Replacing conventional concentrates with sprouted barley or wheat: Effects on lactational performance, nutrient digestibility, and milk fatty acid profile in dairy cows.

Finite natural resources, rising human population, and climate change pose challenges to traditional crop production. Hydroponically grown fodder (i.e., sprouted grains) can be an alternative feed source for dairy cows; however, only sprouted barley has been investigated in low-producing cows. We aimed to evaluate the impact of replacing conventional concentrates with sprouted barley or wheat, grown using hydroponics, on milk production, nutrient digestibility, and milk fatty acid profile in high-producing cows. Twenty-four multiparous Holstein cows [3.25 ± 1.33 lactations; 102 ± 23 d in milk (DIM); 49 ± 4 kg/d of milk] were used in a replicated 3 × 3 Latin square design with 21-d experimental periods. Following a 2-wk covariate period, cows were fed 1 of 3 experimental diets: a total mixed ration (1) without sprouted grains (Control), or with (2) 10% sprouted barley (Barley) or (3) 10% sprouted wheat (Wheat) on a dry matter (DM) basis. Experimental diets were formulated to be isoenergetic and isonitrogenous with sprouted grains that replaced ground corn, soybean meal, canola meal, and dextrose. Sprouted grains were grown using a semi-automatic hydroponic system and harvested after 6 d of growth. Data and sample collection occurred during the last 3 d of the covariate and experimental periods. Wide ranges were observed for the DM percent of sprouted grains (12.1 to 22.9% and 13.3 to 25.7% for barley and wheat, respectively) and the ratio of sprouted fodder to seed (0.67 to 1.07 for both barley and wheat). Feeding sprouted grains did not modify yields of milk or energy-corrected milk (ECM); however, dry matter intakes (DMI) were lower for Barley, relative to Control. Feed efficiencies were greater for Barley than for Control (1.49 ± 0.03 vs. 1.43 ± 0.03 for milk yield/DMI; 1.85 ± 0.03 vs. 1.73 ± 0.04 for ECM/DMI). Yields and concentrations of milk components (i.e., fat, true protein, and lactose) were not impacted by treatment. Milk urea-N concentrations were greater for Wheat, relative to Control or Barley. Body weight (BW; 752 ± 3 vs. 742 ± 3 kg) and BW gain (6.53 ± 2.99 vs. -9.33 ± 2.91 kg/21 d) were higher for Wheat than for Control. Apparent total-tract digestibility of organic matter was greater for Wheat, relative to Barley. Digestibilities of neutral detergent fiber and starch were higher for Wheat and Control, relative to Barley, and crude protein digestibility was greater for Wheat, relative to Barley and Control. Rumination and physical activity were not impacted by treatment. In summary, replacing traditional concentrates with sprouted grains grown using hydroponics improved milk production efficiency (barley sprouts) or enhanced body weight gain (wheat sprouts). A life cycle assessment needs to be conducted to determine the net impact of this feeding strategy for the dairy industry.