Why calf pre-weaning average daily gain is important
Pre-weaning nutrition has a significant impact on the lifetime production of animals. It is also the period when the calves have the highest feed conversion efficiency.
Milk production in dairy cows is a function of the amount of milk produced by each secretory cell, and the number of secretory cells in the mammary gland. Enhanced pre-weaning nutrition can impact the size of the secretory cell population in heifer replacement calves.
The major period for the growth of the mammary gland is during the calf pre-weaning phase or first isometric growth phase. Research¹ has demonstrated that increased weight gains during this phase leads to higher milk production.
For every additional 0.1 kg per day of pre-weaning average daily gain (ADG), first lactation milk yield can be increased by up to 155 kg and those calves then go on to be twice as likely to have a greater first-lactation milk yield².
With enhanced pre-weaning nutrition, significant improvements to heifer and cow reproduction can be gained through earlier attainment of puberty¹, conception age, and age at first calving³.
Pre-weaning ADG can be improved by increasing the calf’s dry matter intake from milk or milk replacer. This can be done by:
1. Feeding higher overall daily volumes, targeting from 12 to 15 percent of a calf’s body weight.
2. Increased frequency of feeding. Note though, that this is not always an option but worth considering especially in the first four weeks of life.
3. Feeding a milk feed that has a higher overall total solids component.
There are many options available, including using a calf milk replacer with a higher protein-to-fat ratio such as 28:22 versus 20:20, or by boosting whole milk solids by adding milk replacer to the mix.
There are benefits to focusing on improving pre-weaning nutrition and many ways this can be implemented within an existing rearing system. It is important first to understand the requirements of the calf, especially during winter with calves requiring extra nutrition due to the colder weather to meet their maintenance requirements.
To discuss a suitable calf milk replacer for your rearing system, contact your local PGG Wrightson Technical Field Representative.
1 Shamay (2005), Moallem (2010), Silva (2002), Godden (2006) and Meyer (2006).
2 Soberon, F., and Van Amburgh, M.E. (2013). Lactation Biology Symposium: The effect of nutrient intake from milk or milk replacer of pre-weaned dairy calves on lactation milk yield as adults: a meta-analysis of current data. Journal of Animal Science 91(2):706-12.
3 Davis Rincker, L E., Vandehaar, M J., Wolf, C A., Liesman, J S., Chapin, L T., and Weber Nielsen, M S. (2011). Effect of intensified feeding of heifer calves on growth, pubertal age, calving age, milk yield, and economics. Journal of Dairy Science 94(7):3554-67.
