Effects of Rosemary distillation residues substitution to oat hay on diet digestibility, metabolic profile and growth performance of Barbarine ewe lambs

Abstract

Introduction - The Rosemary is an aromatic and medicinal plant widely available in the Mediterranean area of which industrydistillation generates voluminous residues that could be an alternative animals’ feed in harsh conditions.
Aim - This study aimed to evaluate the effect of hay substitution by rosemary distillation residues (RR) in crude form (CRR) or as pellets (PRR) on lamb’s performance, digestibility and nitrogen retention. The metabolic profile and the rumen fermentation parameters were also determined.
Materials and methods - 24 ewe-lambs (average body weight: 24 + 1.3 kg) were divided into 3 groups receiving 500 g of concentrate plus 600 g of oat hay for control group (C), 600 g of crude RR for CRR group and 600 g of RR enriched pellets in PRR group.
Results and Discussion - Dry matter (DM) intake was similar for hay, CRR and PRR. The DM and crude protein digestibility was not affected by the dietary treatment. The nitrogen balance was positive for all regimens. The rumen ammonia concentration was higher for C and PRR groups, while the volatile fatty acids concentration was similar among groups. The lamb’s growth was similar among groups. The cost of gain was reduced (P<0.05) for lambs fed RR diets. The glycaemia and uraemia were higher (p<0.001) for PRR.
Conclusion - In conclusion, the RR can be used in lamb’s feeding at reduced cost without altering lamb’s growth and rumen functionality.