Duration of restraint and isolation stress as a model to study the dark-cutting condition in cattle.

Posted in: Welfare by admin on January 1, 2005 | No Comments

The duration of restraint and isolation stress (RIS) on endocrine and blood metabolite status and the incidence of dark-cutting LM were assessed using Holstein steer calves. Treatments included unstressed controls (NS), or a single bout of RIS for 2, 4, or 6 hours. Serum cortisol and plasma lactate increased during the first 20 minutes after the RIS application and remained high throughout the 6 hours of RIS. Plasma glucose and insulin concentrations were greater for RIS calves than NS calves after 80 and 100 minutes of stressor application respectively. RIS did not affect plasma NEFA concentrations. Slaughter occurred within 20 minutes of completion of RIS. The pH of the LM from calves subjected to 6 hours of RIS was greater than 6.0 and was higher than that of NS calves and 2 and 4 hour RIS calves 24 and 48 hours post mortem. Concentrations of muscle glycogen did not differ between the treatments and the LM lactate concentrations tended to be lower in calves subjected to 6 hours of RIS. The LM of calves subjected to 6 hours of RIS had more bound and less free moisture than the LM from NS calves and calves subjected to 2 or 4 hours of RIS at 48 hours after exsanguination. Furthermore, the LM from RIS calves was darker than the LM of NS calves. Calves subjected to 6 hours of RIS had the greatest visual color scores for the LM and NS calves had the lowest. Cases of dark-cutting resulted from calves in all treatments except the NS treatment. Therefore, RIS may have been proven to be a reliable animal model with which to study the formation of the dark-cutting condition.

Preferences of sheep for different types of pen flooring

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Sheep preference for different types of pen flooring were tested using two lying areas with one of the following flooring materials: 1) solid wood versus rubber mats, 2) expanded metal versus solid wood, 3) solid wood versus straw, or 4) expanded metal versus straw. In experiment one, 16 ewes were divided into four groups to test their preferences. In experiment two, eight ewes were individually tested, first fully coated, then once shorn. In experiment one, the first animal that lay down after feeding preferred to lie on straw over wood or metal, and preferred to lie on wood over metal. Unshorn ewes did not show a flooring preference. In experiment two, individually housed, unshorn ewes preferred wooden flooring to rubber mats, and tended to choose expanded metal flooring to straw. The other treatments did not show any preferences. Once shorn, the ewes preferred wooden flooring to expanded metal, straw to wooden flooring, and straw to expanded metal flooring. A preference between rubber mats and wooden flooring did not exist. For unshorn ewes, the mean lying time (% of observations) for all treatments was 64.7 %. There were no significant differences between treatments. In the first 2-3 days post-shearing, mean lying time (% of observations) was 43 %. The lying times for pre-shearing and post-shearing differed when the ewes were housed in pens with no straw, but not when ewes had access to straw. There was indication that shorn ewes preferred softer floors with low thermal conductivity (straw and wood), but this was not noted for unshorn ewes. Access to straw in the first week after shearing may improve animal welfare, which is concluded from the less dramatic reduction in lying time after shearing when ewes have access to straw.

Cross-sucking and other oral behaviours in calves, and their relation to cow suckling and food provision.

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When calves are unable to suckle, it is thought that they begin to develop abnormal oral behaviour, although it is not known whether this behaviour occurs because the calf needs access to its dam or whether a multiple suckling system would suffice to prevent the behaviour from developing. An initial experiment examined the behaviour of calves that suckled their own dam or another cow for 15 minutes each day and compared that to the behaviour of artificially-reared calves that had no opportunity to suckle. Calves that were allowed to suckle consumed more milk than calves that were reared artificially. Cross-sucking behaviour was greater in non-suckled (artificially reared) calves than in suckled calves. Cross-sucking was at its highest frequency 1 minute after the end of milk feeding in the non-suckled calves, and declined linearly to negligible levels at 13 minutes after milk feeding had occurred. Most of the cross-sucking behaviour (78 %) was directed at the inguinal (udder/scrotal) region of other calves. For suckled calves, however, more of the cross-sucking behaviour (81 %) was directed at the mouths of other calves. Calves that had been artificially reared spent more time consuming concentrate feed and consumed more feed than suckled calves, suggesting that food ingestion could provide a replacement stimulus. A second experiment found that before weaning, the time calves spent licking their pen or bucket increased until feed intake was sufficient to stimulate significant amounts of rumination. After weaning, the behaviours decreased. Conclusions stated that cross-sucking of artificially-reared calves could be prevented by providing short access to either the calf’s dam or another cow for two short periods each day. When a cow was absent and no suckling could occur, the calves licked inanimate objects repeatedly until the consumption of solid feed was sufficient to stimulate rumination.

Repeated transport and isolation during pregnancy in ewes: Effect on the reactivity to humans and to their offspring after lambing

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The reactivity of ewes to their lambs and to humans after lambing was examined. Six weeks prior to lambing, the ewes were repeated exposed to several stressors that varied in intensity. The ewes were stressed by transporting them alone, isolating them or isolating them with a dog. The ewes were underwent a stressful session twice a week. Each session last one hour, and in total, each ewe underwent 10 sessions. The control ewes were not disturbed. Blood samples were collected during the first, fifth and ninth stress sessions, in order to measure their cortisol response. The ewe’s maternal reactivity and fear of humans was measured in seven scenarios. One hour after birth, a human approached the lambing site and the lamb. Five minutes after tagging someone held the lamb. Six hours after birth the ewe was forced across a hallway to reach her lambs. Six hours after birth, in order for the ewe to remain close to her lamb, she was forced to tolerate the presence of a human. The ewe was also separated from the lamb and forced to enter the lamb box. One month following birth, a human approached the ewe, and then measured the flight distance of the ewe. The highest cortisol response was measured in ewes that were transported, during the first and ninth sessions. The ewes did demonstrate habituation to every treatment over time. During the tests conducted one and six hours after birth, ewes that were isolated attempted to maintain contact with their lambs, while the ewes that were transported did not. The control ewes response was moderate compared to the transport and isolation treatment ewes. One month after birth, the isolated ewes continued to show less avoidance of humans than transported ewes, while the control ewes remaining intermediate between the responses of the other two treatments. There were also correlation found between the cortisol response during the stress and the responses made 1 hour, 6 hours and 1 month after birth. The variation in the ewes’ behaviour after lambing was likely due to the different stressors causing varying degrees of fear towards humans. The behaviour is not related to the ewe developing a weaker mother-young bond. Hence, repeated isolation reduced the ewe’s fear of humans, while repeated isolated transportation increases a ewe’s fear of humans.

Nitric oxide blunts the endothelin-mediated pulmonary vasoconstriction in exercising swine

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Nutritional and physiological responses of growing pigs exposed to a diurnal pattern of heat stress

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Understanding the impact of changes in the environment on the nutritional and physiological status of the pig will facilitate development of appropriate environmental management and feeding strategies (DeShazer, 1982). The objective of this study was to characterise the nutritional and physiological responses of growing pigs, with particular emphasis on effects on acid–base and thermal homeostasis, when exposed to a diurnal pattern of heat stress. It was found that a diurnal pattern of heat stress fluctuating between 20°C and 38°C within 24 h did not affect mineral
metabolism in growing pigs and had limited effect on acid–base balance. Therefore, pigs have the ability to recover from the effects of heat stress if periods of heat stress are followed by periods of thermal comfort. The diurnal pattern of heat stress had an effect on the physiological status of pigs resulting from the mechanisms (e.g., increased respiration rates) used to maintain thermal homeostasis and associated renal compensation. Therefore, strategies for managing pigs exposed to heat stress should focus on ways (e.g., provision of cool drinking water) of enhancing the pig’s ability to dissipate excess body heat, and should recognise the impact of thermal stress on acid–base parameters.

CQA® and the New Medicated Feed Regulations

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Recently the CQA program was thoroughly reviewed. Changes have been made to the feeding perspective, which includes medicated feeding. There has been an entirely new chapter added that applies to on-farm mixers. There are new regulations set forth on producers obtaining licenses. For more information, refer to the full article.

Panel Presentation: Occupational Health & Safety Inspections

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OH&S exists to make workplaces safer, farms included. There are as many fatalities on the farm as there are in all other workplaces annually in Saskatchewan. The OH&S committee has committed to performing 300 agricultural workplace inspections per year. Items that may be included in these inspections is the workplace responsibility system (OH&S committee), worker training, regulations concerning the workplaces (such as environment, layout, etc.), personal protective equipment, and any dangerous heights (e.g. – feed bins). Hydrogen sulphide regulations can be reviewed, as can biological relations. This involves medications and/or hormones being used, the purpose for use, and conditions for administration (e.g. – is it safe to handle by pregnant workers?).

Implementing a Systematic Approach to Disease Control and Prevention

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As hog farms today move from small-scale to large-scale operations, disease control and prevention needs to be looked at from an overall point of view. The reactionary approach to disease control really only appears to be effective in high-health systems. The Product Based Approach utilizes well-marketed medications of the pharmaceutical companies to “prevent” disease. This makes producers feel secure in that they did everything they could to prevent disease. The current method that is under development is the Systematic Approach, which will be part of the business plan and/or budget. This approach looks at disease as a cost of production and diminished production. To control diseases one must educate the workers, define the background disease status, allow easier information management, and make decisions and take action. Specific disease risks must be taken into account and planned for as well. Investment in this type of system will eliminate excess costs and unnecessary drug use and decrease vulnerability to the impact of pathogens.

Feasibility of carotid stent deployment in swine using an electromagnetic navigation device for catheter guidance size

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