The accumulation of skin lesions and their use as a predictor of individual aggressiveness in pigs

Posted in: Welfare by admin on January 1, 2006 | No Comments

Under wild conditions, the ancestors of the domestic pig cohabit in small, genetically related matriarchal groups. Outside of the mating season, aggression between individuals is infrequent and rarely injurious; a feature common to domestic pigs housed in an extensive enclosure (Stolba and Wood-Gush, 1984, 1989; Mendl, 1995). Group social stability is facilitated by the infrequent and gradual integration of new members to the group (Mauget, 1981), close kinship, the preservation of individual space and the use of threats and non-aggressive behaviour to maintain dominance relationships (Mendl, 1995). In contrast, many commercial pigs are repeatedly exposed to sudden mixing episodes with unrelated animals in an environment that limits effective dispersal and the display of appropriate submissive behaviour. Under these conditions, post-mixing aggression is intense during the first 24 h after mixing (Meese and Ewbank, 1973), but varies considerably between members of the group (Mount and Seabrook, 1993; Erhard et al., 1997). The number of skin lesions (lesion score, LS) has frequently been used as a proxy indicator of the extent of post-mixing aggressive behaviour. This approach offers a rapid means of assessing aggressiveness of a large number of pigs and has been used commonly when investigating the development of aggression over several days or weeks or when using large social group sizes (e.g. Francis et al., 1996; Erhard et al., 1997; Spoolder et al., 1999; Turner et al., 1999, 2000, 2002). The objective of this work was to investigate the factors that contribute to LS in order to assess the validity of LS as a measure of individual aggressiveness. After mixing into new groups of 12, the durations of reciprocal fighting and bullying, the proportions of fights initiated, won and lost and physical attributes of the pigs were investigated for their impact on LS using multiple regression on a sample of 342 growing pigs. Pig live weight was the single greatest determinant of LS. The duration spent in reciprocal fighting and being bullied were also significant determinants of the LS and contributed to the total LS in proportions of 0.17 and 0.14, respectively. The proportion of fights initiated, won and lost did not influence the LS for pigs of a given weight. On an individual pig basis, it was impossible to establish the relative importance of reciprocal fighting and the receipt of bullying to the accumulation of lesions by reference to the total LS alone. Engagement in reciprocal fighting was found to result in lesions to the anterior third of the body, whilst the receipt of bullying resulted in lesions accruing on the caudal third of the body. Reference to the location of lesions, in addition to their number, is a refinement of the methodology that potentially allows discrimination of pigs that accumulate lesions as a result of reciprocal fighting or receipt of bulling. A partial replication of the experiment at a second unit (n = 84 pigs) with different genotypic, environmental and husbandry conditions confirmed that the duration spent in reciprocal fighting and being bullied were significant determinants of the LS and that the LS approach is applicable across units. These results suggest that the LS methodology provides a rapid means of estimating aggressive behavioural phenotypes when reference is made to both the number and location of lesions and pig weight and pen identity effects are accounted for.

Circovirus – What is this New Disease?

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Porcine circovirus type 2 (PCV2) is found all over the world in domestic pigs. It was first identified in Western Canada in 1991. PCV2 is associated with a number of disease syndromes termed porcine circovirus diseases (PCVD). Post weaning multi-systemic wasting syndrome (PMWS) is the most economically significant expression of the disease, and it can have a severe impact on nursery and/or grower production. PCV2 can be found in all herds, but not all herds have PMWS. We believe that other factors in addition to the virus are needed to trigger PMWS. Some of these factors include the co-existence of other diseases agents such as PRRS, as well as management or production issues such as overcrowding, mixing, grain molds, and other stresses. Also, we believe that there has been some genetic change in the virus compared to the original virus. The new “strain” of the virus has been identified in herds that have experienced the most significant clinical problems. PMWS generally affects pigs that are around 2 to 4 months old. The common clinical signs are wasting or weight loss, pale or yellowish skin color, labored breathing, and diarrhea. Very commonly, affected pigs will have noticeably enlarged lymph nodes. Most herds have seen individual pigs affected with PMWS. On the other hand, more frequently there are reported cases of “herd breaks” with PMWS where the morbidity (number of affected pigs) can range from 4 to 30%, and the mortality (death loss) can reach as high as 20%. Management of PCV2 and PMWS has been very frustrating. There are no effective treatments for affected pigs. Two vaccines have recently been made available in Canada on an “emergency release basis” so we are hopeful that these will assist in control of the disease. To this point, most of the control strategies have been focused on general management principles that help ensure a healthy pig population and minimize viral shedding. It is difficult for us to tell you what steps to take to prevent PMWS if you have not experienced the disease. All the usual bio-security rules should be adhered to as well as possible to try to prevent introduction of the “new strain” of the virus. Good management principles at farrowing, nursery and finisher stages should be followed to minimize the ability for the virus to express itself clinically.

A Successful Nursery Nutrition Program

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There are many strategies for feeding weaned pigs, but a recent article by five scientists from Kansas State University helps to clarify some of the most important points to ensure a successful nursery nutrition program. First: it’s best to start with as heavy and old a pig as feasible. Second: switch from complex to simple diets as quickly as possible. Third: provide good management — start pigs promptly on feed and water and continually monitor and adjust feeders.

CFIA Carcass Inspection Procedures and Standards: Impact on Producers

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The focus of the CFIA is food safety. When there is a question as to a food or a process being safe or unsafe, the decision is always to make a mistake on the side of safety. In the slaughter plants, this means that if there is a question, the part is either sent as animal food or condemned. There was a directive (or change in procedure) issued in December of 2004 that has changed marking and identifying procedures in slaughter plants. This directive details the responsibilities of the plant personnel and the CFIA personnel. There are now 3 categories of defects: Operator Managed Conditions (such as contamination or over-scalding), CFIA/Operator Managed Conditions, and CFIA Managed Condition. Four items that cause the greatest loss to producers include abscesses (most significant reason for loss), arthritis (about 14% of all carcasses being condemned and about 50% of trim weight), adhesions (about 6 or 7% of the trims), and the deduction for boars and ridglings. Lower trims can be realized by preventing or reducing injuries, preventing or reducing systemic infections, preventing or reducing respiratory problems, and marking all piglets that have not had 2 testicles removed and removing them later.

Optimal Incentives under Moral Hazard and Heterogeneous Agents: Evidence from Production Contracts Data

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Use of Electrolytes to Encourage Early Feed Consumption

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Early-weaned piglets lose an average of 6.9 ± 2.4 % of their body weight in the weaning process. They lose weight for an average of 2.4 ± 1.2 days and regain weaning weight at 3.7 ± 0.98 days. This growth check is a welfare concern as, during this period, piglets are not consuming enough feed and water to meet their physiological needs. It is also a high-risk period for disease, especially diarrhea, and a period of economic loss. Diarrhea, at the time of weaning, can add to the risk of dehydration if piglets are not consuming adequate amounts of water. Up to the point of weaning, young piglets have gained most of their fluid and nourishment through nursing. After weaning, piglets have to learn to consume water and dry feed separately. This may be difficult for some piglets to learn and inadequate water consumption can lead to dehydration. Earlier work has shown that piglets weaned into pens with water and feed show an increase in hematocrit indicative of failure to maintain adequate water consumption. In fact piglets weaned into pens with water and piglets transported without water show similar increases in hematocrit. Adequate water consumption is also necessary to encourage feed consumption. Water consumption by early-weaned piglets is therefore important for early recovery. In this research project we asked the question: If we added something which tasted good (electrolyte solution) to the water would we increase water consumption in the critical 3 day growth check period post weaning? Seventy-two piglets were weaned at 17±1 day of age. Half of this group was placed in simulated transport for 24 h and the other half were placed straight into pens with feed and water. A medicated diet was supplied in standard feeders. Water was supplied through standard water nipples and was gravity fed from containers that could be weighed to measure water consumption. These containers were filled with tap water or water containing an electrolyte solution for 3 days after entry into the pens. On the 4th day all pens received tap water only. The study confirmed that the use of electrolytes in water may help piglets to retain weight and fluid status during the first week after weaning. However, more work is needed to determine the dose and number of days which will be needed to encourage fluid consumption but which will also encourage feed consumption. Spill is also a problem that will need to be addressed.

Factors affecting longevity in maternal Duroc swine lines

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Alberta Pork chair urges greater collaboration throughout pork industry

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The Alberta pork industry will need to work more cooperatively with each other and
think more creatively if it is to have a fighting chance against the challenges it faces
today and in the future, says the chairman of Alberta Pork, the organization which
represents the province’s pork producers.
In a presentation at Alberta Pork’s Annual General Meeting (AGM), Herman Simons
urged all pork industry participants to buy into the Revitalization Strategy developed by
the industry and its partners this year and, in many cases, think beyond it. “We have to
come to grips with the idea that good environmental and animal welfare practices are
baseline expectations of today’s consumers. The next step is differentiating ourselves in a
market built on those expectations,” he says.
Key to this will be the entire industry’s ability to work together toward a common goal of
prosperity.

A Laboratory Scale Sequencing Batch Reactor with the Addition of Acetate to remove Nutrient and Organic Matter in Pig Slurry

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Can Valuable Bioactive Compounds be Obtained from Composted Swine Manure?

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Composted swine manure was examined for the presence of antibacterial and antifungal activities. While commercial composts show some antibacterial activity composted swine manure demonstrated inhibitory activity against Gram-positive bacteria and fungi. Weaker inhibitory activity against Gram-negative bacteria was also detected in composted swine manure. It is likely that these antimicrobial activities are due to compounds produced by bacteria or fungi present in the composted swine manure. An antifungal compound of possible commercial and agricultural significance is present in composted swine manure. Antibacterial agents of the same significance are also present.