Subclinical ketosis in dairy cattle – the silent profit robber

Successful calving, healthy metabolic functions postpartum and good milk performance in lactation depend highly on the transition period (three weeks before and after calving) of dairy cows where they should be able to manage energy intake and overcome negative energy balance. Subclinical ketosis is one of the metabolic diseases associated with negative energy balance during the transition period. Subclinical ketosis is manifested by the elevated BHB (beta-hydroxybutyrate) concentration in blood, urine and milk in dairy cattle, especially in the first 2-3 weeks after calving. The prevalence of subclinical ketosis is around 934% in dairy cattle farms. According to Duffield (2000), subclinical ketosis may start at serum BHB above 1,000μmol/L. However, at exactly what level individual cows will express clinical signs are extremely variable. Furthermore, there are studies in which the cut off value is expressed as 1,200μmol/L. Subclinical ketosis causes losses through decreased milk production and association with periparturient diseases. Serum BHB concentrations of 1,200μmol/l or above in the first week following calving were associated with increased risks of subsequent abomasal displacement and metritis, whereas the critical BHB threshold in the second week postpartum for the risk of abomasal displacement was set at ≥1,800μmol/l. The best threshold for predicting subsequent risk of clinical ketosis from serum obtained during week one and week two postpartum was 1,400μmol/L of BHBA. Impacts on milk yield begin at BHB ≥1,200μmol/l for week one postpartum and ≥1,400μmol/L for week two postpartum. Duffield et al. (2009) has summarised the impact of elevated blood BHB on milk production in first and second week postpartum in Table 1. Having increased blood BHB (≥1,800μmol/L) in the first week of lactation is associated with milk loss of 300kg/cow for the entire lactation. Simililarly, Gustafsson et al. (1993) reported a loss of 328kg milk (fat corrected milk) due to high blood BHB concentration. As Leblanc (2010) summarised; subclinical ketosis in the first or second week after calving is associated with: l3-8 times increased risk of left displacement of abomasum. lThree times greater risk of metritis when serum BHB in the week one postpartum was >1,200μmol/L. l4-6 times increased risk of clinical ketosis. lIncreased probability of subclinical endometritis at week four postpartum, increased duration and severity of mastitis. All these above indicate that subclinical ketosis is a very important metabolic disease which can impact production in dairy cattle farms. It is mostly underestimated and overseen.