Ekologisk slaktgrisproduktion Del 2, Produktion, djurhälsa, välfärd, funktion och miljö
Olsson, Anne-Charlotte; Wachenfelt, Hans von; Jeppsson, Knut-Håkan; Svensson, Gunnar; Botermans, Jos; Svendsen, Jørgen; Andersson, Mats
The organic slaughter pig production in Sweden needs to be greatly enlarged. Therefore an interdisciplinary research program for organic pig production (EKOPIG) with funding mainly from Formas and SLU has been initiated. Part of this program (Part IV) has been carried out at SLU-Alnarp. These studies have focused on housing systems for organic growing-finishing pigs. The aim was to compare different housing systems for organic growing-finishing pig production, taking into account the animals and their well-being, production, straw usage, health status, labour requirements, environmental aspects, plant nutrient utilization and leakage of nitrogen, phosphorus and potassium, pasture damage, etc., in order to obtain a comprehensive impression of the different solutions. A brief summary of the thoughts behind the experimental design, aims, parameters investigated and the most important results are presented in Tables 1a, 1b and 1c. As a part of the project and in order to be able to carry out the actual study, an animal house for organic growing-finishing pig production has been constructed at JBT’s research station (=Eko-barn). The Eko-barn has room for 128 pigs in 8 pens of 16 animals per pen. Four pens are designed to have deep straw bedding on the lying area, whereas the remaining four pens have a hut on the lying area with straw bedding and a slanted floor ”straw-flow” on the activity area (Figure 1, 2, 3 and 7). All pens have an outdoor concrete area (Figure 4) and furthermore four pens have access to pasture during summer time (Figure 5, 6). For more details with respect to the building and pen design see the Report Organic growing-finishing pig production, Part 1. A total of five batches have been raised in the Eko-barn, of which three were during the so-called winter period (batches 1, 2 and 4), and two during the so-called summer period (batches 3 and 5). Batch 1 was considered to be a pilot study since the handling and management routines in the newly constructed building had to be established and adjusted. The results from that batch therefore were not included in the final calculations. In Table 2, there is a summary of the experimental conditions and studies carried out during the different batches. Due to various problems with the organic feed, a total of three different types were used during the experiment. The nutrient and protein contents of the different feed mixtures are shown in Table 3. The production results showed that the growth and feed conversion were better during the summer batches than during the winter (Table 4). On average, the pigs grew about 800 g per day and had a feed conversion of 2.9 kg feed/kg growth (ca 36 MJ ME/kg growth) during the summer in comparison with 750 g per day and 3.2 kg feed/kg growth (ca 39 MJ ME/kg growth) during the winter. On the other hand, a considerably better classification and greater percentage of best paid pigs were found during the winter batches produced (Table 4). This could be explained by the organic feed mixture used for summer batch 3 (Eko 2) being poorly balanced, resulting in a poor classification at slaughter for the animals (Table 2 in Appendix). This affected the average values for both summer batches. Straw consumption was considerably greater during the winter than the summer, and the usage was larger in the deep straw bedded pens than in the straw-flow pens (Table 5). No pigs were treated for or showed symptoms of respiratory disease and there were no signs of tail biting. On the other hand, there were quite a number of problems with gastrointestinal disease and diarrhoea, which the pigs brought from the conventional herd they originated from (Table 3 in Appendix). The summary of slaughter notations (Table 6) indicated a relatively high number of registrations of liver damage due to parasites. Studies have been carried out with respect to the necessity of vaccinating for erysipelas, and these results will be further analysed and reported separately. Injury studies of the animals generally showed few injuries, the frequency of which were reduced during the finishing period. The type of outdoor living (only concrete yard or concrete yard and pasture area) did not affect the injury picture (Table 7). In order to study and evaluate the pen function, the utilisation of the pasture areas/yards and roughage by the pigs, their dunging behaviour and their well-being in general, a number of function and behaviour studies were carried out (Tables 9-11, and Figures 8-13). From these results, it was concluded that the activity level of the pigs was the same, irrespective if they had access to the pasture yards or only the concrete area. On the other hand, pigs with access to the pasture and the concrete yards, chose the pasture yards when they were active (Tables 9-10, Figure 10). Dunging studies showed that the pigs preferred to dung on the outside concrete yard whereas they urinated more often inside (Table 11, Figure 11). None of these studies indicated that they urinated or dunged in the lying area of either of the pen types. Hygiene studies showed, however, that there had been a certain amount of dirtying in the lying area, especially in the deep straw bedded pens (Figure 14), even if the hygiene as a total score did not differ between the two pen types (Table 12). The production and distribution of manure/plant nutrients on the different pen areas and the evaluation of the ammonia emission were studied using measurements of the amount of manure and plant nutrient balances. It was found that the NH3-emissionen was approximately 4 times as large from the Eko-barn as from a conventional barn (Table 8 in Appendix). It was evaluated that the higher crude protein content of the organic feed and the poorer feed conversion contributed by a factor of about 1.75 times, and the larger dirty areas by a factor of about 2.25 times. These data indicated that the larger dirty areas are as interesting as the feed when focussing on measures for reducing the nitrogen emission. Ground sample analyses made in the autumn after the pasture season showed an increase in the nitrogen levels in the topsoil (0 to 60 cm) of 24 kg N per ha. This part of the nitrogen should possibly constitute an environmental risk, since it can leach out to the ground area during the late autumn and winter precipitation. The analyses of the ground samples indicated, however, that the major portion of the nitrogen calculated to be in the limited size pasture yards (ca 166 kg N per ha in the pasture yards of 96 m2 per pig) should have been utilised by the plants and grass in the yards. In summary, it can be concluded that the functioning of the organic research animal house was good. It has been easy to manage and supervise the animals due to, among other things, that they were feed inside the house. Since the pigs were fed in troughs, it has also been possible to feed them restrictively without problems during the last part of the finishing period. In addition, the design of the animal house has made it simple to weigh the pigs before slaughter. Therefore, conditions for feeding to obtain a high meat percentage and to slaughter out in the best paid weight interval were good in the animal house design tested. The welfare of the animals was considered to be good in the Eko-barn. Behaviour and injury studies showed that the pigs used all the larger area at their disposition. This apparently led to fewer aggressive incidents and injuries in comparison to those occurring in conventional production. The pigs in the Eko-barn had also fewer slaughter notations due to lung problems than the conventional pigs had. In contrast to the effect on the welfare of the pigs, however, it was noted that the larger areas resulted in an undesirably high ammonia emission. This larger environmental load, in comparison to that of conventional production, is not compatible with the entire idea behind organic production, and is considered to be an important problem for future research in order to obtain a truly sustainable and lasting organic pig production.
slaktgrisar; EKOPIG; djurhållning; ekologisk produktion; inhysningssystem; stallbyggnader; KRAV
Rapport / Sveriges lantbruksuniversitet, Institutionen för jordbrukets biosystem och teknologi (JBT)
Publisher: Institutionen för jordbrukets biosystem och teknologi (JBT), Sveriges lantbruksuniversitet
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