Use of indirect calorimetry to evaluate utilization of energy in lactating Jersey dairy cattle consuming diets with increasing inclusion of hydrolyzed feather meal

摘要

A study using indirect calorimetry and 12 lactatingmultiparous Jersey cows (53 ± 23 d in milk at thebeginning of the experiment; mean ± standard deviation)was conducted to evaluate the utilization ofenergy in cattle consuming diets containing increasinghydrolyzed feather meal (HFM). A triplicated 4 × 4Latin square design with 35-d periods (28-d adaptionand 4-d collections) was used to compare 4 differentdietary treatments. Treatments contained (DM basis)HFM at 0% (0HFM), 3.3% (3.3HFM), 6.7% (6.7MFM),and 10.0% (10HFM). Diets were formulated such thatHFM replaced blood meal and nonenzymaticallybrowned soybean meal. With increasing HFM, linearincreases were observed for dietary NE_L content (1.61,1.64, 1.69, and 1.70 ± 0.042 Mcal/kg of DM for 0HFM,3.3HFM, 6.7MFM, and 10HFM, respectively), and theefficiency of converting ME to NE_L (0.708, 0.711, 0.717,and 0.719). Apparent total-tract digestibility of CP linearlydecreased with increasing HFM (63.4, 61.1, 59.9,and 58.6 ± 1.46% for 0HFM, 3.3HFM, 6.7MFM, and10HFM, respectively), whereas long-chain fatty aciddigestibility increased with increasing HFM (77.2, 77.7,78.5, and 80.6 ± 1.30%). With increased inclusion ofHFM, fecal N excretion increased (199, 230, 239, 237± 12.1 g/d for 0HFM, 3.3HFM, 6.7MFM, and 10HFM,respectively), whereas urinary N excretion decreased(166, 151, 155, and 119 ± 14.8 g/d). Increasing theconcentration of HFM resulted in a quadratic effect onDMI (19.6, 20.2, 20.3, and 19.1 ± 0.79 kg/d for 0HFM,3.3HFM, 6.7MFM, and 10HFM, respectively) and milkyield (31.7, 32.0, 31.9, and 29.7 ± 1.32 kg/d). IncreasingHFM linearly decreased the milk protein concentration(3.34, 3.29, 3.23, and 3.23 ± 0.158 for 0HFM,3.3HFM, 6.7MFM, and 10HFM, respectively) and yield(1.05, 1.05, 1.02, and 0.96 ± 0.040 kg). The inclusion ofHFM did not affect energy-correct milk yield (averageof 39.3 ± 1.54). Results of this study suggest that HFMcan increase dietary NE_L content compared with bloodmeal and nonenzymatically browned soybean meal andmaintained energy-corrected milk yield; however, feedingHFM at greater than 6.7% of diet DM decreasedDMI, and protein availability may have been reducedwith increased HFM, leading to a linear decrease inmilk protein concentration and yield.