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Use of Stochastic Simulation to Evaluate the Reduction in Methane Emissions and Improvement in Reproductive Efficiency from Routine Hormonal Interventions in Dairy Herds.

Archer SC, Hudson CD, Green MJ - PLoS ONE (2015)

Bottom Line: In some circumstances improvement in reproductive efficiency using the programmes investigated was associated with reduced cost and methane emissions compared to reliance on detection of oestrus.Efficiency of oestrus detection and the time to commencement of breeding after calving influenced variability in changes in cost and methane emissions.For an average UK herd this was a saving of at least £50 per cow and a 3.6% reduction in methane emissions per L of milk when timing of first insemination was pre-set.

View Article: PubMed Central - PubMed

Affiliation: School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Leicestershire, United Kingdom.

ABSTRACT
This study predicts the magnitude and between herd variation in changes of methane emissions and production efficiency associated with interventions to improve reproductive efficiency in dairy cows. Data for 10,000 herds of 200 cows were simulated. Probability of conception was predicted daily from the start of the study (parturition) for each cow up to day 300 of lactation. Four scenarios of differing first insemination management were simulated for each herd using the same theoretical cows: A baseline scenario based on breeding from observed oestrus only, synchronisation of oestrus for pre-set first insemination using 2 methods, and a regime using prostaglandin treatments followed by first insemination to observed oestrus. Cows that did not conceive to first insemination were re-inseminated following detection of oestrus. For cows that conceived, gestation length was 280 days with cessation of milking 60 days before calving. Those cows not pregnant after 300 days of lactation were culled and replaced by a heifer. Daily milk yield was calculated for 730 days from the start of the study for each cow. Change in mean reproductive and economic outputs were summarised for each herd following the 3 interventions. For each scenario, methane emissions were determined by daily forage dry matter intake, forage quality, and cow replacement risk. Linear regression was used to summarise relationships. In some circumstances improvement in reproductive efficiency using the programmes investigated was associated with reduced cost and methane emissions compared to reliance on detection of oestrus. Efficiency of oestrus detection and the time to commencement of breeding after calving influenced variability in changes in cost and methane emissions. For an average UK herd this was a saving of at least £50 per cow and a 3.6% reduction in methane emissions per L of milk when timing of first insemination was pre-set.

No MeSH data available.


Related in: MedlinePlus

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.Data for 10,000 herds of 200 cows were simulated (Table 2). 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 (Table 5). 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.
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pone.0127846.g005: 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.Data for 10,000 herds of 200 cows were simulated (Table 2). 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 (Table 5). 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.

Mentions: The major factors that determined changes in cost are shown in the final models in Table 5. These models explained 65%, 68%, and 8% of the model variance for the Ovsynch, Ovsynch with progesterone, and double prostaglandin programmes respectively; residuals were distributed normally (Table 5). The impact of comparable changes in model input parameters (from the mean to the upper quartile) on change in costs with other inputs held at the mean is shown in Table 6. The hormonal interventions were all most financially beneficial if herd voluntary waiting period exceeded 50 days. For the Ovsynch based programmes (Groups 2 and 3; Table 6), comparable changes in submission and pregnancy risk, at mean values of other inputs were associated with similar magnitude of change in cost but in opposing directions, indicating that these approaches would be economically beneficial in herds with low submission risk, but relatively high pregnancy risk. Ovsynch programmes were more economically beneficial when the depreciation cost of cull cows increased (Table 6). Cost savings through the Ovsynch programme (Group 2) exceeded drug costs except if submission risk exceeded 0.5 (Fig 4). Results for supplementing the Ovsynch programme with progesterone (Group 3) were similar to use of Ovsynch alone (Group 2); therefore the marginal benefit of progesterone supplementation is shown in Fig 5. With other inputs held at the mean, cost savings through progesterone supplementation failed to exceed the marginal cost of treatment for herds with pregnancy risk < 0.2, or submission risks > 0.5, otherwise the decision would depend on the balance of voluntary waiting period and submission risk (Fig 5). Comparable multivariate plots for the double prostaglandin programme confirm that cost savings may fail to exceed drug costs unless the herd voluntary waiting period is reduced (Fig 6).


Use of Stochastic Simulation to Evaluate the Reduction in Methane Emissions and Improvement in Reproductive Efficiency from Routine Hormonal Interventions in Dairy Herds.

Archer SC, Hudson CD, Green MJ - PLoS ONE (2015)

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.Data for 10,000 herds of 200 cows were simulated (Table 2). 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 (Table 5). 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.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465033&req=5

pone.0127846.g005: 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.Data for 10,000 herds of 200 cows were simulated (Table 2). 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 (Table 5). 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.
Mentions: The major factors that determined changes in cost are shown in the final models in Table 5. These models explained 65%, 68%, and 8% of the model variance for the Ovsynch, Ovsynch with progesterone, and double prostaglandin programmes respectively; residuals were distributed normally (Table 5). The impact of comparable changes in model input parameters (from the mean to the upper quartile) on change in costs with other inputs held at the mean is shown in Table 6. The hormonal interventions were all most financially beneficial if herd voluntary waiting period exceeded 50 days. For the Ovsynch based programmes (Groups 2 and 3; Table 6), comparable changes in submission and pregnancy risk, at mean values of other inputs were associated with similar magnitude of change in cost but in opposing directions, indicating that these approaches would be economically beneficial in herds with low submission risk, but relatively high pregnancy risk. Ovsynch programmes were more economically beneficial when the depreciation cost of cull cows increased (Table 6). Cost savings through the Ovsynch programme (Group 2) exceeded drug costs except if submission risk exceeded 0.5 (Fig 4). Results for supplementing the Ovsynch programme with progesterone (Group 3) were similar to use of Ovsynch alone (Group 2); therefore the marginal benefit of progesterone supplementation is shown in Fig 5. With other inputs held at the mean, cost savings through progesterone supplementation failed to exceed the marginal cost of treatment for herds with pregnancy risk < 0.2, or submission risks > 0.5, otherwise the decision would depend on the balance of voluntary waiting period and submission risk (Fig 5). Comparable multivariate plots for the double prostaglandin programme confirm that cost savings may fail to exceed drug costs unless the herd voluntary waiting period is reduced (Fig 6).

Bottom Line: In some circumstances improvement in reproductive efficiency using the programmes investigated was associated with reduced cost and methane emissions compared to reliance on detection of oestrus.Efficiency of oestrus detection and the time to commencement of breeding after calving influenced variability in changes in cost and methane emissions.For an average UK herd this was a saving of at least £50 per cow and a 3.6% reduction in methane emissions per L of milk when timing of first insemination was pre-set.

View Article: PubMed Central - PubMed

Affiliation: School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, Leicestershire, United Kingdom.

ABSTRACT
This study predicts the magnitude and between herd variation in changes of methane emissions and production efficiency associated with interventions to improve reproductive efficiency in dairy cows. Data for 10,000 herds of 200 cows were simulated. Probability of conception was predicted daily from the start of the study (parturition) for each cow up to day 300 of lactation. Four scenarios of differing first insemination management were simulated for each herd using the same theoretical cows: A baseline scenario based on breeding from observed oestrus only, synchronisation of oestrus for pre-set first insemination using 2 methods, and a regime using prostaglandin treatments followed by first insemination to observed oestrus. Cows that did not conceive to first insemination were re-inseminated following detection of oestrus. For cows that conceived, gestation length was 280 days with cessation of milking 60 days before calving. Those cows not pregnant after 300 days of lactation were culled and replaced by a heifer. Daily milk yield was calculated for 730 days from the start of the study for each cow. Change in mean reproductive and economic outputs were summarised for each herd following the 3 interventions. For each scenario, methane emissions were determined by daily forage dry matter intake, forage quality, and cow replacement risk. Linear regression was used to summarise relationships. In some circumstances improvement in reproductive efficiency using the programmes investigated was associated with reduced cost and methane emissions compared to reliance on detection of oestrus. Efficiency of oestrus detection and the time to commencement of breeding after calving influenced variability in changes in cost and methane emissions. For an average UK herd this was a saving of at least £50 per cow and a 3.6% reduction in methane emissions per L of milk when timing of first insemination was pre-set.

No MeSH data available.


Related in: MedlinePlus