Lactational performance, enteric gas emissions, and plasma amino acid profile of dairy cows fed diets with soybean or canola meals included on an equal protein basis

摘要

This study investigated the effects of feeding solventextractedcanola meal (CM), extruded soybean meal(ESBM), or solvent-extracted soybean meal (SSBM)on an equivalent crude protein basis on performance,plasma AA profiles, enteric gas emissions, milk fattyacids, and nutrient digestibility in lactating dairy cows.Fifteen Holstein cows (95 ± 20 d in milk) were usedin a replicated 3 × 3 Latin square design experimentwith 3 periods of 28 d each. Treatments were 3 dietscontaining 17.1% CM, 14.2% ESBM, or 13.6% SSBM(dry matter basis). Vegetable oil was added (canola oilfor CM or soybean oil for SSBM) to equalize the etherextract concentration of the diets. Rumen-protectedMet was supplemented targeting digestible Met supplyof 2.2% of metabolizable protein in all diets. Canolameal increased dry matter intake (DMI) by 5.9 and8.9% in comparison with ESBM and SSBM, respectively.Milk urea nitrogen was lowest in CM, followedby SSBM, and was highest for ESBM. No differenceswere observed in feed efficiency, energy-corrected milkyield, and milk composition or component yields amongtreatments. Cows fed CM emitted less enteric CH_4 perkg of DMI compared with both ESBM and SSBM, butCH_4 emission intensity (CH_4 per kg of energy-correctedmilk) was similar among treatments. In summary, replacementof ESBM or SSBM with CM, on an equalcrude protein basis, in the diet of lactating dairy cowsenhanced DMI, but yields of energy-corrected milkand milk components and feed efficiency were similaramong treatments.