Importance of dry cow feeding
Boersema also discussed epigenetics, the study of the ways in which expressed heritable traits are modified by the environment around them or other outside influences. He referred to epigenetics as the switching on or off of gene expression to provide everlasting change in the performance of a calf or heifer. Some of this ‘switching on’ and ‘switching off’ happens during pregnancy, he said, including circumstances that influence future fertility, calf size and gut maturation. “We know if we don’t feed cows well in the last 2 months of pregnancy that the development of the gut is not right, and this in turn can lead to problems with diarrhea in calves.” Another example; IgG [immunoglobulin G] is not taken up in cows that are fed low protein during the dry period. Boersema: “At least 14% raw protein improves the immune status of the calf. It all has to do with gut maturation.”
Long-term effects of colostrum
Colostrum intake is extremely important to the growth and development of a newborn calf. It supplies energy and assists in the development of the immune system. It contains proteins that are not found in cows’ milk, as well as insulin, which is needed during the first 4 days of life to assist in the update of glucose.
Research shows that the first feeding of colostrum has a tremendous effect on later life. After birth we have 3 or 6 months of growth to really capitalise on genetic expression and colostrum plays a big part in this. Calves that receive 4 liters of colostrum at first feeding – within 2 hours of birth – see an improvement in growth rate. Furthermore, age to first insemination decreases, and survival into second lactation improves. Finally, the sum of first and second lactation yields also increases. During the milk period at the end of the pre-puberal phase, Boersema said farmers have the ability to accelerate growth up to 1 kg/day. As a result, milk production can be increased by as much as 1,500 kg during the first lactation, he said. “If you feed a calf well and it grows well, then it will give good milk,” he said.