Effect of rumen-protected lysine supplementation of diets based on corn protein fed to lactating dairy cows
نویسندگان
چکیده
This trial tested whether rumen-protected Lys (RPL) supplementation would improve the nutritive value of rumen-undegradable protein (RUP) from corn protein. Thirty-two lactating Holstein cows were blocked by days in milk and parity into 8 squares 4 each replicated × Latin squares. Treatments provided all supplemental crude from: (1) soy (67% expeller soybean meal plus 33% solvent meal); (2) a blend (33% meal, 17% 25% gluten distillers dried grains with solubles); (3) (50% 50% or (4) RPL [diet 3 top-dressed (125 g/d AjiPro-L Generation 1, supplying an estimated 20 g absorbable Lys/d)]. Diets contained (dry matter basis) 22% alfalfa silage, 43% 18% ground high-moisture dry corn, 2.4% mineral-vitamin premix, 1.5 to 3.9% hulls, 15% protein, 30 32% neutral detergent fiber predicted contain equal rumen-degradable RUP, metabolizable Cows within randomly assigned treatment sequences fed diets for 4-wk periods before switching; production data blood samples collected during last 2 wk period. Data analyzed using mixed procedures SAS. Intake was highest on diet intermediate 3, lowest 4; body weight gain 1 4. Intakes changes reflected differences milk/dry intake, which 3. Milk yield lower (44.3 kg/d) than 2, (average 45.8 1.35 kg/d), (1.30 (1.25 kg/d). No effects detected ruminal metabolites. Free nonessential amino acids total AA elevated plasma reflecting reduced utilization synthesis. These results indicated that dilution RUP did not reduce supplementing protein-based increased 1.1 kg milk/d 50 true protein/d.
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 2021
ISSN: ['0022-0302', '1525-3198', '1529-9066']
DOI: https://doi.org/10.3168/jds.2020-19835