We have just gotten by the holidays and some of the Southern States and Purebred breeders are starting their calving for the new year. Others may be waiting a few months before spring calving starts or they may even wait for pastures to green up before calving begins. It is a critical time to make sure your cows are consuming their vitamin and mineral supplements to help cows enter calving on a high plane of nutrition, including their vitamin and mineral status.
We can break down the type of minerals into Macro and Micro, or sometimes called “Trace” minerals. Macro minerals such as Phosphorus, Calcium, Sulfur, Magnesium and Potassium are regulated in a different manner than are Trace minerals such as Copper, Zinc, Manganese or Selenium. For the most part Macro minerals are controlled homoeostatically whereby the body looks to maintain them at an equilibrium or balance in a normal physiological state.
Trace minerals on the other hand have been described by R. J. Van Saun, 2007, from the Department of Veterinary and Biomedical Sciences at Penn State Univ., to be controlled through movements in “pools” within the body. What this means is that trace minerals are often associated as a component in one of several types of pools. They can be associated with metalloenzymes or a biochemical function pool, transported by carrier proteins as part of a transport pool, or stored as a metal complex, referred to as storage pools. The body will try to maintain the necessary levels of activity or biological processes that these pools support depending upon the nutritional status of the animal.
When diets are properly fortified, excess trace minerals will be stored and can help maintain these pools for optimum biological functions. When diets are deficient, or mineral antagonists are present in the diet, trace mineral stores from the liver will be mobilized to help maintain the biological and biochemical pool activities they support. This will take place until nutritional status increases or trace mineral excretion is reduced so that mineral retention is improved.
By looking at trace mineral status in this manner we can describe mineral deficiency in 4 phases:
- Depletion – loss of mineral in storage
- Deficiency – loss of mineral in the transport pool
- Dysfunction – compromise of the function pool
- Disease – clinical signs associated with reduced function of a metalloenzyme
Subclinical disease occurs in the Dysfunction and Disease phases. These can be observed as reduced growth rates, or reproductive efficiency, compromised immune function or other decreases in production performance or health status. This is why nutrition prior to calving is critical in producing healthy calves in addition to cows cycling on time and breeding early in the breeding season.
If we look at a few key nutrients it further supports the need to stay on top of your mineral and vitamin supplementation all the way through the winter. It has been found in several studies that maternal liver trace mineral concentrations are lower than fetal liver trace mineral levels. These fetal liver trace mineral concentrations have been reported in some cases to be more than twice that of their dams. It is interesting that there must be some mechanism for the dam to preferentially allow for greater storage in the fetus than in her own liver.
It is interesting to note that milk does not provide adequate supplies of Copper, Iron, Zinc or Selenium to meet calf requirements. Newborn calves will rely on liver stores until their diet can help meet requirements. This may take weeks or months before any significant contribution can come from the diet in beef calves raised on pastures. This is not the case for fat soluble vitamins such as Vitamin A and E. These vitamins are primarily supplied via the colostrum upon calving. This makes nutrition prior to and after calving extremely important for the cow herd. Important prior to calving because key trace minerals are stored in the liver of the fetus and equally important after calving as key vitamins and selenium that are delivered via the colostrum.
As you can see, if you want to minimize calf health challenges, maximize reproductive efficiencies and optimize calf growth, don’t let your mineral and vitamin nutrition fall short prior to calving. Deficiencies prior to calving can easily decrease the Trace mineral pools that help make sure fetal liver stores will help them in the first few months of life. Don’t let your mineral feeders go empty if you’re using a dry granular mineral program. CRYSTALYX® also offers mineral formulations or the Breed-Up product line that is specifically fortified for cows prior to calving up to breeding.