By Stephen B. Blezinger, Ph.D., PAS, Ruminant Product and Technical Manager at Trouw Nutrition USA.
The management, nutrition and subsequent performance of calves is a topic of constant debate. Generally, this discussion begins with the period immediately after birth through the growing animal’s life. How a young animal performs after birth is often tied directly to the dam carrying that calf. From conception on, the cow provides the nutritional needs and assists in growing and developing the fetus. Since this period of growth (from conception to birth) is the most rapid growth phase in the life cycle of the animal, this is also when genetic mapping takes place. Providing the nutritional needs of the cow is critical for the calf and is tied to the young animal’s health and developmental performance.
One very specific area of focus in recent years has been on the trace mineral (TM) status of the cow, the fetus and subsequently the newborn calf. This status can have significant long term effects on how the calf performs through life. The developing fetus is totally dependent upon the availability of essential nutrients through the placenta from the dam’s blood. As a result, fetal nutrient status is reflective of maternal nutrient status. Maternal nutrients available to the fetus would include those from the cow’s diet as well as reserves mobilized from the cow’s body, if needed. Numerous studies have observed the fetus’s liver concentrating ability for minerals, i.e., fetal liver mineral concentrations, to exceed maternal values. For example, a decline in the cow’s liver copper concentration during late pregnancy would be consistent with her transfer of minerals to the fetus. As a result, if the cow is deficient in critical nutrients, it is likely the calf will be as well.
Micro or trace minerals are essential nutrients necessary to support nearly all physiologic, metabolic and structural functions of the body. Trace minerals such as Copper (Cu), Iron (Fe), Manganese (Mn), Selenium (Se) and Zinc (Zn) are involved in countless enzyme systems which facilitate and drive the various body processes, at this stage, those related to health performance, such as Zn, Cu and Se are critical. The TM levels are controlled predominantly through movement between storage, transport and biochemical functions in the body.
During the early periods after calving, almost all essential nutrients are adequately provided by milk consumption. However, a number of critical micronutrients, namely Cu, Fe, Mn and Zn are not provided effectively by milk consumption alone, thus requiring additional sources to meet daily needs (Table 1).
Table 1. Average Milk Concentrations of TMs as Compared to NRC Recommendations
Mineral Milk (ppm) NRC recommendation for growth (ppm)
Copper 0.052 10
Zinc 3.960 30
Manganese 0.021 20
Selenium - 0.1
Because of this, fetal liver nutrient reserves play an important role in maintaining adequate concentrations of these trace elements to support the daily requirements in the young animal. Liver mineral reserves at birth are supported by consumption of colostrum, a highly concentrated source of most essential minerals. And, as would be expected, maternal mineral status will influence mineral concentration in colostrum. As colostrum production declines and stops, the availability of the trace minerals from this source also ceases.
So what are the message here?
1) Trace mineral status in calves significantly affect processes required for life, growth and development. Compromising this status is detrimental to the fetus and young calf.
2) During gestation and shortly after birth the calf is affected by the TM status of the cow. If the cow is deficient in TMs the calf probably will be deficient as well.
3) Proper TM supplementation of the cow can improve the TM status of the fetus and the young calf promoting proper development, health and growth.
4) Proper supplementation of the young calf through milk replacers, milk fortifiers and starter feeds is critical to the development and support of the immune system, as well as growth and development. These supplements need to be properly balanced for all minerals.
Proper TM supplementation can be a deciding factor in the life of the fetus and young calf. Use of a well designed TM program is critical. Research has shown that inclusion of organic trace mineral sources can have a positive effect on the TM status of the cow throughout pregnancy and the calf pre and post birth. Proper TM nutrition and program design is a critical component of a complete and well designed calf management program.