Use of Stochastic Simulation to Evaluate the Reduction in Methane Emissions and Improvement in Reproductive Efficiency from Routine Hormonal Interventions in Dairy Herds
Fig 2
Model predictions of mean marginal change in methane emissions (g per L of milk produced) through supplementing the Ovsynch programme with progesterone in herds with varying, risk for cows being identified in oestrus and inseminated, and pregnancy risk following insemination.
Data for 10,000 herds of 200 cows were simulated (Table 2). Methane emissions per cow were estimated from daily forage dry matter intake, forage quality, and replacement risk. Cumulative milk yield per cow was estimated based on parity, stage of lactation, and stage of gestation. Associations with input parameters were evaluated in a linear model (Table 3). Mean predicted methane emissions in the Ovsynch scenario were subtracted from that for use of Ovsynch with supplementary progesterone to give the expected change in methane per L milk produced. Negative values indicate reductions.