«Institut für Tierzucht und Tierhaltung der Christian-Albrechts-Universität, Kiel JOACHIM KRIETER Evaluation of different pig production systems ...»
Arch. Tierz., Dummerstorf 45 (2002) 3, 223-235
Institut für Tierzucht und Tierhaltung der Christian-Albrechts-Universität, Kiel
Evaluation of different pig production systems including economic,
welfare and environmental aspects
The aim of the study is to evaluate different production systems in pig farming including economic, animal
welfare and environmental aspects with computer simulation. The computer model considers a vertically integrated system with farrowing, weaning, fattening and slaughtering stage as well as the transportation of pigs between theses stages. Housing systems were distinguished in individual and group housing with partly/fully slatted flooring or straw. Housing conditions were scaled to animal welfare in a decreasing order from straw, social contact to movement. Environmental issues were measured by nitrogen (N) and phosphorous (P) excretion.
With standard pork production (slatted floors, individual housing of sows, small groups of fattening pigs) the cost per fattening pig accounted for € 131.72, N- and P-excretion were 7.1 and 1.2 kg per head. Group housing for gestating sows (slatted floor) and a higher number of fattening pigs per group increased welfare scoring by 25%. Cost, N- and P-excretion were reduced by 3.5, 5.1 and 5.2%. Group housing of sows during lactation, mating and gestation (with prolonged lactation length 5 weeks; welfare scoring 100%) and straw in each stage raised production cost by 24.6% (€ 32.31), N- and P-excretion were enhanced to 8.0 kg (12.7%) and 1.3 kg (10.5%) per head.
Key Words: pig, production systems, economy, welfare, environment Zusammenfassung Titel der Arbeit: Vergleich verschiedener Produktionssysteme beim Schwein hinsichtlich Ökonomie, Tiergerechtheit und Umweltwirkung Der vorliegende Beitrag vergleicht verschiedene Produktionssysteme beim Schwein hinsichtlich der Ökonomie, der Tiergerechtheit sowie den N- und P-Ausscheidungen mit einer Computersimulation. Das Simulationsmodell generiert ein vertikal integriertes Produktionssystem mit den Stufen Ferkelerzeugung, Aufzucht, Mast und Schlachthof und berücksichtigt ferner die Transporte zwischen diesen Stufen. Die Haltungsverfahren wurden in Einzel- und Gruppenhaltung (Klein-/Großgruppen) auf Voll-/Teilspaltenboden oder Stroh differenziert. Die Bewertung der Haltungsverfahren bezüglich der Tiergerechtheit basiert auf Ergebnissen der operanten Konditionierung. Die Komponenten Stroh, soziale Kontakte und Bewegung wurden in abnehmender Rangfolge gewichtet. Die Einschätzung der Umweltwirkung orientierte sich an den N- und P-Ausscheidungen.
In der Ausgangssituation (Einzelhaltung – Sauen, Kleingruppen – Aufzucht, Mast; Vollspaltenboden) betrugen die Produktionskosten € 131,72 je Mastschwein, die N- und P-Ausscheidungen 7,1 und 1,2 kg. Gruppenhaltung der tragenden Sauen und die Erhöhung der Anzahl Mastschweine je Gruppe steigerte die Tiergerechtheit um 25%, die Kosten sowie die N- und P-Ausscheidungen reduzierten sich um 3,5, 5,1 und 5,2%. Gruppenhaltung in allen Reproduktionszyklen (mit verlängerter Säugezeit von fünf Wochen) und Stroh als Einstreu erhöhten die Produktionskosten um 24,6% (€ 32,31), die N- und P-Ausscheidungen stiegen auf 8 kg (12,7%) und 1,3 kg (10,5%) je Mastschwein.
Schlüsselwörter: Schwein, Produktionssysteme, Ökonomie, Tiergerechtheit, Umwelt 1. Introduction In time of BSE, foot and mouth disease and classical swine fever public concern about quality of animal products and the way of production including food safety and animal welfare has grown. The main focus in public debates about the way in which KRIETER: Evaluation of different pig production systems farm animals live concerns the housing conditions. This context is reflected by the legislation and regulations by the EU and the national administrative involvement.
These regulations have a great impact on pig production and will modify the feature of pig facilities and management tools which influence pig production cost. The present paper elaborates different production systems in pig farming concerning economic, welfare and environmental issues. The analysis was performed with a computer model which simulates a vertical integrated pork production chain. Thus the model estimates the effects of different housing systems on the production cost, welfare and the excretion of Nitrogen and Phosphorous at various stages of a pork production chain.
2. Material and Methods 2.1 General Concept In general the simulation model includes an integrated production chain with vertical linkages between the four stages: the farrowing, rearing, fattening and slaughter of pigs. In the farrowing stage feeder pigs are produced, which are passed onto the fattening stage at a live weight of 28 kg. Animals are slaughtered at a live weight of 115 kg. Carcasses are marketed as a whole or processed further to valuable cuts (e.g.
ham, cutlet, belly).
The model is based on a deterministic approach using fixed probability distributions (e.g., different culling rates for sows within cycle; pathological lesions for slaughterpigs).
Three types of parameters (in-, output) were distinguished for each stage:
biological/management variables, technical and economic factors. Biological factors imply parameters such as litter size born alive, days open, daily gain, feed intake and also management aspects such as time to weaning. Technical factors primarily include housing systems for lactating, mating and gestation sows, weaned and fattening pigs.
2.2 Technical factors The model regards alternate housing conditions for sows, feeder and fattening pigs (s.
Table 1). In the base situation lactating sows were kept in farrowing crates with fully slatted flooring. Mating and gestating sows were housed individually without access to straw. Sows were fed automatically, saving labour time using different diets for lactation and mating/gestation. Feeder and fattening pigs were kept in small groups with fully slatted flooring. Fattening pigs were fed automatically using ´one phase feeding´.
Alternate systems was chosen according to the current distributions and trend (HENDRIKS, et al., 1998) as well as available information about performance and cost and future legislation in the EU. For lactating sows alternative systems were crates and integrated group housing systems with straw (GERTKEN, 1992). Loose or partly loose housing systems within stalls during lactation was neglected due to missing data about cost and performance level. For mating and gestating sows alternate systems based on group housing with and without straw. Feeding of sows was performed with an electronic controlled feeding station. Similar housing conditions were used for feeder and fattening pigs (large groups with slatted flooring or deep litter). In addition partly slatted flooring and systems with restricted straw were included because these systems are becoming increasingly popular.
Arch. Tierz. 45 (2002) 3
2.3 Biological/management input values Major input values for each stage used in the default and alternative situations are summarised in Table 2. Default values are determined using results from official consulting services (CLAUS et al., 2000; VIT, 2000). Parameters (biological/economical) for the alternative housing conditions base on literary review (KTBL, 1999; KEMPKES, 1997; WEBER, 1997; DE BAEY-ERNSTEN and ACHILLES, 1997; DE BAEY-ENSTEIN, 1997; DE BAEY-ERNSTEIN, 1996;
SCHÄFER-MÜLLER und STAMER, 1996; ELLERSIEK, 1999a,b; GOURMELEN et al., 2000; RANTZER und SVENDSEN, 2001a,b; WOLTER et al., 2001; GERTKEN, 1992; JENSEN et al., 2000; TURNER and EDWARDS, 2000; HÖGES and ACKERMANN, 1998).
Table 2 Major biological / management factors for different stages and production systems of the production chain (Biologische Parameter für die verschiedenen Stufen und Haltungsverfahren der Produktionskette) Alternative housing systems3) Stage / System Default
The model starts with the generation of sow performance. Based on a gestation period of 115 days, lactation length 28 (default) and 8 or 10 days from weaning to first breeding (different for prima- and multiparous sows) the production cycle was at least 150 days. On average, the production cycle is longer due to reproduction failure (e.g.
rebreeding, abortion). Group housing for mating sows increased interval weaning to estrus and rebreeding because management tools are demanding. Litter size and piglet mortality were simulated over ten litters with non-linear pattern for litter size born alive and piglet mortality (DE VRIES, 1989; BRANDT, 1984). An average of 10.2 piglets were born alive and piglet mortality amounted to 16.3. In integrated group housing system piglet mortality was enhanced by 5% (GERTKEN, 1992). Culling percentage of sows differed between litters (DE VRIES, 1989; KRIETER, 1994).
Culled sows were replaced by gilts which were integrated into the herd with 180 days.
Average lifetime was calculated with 5.5 litters per sow.
Growth performance is of major importance with respect to feed efficiency and production cycles realised per year. The growth performance of feeder and fattening pigs was described using the Gompertz function (DOURMAD et al., 1992; KRIETER and KALM, 1989) with the formula BWt = K * (BWi/K)exp(-I*t) with BWt=body weight at age t, BWi = initial body weight and K and I = parameters of the Gompertz function. Daily gain of feeder and finishing pigs are 420 and 720g in the base situation. Large groups with bedding (deep litter) slightly reduced growth performance (5%) in the rearing and fattening stage. In contrast, larger groups with slatted flooring improved daily gain mainly due to better hygiene (all-in, all-out) and altered feeding systems. 14 days were needed to empty, clean and desinfect batches.
Averaged daily feed intake of feeder and finishing pigs was within the range of 800 to 2140 g in the base situation (e.g. depending on daily gain).
In the default scenario postweaning mortality was 1%, in the fattening period the mortality rate amounted for 3%. Mortality of pigs took place in the half during the particular period. The weight of carcasses is related to live weight and killing out.
Killing out was set to 79%, the mean carcass weight corresponded to 90.9 kg. In the present study, payment accounted only for lean meat percentage. Lean meat percentage is slightly negatively correlated with daily gain (SCHWERDTFEGER, 1992). Thus, lean meat is diminished using large groups size with slatted flooring.
2.4 Economic factors The major economic factors are described in Table 3. Major cost components of the production chain were feed, investment, labour and other cost (e.g. energy, insurance, veterinarian, straw). The main differences between the alternate production systems concern the components investment, labour and other cost which is demonstrated at the fattening level: use of larger group size (40 pigs per group) with slatted flooring reduced cost compared to the default situation by € 51 per place due to lower input for batch equipment. If pigs were kept on straw, cost for building (incl. repairs) declined by € 131 (restricted straw: 0.2 kg per pig and day) or € 205 (deep litter: 1.5 kg per pig and day).
Additionally to labour (increase by 31 or 41%) straw raised production cost by mechanisation, purchase, storage and manure, whereas energy supply was diminished.
In total other cost were enhanced by € 5.91 (SM-ST) and € 11.4 (LA-ST) per fattening pig.
Arch. Tierz. 45 (2002) 3
2.5 Evaluation of the different production systems The different systems were evaluated by cost, welfare and N- and P-excretion.
Cost were considered as opportunity cost and were presented on an animal basis (fattening pig) at the different stages. Cost are partitioned in categories such as investment, feed and labour cost as well as other cost in each stage. Comparisons of the cumulative cost at the slaughtering level are adjusted for different prices due to e.g.
lean percentages and pathological lesions.