SOLS

Posted in: French Articles by admin on January 1, 2007 | No Comments

SOL ET LE CYCLE DES ÉLÉMENTS FERTILISANTS
Le sol fournit un support aux plantes et il joue un rôle important dans le cycle des éléments
nutritifs/fertilisants, en emmagasinant ceux-ci dans certaines conditions et en les rendant disponibles aux
plantes dans d’autres conditions. Selon l’élément et les variations dans les caractéristiques du sol (comme
texture, structure, pH, densité, contenu en matière organique, drainage, concentrations des macro et micro
éléments, capacité d’échange cationique et le niveau d’activité des micro-organismes), le climat, le cycle
des éléments et la capacité des plantes à récupérer ces éléments, son cycle sera grandement affecté par la
localisation (OMAFRA, 1994b). La disponibilité des éléments pour les plantes varie avec le temps;
seulement une fraction de ce qui est appliqué est utilisée la première année par les plantes et la portion
restante devient disponible aux plantes lentement sur les années qui suivent. Pour le N, cette fraction
varie de 50 à 70% d’utilisation la première année; pour le P, la portion utilisée la première année peut
varier de 10 à 40% selon le mode d’épandage et pour le potassium (K) l’utilisation représente de 20 à
25% (OMAF 1994b; FB 1994). La détermination d’un taux d’épandage ne peut donc pas être faite en
considérant seulement les éléments présents dans le fumier/lisier et les besoins des plantes à fertiliser.
Pour les éléments comme le N, qui est libéré en quantité relativement importante par la minéralisation de
la matière organique dans les sols (50 – 100 kg N/ha par an), la capacité du sol à libérer des éléments doit
être considérée et des analyses de sol doivent être réalisées de manières régulières pour déterminer les
éléments additionnels qui sont nécessaires aux plantes et qui ne sont pas déjà disponibles dans le sol
(Lorimer 1995; OMAF 1994b; Schmitt et Rehm 1997; Goss et al. 1996). De plus l’estimation des
rendements de culture devraient être basés sur les rendements des années antérieures. Une surestimation
de rendement peut entraîner une surfertilisation et un lessivage ou une accumulation d’éléments
fertilisants au niveau du sol. Toutefois une sous-estimation de rendements peut entraîner une sousfertilisation
et ainsi réduire les rendements et la marge de profit ( OMAF 1994b; Schmitt et Rehm 1997;
Lorimer 1995).
Différentes réactions vont survenir après l’épandage. Certaines pertes se produiront sous forme de
volatilisation de N (NH3), de ruissellement, d’érosion, de lessivage et de dénitrification (pertes directes de
N sous forme de N2, N2O ou NO) (FB 1994; OMAF 1994b). Le N et le P sous formes minérales sont
trouvés dans le fumier/lisier mais la plus grande partie de ceux-ci est présente sous forme organique.
Le P est retenu par les particules dans le sol jusqu’à une certaine concentration, toutefois lorsque plus de
P est ajouté du lessivage se produira (FB 1994; Evans et al. 1984; Lorimer 1995; Simard et al. 1996). Le
P inorganique est cependant très mobile et s’attache aux particules de sol et le mouvement du P
surviendra par érosion éolienne et hydrique (OMAF 1994b; Lorimer 1995). Un résultat d’analyse de sol
donnant une concentration en P de plus de 30 ppm indique que les taux d’application de fumier/lisier
doivent être ajustés et que le P doit devenir l’élément limitant dans le calcul des taux d’épandage
(Lorimer, 1995). Pour ce qui est du P, des taux élevés d’épandage entraîne une augmentation de la
concentration de P dans le sol avec le temps. Par exemple, des analyses faites dans les premiers 20 cm
d’un loam limoneux ont montré une augmentation de 50% de la concentration en P de 42 ppm en 1990 à
63 ppm en 1996 et ce pour un taux d’épandage de 77 kg de /ha-an. Pour la même période, la
concentration a augmenté de 49 à 85 ppm pour un taux d’épandage de 97 kg de P/ha-an (Randall, 1997).
Le N présent dans le lisier non traité est principalement sous forme organique et ammonium (NH4
+) et
n’est pas mobile lorsqu’incorporé dans le sol (OMAF 1994b). La forme organique du N et du NH4
+ peut
toutefois se déplacer aux eaux de surfaces si le lisier n’est pas incorporé après l’épandage et que
d’importantes précipitations surviennent causant du ruissellement. Dans le sol, la minéralisation
transforme la partie organique du N en NH 4
+, et généralement la nitrification suivra pour transformer le
NH4
+ en NO3
-. Les sols qui ont un haut taux de NO3
– sont plus propices au lessivage de ce composé vers
les eaux souterraines ou vers le s eaux de surface particulièrement si les sols sont équipés de systèmes de
drainage car cette forme de N est très mobile dans les sols. Le lessivage à travers les sols jusqu’à la nappe
phréatique peut se produire sur une longue période selon la quantité de précipitations qui survient. De
manière à rencontrer les quantités de N nécessaires aux plantes, la contribution en N du sol avant la
fertilisation par engrais minéraux ou organiques (fumier/lisier), la minéralisation du N provenant de la
matière organique, la contribution directe de N de l’atmosphère et la contribution provenant de l’engrais
appliqué doivent tous être considérées (Lorimer 1995; FB 1994; Goss et al. 1996).

A rotational hot gas heating system for bioreactors

Posted in: Energy by admin on | No Comments

A rotating arm made from Teflons pipe perforated with slots for distributing hot gas in a
bioreactor was developed. The rotating movement helps spread the
hot gas to the slurry, which assists in mixing the suspended solids in the reactor. It was found that using Teflons parts and a low oxygen flue gas burner, the
system has the potential to lower the cost of heating bioreactors, aerobic or anaerobic.

Mexico’s Changing Pork Industry: The Forces of Domestic and International Market Demand

Posted in: Economics by admin on | No Comments

Once dominated by traditional and small-scale production
systems with little regulation, Mexico’s pork industry
now includes modern, vertically integrated production
systems and federal inspection of packing and processing
plants. Recent structural changes have resulted in three
distinct segments within the production and processing
sectors as the industry works to adjust to international and
domestic demand for better product quality, stricter sanitary
practices, and increased supplies yet continue to meet
the needs of low-income consumers. As the structural
changes continue, the industry faces several challenges that
will affect its ability to become both internationally and
domestically competitive. To meet these challenges, the
Mexican government is faced with decisions about implementing
and enforcing regulations and providing incentives
to encourage continued development and best serve
domestic consumers.

The welfare of gestating sows in conventional stalls and large groups on deep litter

Posted in: Welfare by admin on | No Comments

Confinement of breeding sows and gilts is one of the most controversial issues in livestock production, together with floor space allowance and lack of bedding (Barnett et al., 2001). However, consideration of the welfare implications of group versus stall housing during gestation is complex. Both housing systems have some clear advantages and disadvantages in relation to pig welfare. For example, individual housing in stalls restricts the sows’ opportunities to exercise, socially interact and interact with other features of the environment, but on the other hand, group housing raises welfare issues concerning space allowance and level of aggression. About 70% of the breeding sows are kept in stalls during gestation (Barnett et al., 2001). The ongoing welfare debate about stall housing has led to the examination of alternative housing systems for breeding sows. There is little information in the scientific literature on the welfare of gestating sows in groups of more than 40 animals and there is no scientific literature on housing breeding sows or gilts in large groups on deep litter. The present experiment measured aspects of the welfare of gestating sows housed in either large groups on deep litter (Hoops) or conventional stalls (Stalls). Six hundred and forty sows were studied, with 40 recently mated sows weekly entering each treatment over an 8-week period; groups of 85 were formed using 40 experimental and 45 non-experimental animals. Sows in Hoops had a higher number of scratches, a higher return rate to oestrus after mating (13.20% versus 7.35%) and there was a trend for higher salivary cortisol concentrations in week 1 of gestation (6.29 nM versus 4.03 nM). Sows in Stalls had a higher incidence of lameness at weeks 9 and 15 of gestation (13.8% versus 0.8% at week 15). There were changes in some leucocyte sub-populations in the Stalls treatment late in gestation: the percentage of neutrophils was higher (46% versus 41% of WBC), the number and percentage of lymphocytes was lower (41.6% versus 46.5% of WBC) and consequently there was a higher neutrophil:lymphocyte ratio (1.22 versus 0.94). There was a trend for a lower reproductive failure in the Stalls treatment (14.5% versus 27.3%); farrowing rate was higher (76.8% versus 66%), and while sows in Stalls weaned fewer piglets per litter (8.31 versus 8.97), the average weaning weight of these piglets was higher (8.69 kg versus 8.01 kg). The combination of these reproductive parameters resulted in sows in the Stall treatment weaning the equivalent of 39 more piglets per 100-mated sows. The results suggest that sows in large groups on deep litter faced greater welfare challenges in the early stages of gestation based on the findings of increased scratches, a higher rate of return to oestrous and a trend for higher cortisol concentrations early in gestation, all possibly a consequence of aggression. In contrast sows in stalls faced greater welfare challenges later in gestation based on a higher incidence of lameness and an increased neutrophil:lymphocyte ratio perhaps as a consequence of increased stress. In conclusion, these data suggest that in both housing systems the welfare advantages and disadvantages change overtime.

Cognitive enrichment affects behavioural reactivity in domestic pigs

Posted in: Welfare by admin on | No Comments

Environmental enrichment can be defined as an increase of the biological relevance of captive environments by appropriate modifications resulting in an improvement of the biological functioning of captive animals (Newberry, 1995). In general, enrichment should present objects or situations to act with a rewarding outcome. In applied ethology improved animal welfare and health as well as an adequate coping with stress are major indicators for assessing the relationship between farm animals and their housing environment. Animals interpret their interactions with the environment in an emotional way on the basis of present and previous experience (Wiepkema and Koolhaas, 1992). This will be the case especially if an animal can expect a rewarding result (Spruijt et al., 2001). Up to now, the development of cognitive tasks to study emotional or hedonic states in animals is rather rare and predominantly restricted to laboratory animals (e.g. Harding et al., 2004; Van der Harst et al., 2005). Therefore, there is an urgent need for increasing experimental research on this field, which should necessarily include farm animals. For this purpose we have recently developed a food-rewarded learning system for pigs using acoustic cues in a combination of classical and operant conditioning techniques (Ernst et al., 2005). The purpose of the present paper was to verify that automated feeding by offering cognitive challenges is functioning reliably and does not impair weight development in replicated trials with pig groups, as should be expected by a successful learning behaviour. However, the main goal was to investigate the effects of a sustained cognitive enrichment on the general behavioural reactivity of domestic pigs. The present study investigated the characteristics of learning behaviour in seven experimental groups (n = 8 individuals each) of growing pigs in postnatal weeks 7–20. The behavioural budget of each group was observed weekly within the housing environment and compared to seven conventionally fed control groups (n = 8), which were supplied with an equal food amount. The alterations of individual behavioural responses after 6 and 12 weeks of cognitive enrichment were analysed in combined open-field/novel-object tests and compared to controls. All experimental pigs were able to discriminate reliably an individual tone that was associated with a locally changing feeding site. Generally, the animals were also willing to work for food (push a button) but this motivation varied considerably between the groups ranging from FR 1 to 10. Sustained cognitive enrichment also affected other behavioural patterns within the housing environment as indicated by an increased locomotor behaviour and less belly nosing. Behavioural test responses were altered towards a greater reduction in open-field activity as well as a reduced excitement and fear behaviour compared to control pigs. Behavioural differences seem to be more pronounced the longer pigs were faced with the cognitive challenge. However, with equal food intake, the weight gain of the experimental pigs was not different compared to the controls. The present study suggests that, in domestic pigs, the presented cognitive enrichment may induce repeated positive appraisals in pigs by the association of successful coping with a demanding behavioural task rewarded by several small portions of food during the day. This appears to agree very well with pigs’ motivational needs and may also be applicable for animal welfare enhancing management of feeding.

Detection of porcine reproductive and respiratory syndrome virus, porcine circovirus type 2, swine influenza virus and Aujeszky’s disease virus in cases of porcine proliferative and necrotizing pneumonia (PNP) in Spain

Posted in: Welfare by admin on | No Comments

Throughput and Economics: Challenges of Constipated Barns

Posted in: Production by admin on | No Comments

Fungal survival in ensiled swine faeces

Posted in: Production by admin on | No Comments

Effects of allometric space allowance and weight group composition on grower-finisher pigs

Posted in: Production by admin on | No Comments

Efficient utilization of pen space without adversely affecting the productivity and well-being of pigs is important for pork production. Previous studies on floor space allowance for grower-finisher pigs have been based on production performance (Edwards et al. 1988; Gonyou and Stricklin 1998) without considering other measures of the welfare of pigs. Lack of space may lead to suppression or displacement of one or more activities causing aberrant behaviour and physiological changes leading to poor welfare and economic performance (Petherick 1983). However, how much extra space can be taken away to minimize cost and to ensure efficient space utilization without adversely affecting well-being and production is not yet well understood. Therefore, the space allowance recommended based on conventional space allowance treatments may not be able to ensure both satisfactory levels of production and welfare along with efficient space utilization. Avoiding weight variation at marketing is essential to minimize discounts for pigs (Payne et al. 1999; Brumm et al. 2002). The effect of rearing pigs of unequal weights together on the final weight of pigs and how space allowance can reduce final weight variation are elusive. In this study, it has been hypothesized that the performance and welfare of pigs improve with increasing space allowance. It is also hypothesized that the performance and welfare of pigs improve by allocating pigs of differing body weights to a group rather than allocating pigs of uniform body weight. The average daily gain, pen efficiency and welfare indicators (injury levels, salivary cortisol concentrations and behaviour) of grower-finisher pigs were evaluated in groups of 19 barrows, at four levels of floor space allowances calculated mathematically (area = k × BW0.667) using a constant k, (with values 0.027, 0.031, 0.034, and 0.037) for a mean final market weight of 116 kg and in two levels of group weight composition (uniform and varying weights – based on uniformity and variation of body weights of pigs within a pen at the beginning of the experiment). The corresponding space allowances at the market weight of 116 kg were 0.64, 0.74, 0.81, and 0.88. The data were analyzed using repeated measure ANOVAs and independent sample T tests. The pigs in 0.64 had a lower average daily gain, spent a lower proportion of time lying in preferred areas and had higher total injury scores and higher number of aggressions than those in 0.88 and 0.81. Pigs in 0.64 had higher overall pen efficiency than those in 0.88, 0.81, and 0.74 allowance treatments. Pigs in the varying weight group spent a higher proportion of time lying in preferred areas than the uniform weight group. Pigs in 0.74 and 0.64 spent lower proportion of time lying isolated than pigs in 0.81. The uniform weight group exhibited more exploratory behaviour than the varying weight group. On fully slatted floors, space allotted considering the final market weight of barrows corresponding to k values of 0.037 and 0.034 were better than 0.027 in terms of growth rate and welfare indicators. The results suggest that grouping grower-finishers according to uniformity or variation in body weight may not provide any differential benefit in overall welfare, although a beneficial effect was observed in terms of injury scores, aggression and lying behaviour by increasing space allowance.

How to Keep Pigs Flowing when Space is Limited

Posted in: Production by admin on | No Comments

As producers improve their reproductive herd performance with both genetics and management, the number of pigs weaned per litter and per week increases. At the same time, slaughter weights are increasing. Combined, these improvements mean too many pigs in the facility and other issues related to pig flow in facilities become a bigger concern. One option to deal with more weaned pigs is to fill a room at weaning to a fixed capacity, with the excess pigs beginning to fill the next nursery room. The challenge in this is that heating and ventilation systems are not designed for partial room fills. A second challenge to this option is that the number of days available for nursery pig growth decline. This creates tremendous stress on the grow-finish rooms since the pigs are now close to 3 kg (6.6 lb) lighter at placement into these rooms. To make this option work, the producer needs to add at least 1 more nursery and/or finishing room. This comes at a huge price since the number of days pens/rooms are not stocked with pigs increases in the system, adding to the capital expense of production. An option that some producers are using is to modify pig flow by going from a weekly farrowing system to a batch farrowing system. That is, instead of farrowing 30 sows every week, they are farrowing 120 sows once every 4 weeks. They accomplish this by breeding for a 2 week period with a 2 week non-breeding period. This keeps weaning age of pigs within a batch fairly close (within 2 weeks) and allows for a large number of pigs to flow through the system at one time (approximately1100 pigs every 4 weeks). Larger groups of pigs also solve the problems of small pig numbers in one or more rooms since there are larger numbers of pigs available for allocation across a number of rooms. One challenge in this scenario is the limit of 6 weeks of nursery capacity (6 rooms) when farrowing occurs every 4 weeks. The solution is to add 2 nursery rooms so that nursery capacity matches farrowing capacity. There then is 8 weeks of nursery capacity, with the pigs remaining in the nursery for 52 days before relocation to growing-finishing rooms. This often means the pigs are 7+ kg (15+ lb) heavier at placement into the growing-finishing phase of production, which results in more opportunities for the pigs to achieve the desired sale weights prior to the need for the space for the next group of nursery pigs. A second challenge is the altered labor intensity in the breeding/gestation and farrowing facility. With batch farrowing, instead of weekly matings, farrowings, weanings, everything is concentrated in a 2 week period with the other 2 weeks having a relatively light labor demand. With the recent approval for dietary inclusion of ractopamine (Paylean®, Elanco Animal Health, Indianapolis, IN) in finishing diets in Canada, growers in both the US and Canada can now use this product to improve daily gain and carcass lean. While use of Paylean® in late finishing diets will improve pig flow from finishing rooms, it doesn’t solve space issues associated with overcrowding in the nursery. Pig flow problems can become very real as the industrymakes genetic and management progress. While all-in/all-out pig flow is desired for maximizing pig health and minimizing disease transfer between multiple ages of pigs in a production system, the reality is that space becomes a very real limit to performance as productivity increases. Future investments in facilities must include consideration of pig flow options so that improvements in reproductive performance and/or further increases in sale weight can be accommodated more readily than is possible with current fixed flow systems.