Environmental impact of dam-calf contact in organic dairy systems: A scenario study

Summary

Systematic separation of cow and calf early after calving is common practice in both organic and conventional dairy farming. The main objective of this paper was to develop different scenarios for dam-calf contact and quantify their effects on milk uptake by the calf and environmental sustainability of the produced milk and meat from these systems. Scenarios were set up of organic dairy systems to analyze the effect of different dam-calf systems with either half-time or full-time contact between cow and calf for 28, 51 or 91 days. Based on experience from practice and literature, we assumed a total milk uptake of 1,110 kg ECM milk with part-time contact and 1,207 kg ECM milk with fulltime contact over 91 days. These scenarios were compared to traditional calf rearing systems with direct separation after birth and milk feeding from a bucket with low or high milk feeding levels of 460 and 630 kg ECM, respectively, in the first 91 days. The scenarios were analyzed at a milk production level of 9,000 kg ECM per cow per year and with a sensitivity analysis covering yield levels of 7,000, 11,000 and 13,000 kg ECM per cow per year. At a production level of 9,000 kg ECM per year and full-time dam-calf contact throughout the milk period, only 85% of the milk produced could be delivered to the dairy company, compared to 93% when a low-level of milk is fed from a bucket. This means that there were fewer kg products to bear the environmental impacts, and hence the carbon footprint and land use from production per kg of ECM milk and meat was increased by between 5 and 9%, while the corresponding increase in impact at the highest yield level of 13,000 kg ECM was only between 4 and 6%. Besides environmental sustainability of cow-calf contact systems, the broader context of such systems