DHIA/Records

Earlier this year, the average age at freshening for first calf heifers in Virginia DHI herds passed a threshold and dropped from 27 to 26 months. In October 1978, the earliest record I have, the average age at first calving in Virginia was 30 months, so this trend has been underway for quite some time. Four months reduction in average age of first freshening over a 30 year period doesn’t sound like much, but it reflects some major changes at the farm level. For most of the 20 th Century, on most Virginia dairy farms, heifers were a “background” enterprise, used to absorb surplus pasture in warmer months and lower quality stored forages for the rest of the year. They grew accordingly – which means slowly. Farmers calved them into the lactating herd to help make “base”. Breeding would be delayed on large groups of heifers for several months to freshen them in the late summer and early fall. It seems that almost no heifers were ever bred “early” to achieve the same purpose, only later. Today, many dairy producers realize that heifers are too valuable to the dairy enterprise to “background” on marginal rations. They also know that it is expensive to keep large groups of older heifers on the farm, even to make base or to feed cheap rations. Reducing age at first calving from 30 to 26 months reduces the number of heifers on a farm by 13%. It also reduces the time between rearing costs and returns from lactating cows. Virginia producers should continue to reduce the age at first calving to 22-24 months, but with awareness that several things must change in the process. Good calf and heifer rearing programs, careful transition management prior to and just after calving, and adequate nutrition for growth, production, and reproduction in first lactation are also required.

DHI Notes...