SEARCH
Industry Partners
Prairie Swine Centre is an affiliate of the University of Saskatchewan
Prairie Swine Centre is grateful for the assistance of the George Morris Centre in developing the economics portion of Pork Insight.
Financial support for the Enterprise Model Project and Pork Insight has been provided by:
Effect of duration of cold stress on plasma adrenal and thyroid hormone levels and immune responses in chicken lines divergently selected for antibody responses.
Posted in: Welfare by admin on January 1, 2004 | No Comments
There is increasing evidence that stress affects various immune processes. Some of these changes are due to hormonal changes involving corticosterone (CORT), triiodothyronine (T3), and thyroxine (T4). Effects of stress depend on the nature of specific stressors (e.g., thermal extremes, diet, pollutants), stress-modifiers (e.g., genetic make-up, duration and severity of the stressors). This study examined the effects of a specific stress (cold stress) with stress-modifiers (duration of stress and genotype of the bird) on immune responses and plasma adrenal and thyroid hormone levels in 3 layer-type chicken lines. Two lines were divergently selected for high (H line) or low (L line) antibody responses to SRBC, and the third line was a randombred control (C). Growing chicks of the 3 lines were feed-restricted at 80% of ad libitum consumption, and subjected to cold stress (CS) at 10oC continuously for 7, 5, 3, 1 or 0 d before immunization with keyhole limpet hemocyanin (KLH). Specific antibody titers to KLH, and in vitro lymphocyte proliferation (LP) upon mitogen stimulation were measured. In addition, adrenal and thyroid hormone levels were measured in the plasma samples collected at the end of CS. No significant effect of duration of CS on specific antibody titers was found in the 3 lines. A significant enhancing effect of CS was found on LP. A significant dose-dependent suppressive effect of CS was found on plasma CORT levels. The authors concluded that CS does not affect specific antibody responses, but may have a modulating effect on cellular immunity and plasma CORT levels, depending on the duration of stress. This is the first study that reveals an absence of significant differences in adrenal and thyroid hormone levels in the described selection lines.
Complexity of behavioural sequences and their relation to stress conditions in chickens: a non-invasive technique to evaluate welfare.
Posted in: Welfare by admin on | No Comments
This study examined the use of behavioural complexity as a potential to assess the stressfulness of an animal’s environment. Chickens were videotaped for 0.5 hr periods and the changes in behaviour analysed to yield a complexity value. This technique was then used to determine the effects on behavioural complexity when birds were exposed to different potential stressors. Differences were found in the behavioural complexity of locomotor and resting behaviours when birds were exposed to food restriction, social crowding through the addition of more birds, and when sand was provided. The direction of these changes was not consistent for all stressors, however, the authors conclude that behavioural complexity is a non-invasive means to assess different housing conditions.
Are cows that consistently enter the same side of a two-sided milking parlour more fearful of novel situations or more competitive?
Posted in: Welfare by admin on | No Comments
This study attempted to find a relationship between the consistency that a cow enters a one of two sides of a milking parlour with her behaviour in a novel environment and her ability to attain fed in a competitive situation. Two groups of twelve cows were chosen from a group of 70. Cows that demonstrated a preference for entering only one side of the parlour were classified as high consistency (HC) cows and entered in the preferred way, on average, 91% of the time. Cows that did not show a strong preference for either entry entered one side 60% of the time and were classified as low consistency cows (LC). For fifteen-minute period after milking, a cow was housed in a new empty pen and her behaviour was observed. Immediately after that set of observations, another cow was introduced to the pen and feed was provided in the bucket. The behaviour of the cow was recorded for 15 minutes or until the two cows stopped feeding or interacting with one another. When HC cows were introduced to the empty pen, they stood motionless longer than LC cows. However, HC and LC cows showed similar amounts of exploratory behaviours (time spent sniffing the pen, number of steps taken, number of vocalizations) when moved into the pen. The authors interpreted the difference in activity as indicating that HC cows were more fearful of the new environment. When a new cow and feed was introduced to the pen the HC cows were began to eat the food sooner and maintained control of the bucket longer than LC cows. HC cows were involved in more aggressive interactions and tended to push the other cow more than LC cows. During the feed competition test, the HC cows stood inactive longer than the LC cows. All cows likely develop some sort of a routine. There is, however, a difference in the social strategies between cows with strong and weak preferences. Those cows that are able to demonstrate a preference may be more capable of successfully executing their social strategy.
Organic livestock production in Europe: Aims, rules and trends with special emphasis on animal health and welfare
Posted in: Welfare by admin on | No Comments
In Europe, organic farming has increased during the last decade. However, the market share is still relatively low. The needs of animals are better met in organic farming systems than in conventional systems. The goal of organic farming is to ensure high standards of product quality, animal health and welfare. As a result, there are high demands on management qualifications. However, there are no guarantees that the high standards will be maintained. The development of quality assurance programs has been suggested in order to ensure that standards are maintained. The criteria for sustainability can only be realized if the standards for animal health and welfare and product quality and environmental security are maintained.
Relationship between Prenatal Survival Rate at 70 days of Gestation and Morphometric Parameters of Vagina, Uterus and Placenta in Gilts
Posted in: Welfare by admin on | No Comments
Swine uterine capacity affects litter size, and it could be used as a selection parameter of reproductive performance. Although there are some controversial results, evidences show that the catheter penetration length is positively correlated with litter size, and it could be used as a tool for predicting selection methods. The aim of this study was to determine whether there is any association between the prenatal survival rate and placental size at 70 days of gestation, the vaginal length [catheter penetration length during artificial insemination (AI)] and the uterine capacity in a homogeneous group of gilts. Sixty-six commercial-line gilts in pre-pubertal phase had their oestrus induced by hormonal treatment [600 UI of Equine Chorionic Gonadtrophin (eCG) i.m. and after a 72-h period 5 mg of luteinizing hormone (LH) i.m.], but only 40 gilts showed cyclicity after induction. The AI catheter penetration length was tested on these 40 gilts at the moment of AI using a
calibrated AI catheter. Four gilts returned to oestrus and the other 36 were killed at around day 69 of pregnancy. The uterine length and weight showed a significant and positive correlation with the prenatal survival rate (p < 0.05). The catheter penetration length was unable to predict the
conceptus survival rate on 70 days of gestation; however, the uterine size influenced the survival rate positively. The mean placental area was positively correlated with the mean placental weight (p < 0.0001), and both with the mean foetal weight (p < 0.0001 and p < 0.001, respectively). The
analysis of the results obtained showed that neither did the catheter penetration length measurement during AI, nor the prenatal survival rate on day 70 of pregnancy predict the uterine capacity, but the uterine and placental size had a significant influence on the prenatal survival and foetus
weight, respectively.
Vocalisation of domestic pigs (Sus scrofa domestica) as an indicator for their adaptation towards ambient temperatures.
Posted in: Welfare by admin on | No Comments
Vocal communication is known to be an important part of communication in both wild and domestic pigs. Calls encode information about the emotional state of an animal and may reflect its need for social and non-social resources. Recently, analysing the vocalisation of farm animals has become an increasingly important tool for evaluating animal welfare. The objective of this study was to test whether the vocalisation of fattening pigs can be used to assess their adaptability to ambient temperatures. The pigs were kept in conditions comparable to those of commercial housing and were exposed to high and low temperatures for several days. The pigs were observed at body weights of 25-35, 50-70 and > 80kg. Vocalisations were recorded during 23.00 to 5.00 h and analysed using an artificial neural network. The results indicate with decreasing temperatures, huddling of pigs to be increased. The increase of huddling was also accompanied by an increase in high-vocalisation. Pigs produce more high-frequent vocalisation and huddled less with increasing weight. The findings of this study suggest that huddling results in a state of discomfort in at least medium and heavy pigs and this is reflected by changes in vocal behaviour. Smaller pigs seem to be less affected by huddling than heavy pigs. In this study, high frequency vocalisation that was produced in situations of disturbed lying behaviour proved to be a powerful indicator for thermoregulatory reactions to low ambient temperatures in medium-weight and heavy pigs. This opens up the possibility to use high-frequency vocalisation for an automatic acoustic monitoring of the behavioural adaptation of fattening pigs towards cold. The use of acoustic monitoring will potentially help animal caretakers to optimize the environmental control.
Endotoxin stress responses in chickens from different genetic lines. 1. Sickness, behavioural, and physical responses
Posted in: Welfare by admin on | No Comments
The study examined the variation in the response to the endotoxin lipopolysaccharide (LPS) in commercial Dekalb chicks or those that were bred for high (HGPS) or low (LGPS) group productivity and survivability (in response to cannibalism and flightiness). Six-week-old chicks housed in colony cages were randomly assigned to either the experimental or the control treatments. The experimental group received an intravenous injection of Escherichia coli LPS (5 mg/kg of body weight), while the control were injected with distilled saline. Clinical symptoms of infection were monitored on 6, 12, 24, 48 and 72 hours after the injection. All the chicks that were injected with LPS exhibited clinical signs of illness. However, the extent of the reaction was genotypically and phenotypically specific. The HGPS chicks underwent brief, but severe behavioural and physical changes, when compared to the Dekalb and LGPS chicks. The body weight gain, organ development and core temperature were most significant in LGPS, lowest in HGPS, while the Dekalb were between the two extremes. The varying responses to the LPS challenges of chicks that underwent different genetic selection indicate that each line adapts differently to stress and their resistance to infection and inflammation. Therefore, when studying the impact that environmental-genetic interactions have on the behaviour and physiology and the subsequent response to stress and disease, the genetic lineage of the chicken needs to be taken into account.
Duration of cold stress modulates overall immunity of chicken lines divergently selected for antibody response
Posted in: Welfare by admin on | No Comments
The effect that the duration of cold stress in reference to how long after the chickens were immunized was studied in three lines of chickens. Two of the lines were bred for either high or low antibody responses and the control was a random-breed line. The chicks were restricted fed at 80% of ad libitum intake levels. Chicks that were 26 days old were exposed to 10ºC temperatures for 0, 2 or 7 days. The chicks were immunized with keyhole limpet homocyanin (KLH) –1, +1, +3, +5 or +7 days following the cold stress. The cellular immunity of the chicks was measured by in vitro lymphocyte proliferation in response to concanavalin A (conA) and KLH. Phagocytosis was measured also measured. The exposure to cold stress negatively affected the body weight gain of the chickens. Exposure to cold stress for seven days significantly enhanced cellular immunity to conA. However, exposure to cold stress for two days had a varying effect on the lymphocyte proliferation in response to conA and was dependent on the chickens’ genetics and the timing of the immunization. The lymphocyte proliferation in response to KLH was enhanced in hens that underwent two days of cold stress 28 days after they were immunized. Cold stress did not affect the antibody response to KLH, but it delayed the mitogen response to conA. The high antibody line of chickens had a higher response to KLH than the other lines. The lymphocyte response to conA was lower in chickens bred to have lower antibody responses. The response of the immune system (phagocytosis) to cold stress was immediate. However, this response was quite variable and the response was not affected by whether they were chickens bred to have high or low antibody responses. When the chickens underwent cold stress for a longer amount of time, the cellular adaptive response, and the humoral immune response were affected to a small degree. There was not an interaction between genetic lines and treatments, which suggests that the genetics that affected the degree of the specific immune response. Overall, when a chicken is feed-restricted and undergoes stress at the same time, their cellular immunity is more sensitive than their humoral immunity. As well, the negative correlation between body weight gains and cellular immunity implies that by enhancing one trait results in the impairment of the other.
Accompanying pre-weaned Thoroughbred foals while separated from the mare during covering reduces behavioural signs of distress exhibited
Posted in: Welfare by admin on | No Comments
During breeding (covering) on some Thoroughbred farms the mare id taken from the box stall in which it is kept with its foal to be serviced by the stallion. The foal is left behind in the stall and often behaves in a manner that would indicate stress and that could result in injury. In this study involving 57 foals, approximately half were accompanied by a handler in their box stall while the mare was absent. The handler stood in the stall and only interacted with the foal if it approached and initiated contact. The non-accompanied foals were left alone in their stalls and observed from outside. Accompanied foals vocalized less and spent less time pawing than did the nonaccompanied foals. Approximately half of the nonaccompanied foals also hurled themselves against the stall wall while non of the accompanied foals did so. The presence of a human in the pen during the mare’s absence reduced the stressfulness of the situation and potentially harmful behaviour.
End-of-cycle bone quality in white and brown-egg laying hens.
Posted in: Welfare by admin on | No Comments
Depletion of bone calcium during the laying cycle results in weakened bones at end-of-lay. The danger of bone breakage in the cage or during handling at disposal is a welfare problem. In this study two strains of hens, one brown (Shaver 579) and one white-egg (Shaver 2000), were studied at the end of lay. The white-egg strain had produced more eggs during the cycle than the brown-egg strain, but the brown-egg strain produced larger eggs with more shell material. The brown-egg strain was slightly heavier at the end-of-lay as well. Bone density of the femur did not differ between strains, but all measures for the humerus and all remaining measures for the femur indicated that the bones of the brown-egg strain were stronger at the end-of-lay. Bone breaking strengths were approximately 20% greater for the brown-egg line. Of the two lines tested, the brown-egg line had better bone quality at the end-of-lay and would be less susceptible to breakage and poor welfare. However, it should be recognized that only one line of each egg type was studied and it cannot be determined if these differences are due to egg-type or unique to the strains studied.