Llanero hay [CP = 24.9 g/kg DM; ash-free NDF corrected for contamination of CP (NDFom,cp) = 782.4 g/kg DM].
In addition, the daily intake of organic matter, neutral detergent fiber assayed with heat stable α-amylase and corrected for ash (aNDFom), acid detergent fiber corrected for ash (ADFom) were quadratically (P < 0.01) improved upon increasing the dietary SBP level while the daily intake and digestibility of ether extract were declined linearly (P < 0.01).
Sorting against neutral detergent fiber corrected for ash and protein (tendency only) and for crude protein was greater for PUB than PRE heifers.
The digestibility coefficients of dry matter, organic matter, neutral detergent fiber corrected for ash and protein, non-fibrous carbohydrates, total carbohydrates and total digestible nutrients decreased linearly (P<0.05), and the digestibility of crude protein was not influenced (P>0.05).
A quadratic effect (P < 0.05) of IDY was observed on the apparent digestibility of dry matter, organic matter, crude protein, ether extract and neutral detergent fiber corrected for ash and protein.
However, the use of SRU did not change the digestibility and digestion rate (kd) and kp of DM, OM, CP and neutral detergent fiber corrected for ash and protein (NDFap).
Apparent digestibility of dry matter, organic matter, and neutral detergent fiber corrected for ash and protein was not affected by RUP level but was lower for PRE compared with PUB heifers.
The CP level affected the intake of dry matter (DM), organic matter (OM), CP, neutral detergent fiber corrected for ash and protein (apNDF), non-fiber carbohydrates (NFC), total digestible nutrients (TDN), and rumen-degraded protein (RDP), as well as the carcass gain (CG) and the feed conversion (FC).
The intakes of dry matter, organic matter, crude protein, ether extract, non-fibrous carbohydrates and total digestible nutrients decreased linearly (P<0.05), whereas the intake of neutral detergent fiber corrected for ash and protein, both in body weight or metabolic weight basis increased linearly (P<0.05).
Conversely, the intake of neutral detergent fiber assayed with a heat-stable amylase and corrected for ash and nitrogenous compounds [aNDFom(n)] in g/day (P = 0.043), and the g/kg body weight (P = 0.011) increased linearly as IDY was added to the concentrate.
