Accelerated growth
Accelerated growth of dairy calves refers to feeding and management strategies designed to increase the rate of growth in young calves beyond traditional norms, typically during the pre-weaning period. The goal is to help calves reach breeding size earlier and improve lifetime productivity. Typically, replacement dairy calves were historically fed 4-5 litres of milk and were weaned as soon as possible, as milk powder was expensive but concentrates less so. However, growth rates were typically 0.3-0.5 kg/day as a lot of energy consumed was required for maintenance particularly during winter. The result was that animals took longer to reach an appropriate bulling weight, were not calving down until approximately 27-30 months and were costing money as the time to start recouping rearing expenses was longer. Older heifers at first calving whilst usually producing more milk in first lactation do not stay in the herd as long as heifers calving around 24 months and therefore have reduced lifetime production and are less profitable, hence there are considerable benefits from better nutrition, particularly during the milk feeding phase when feed efficiency is at its highest.
What it involves
Higher nutrition: Feeding more whole milk or milk replacer (often higher protein and fat content).
A longer weaning period to encourage starter intake as calves fed higher levels of milk will drink milk in preference to consuming concentrates
Optimal housing and health: good ventilation, hygiene, and disease prevention (a must for any system of calf rearing)
Monitoring growth: Targeting higher average daily gains (ADG), often 0.8–1.0 kg/day compared to traditional 0.5–0.6 kg/day.
Potential benefits
Technology investigation below on accelerated growth and associated weaning strategies
- Earlier breeding and calving: heifers can calve at 22–24 months instead of 26–28 months.
- Reduces rearing costs per animal.
- Higher milk production: studies show accelerated growth-fed calves often produce more milk in their first lactation (up to 400–600 litres extra). However, getting the milking heifer back in calf and continued growth may be a better priority, rather than more milk
- Improved health and immunity: better nutrition supports immune function and reduces disease risk.
- Better body development: enhanced skeletal and organ growth, not just fat deposition.
CAFRE has been feeding higher levels of milk powder since moving into the new calf house facilities, (approximately 60kg powder, if all consumed). Whether this is considered ‘accelerated growth’ is debatable as growth rates are only about 50g/day higher compared to previous feeding regime (6 litres/day) and milk production from the subsequently calved heifers has not changed much. See summary below for heifer details when on milk.
