The fact that dairy heifers that calve at 22-24 months of age are the most productive, most cost effective and have fewer health problems in first lactation is well understood. Producers are well aware that to be in-calf at fifteen months of age and calve at 24 at an appropriate size, Holstein heifers have to gain an average of 850g per day.
However, how that weight is deposited depends to a large extent on the age of the animal. For instance, a 4 week old pre-weaned heifer will be growing by creating almost entirely bone and muscle tissue. In contrast, an 18 month old heifer will be depositing far more weight as fat.
The association between excessive fat deposition in maiden heifers and first lactation health problems is well established. Fat heifers are more likely to suffer from dystocia, retained placenta and metritis than heifers of a normal body condition score. As body fat supresses appetite in cattle, fat heifers eat less after calving making them prone to poor performance and ketosis.
This means that early growth is far more beneficial to heifer health and production than later growth. The good news is that early growth is far more efficient than later growth (newborn calves require 2-3 kg food for every kg growth whereas adult cattle can require up to 8kg!).
Maximising your heifer growth rates in the first six months of life by minimising disease and paying careful attention to husbandry and nutrition means that you won’t have to play “catch up” further down the line and end up with animals that have deposited too much fat.
The first step is to measure and monitor. This means knowing your average daily live weight gains, disease and mortality rates throughout rearing.
It really is the case that early growth means more milk further down the line.
If you would like help assessing your current heifer performance and some ideas on how to make improvements then our 0-6 youngstock team of vets and vet techs can help. Give us a call and speak to Esme Moffett or Tom Shardlow.