Situation of Classical Swine Fever and the Epidemiologic and Ecologic Aspects Affecting Its Distribution in the American Continent

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Behavioural, endocrine and immune consequences of mixing in weaned piglets.

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Weaning often combines several stressful events such as sudden change of diet and mixing with unfamiliar piglets. These sudden changes induce behavioural, endocrine and immune alterations and are followed by a transient reduction of growth and digestive disorders. At weaning, the physiological effects of social reorganization could be masked by the much more important effects of the diet change. The aim of this study was to evaluate the reactivity of piglets to mixing by dissociating social reorganization from weaning itself. This study investigated the influence of mixing five days after weaning, when most of the acute physiological adjustments of weaning have disappeared. The response to mixing was assessed by measuring salivary cortisol, blood lymphocyte proliferation, interferon- production and behavioural activity. Cortisol levels were increased after mixing and returned to basal values within 24h and the blood lymphocyte level was not affected by mixing. Mixing increased resting behaviour. Piglets seemed to avoid conflicting encounters by diminishing the synchronization of their activities with their new group. The results of this study show that mixing young piglets is stressful but that animals develop behavioural strategies to adapt to the situation.

Effect of increased floor space on aggressive behaviour in male turkeys (Meleagris gallopavo)

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Turkey production in recent years has become very competitive and highly specialized. Fast-growing strains of turkey broilers are usually housed in large buildings, which may contain 1000-25,000 birds at stocking densities up to 60 kg/m2. Under commercial rearing conditions, domestic turkeys are often aggressive towards ‘pen-mates’, and this may lead to serious injuries or even death. Restricted space, as a consequence of high stocking density might prevent the attacked bird from retreating from its opponent. This study examined the aggressive response in 10 groups of five familiar turkey toms, comparing behaviour to an unfamiliar conspecific that is introduced to two pens of different sizes. Groups were tested both in small and in a large pen for 30 min. In the small pen they observed significantly more aggressive pecks and threats to the introduced bird. In the larger pen introduced birds kept a greater distance from the group than in the small pen. The mean number of fights and chases per test was not different between the two pens. In summary the present study shows that in small groups of turkeys, an increase in floor space reduces the number of aggressive pecks and threats aimed at an introduced unfamiliar conspecific. It is concluded that one of the reasons for high injury rates in fattening turkey toms reared under commercial breeding conditions might be the restricted space due to high stocking density which prevents the birds from moving far enough away from attacking conspecifics to avoid injuries.

Milking of Brown Swiss and Austrian Simmental cows in a herringbone parlour or an automatic milking unit.

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Automatic milking systems (AMS), consisting of one or more automatic milking units in a loose-house system, have become increasingly common in recent years. The milking process as well as the management in AMS differ from conventional systems and may influence the health and welfare of cows in various ways. For example, the daily rhythm and herd synchronization is influenced as cows in the AMS get milked singly at any time of day. In this particular study Dairy cows’ stress responses during normal successful milking in a herringbone milking parlour (HMP) were compared with their responses during normal successful voluntary milking in an automatic unit. The study used 42 cows: 12 Simmental and 11 Brown Swiss in the AMU, and 10 Simmental and 9 Brown Swiss in the HMP. After effects of milk yield, day of lactation and time of day had been taken into account, milking lasted longer in the HMP than in AMU. Location of the teats by the robot took longer in Simmental than in Brown Swiss cows. Kicking and stepping with hind legs was less frequent in the AMU than in the HMP. Brown Swiss cows stepped less than Simmental cows in the AMU. There was no difference between groups in heart rate during milking. The AMS group had higher milk cortisol values than the HMP group. This was probably not related to milking itself, but to other aspects of the system, and the absolute values were not very high. In summary, cows showed more behavioural signs of discomfort and aversion in the HMP than in the AMU. Simmental cows may be more vulnerable during milking than Brown Swiss. There were no indications of more stress in the AMU than in the HMP.

Vocalization of farm animals as a measure of welfare

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Homeostasis is maintained or regained through the stimulation central nervous system by external events affecting emotion, hormonal concentrations affecting mood, and appetitive behaviour (thirst and hunger). Specific behaviours, such as vocalization, may accompany particular states of mood or emotion. Vocalizations (such as distress utterances) may also affect the welfare states of conspecifics. Therefore, vocalizations by farm animals could be an effective tool to use when attempting to understand welfare states. Research into this area has increased, with attempts to decipher the meaning of various vocalizations. This paper focuses on the current state of research into pig, cattle and poultry vocalizations. Current sound analysis techniques give the ability to discriminate, analyze and classify specific vocalizations. With these tools, future research should focus on connecting specific utterances with specific environments, behavioural contexts and physiological parameters. This information will provide non-invasive tools for judging welfare states.

Designing better water troughs: dairy cows prefer and drink more from larger troughs.

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This study examined the preference of cows on pasture for different types of water troughs. In initial studies, the cows were allowed to drink from two water troughs that differed in height and surface size. The cows preferred to drink from the taller (60 vs 30 cm), larger (approximately 50% more surface area) trough. In a second study the smaller trough was raised to the same height as the larger trough, and the cows did not should a strong preference. When given access to only one trough, for periods of 24 hrs, the cows drank more from the taller, larger trough. Water intake is particularly important for dairy cows and the results of this study suggests that high levels of intake will be more easily maintained if large, high troughs are used.

Cubicle housing systems for cattle: comfort of dairy cows depends on cubicle adjustment.

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The type of housing system a dairy cow is kept in can affect her welfare. Recently the industry has reduced the use of tethers in dairy cows because they cause stress, prevent social contact and cause problems with movement. More often dairy cows are housed in a cubicle system, but there are also some disadvantages to this system such as mild injury and the cows’ unwillingness to lie in the cubicle. The paper first discusses a survey of various farms in France that used the cubicle system. The survey compared various parameters associated with housing dairy cows in cubicles. It also examined cleanliness, lying/standing movements, behaviour, injuries and size. After the survey an experiment was conducted to compare different types of cubicles. Compliance with the recommended cubicle dimensions was quite low, as the cubicles often were too short or too narrow. The survey also determined that as the number of cubicles available for all the cows within the herd decreases, the level of injuries sustained by the cows increases. One strikingly important feature of the cubicle was the neck rail. More specifically the height of the neck rail in the cubicle can affect how a cow positions herself within the cubicle as well as her ability to stand up or lie down. High neck rails were found to make movement and positioning within the cubicle very difficult and were associated with a higher level of injury.

Immunohistochemistry for the detection of swine hepatitis E virus in the liver

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Swine hepatitis E virus (HEV) antigen was detected immunohistochemically in formalin-fixed, paraffinembedded hepatic tissue from 30 naturally infected pigs. Thirty pigs from 30 different herds were selected on the basis of positive results for reverse transcription-polymerase chain reaction. Positive cells typically exhibited a red reaction product in the cytoplasm without any observable background staining. Swine HEV antigen was consistently detected in liver from all 30 pigs tested. A strong immunohistochemical signal was seen within a variable number of hepatocytes in multifocal lobules. The signal involved the majority of hepatocytes diffusely or was confined to foci of
liver cells. Positive immunohistochemical signals were also detected in small and large intestine, lymph node, tonsil, spleen, and kidney. The immunohistochemistry technique developed in this study proved useful for the detection of swine HEV in formalin-fixed, paraffin-embedded tissues
taken from naturally infected pigs and may be a valuable tool in studying the pathogenesis of swine HEV infection.

Lying behaviour and adrenocortical response as indicators of the thermal tolerance of pigs of different weights.

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Optimal temperature ranges of fattening pigs at different weights were assessed by examining the behavioural and adrenocortical responses of pigs to a range of ambient temperatures. Cortisol concentration was analyzed by taking saliva samples from the pigs. Behaviours measured included lying behaviour. Depending on ambient temperature, pigs chose different areas for resting. When temperature increased, pigs would lie in the dung area away from penmates more often. Heavier pigs lied without contacting their penmates more often than their lighter counterparts. Lying without penmate contact occurred 5 to 7 °C lower than lying in the dung area. As temperature decreased, huddling behaviour increased. As pig weight increased, huddling occurred more at lower temperatures. For pigs over 85 kg body weight, there was a significant increase in cortisol levels when ambient temperature increased. The results of the present study indicated that, for pigs weighing 25 to 35 kg and housed on partially slatted floors, temperature range within the thermal tolerance of pigs was 19 to 21 °C. At 50 to 70 kg body weight, the range was 10 to 17 °C. For pigs over a body weight of 85 kg, temperature range within their thermal tolerance was 5 to 17 °C.

The effect of rearing regime on the development of the mammary gland and claw abnormalities in high genetic merit Holstein-Friesian dairy herd replacements.

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The effect of rearing regime on mammary gland development and claw abnormalities was assessed using Holstein-Friesian heifers. Treatments included 1) heifers reared to calve at 540 kg and offered grass-silage based diets during the winter and grass-based diets during the summer; 2) heifers reared to calve at 620 kg and offered grass-silage based diets during the winter and grass-based diets during the summer. They also received additional supplements; 3) heifers reared to calve at 620 kg and were offered a straw/concentrate diet during the winter and a grass-based diet during the summer; 4) heifers reared to calve at 620 kg and fed a straw/concentrate diet in both the winter and summer and were housed. By increasing the plane of nutrition, the weight of dissected udder fat increased, but there was no effect on the weight or chemical composition of dissected udder parenchyma. Fat deposition in the udder was reduced and the proportion of parenchyma in the udder was increased by offering straw- compared with silage-based diets. There were no effects on weight of fat when heifers were housed during the first summer and offered straw-based diets compared with those heifers turned out to grass, although there was a tendency towards a reduction in the proportion of parenchyma in the udder. Values for heel height, lateral claw length and heel erosion scores were lower for heifers reared on a low plane of nutrition. A higher plane of nutrition increased live weight/sole area, although it was only significantly higher for treatment 3 compared with treatment 1 heifers. Housing heifers the first summer increased the incidence of feet lesions in the white line and solear area relative to turning heifers out to grass that first summer.