Digestibility by lambs and nutritive value for lactating ewes of a total mixed ration containing Cephalaria joppensis silage as wheat silage substitute

Abstract

This study examined digestibility for lambs and nutritive value for lactating ewes of a total mixed ration (TMR) containing Cephalaria joppensis (CJ) silage as a wheat silage substitute. Yield of CJ forage was 16.4t dry matter (DM) per ha, which is 37% higher than that of the neighboring wheat. The fresh-cut wheat and CJ were packed separately and wrapped in polyethylene layers to produce bales of silage kept outdoors for 90 days. The CJ and wheat silage bales were opened, combined with alfalfa hay (at a 2:1 ratio, DM basis) and mixed with additional TMR components, repacked and rewrapped to produce TMR bales kept outdoors for 30 days. The packing and wrapping created anaerobic conditions and ensilage occurred within the TMR bales, resulting in a significant reduction in pH of the wheat-TMR (W-TMR) and CJ-TMR from 6.02 and 6.07, respectively, to 4.1 and 4.4, respectively. DM loss in the two types of TMR bales during ensilage was similar. Experiment 1 measured the intake and digestibility of the ensiled W-TMR vs. CJ-TMR by two groups of six Assaf lambs each, fed individually in metabolic cages. Intake and digestibility of DM, crude protein and neutral detergent fiber were similar for the two TMRs tested. However, cellulose digestibility was slightly higher in the W-TMR. Experiment 2 measured milk production and composition in two groups of 45 lactating Assaf ewes each, fed the two ensiled TMRs plus a constant amount of mixed concentrate pellets. The ewes fed the CJ-TMR were characterized by similar yields of daily milk (2.26–2.36kg), protein (0.11kg), fat (0.15kg) and 6% fat-corrected milk (3.06–3.08kg), but slightly higher concentrations of protein, fat and total milk solids compared with sheep fed the W-TMR. Changes in body weight and body condition score were similar in the two groups of ewes. Data show that CJ silage can be included in a TMR for lactating sheep as high-quality forage, with a nutritive value similar to that of wheat silage.