Monitoring body condition score (BCS) is not a new concept, but there has been a lot of research and industry-wide discussion about BCS recently. BCS is not only affected by ration balancing and delivery, it is affected by pen moves, stocking density and dystocia or poor maternity handling. BCS is also heritable and all bulls that are genomic tested can receive a BCS evaluation.
Loss of body condition in the post-fresh period due to negative energy balance leads to fat mobilization. A first test fat to protein ratio greater than 1.4 is indicative of this process. Cows with higher fat to protein ratios have been shown to have higher BHBA levels and greater loss of body condition in the first four weeks post-fresh (Sawall and Litherland, UMN, 2014).
BHBA levels over 1.2 mmol/L indicate subclinical ketosis. The average frequency is 25-30% of cows experiencing subclinical ketosis according (McArt, et al, March 2015). This article also puts the cost of subclinical ketosis at $117/case. That is about $30,000/ year on a 1,000 cow dairy with a 25% subclinical ketosis rate. That cost rises significantly if further disorders, such as displaced abomasum or metritis are subsequent.
BCS is included in the ICC$ index to help improve transition cow health. The difference
in fat to protein ratio for cows 40-100 DIM, all in the same herd, at different genetic levels of ICC$ is apparent (see graph 1).
Additional articles (Randall et al, June 2015; Bicalho et al, July 2009) discuss correlation between low body condition and predisposition to lameness due to thinning of the digital cushion.
A presentation at the 2015 American Dairy Science Association annual meeting, and research at the University of Wisconsin have both evaluated loss of body condition in the fresh period and consequential reduced reproductive performance. Dr. Fricke’s research showed cows that lost BCS between 0-21 DIM had a 25% conception rate at first service, cows that maintained body condition had a 38% conception rate at first service, and those that gained BCS had an 84% conception rate at first service!