Model predictions of mean marginal change in cost (£/cow/year) through supplementing the Ovsynch programme with progesterone in herds with varying voluntary post-partum non-breeding time (VWP), risk for cows being identified in oestrus and inseminated, and pregnancy risk following insemination.

<p>Data for 10,000 herds of 200 cows were simulated (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127846#pone.0127846.t002" target="_blank">Table 2</a>). The cost of each programme /cow per year was determined from the proportion of cows that were culled due to failure to conceive by 300 days in milk, the number of inseminations required, and the difference in cumulative milk yield per cow. Associations with input parameters were evaluated in a linear model (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127846#pone.0127846.t005" target="_blank">Table 5</a>). The mean predicted cost of the Ovsynch scenario was subtracted from that for use of Ovsynch with supplementary progesterone to give the expected marginal change in costs. Negative values indicate financial gain.