pigs with a high space allowance manipulated the rooting material more. Finally, increased manipulation of pen mates and pen components just before allocation of new rooting material suggest that the amount available just before the next allocation was insufficient to maintain material manipulation.

Prenatal flavor exposure affects growth, health and behavior of newly weaned piglets

Young animals can learn about flavors from the maternal diet that appear in the amniotic fluid and mother's milk, which may reduce neophobia for similarly flavored food types at weaning. Flavor learning may be beneficial for piglets, which after the rather abrupt weaning in pig husbandry frequently show a period of anorexia, reduced health, and stress-induced behaviors. We investigated the effects of pre- and postnatal flavor exposure through the maternal diet on acceptance of a similarly flavored food and subsequent growth, health and behavior of newly weaned piglets. Sows were offered anise-flavored (F) or control (C) food during late gestation. Piglets were cross-fostered after birth, with each sow fostering 5 piglets from an F sow and 5 from a C sow. During lactation, sows were offered F or C food, resulting in FF, CF, FC and CC piglets. Piglets were weaned on day 25 and were given both control and flavored food for two weeks using a double food choice approach. The flavored food was not preferred. Yet, prenatally exposed animals showed a higher food intake and a higher body weight in the first days after weaning, and a lower occurrence of diarrhoea than non-exposed piglets. Prenatal exposure also increased the latency to fight, and reduced oral manipulation of pen mates and mounting during the first two weeks after weaning. Prenatal exposure, but not postnatal exposure alone, to anisic flavor through the maternal diet reduced weaning-associated problems in piglets and enhanced their health and welfare in the period after weaning.

Effects of feeding level and access to rooting material on behaviour of growing pigs in situations with reduced feeding space and delayed feeding

Seventy-two pigs, housed in groups of four, were allocated to either (1) ad libitum feeding with access to wood chip, (2) restrictive feeding with access to wood chip or (3) restrictive feeding without access to wood chip. The effects of feeding level (treatment 1 vs. 2) and access to wood chip (treatment 2 vs. 3) were investigated in a normal situation, a competitive situation (reduced feeder space) and a conflict situation (delayed feeding). During normal days the pigs without access to wood chip manipulated the floor more, both on a 24 h basis and during the first hour after feed allocation, but the level of manipulating floor in these pigs did not reach the level of manipulating wood chip among pigs on treatment 2. During normal days restrictively fed pigs spent less time feeding on a 24 h basis, but more time feeding during the first hour after feed allocation than ad libitum fed pigs. When feeder space was reduced restrictively fed pigs stood more and were more aggressive during the first hour after feed allocation, but when feeding was delayed restrictively fed pigs were less aggressive during the first hour after normal feeding time. Generally, access to wood chip stimulated explorative behaviour and reduced manipulation of floor and pen mates. However, it had no effect on the response to reduced feeding space or delayed feeding. On the other hand, restrictive feeding increased aggression when feeder space was reduced.

Tail biting: An important and undesirable behaviour of growing pigs

Environmental enrichment, adequate space and the ability to separate a living area into suitable functional areas are key elements for pig welfare. In this study, a two-level pen for nursery pigs was explored with the aim of analysing the use of space and the impact on pig behaviour, health and performance. Therefore, per batch, three experimental groups in pens with elevated platforms (two-level pens) and one control group in a standard pen were formed after weaning at the age of 4 weeks. Thereafter, groups were studied for a period of 6 weeks. In a total of eight batches (n = 882 pigs), the occurrence of skin lesions was determined per individual using a lesion score, and in seven batches (n = 761 pigs) individual daily weight gain was analysed. In five batches (n = 450 pigs), the individual use of space and the behaviour of pigs were investigated by direct observation (4 h per day on 2 days in weeks 1, 3 and 6 of the housing period, respectively). Results revealed that 98.9% of pigs (n = 445) were observed on the elevated platform at least once. The probability that an individual pig used the platform was significantly higher than 0.95 (P < 0.0001, confidence interval = 0.977, 1). The use of the platform was not affected by sex (odds ratio (OR) = 1.013, P = 0.937). However, the probability of observing an individual on the elevated platform increased with increasing BW during the experimental period (OR = 1.043, P < 0.0001). The presence of a platform decreased the probability of seeing a pig fighting (P = 0.014) and increased the probability of observing locomotor behaviour as opposed to lying (P < 0.0001). In two-level pens, pigs sustained fewer skin injuries than in standard pens (day 41: OR = 0.731, P < 0.0001). Over 41 days of experiment, pigs in two-level pens had higher daily weight gains than animals in standard pens (416 versus 393 g/day, P = 0.006). We conclude that usable space for nursery pigs can be effectively extended by introducing elevated platforms into the pigs’ pen. Furthermore, pigs may benefit from two-level systems by establishing spaces for activity as well as for retreat from other pen mates, thereby reducing aggressive behaviour and social stress. The installation of two-level pens is therefore encouraged, if they are intended to provide more space than legally stipulated.

Effect of pen mates on growth, backfat depth, and longissimus muscle area of swine

Records on final BW (kg), backfat depth (cm), and LM area (cm(2)) of pigs from a University of Nebraska Large White/Landrace composite population were analyzed to estimate the effects of pen mates. Measurements were at approximately 180 d of age for 3,524 pigs in 351 pens (9 to 11 pigs per pen) farrowed from 1999 to 2005. The area of each pen was 8.13 m(2). The full model (M1) included the fixed effects of contemporary group, sex, line, and the covariates of age and inbreeding coefficient, and included random direct genetic, genetic pen-mate, permanent environmental, pen, litter, and residual effects. A derivative-free algorithm was used to obtain REML estimates of variance components for final BW adjusted to 180 d of age with M1 and 7 reduced models, and with 4 reduced models for the carcass traits. For final BW, likelihood ratio tests showed that M1 did not fit the data better than model 2 (permanent environmental effect omitted from M1) or model 3 (pen omitted from M1). Model 2 was not significantly (P > 0.05) better than model 3, which shows that variance attributable to pen effects and permanent environmental effects cannot be separated. Large sampling variances of estimates of the pen component of variance for models with pen-mate effects also indicate an inability to separate pen effects from the effects of pen mates. When pen-mate genetic effects were not in the model, estimates of components of variance and the fit of the data were the same for models 4 (included both permanent environmental and pen effects), 6 (included pen effects), and 7 (included permanent environmental effects), which shows that including both pen and permanent environmental effects was no better than including one or the other. Models 4, 6, and 7 were significantly better than model 8, which did not include pen-mate effects and pen effects, implying that pen effects are important. The estimate of pen variance with model 2 was approximately (number of pen mates - 1) times the estimate of variance of pen-mate permanent environmental effects with model 3. Patterns of estimates of variance components with models 2, 5, 6, and 8 for backfat depth and LM area were similar to those for final BW. Estimates of direct genetic variance and phenotypic variance were similar for all models. Estimates of heritability for direct genetic effects were approximately 0.40 for final BW, 0.45 for backfat depth, and 0.27 for LM area. Estimates of heritability for pen-mate genetic effects were 0.001 for the 3 traits for models including either pen or permanent environmental effects. Under the management conditions for this experiment, the conclusion is that the model for genetic evaluation should include litter effects and either pen effects or pen-mate permanent environmental effects and possibly genetic pen-mate effects, in general agreement with the results of studies of different populations at other locations.

Respiratory infections in Norwegian dairy calves

The aims of this study were to estimate the seroprevalence of respiratory agents in Norwegian dairy calves and to identify risk factors for respiratory disease. The participating 135 herds were randomly selected from those in The Norwegian Dairy Herd Recording System with at least 15 cow years. Each herd was followed for 1 yr. Blood samples from calves of >150 d of age (n = 1,348) were analyzed for antibodies against parainfluenza virus 3, bovine coronavirus (BCoV), bovine respiratory syncytial virus (BRSV), and Mycoplasma bovis. Calves reported to have been on pasture (n = 139) were tested for antibodies against Dictyocaulus viviparus. Seroprevalences for parainfluenza virus 3, BCoV, BRSV, and D. viviparus at the calf level were 50.2, 39.3, 31.2, and 4.3%, respectively. No calves were antibody positive for M. bovis. Calves in herds with BCoV-seropositive calves had an increased risk of respiratory disease compared with herds in which BCoV antibodies were not detected [hazard ratio (HR) = 3.9], as had calves in herds in which the majority (>54%) of the sampled calves were seropositive for BRSV (HR = 2.7). Other factors found to increase the risk of respiratory disease in calves were shared housing with cows during the first week of life compared with separate housing (HR = 16.7), a larger herd size (>50 cow years) compared with smaller herds (HR = 8.2), more than an 8-wk age difference between calves housed together in the same group pen compared with having pen mates of a more similar age (HR = 3.9), previous recordings of diarrhea compared with no recorded diarrhea (HR = 3.9), and leaving calves with dams for >24h after birth compared with earlier separation (HR = 3.5).

Evaluation of different techniques for pregnancy diagnosis in sheep

Fifty Corriedale ewes were used in this study to evaluate pregnancy diagnosis in sheep. Ewes were bred under a pen mating system and pregnancy diagnosis was initiated from day 15 post-mating, applying the diagnostic techniques of trans-abdominal real-time B-mode ultrasonography, Preg-alert (A-mode ultrasonography), the Doppler ultrasonic fetal pulse detector or the plasma progesterone concentration assay (EIA). These tests were repeated fortnightly on all the ewes until the onset of lambing. The accuracy of trans-abdominal real-time B-mode ultrasonography (68%) at days 15–30 of pregnancy increased to 100% by days 61–75 and remained constant until lambing. The accuracy of the Preg-alert (56%) diagnosis at days 31–45 increased to 94% by days 91–105 of gestation and then decreased to 82% from days 136 of gestation to lambing. The accuracy of both the Doppler ultrasound (56%) at days 31–45 and plasma progesterone assay (98%) at days 15–30 of gestation increased to 100% at days 76–90 and 46–60 of gestation, respectively and remained constant until parturition. The mean plasma progesterone concentration at days 0–6 (1.41 ± 0.21 ng/ml) increased to 4.0 ± 0.87 ng/ml at days 16–30 (days 18.23 ± 0.78) post-mating. Animals returning to estrus recorded less than 1 ng/ml at days 18.23 ± 0.78 post-mating. The accuracy of both the B-mode ultrasonic technique (78%) and plasma progesterone assay (98%) was significantly higher ( P < 0.05) than the accuracy obtained with the A-mode and Doppler ultrasound (both 56%) at days 31–45 of gestation. The study concluded that real-time B-mode ultrasonography is the earliest, most accurate, safest, fastest and most economical method of pregnancy diagnosis in sheep at farm level. The A-mode and Doppler methods can also be used under field conditions, where sophisticated laboratory facilities are not available. Plasma progesterone assays (EIA) can be used as a means of early pregnancy diagnosis in organized sheep farms with fair accuracy.

Transmission of Salmonella to broilers by contaminated larval and adult lesser mealworms, Alphitobius diaperinus (Coleoptera: Tenebrionidae)

The ability of the lesser mealworm, Alphitobius diaperinus (Panzer), commonly known as the darkling beetle, to transmit marker Salmonella Typhimurium to day-of-hatch broiler chicks was evaluated, as well as the spread to nonchallenged pen mates. In trial 1, day-of-hatch chicks were orally gavaged with 4 larval or 4 adult beetles that had been exposed to marker Salmonella-inoculated feed for 72 h. In addition, chicks were gavaged with the marker Salmonella in saline solution. These chicks were then placed into pens to serve as challenged broilers. In trial 2, all pens received 2 challenged chicks that were gavaged with larvae or beetles that had been exposed to marker Salmonella-inoculated feed for 24 h and then removed from the inoculated feed for a period of 7 d. At 3 wk of age, cecal samples from the marker Salmonella-challenged broilers and from 5 pen mates in trial 1, or 10 pen mates in trial 2, were evaluated for the presence of the marker Salmonella in their ceca, and at 6 wk of age, all remaining pen mates were sampled. To monitor the presence of the marker Salmonella within pens, stepped-on drag swab litter samples were taken weekly. For the Salmonella-saline pens, 29 to 33% of the broilers that had been challenged and 10 to 55% of the pen mates were positive at 3 wk of age, and only 2 to 6% had positive ceca at 6 wk. For the pens challenged with adult beetles, 0 to 57% of the challenged broilers and 20 to 40% of the pen mates had positive ceca at 3 wk, and 4 to 7% were positive at 6 wk. The pens challenged with larvae had the greatest percentage of marker Salmonella-positive broilers; 25 to 33% of the challenged broilers and 45 to 58% of pen mates were positive at 3 wk, and 11 to 27% were positive at 6 wk. These results demonstrated that ingestion of larval or adult beetles contaminated with a marker Salmonella could be a significant vector for transmission to broilers.

Untersuchungen zum Beschäftigungsverhalten von weiblichen und kastrierten männlichen Mastschweinen

Abstract. Title of the paper: Investigation on occupational behaviour of female and castrated male fattening pigs In four rounds 144 fattening pigs of both sexes were brought in four pens (two of them were littered, two without any litter). Their occupational behaviour was recorded at the time of bringing the pigs into the pen, at the beginning, at the middle and at the end of the fattening period using an infrared-video-technology and a time lapse video recorder. In every pen three occupational tools (pendular beam, cross of chains and lifting beam) were offered to the pigs. At the 1st recording the behaviour of all pigs was analysed, at the other fattening periods the behaviour of six focal pigs of both sexes per pen was analysed always over 24 h. At the time the pigs were brought into the pens no significant differences between the two sexes could be observed concerning the latency until the pigs had the first contact to the different occupational tools, whereas both sexes needed longest for their first contact to the cross of chains. During the other fattening periods the duration of occupation with the cross of chains (♂=0.06 %; ♀=0.08 %, p&lt;0.086) and the pendular beam (♂=0.15 %; ♀=0.2 %, p&lt;0.087) by the female pigs tended to be longer than the one shown by the castrated male pigs. Thereby both sexes used the cross of chains longer for occupation than the pendular beam and the lifting beam. The female pigs occupied themselves significantly longer with the straw in the littered pens, the floor in the pens without straw, the pen’s equipment and the pen mates than the castrated male pigs did. In contrast the castrated males used the trough significantly longer for occupation. In this study female pigs were more active, whereas the castrated male pigs spent a significantly longer time feeding and tended to spend more time lying and had better daily gains.

Spatial learning in pigs: effects of environmental enrichment and individual characteristics on behaviour and performance

This study investigated the effects of both environmental enrichment and individual behavioural characteristics on spatial cognitive capabilities of pigs, using a novel latent spatial learning paradigm based on Tolman's detour experiments (1948). Pigs were housed either in 'barren' pens or in pens enriched with straw bedding from birth. Pigs were restrained in a Backtest at 10 and 17 days postpartum. Based on their escape behaviour in this test, which has been shown to reflect their behavioural style, six 'high-resisting'(HR) and six 'low-resisting' (LR) pigs were selected from each housing environment (n = 24 in total). At 12 weeks of age, pairs of pen mates (LR and HR) were exposed to a maze three times (exploration trials). Pigs were then placed individually in the maze, and social reinstatement proved to be a strong incentive to find the exit leading to the home pen. We subsequently blocked the direct route to the exit, forcing animals to find a detour (memory test 1, MT1). This test was repeated once to investigate the relative improvement, i.e. detour learning (memory test 2, MT2). Housing condition and Backtest response strongly affected exploration patterns. In spite of this, no effects on performance during the subsequent memory tests were found. Performance was substantially improved in MT2, indicating that once a goal is apparent, pigs are able to solve a complex spatial memory task easily. In conclusion, social reinstatement provided a good incentive to complete a spatial task, and the substantial improvement in performance between MT1 and MT2 stresses the need for task complexity when testing spatial memory in pigs. Housing conditions or individual behavioural style did not affect spatial memory during MT1 or MT2. However, housing environment and behavioural style strongly affected explorative behaviour of pigs in an unfamiliar maze during both exploration trials and memory tests. This implicates that apparent effects of environmental enrichment on spatial learning and memory in pigs might reflect differences in explorative patterns rather than in cognitive processes.

Performance, behavior, and welfare of Friesian heifers housed in pens with two, four, and eight individuals per concentrate feeding place1

The objective of the present study was to examine the effects of increasing the number of heifers per concentrate feeding place on performance, behavior, welfare indicators, and ruminal fermentation of feedlot heifers. Seventy-two Friesian heifers were used in a factorial arrangement, with 3 treatments and 3 blocks of similar BW. Treatments consisted of 2 (T2), 4 (T4), or 8 (T8) heifers per each place in the concentrate feeder (8 heifers/pen). Concentrate and straw were fed at 0830 h in individual feeders that allowed ad libitum consumption. During 6 periods of 28 d each, DMI and ADG were measured, and blood and rumen samples were taken. Fecal glucocorticoid metabolites and behavior were measured at periods 1, 3, and 6. Final BW, ADG, and G:F were not affected by treatments. Variability in final BW among heifers sharing the same pen tended to increase (P = 0.06) and concentrate intake decreased linearly as competition increased. The proportion of abscessed livers responded quadratically, being 8, 4, and 20% for T2, T4, and T8, respectively. Concentrate eating time decreased (P = 0.001) and eating rate increased (P = 0.05) linearly, whereas the variability between pen mates in concentrate eating time was greatest in T4 and T8. Increasing competition resulted in a quadratic response (P = 0.02) in daily lying time (greatest in T2), whereas standing time increased linearly (P = 0.02). The number of displacements among pen mates from the concentrate feeders, as well as the total sum of displacements, increased linearly (P < 0.05) with increasing competition. The pen average of fecal glucocorticoid metabolites was not affected by treatments (P >/= 0.16) but the pen's maximum concentration responded quadratically (P < 0.001), being greatest in T8, with dominant heifers being the most affected. Serum haptoglobin concentration increased linearly (P = 0.05) with competition, particularly within the most subordinate heifers. Increased competition reduced (P < 0.05) ruminal pH only in periods 1 and 2 and increased ruminal lactate (P = 0.02). Increasing competition at the concentrate feeders increased the variability in final BW but performance was not affected. Detrimental effects on animal welfare might be deduced from the altered feeding behavior, reduced resting time, and increased aggression. Ruminal lactate and blood haptoglobin indicate that the risk of rumen acidosis might increase with competition, whereas liver abscesses increased at 8 heifers per feeder.