The following bullet points from www.foragebeef.ca provide some background and pointers regarding the early weaning of calves. Provided proper management and nutritional needs are met, early weaning will not increase morbidity and mortality rates.
Early-weaned calves learn to eat palatable rations quickly; introduction to creep feeders and stock tanks pre-weaning will get calves settled quicker. Stressful procedures like castration and dehorning should be performed well ahead of early weaning.
Management and feeding of very early-weaned calves (<120 days of age) is best achieved in a dry lot/confined-feeding situation.
The younger the weaning age of the calf, the higher the energy and protein levels need to be.
Early-weaned calves (>120 days of age) can be backgrounded on pasture and have comparable performance to normal weaned (200 days) calves, provided there's sufficient forage quality and quantity.
Very early-weaned calves (<120 days of age) backgrounded in a dry lot setting and fed to slaughter may have reduced carcass weights due to finishing sooner. There are no adverse effects on carcass quality grades and/or yield, however.
Calves weaned at 120 days or more will have comparable finished weights, carcass qualities and yields to that of normal-weaned calves (200 days).
Provided very early-weaned calves (<120 days of age) are not on an energy-restricted diet (<1.5 lbs. /day), there will be no adverse effects on age of puberty and cyclicity in heifer calves.
Very early weaning (<120 days) and or temporary weaning may improve conception rates in younger poor body-conditioned (<2.0; scale 1-5) cows and heifers by 25%.
Very early weaning (<120 days) and early weaning (>120 days) will reduce grazing pressure and/or the grazing needs for the cow herd by at least 25%.
Very early weaning (<120 days) and early weaning (>120 days) will reduce the nutritional needs for protein and energy by 30% or more and is an excellent management tool to better match the cow requirements to what is provided by the pasture.
Very early weaning (<120 days) and early weaning (>120 days) will significantly improve cow body weight and body condition going into the winter. These increases can be used to reduce the cost of winter feed from $50 - $100 / hd.
Using enterprise budget analysis can significantly reduce the cost of production and improve returns for cow calf producers through increasing the grazing opportunities, reducing cow nutritional requirements, reducting winter feed costs and improving conception rates. -- Joe Roybal