Replacement Heifers

Most modern dairy systems now target calving at 22 - 24 months of age. This is to optimise life-time performance. 

Calving earlier usually means that the replacement heifer is not developed/matured adequately. Calving later results in extra costs and very often without better animal performance.

Therefore it is paramont to ensure that calves reach their target weight for ages. These targets are outlined in the following articles. The precise targets depends on your system and the type of genetics involved.

For more information see:

http://www.dpi.vic.gov.au/DPI/nreninf.nsf/childdocs/-89E7A8DAFEA417624A2568B30004C26A-BBB90E3F477D0B74CA256BC700811C92-95F19DA354E9D3664A256DEA00277FD6-F6CD25F14A8283D5CA256BCF000BBFE3?open

http://www.iowabeefcenter.org/pdfs/bch/01100.pdf

http://www.ag.ndsu.edu/news/columns/dairy-focus/dairy-focus-know-the-cost-of-raising-replacement-heifers/