Comparison of in vivo and in silico growth performance and variability in pigs when applying a feeding strategy designed by simulation to control the variability of slaughter weight

Abstract

Variability in bodyweight (BW) among pigs complicates the management of feeding strategies and slaughter.Including variability among individuals in modelling approaches can help to design feeding strategies to controlperformance level, but also its variability. The InraPorc model was used to perform simulations on 10 batches of 84 crossbred pigs each to characterise the effect of feeding strategies differing in amino acid supply or feed allowance on the mean and variation in growth rate. Results suggested that a feed restriction reduces the coefficient of variation of BWat first departure for slaughter (BW1) by 34%. Growth performance obtained from an in silico simulation using ad libitum and restricted feeding plans was compared with results obtained in an in vivo experiment on a batch of 168 pigs. Pigs were offered feed ad libitum or were restricted (increase in feed allowance by 27 g/day up to a maximum of 2.4 and 2.7 kg/day for gilts and barrows, respectively). A two-phase feeding strategy was applied, with 0.9 and 0.7 g of digestible lysine per MJ of net energy (NE) in diets provided before or after 65 kg BW, respectively. Actual growth was similar to that obtained by simulation. Coefficient of variation of BW1 was similar in vivo and in silico for the ad libitum feeding strategy but was underestimated by 1 percentage point in silico for the restriction strategy. This study confirms the relevance of using simulations performed to predict the level and variability in performance of group housed pigs

Precision feeding can significantly reduce lysine intake and nitrogen excretion without compromising the performance of growing pigs

“…This control treatment (3P) provided to all the pigs of this group and within each feeding phase a fixed blend of feeds A and B determined based in the requirements of the 80th percentile pig of the population. This lysine level was previously suggested to maximize the response of the population in terms of BW gain and it is in agreement with other in vivo (Brossard et al, 2014) and in silico results (Brossard et al, 2009). These later authors suggested that oversupplying the average pig of the population by 15% at the beginning of the feeding phase maximizes population performances.…”

“…The ratio between feeding costs and weight gain was also reduced (P < 0.05) by 6%, 6% and 5% in the MP110, MP100 and MP90 feeding treatments, respectively, in relation to the 3P treatment. Corroborating the current findings, the economic benefits of precision-feeding programs were already reported previously in silico Brossard et al, 2014) and in vivo (Niemi et al, 2010) studies. Feeding individual pigs with daily tailored diets reduces excesses of the most expensive nutrients and ingredients, but the magnitude of the reduction in feeding costs depends on current local ingredient prices.…”

Effect of observed individual data of performance and excretion on life cycle assessment of piglets

“…Besides, using technical performance indicators based on the agroindustry to evaluate the effect of feeding strategies must be done carefully in an LCA study. Different researches (Brossard et al, 2009;Brossard et al, 2014) have demonstrated the effects of between-animal variability on pig performance and requirements, which could affect both performance and excretion.…”

Economic and environmental assessments of combined genetics and nutrition optimization strategies to improve the efficiency of sustainable pork production

“…The recorded experimental data for all fattening pigs were imported into the population version of InraPorc ( Brossard et al, 2014 ), which simulates the performance of pigs in response to different nutritional strategies ( van Milgen et al, 2008 ). The imported data were first used to calibrate an individual growth performance profile based on the Gompertz growth function for each pig.…”