Early May is a good time to weigh replacement heifers before they go to the bull. This weight should then be used as part of the final criteria to select replacements, especially for herds that calve heifers at 24 months of age.

Ideally, such heifers should weigh around 60% of mature cow weight when bred and 90% of mature cow weight when calving.

Challenge

For a herd with cows averaging 750kg, this means heifers need to weigh at least 450kg by the time breeding kicks off in the coming weeks, which can be a challenge for many herds.

Where cows typically weigh 700kg, then heifers should weigh a minimum of 420kg. Hitting these weights greatly improves the prospects of getting heifers back in-calf for a second year.

Follow up the May weighing with one in June, which can be tied in with a worm dose. Give replacements priority grass over the summer and weigh regularly to monitor performance.