Can Supplementation with the Cow Start Complete Bolus Result in Elevated Blood Calcium Status in a Group of At-Risk Dairy Cows During the First Four Days of Lactation

The prophylactic supplementation of freshly calved multiparous cows with oral calcium supplements (bolus, drink, drench, paste) has increased in popularity in recent years. Oral calcium supplements are generally only effective for 12 hours, yet the high-risk period for hypocalcaemia in freshly calved multiparous cows is 48 hours post-partum. Therefore, a second application 12 hours post-partum is suggested by manufacturers, yet due to labour shortages on dairy farms, it is very common for the second application to not be carried out. The objectives of this study were to ascertain if a the administration of a single dose of the sustained release bolus (Cow Start Complete, Anchor Life Science, Co. Cork, Ireland) given to the cow at calving, could offer the combined benefits of elevated calcium status over the first 48 hours post-partum from a labour efficient single dose given at calving and also to evaluate if this enhanced calcium status could have a positive effect on daily rumination time and milk production yields in the first three months of lactation. The two groups consisted of an un-supplemented control (CON) group and a Cow Start Complete (CSC) group in which cows were given a single bolus dose at the point of calving. The CON group experienced a clinical milk fever (Blood Ca <1.5mmol/L) incidence rate of 13.3% compared to 0% for the CSC group. Cows given the CSC treatment had significantly (P<0.0001) higher total blood calcium levels (2.14 mmol/L) from the point of calving (0h) to 4 days post-partum (96h) compared to CON (1.98mmol/L), with significant increases at 12h (P<0.01), 24h (P<0.001) and 36h (P<0.01) post-partum. Rumination time for CSC cows (471mins/day) was significantly (P<0.05) higher during the first 14 days post-partum when compared to CON (434mins/day) group. Milk production was also significantly (P<0.01) higher for CSC cows (+1.8kg/day) than in CON cows during the first 90 days of lactation. These findings demonstrate that the convenience of giving a single dose of CSC at calving, can be combined with desired outcomes in a range of key benefits in freshly calved multiparous cows.