A clear recommendation is that dry cows should be moved to the close-up pen before their due date. Reason is that, for a lactating cow to be successful, she needs to be able to mobilize calcium from her bones. This process can take 10 to 15 days. Without adequate time to prepare for lactation, milk fever can be a major issue. When we change the diets provided during the close-up period, we allow the cow more time to mobilize calcium. Additionally, she also needs time for her rumen to adapt to the forages and higher energy diets which are essential to absorb nutrients and prevent problems after calving.
Today’s concern are not clinical diseases and their treatment cost, but “subclinical metabolic disorders” which affect dairy cows severely. Metabolic disorder i.e. subclinical hypocalcemia (SCH) is considered as “a gateway disease”. The reason is that it is associated with increased risk of periparturient problems that have long-term consequences to production, reproduction, and survival. Research findings (Reinhardt et al., 2011) clearly indicate that cows are more susceptible to hypocalcemia as the lactation number increases.
In 2014, Martinez and coworkers studied the impact of subclinical hypocalcemia beyond milk fever. They induced SCH through 5% ethylene glycol tetra acetic acid (intravenous infusion) treatment for 24 hours. They reported that SCH significantly (* P<0.01) reduced dry matter intake, increased non esterified fatty acids (NEFA) concentration, reduced rumen contractions and decreases neutrophil functions as compared to Normocalcemic cows.
Martinez et. al. (2012) also studied the effect of normocalcemia / SCH and its effects on metritis incidences when a cow is in a high-risk situation. A high risk situation was described as a cow being diagnosed with dystocia, twins, still born or retained foetal membranes.
Normocalcemic cows in a high-risk situation showed 20% incidences of metritis, whereas subclinical hypocalcemic cows showed 77.8% incidences of metritis in the similar high-risk situation.