Field Pea Can Be Included in Fattening Concentrate without Deleterious Effects on the Digestibility and Performance of Lambs

SIMPLE SUMMARY: The partial substitution of soybean by field pea (Pisum sativum), a local source of protein, has been encouraged to reduce the dependency of Europe on soybean imports. However, only up to 15% of field pea inclusion in the fattening concentrate of light lambs is recommended. The aim of this study was to evaluate the outcomes of the inclusion of field pea in the fattening concentrate on the apparent digestibility, nitrogen balance, animal performance and carcass characteristics of lambs. For that, four isoenergetic and isoproteic concentrates with different proportions of field pea (0%, 10%, 20% and 30%) were compared. The main results were that the in vivo apparent digestibility of the nutrients and retained nitrogen were not affected by field pea inclusion. The performance traits were similar among concentrates, but carcass weight and dressing percentage changed cubically with the inclusion of field pea. Therefore, inclusion of field pea in fattening concentrates above current recommendations could be advisable depending on the prices and availability of the feedstuffs. ABSTRACT: The inclusion of different proportions of field pea (0%, 10%, 20% and 30%) for partially replacing soybean in the fattening concentrate of lambs was studied for its impact on apparent digestibility and performance during fattening. In the in vivo digestibility trial, 12 lambs (33 kg body weight) were placed in metabolic crates for two periods and received restricted amounts of concentrate and straw. The performance trial involved 54 lambs (13.4 kg body weight) that received concentrate plus straw ad libitum from weaning to slaughter. The intake of crude protein was higher in the 0% pea group than in the other groups (p < 0.05). The inclusion of field pea did not affect the digestibility, N retained or blood metabolites. In the performance trial, most traits were not affected, although a cubic effect of field pea inclusion on hot carcass weight and dressing percentage was observed (p < 0.05). The inclusion of field pea did not affect total protein, urea or β-hydroxybutyrate concentrations but it affected creatinine and cholesterol concentrations (p < 0.05). In conclusion, field pea can constitute up to 30% of the fattening concentrate of lambs without deleterious effects on the digestibility and performance during fattening, and with minor effects on carcass characteristics.