Methane production and whole-animal energy utilization in lactating Jersey dairy cows fed a bromoform-containing feed...

Methane (CH₄) is an anthropogenic GHG produced by ruminant animals in their conversion of feed to milk or meat. Alga Bio 3.0 (ALB) is a proprietary feed additive (Alga Biosciences Inc.) containing stabilized, synthetic bromoform, which is known to reduce CH₄ emission in the rumen of cattle. The objective was to evaluate the effects of feeding increasing inclusion of an algae feed additive containing bromoform on DMI, energy and N utilization, total gas production with headbox-style indirect calorimetry, and milk production in lactating Jersey cows. Twelve mid lactation multiparous Jersey cows were used in a quadruplicated 3 × 3 Latin square design consisting of 3 periods of 28 d each. Treatments were randomly assigned so that cows consumed increasing concentrations (DM basis) of ALB: 0% of diet DM (0CTRL), 0.46% of diet DM (0.46LOW), and 0.93% of diet DM (0.93HIGH). Increasing ALB inclusion linearly reduced CH₄ production by 19.7% in L/d and 18.4% in L/kg DMI (430, 392, 345 ± 22.02 L/d and 22.8, 20.6, 18.6 ± 1.04 L/kg DMI), and linearly increased hydrogen gas production (none detected, 15.6, 62.4 ± 22.21 L/d). No differences were observed in DMI, milk yield, or ECM averaging 18.9 ± 0.56, 28.4 ± 0.69, and 35.1 ± 0.84 kg, respectively. Milk fat percentage linearly decreased with increasing ALB inclusion (5.22%, 5.04%, 4.92% ± 0.136%), but no difference was observed in milk fat yield (average 1.42 ± 0.048 kg/d). No difference was observed in DM, NDF on an OM basis, CP, starch, and crude fat digestibility averaging 65.6% ± 0.50%, 43.4% ± 0.99%, 67.1% ± 0.64%, 94.3% ± 0.34%, and 73.9% ± 1.88%, respectively. Increasing inclusion of ALB linearly increased the concentration of ME of the diet (2.49, 2.50, 2.55 ± 0.022 Mcal/kg). The efficiency of converting digestible energy (DE) to ME linearly increased (0.88, 0.89, and 0.89 ± 0.003 Mcal/Mcal). Milk samples were analyzed for presence of bromoform residues, and the concentrations were below the limit of detection. Results suggest that ALB can reduce CH₄ production by up to 19.6% in lactating dairy cows, leading to increased efficiency of converting DE to ME.