Intake, digestibility rumen fermentation and nitrogen balance in lambs offered alfalfa and tall fescue-mixtures harvested and ensiled after a frost

The objective of this study was to determine the effect harvesting alfalfa ( Medicago sativa L.) and tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] after frost ensiling mixtures these forages on silage fermentation characteristics, intake, digestibility ruminal by ewe lambs. Forages were harvested in October 2017, wilted, blended as either alone, 67% + 33% novel endophyte-infected fescue, or 100% fescue. Twenty bins lined with 2 plastic bags, packed (n = 5/trt) respective forages, stored for 3 months, then assigned randomly Dorper lambs 20; mean BW 34.7 ± 6.65 kg) offered ad libitum consumption. Lambs allowed 14 d adaptation followed 5 total feces urine collection. Data analyzed using PROC-MIXED SAS orthogonal polynomial contrasts used identify trends associated different proportions alfalfa. Silage acids, lactate, acetate concentrations increased linearly P < 0.01), while ammonia decreased quadratically 0.01) increasing silage. lactate acids (g/kg acids) 0.02) fescue-to-alfalfa ratio. Dry matter (DM) organic (OM) intake BW), digestibility, digestible DM OM BW) proportion silages. Total volatile fatty (VFA), well isovalerate branched-chain VFA 0.05) quadratically, butyrate valerate concentration All N utilization measurements (intake, absorption retention) 0.01). Ensiling that a may improve forage but reduce compared feeding undiluted • High moisture content weather conditions restrict making hay frost. Tall accumulates sugars fall which should enhance qualities. Adding improved measurements. Intake sheep more added prior ensiling. Nitrogen use reduced adding