Rumen Function and Lameness in High Intake Grass Based Dairy Cows of the South Island of New Zealand

Contemporary dairying in the South Island (SI) of New Zealand is pasture based, commonly with large herds (>600) and aggressive pasture management to maintain high feed quality across the lactation season. Lameness in this system is a dominant health and welfare concern, and a common industry explanation is sub-clinical laminitis due to the high sugar and low fibre of the pastures inducing SARA. Despite this, there was no existing research on rumen function in this system. This project sought to describe rumen function and any possible role in lameness in very high production grass fed cows in situ in a typical commercial SI system.
In 2005-07 15 rumen fistulated cows were run with the Lincoln University herd (n=670). For 96h periods each month across the season, rumen pH, temperature and motility were logged every 15s via indwelling probes. Rumen samples were obtained twice weekly for SCA and NH3 analysis, and microbiota assessment using DGGE. In addition, specific five by five cow cross-over experiments examined the effect of straw feeding on pH, motility, and rumen microbiota ...