Economic assessment of amino acid deficiency or feed restriction during the pig fattening period

Abstract. The profitability of pig farms is influenced greatly by feed efficiency and carcass grading. The aim of this study wasto assess the economic impact of two feeding strategies during the fattening period, compared to that of a control (T), which was ad libitum feeding with no amino acid deficiency. The first strategy was ad libitum feeding with a threephase sequence limited in amino acids (CA). The second strategy was restricted feeding at 85% of the ad libitum without amino acid deficiency (RA). Each of the three feeding strategies was applied to 48 gilts and 48 barrows, crossbred between Pietrain sires and Large White × Landrace sows, reared in pens of 6 pigs. Technical performances were estimated using a general linear model by pen. Then, the feed conversion ratio (FCR) was standardized to the range of 30-120 kg. The lean meat content (LMC), assessed by the Image-Meater carcass classification method, was standardized to 120 kg. These criteria were used to assess the economic feeding margin of each strategy. Therefore, they were input in the ‘Calculate’ simulator, which was developed by IFIP in the French production conditions, available on the GT-DIRECT portal (https://gtdirect.ifip.asso.fr). Two extreme economic contexts were considered using two assumptions for fattening feed price (HIGH: 290 €/T and LOW: 152 €/T). FCR were 2.57, 2.75 and 2.74 kg/kg for T, CA and RA strategies respectively. LMC were 60.9, 60.4 and 62.4% for T, CA and RA strategies respectively. The CA margin was lower than that of T, by € 3.4 and € 5.6 per pig produced for the LOW and HIGH feed price contexts respectively. The predominant effect was that of feed price, which penalized feed cost due to an FCR higher by 0.1 kg/kg. The RA margin was also lower than that of T, by € 0.7 and € 2.8 per pig produced for the LOW and HIGH feed price contexts respectively. The higher FCR (+0.17 kg/kg) induced an increase in feed cost which was compensated only partially by the rise of output due to the better LMC (+1.5 percentage point). Feeding strategies allowing the FCR to be controlled are to be favoured, especially in a context of high feed prices, so as not to degrade the economic results of the farms. Meeting amino acid needs and mastering feed restriction remain essential.