According to Roberts, this strategy of providing less feed may reduce costs of developing each replacement heifer by more than $31 and extend their lifespan, with important ramifications for lifetime efficiency and profitability. Feed represents 50 to 55% of total costs of developing replacement heifers.
In their study, begun in 2001, heifers were divided into two lifetime treatment groups: The control group was fed according to industry guidelines, and the restricted group was fed (on a body-weight basis) 80% of feed consumed by their control counterparts for 140 days, ending when they were 1 year old.
Better selection
The restricted heifers grew slower and weighed less at any point in time as a consequence of less feed. Final pregnancy rates were 87% for restricted heifers and 91% for controls.
According to Roberts, restricting feed allows nature to decide which heifers were reproductively efficient: Less efficient heifers would eventually fail to reproduce and be culled if restricted, whereas feeding more would keep them in production but result in more expense for the producer.