27 February 1998

SAC says extended lactations for high yielders worth ££s

By Simon Wragg

EXTENDING the lactations of high yielding cows by moving to 18-month calving intervals could boost margins by £160 plus through improved performance and herd health, says the SACs head of production systems, David Roberts.

Speaking at the Alltech feed conference, Birmingham, Dr Roberts urged producers to consider extended lactation as an option to improve margins. "Drying off high yielding cows to fit 12-month calving intervals could be affecting cow health and reducing margins," he warned

Vet bills peak around calving and the first three months of lactation, he said. Most metabolic disorders, such as mastitis and lameness, occurred at this time.

According to the SACs head of animal physiology, Chris Knight, US research showed that managing high yielding cows on 18-month calving systems cut vet bills by 25%, culling rates by 27% and added £160 extra margin a cow.

"By definition, 18-month calving reduces risk of metabolic disorders and culling due to infertility, as production changes only occur each year-and-a-half, rather than yearly," said Prof Knight.

At SACs Hannah research station 24 high merit cows are being tested on the 18-month system. But Prof Knight said results were two years away. "As a producer with high lactation cows I would be looking to extend lactations. Producers should ask their vet about the implications."