Reducing environmental impacts of feed using multiobjective formulation: What benefits at the farm gate for pig and broiler production?

Feed production is the main contributor to several environmental impacts of livestock. To decrease environmental impacts of feed, those of feedstuffs should be considered during formulation. In particular, multiobjective feed formulation (MOF) can help reduce several environmental impacts simultaneously while keeping any increase in feed price moderate. The objective of this study was to assess environmental benefits of MOF at the farm gate for fattening pigs and broilers. For pigs, three feeding strategies were tested: classic 2-phase (2P), 2-phase with lower net energy content (2P-), and multiphase (MP). For broilers, two strategies were tested: classic 3-phase (3P) and 3-phase with higher digestible amino acid contents and lower metabolisable energy content (3P+). Diets were formulated using both least-cost formulation (LCF) and MOF, yielding six pig scenarios and four broiler scenarios. Environmental impacts at the farm gate were estimated using a modelling approach based on life cycle assessment. Indicators for six impact categories were then calculated: climate change (CC), cumulative non-renewable energy demand (CEDNR), acidification (AC), eutrophication (EU), land occupation (LO), and phosphorus demand (PD). As expected, MOF had lower farm-gate impacts than LCF (as much as -13%), but the degree of decrease varied by feeding strategy and impact. For pigs, MOF was equally effective in all strategies at reducing PD (-6 to -9%) and AC (-2%). In contrast, MOF was more effective in 2P and 2P- at decreasing CC (-5% to -7%), LO (-9% to -13%) and EU (-6% to -8%) than in MP (CC: -2%; LO: -4%; EU: -3%). The benefit of MOF was found greater in 2P (-7%) than in other pig strategies for CEDNR (-3 to +0%). For broilers, MOF was equally effective in both strategies tested at decreasing PD (-12%), AC (-2%), and EU (-4%). For CC and CEDNR, MOF was more effective in 3P (CC: -9%; CEDNR: -11%) than 3P+ (-6% for both impacts), but not for LO (+3% in 3P vs -1% in 3P+). These differences were due mainly to differences in animal performance (especially feed conversion ratio) among the strategies tested. Finally, in all scenarios, gross margin at the farm gate decreased with MOF comparatively to LCF (pigs: -3% to -11%); broilers: -7% to -11%). These results demonstrate the importance of comprehensive economic and environmental optimisation of feeding strategies by simultaneously considering feed impacts, animal performance, and manure management. To do so, further research is therefore required to develop new modelling tools.

Short cold exposures during incubation and postnatal cold temperature affect performance, breast meat quality, and welfare parameters in broiler chickens.

Cold stimulations during egg incubation were reported to limit the occurrence of ascites in broilers subjected to cold temperature after 14 d of age. However, data are lacking on the impacts of such strategy in case of cold temperature conditions at start. This study aimed to evaluate the effects of incubation and posthatch cold challenge on performance, breast muscle integrity, and meat processing quality in broiler chickens. Ross 308 eggs were incubated under control temperature (I0, 37.6°C) or subjected to 15°C during 30 min on day 18 and 19 of incubation (I1). Chicks from each group were reared in floor pens either at standard rearing temperature (T0), from 32°C at 0 d to 21°C at 21 d of age, or exposed to colder rearing temperature (T1), from 29°C at 0 to 21°C at 21 d of age. All birds were then kept at 21°C until slaughter (day 40), when body weights (BW), feed conversion ratio (FCR), breast muscle yield, meat processing quality, and the occurrences of meat defects, hock burns, and pododermatitis were recorded. No significant impact of incubation conditions on hatchability was observed. At day 40, BW was more under T1 than under T0 conditions, with T0 females (but not males) presenting more BW after I1 than after I0 conditions. In the whole period, T1 chickens presented lower FCR than T0 chickens and higher breast meat yields at day 40. The occurrence of white striping was more in I1T1 males than in all other groups, except for the I0T1 males. Hock burns were more frequent in I1T1 males than in all females and I0T0 males, whereas the occurrence of pododermatitis was lower in T0 males than in other groups. Despite some positive effects of I1 incubation on growth after starting under low ambient temperature, this study reveals the limits of such strategy concerning chicken health and welfare, demonstrating that early thermal environment is a major component of the quality and sustainability of chicken meat production.