Feed Intake and Weight Loss Before and After Weaning and the Effect on Reproductive Performance

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Feed restriction during late lactation in primiparous sows results in increased catabolism and has traditionally resulted in reduced litter gains, a marginal increase in the weaning-to-estrus interval (WEI), and reduced embryonic survival and development to day 30 of gestation in the subsequent litter. However, in recent studies even these detrimental effects have not been consistently observed. Even when sows are induced to lose large amounts of body weight during late lactation, the resulting WEI and embryonic survival rates are comparable to sows that lose marginal amounts of body weight. An established experimental design was used to study the effect of feed restriction during the last week of lactation in primiparous sows on litter growth, WEI and embryonic growth and development. As an extension of these investigations, the effect of feed restriction during late lactation on feed intake and sow metabolic state between weaning and breeding was also examined. Control (CON) sows were fed their predicted voluntary feed intake from day 15 to day 21 of lactation, restrict (RES) sows were fed 50% of their predicted voluntary feed intake over the same period. As expected, 50% feed restriction between day 15 and day 21 (weaning) of lactation resulted in greater body weight and backfat loss, and compromised litter gains in RES compared to CON sows. However, between weaning and breeding RES sows consumed more feed and gained more weight and backfat depth than CON sows, resulting in no significant differences in weight or backfat depth at breeding. There were no significant effects of treatment on sow reproductive parameters as measured by WEI, ovulation rate, embryo number and survival, or embryo characteristics. It was concluded that under good management practices, acceptable production performance is achievable even in first parity sows that are catabolic after weaning. 93% of sows returned to estrus within 10 days, 100% of sows were bred, and 89% conception rate was achieved. Maximizing feed intake of first parity sows after weaning may negate short-term detrimental effects of lactational catabolism.

Influence of access to grass silage on the welfare of sows introduced to a large dynamic group

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This experiment investigated the effects of providing access to grass silage on the welfare of sows
introduced to a large dynamic group. Two treatments were applied: (1) access to racks containing grass
silage (offering an average of 1.9 kg silage/sow/day), and (2) control treatment with no grass silage racks. It was found that overall the levels of aggression to which newly-introduced sows were exposed on the day
of introduction to the group were low, and did not differ significantly between treatments. In
addition, injury levels measured 1-week post-introduction to the group did not differ significantly between
treatments. Sham chewing behaviour was more prevalent in the post- rather than the pre-feeding
yard, and was significantly reduced in both resident and newly-introduced sows when silage was
provided

Macronutrient digestibility in Kadon pigs fed diets with isonitrogenous amounts of various carbohydrate sources

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The behaviour, welfare, growth performance and meat quality of pigs housed in a deep-litter, large group housing system compared to a conventional confinement system

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Deep-litter, large group systems have been developed as an alternative housing system for growing pigs. These systems are cheaper to establish and are perceived as being more welfare friendly for pigs, compared to conventional housing systems. Deep-litter, large group systems offer more pen space per pig (approximately 1 m² per pig), larger group sizes (ranging from 150 to 2000 pigs per pen), an enriched environment, (an environment which provides an outlet for rooting and foraging in deep bedding), together with the opportunity for increased social interaction among pigs (Morrison et al., 2003a,b). Conventionally, pigs are housed in more confined systems with fully, or partially slatted floors, liquid effluent system, group sizes ranging from 5 to 50 pigs with a floor space allowance of approximately 0.7 m² per pig. Anecdotal evidence suggests that pigs raised in deep-litter, large group systems are less fearful of humans and novel objects and are easier to handle when transporting. It is difficult to compare housing systems since they are often confounded by factors such as pen space, group size, environment and substrate provision. The scientific literature is deficient in information on the relationships between these factors and pig behaviour in large multi-factorial experiments. The aim of this experiment was to compare the behaviour, welfare, growth performance, and meat quality of pigs in a deep-litter, large group housing system compared to a conventional housing system. Castrated males were housed from 9 weeks of age in a conventional housing (15 pigs/pen; 1.0 m²/pig) or deep-litter, large group housing system (90 pigs/pen; 1.7 m²/pig). Behavioural observations and stress physiology measurements were conducted at 9, 17 and 22 weeks of age. The willingness of the pigs to approach a novel object was assessed using a standard novel object test at 22 weeks of age. Pigs in the deep-litter, group-housing system spent more time standing, locomoting, and interacting with their environment compared with contemporaries housed in the conventional system. At 17 weeks but not at 9 or 22 weeks, pigs in the conventional housing engaged in more social interactions than deep-litter housed pigs. Salivary cortisol was higher in deep-litter pigs compared to conventional pigs at 9 weeks of age but was similar at 17 and 22 weeks of age. Pigs in the deep-litter, large group system exhibited more exploratory behaviour compared to conventionally raised pigs in the novel test. Loins from pigs housed in the deep-litter, large group treatment had lower loin pH, more purge loss, more glucose in purge and were lighter in subjective colour than loins from conventionally housed pigs. A trained sensory panel detected no differences in tenderness, juiciness or overall desirability of loins from deep-litter or conventionally housed pigs. In this experiment, the housing system modified pig behaviour, fearfulness and stress physiology (at 9 weeks of age) but these differences did not negatively impact meat quality.

Overview of PCVD – The Disease in Eastern Canada & US vs. Europe

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Starting at the end of 2004, and particularly since the beginning of 2005, cases of post-weaning multi-systemic wasting syndrome (PMWS) in Quebec increased dramatically. Simultaneously in Ontario and a little later in North Carolina, the same phenomenon of dramatic increase in PMWS cases was observed. This paper tries to shed some light on the possible reasons why this may have occurred and on what can be done to control the losses. This paper also briefly looks at some of the conditions, other than PMWS, that might be associated with porcine circovirus type 2 (PCV2), and at a few similarities and differences that may exist between the European situation and the one we have to deal with in Eastern Canada and the US. The acronym PMWS is gradually being replaced in Europe by PCVD (porcine circovirus disease) and in North America by PCVAD, (porcine circovirus associated disease). Reasons for this switch include: 1) wasting is not specific to PCV2; 2) PCV2 has been associated with conditions in pigs other than PMWS; 3) the word wasting might have a negative impact on public perceptions of the swine industry, and of the safety of pork. Two main positions are currently debated. There are those who believe that PCV2 is the cause of PCVD, although other factors or agents may contribute significantly to the losses associated with it in the field, and that another as-yet-unidentified agent, often called agent X, might be the real culprit. The virus can be transmitted in various ways, it has been reported to be excreted through nasal and ocular secretions, urine, feces and colostrums, it is also present in semen and some boars have been found to shed it for at least 24 weeks (McIntosh et al, 2005); it is very persistent in the environment, and pigs from herds with no clinical signs can contract the disease if placed in contact with sick pigs, or if placed in close proximity (Kristensen et al, 2004). Many other ways that PCV2 can be transmitted are also summarized in this paper. The best chances of success or improvement when PCVD is a problem are genetic changes, vaccination, management changes, serotherapy, the control of other diseases, like PRRS, that can trigger the condition or increase its severity and depopulation/repopulation. Strategies that have been suggested to help control PCVD include: reduce the number of weaned or feeder pig sources; reevaluate the vaccines and vaccination programs used; use disinfectants (e.g. Virkon S) that have good activity against PCV2; batch farrowing every 2, 3, 4 or even 5 weeks; partial depopulation of the nursery; bioflavonoids, vitamin E and Se, antioxidants, mash feed, feeds with larger particle size, restricted feeding, no feed changes after moving pigs, richer diets; no hospital pens, either euthanize sick pigs or move them elsewhere; increase weaning age; acetaminophen, acetylsalicylic acid, florfenicol, tilmicosin; closing the herd; use measures to improve colostrum intake; all piglets to suckle their natural mothers for the first 24 hours. The list seems almost endless and one must admit that the results obtained have been very variable, and quite frequently disappointing. There are, however, situations showing that management strategies and infection pressure may have a significant impact on the outcome. PMWS/PCVD/PCVAD has produced severe losses for pig producers in many areas of the world. While North America has to a certain extent avoided these severe losses until recently, we now have areas where losses are unacceptably high and solutions have to be found. Different control alternatives have been briefly discussed in this paper. In my opinion the two approaches most likely to make our lives easier with this condition are genetics and vaccines. Some genetic lines or combinations are clearly more resistant to PCVD than others, and the preliminary results obtained with vaccines are very encouraging. An effective and practical control of the problems associated with PCV2 now appears possible.

Zinc uptake in swine intestinal brush border membrane vesicles using a 65Zn/69mZn duel isotope experiment

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Supplemental zinc as ZnO is routinely added to nursery pig diets at 15 to 20 times the nutritional requirement to alleviate physiological stress and enhance performance. The mechanism by which Zn accomplishes this function is unknown, however, high concentrations of Zn are excreted in the environment at undesirable levels. To study Zn uptake, we developed a multi-stage digestion model followed by exposure to swine intestinal brush border membrane vesicles (BBMV). We report on the feasibility of using a duel label (65Zn and 69mZn) to simultaneously quantify the competitive uptake of Zn from co-existing zinc supplements using our BBMV model.

Relationship between residual energy intake and the behaviour of growing pigs from three genetic lines

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Improved feed efficiency is one of the major objectives of animal breeding. Measurement of residual metabolizable energy intake (RMEI) has been proposed and studied as an alternative to the feed to gain ratio to evaluate feed efficiency in laying hens (Bordas and Merat, 1980), dairy cattle (Korver, 1988) and pigs (Mrode and Kennedy, 1993). The RMEI is the difference between actual energy intake and the estimated energy requirements for maintenance and production. Variation in RMEI between animals may result from differences in maintenance requirements or in the utilization of dietary energy for production. However, the variation in RMEI may also result from measurement errors or errors in the estimation of its components (Luiting, 1991). For instance, differences in animal’s activity might be an important source of variation in maintenance requirements (de Haer et al., 1993). Thus, Luiting (1991) demonstrated that hen lines selected for high RMEI produced more heat than those selected for low residual feed intake, resulting in part from their enhanced physical activity (between 30 to 50% higher). More recently Gabarrou and Géraert (1994) suggested that this increase in heat production could result from an increased basal metabolic rate, physical activity or diet induced thermogenesis. de Haer et al. (1993) found that RMEI was strongly correlated with feeding frequency and duration, indicating that RMEI increases when feeding activity increases. These authors indicated that feeding activity alone explains 44% of the variation in RMEI. According to these results it can be hypothesized that, between genotypes or between individuals, RMEI variation results from variation in animal behaviour, the latter being an important determinant of energy requirements for maintenance. In particular, differences in nervousness, aggressiveness and physical activity in pigs might be at the origin of differences in RMEI. In growing pigs from three genetic lines, namely Genex Meishan-derived dam line (GM), Synthetic Genex 3000 (SG) and purebred Large White (LW), RMEI was determined and related to behaviour by factorial Partial Least Squares analysis. Behaviour was measured by observations of daily behaviour in the pen, postures, feeding behaviour, aggressive behaviour after mixing and ease of handling at weighing. The RMEI obtained for the GM pigs was lower (P=0.003) than that of the two other lines studied (LWand SG). This difference may result from inaccuracy in the estimation of requirements. A small proportion of these differences were explained by differences in behaviour. Indeed, standing posture, time spent in the feeder, toy manipulation, aggressive and locomotor behaviour explained part of the variation in RMEI, presumably because an increase in these physical activities induces higher energy expenditure. Vocalisations during manipulations at weighing were the only behaviour related to stress that influenced RMEI.

30 pigs/sow/year – Impacts on the Sow

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Since the early 1990s, the application of genetic selection for litter size has led to an increase of up to 3.5 pigs per litter at dam line nucleus level, with the largest improvements shown in the French and Danish breeding programs. This has translated into the potential for a total litter size born of 15 or more piglets, providing the possibility for commercial producers to wean more than 30 pigs/sow/year (psy). However, there are a number of disturbing negative aspects of the rush towards increased sow productivity, which have implications for the sow and also her progeny’s health, growth, efficiency and carcass quality. Foxcroft (2007) described the phenomenon of pre-natal programming, and suggested that the large increase in ovulation rate in modern, higher parity, sows leads to uterine crowding, intra-uterine growth retardation in the embryo and foetus and a reduction in muscle fibre numbers. In practice, this leads to a number of problems, including lower immune status (Harding et al., 2006), and slower growth and poorer carcass quality in pigs from litters with a low average birthweight (Foxcroft et al., 2007). The other negative change that has taken place is that sow death rates have gone up significantly, especially in North America (Peet, 2005b). While the reasons are complex, there seems no doubt that the greater nutritional and physical strain on the sow as a result of the increased productivity is a major factor. Also, the decrease in gilt and sow backfat levels as a result of selective breeding for leaner, fast growing and efficient pigs, means that they have less tolerance to deficiencies in management, environment and nutrition. Lean animals are more prone to physical injury, which may lead to culling. Another factor is the intensification of production systems leading to harsher conditions, which are more likely to lead to injury, combined with a lack of suitable hospital facilities to deal with sick, injured or disadvantaged gilts and sows. The focus of management should be to nurture the gilt and second parity sow so that she reaches the highly productive 3-6 parity stage, thereby increasing average sow longevity. Foxcroft et al. (2007) reviewed information indicating that when high numbers of developing embryos implant in the uterus early in gestation (up to day 30), those that survive to term develop into compromised pigs with reduced growth potential. Piglets from litters with low average birthweight are all compromised, regardless of their relative birthweight within that litter. There are two aspects of dealing with this situation in respect to the gilt and sow. The first is to improve the nutritional status of the female in order to increase the nutrient supply to the developing embryos. The second is to improve the size and quality of the follicles released in order to reduce the “pre-natal programming” effect. Both of these will help to improve the quality of the piglet born and its growth potential. Herds with very high litter size tend to have a disproportionately high number of stillborn piglets, which is likely due to a lack of thriftiness caused by pre-natal influences. Therefore, close monitoring of farrowing, and management measures to reduce stillbirths, have become essential in herds with high numbers born. This will also lead to a reduction in post-farrowing piglet deaths by increasing piglet viability. Also, measures to increase survival, such as drying piglets off after birth, assisting them to suckle and placing them under a heat source, will be especially helpful to low birthweight litters. There is a wide range of nutritional and management strategies that can be used to counteract these potential problems. However, further work is required to understand the implications of higher litter size for management systems after weaning and the comparative economics of managing pigs based on their average litter birthweight or according to individual body weight.

An Overview of the Animal Care Assessment Program

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The treatment and care of animals is important, as is outlined in the 1984 Code of Practice for the Care and Handling of Farm Animals: Pigs. These codes provide information about recommended practices to produces and interested parties. There is now a program in development that looks at promoting sound animal care practices on Canadian hog farms, providing a mechanism to demonstrate that the practices are being followed, and building confidence throughout the supply chain and consumers. This program is called the ACA. This program will be delivered through the CQA agency in each province. This program will efficiently be implemented in the near future.

Relationship between growth and non-nutritive massage in suckling pigs

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Nursing in piglets relies on a particularly complex communication system, due in part to piglets being a precocial and a polytocous species lacking a milk cistern, such that milk is available at all teats simultaneously only for very short periods of time throughout the day. After lactation is established during the first couple of days, nursing becomes synchronous and cyclical, with all piglets suckling simultaneously every 30–70 min, over 20 times a day (Fraser, 1980; Lewis and Hurnik, 1985). These regular nursing bouts include five discrete phases that are observable in both domestic (Fraser, 1980) and wild breeds (Horrell, 1997). The first three phases involve the communication and coordination between the sow and her litter to ensure piglets arrive at and stimulate the udder to induce milk ejection (Algers, 1993; Bazer et al., 2001). Once the sow and piglets are synchronized and the udder has received adequate stimulation, the fourth phase, milk ejection, occurs (Fraser, 1980). The fifth and final phase of piglet nursing involves massage after milk is ejected. This period involves both massage and slow sucking (Fraser, 1980) and is very variable in length, depending on whether the sow or piglets terminate the nursing bout (Jensen et al., 1998) and on the age of the piglets (Horrell, 1997). The final massage is generally longer in duration than the massage prior to milk ejection (Algers and Jensen, 1985) and involves the expenditure of substantial amounts of energy (Klaver et al., 1981) that would seem to be counterproductive for animals trying to survive and grow. The objective of this experiment was to determine if there is a relationship between non-nutritive massage and growth in the young pig over the course of lactation. The suckling behaviour of 195 piglets from 20 litters was observed during at least three nursing bouts on each of three separate days. Piglets were weighed at birth and at 15 days post-partum, and 15-day growth rates were calculated. There was a significant difference between and within litters in suckling behaviour performed after milk ejection. Growth rates were negatively correlated with suckling during the final massage for individual piglets (r = -0.26; P < 0.003) and entire litters (r = -0.79; P < 0.001). Slower growing piglets also performed more suckling behaviour between nursing bouts r = -0.23; P < 0.05) and during incomplete nursing bouts (r = -0.30; P < 0.01) Piglets that performed the final massage consistently grew slower than those not involved with this costly behaviour. This data supports the hypothesis that massage after milk ejection is representative of piglets’ nutritional need. However, it appears that a lengthy massage does not result in an overall net return on piglet growth rate.