Written by Darian Livingstone | Ceres Industries
(306) 653-7258 |
Zinc is regarded as one of the most important minerals in livestock diets. In the 1950's, the importance of zinc was discovered when numerous disorders like skin, hair, and wool abnormalities, immune dysfunction, reproductive failure were observed in deficient animals.
Generally speaking, forages and legumes contain sufficient quantities of zinc. However, in a study by Underwood (1981), it was observed that there are numerous areas with zinc-deficient soils that result in forages that are also zinc-deficient. This is especially important to note since there are other components in forages that bind to zinc, making it even less available to the animal.
For example, iron decreases the bioavailability of zinc because they have the same absorption sites in the gastrointestinal tract. Phytic acid, a naturally occurring chemical in plants, also hinders zinc absorption. These examples should emphasize the importance of feed testing and proper mineral supplementation. Being aware of what is in your feed can help formulate a diet that will maximize your livestock's performance.
The National Research Council recommends beef cattle consume 20-40 mg of zinc per kg of their diet, while dairy cattle require at least 40 mg. This is similar to sheep and goats, who require approximately 30 and 40 mg per kg of diet respectively. The maximum tolerable level of zinc for all classes of animals is 500 mg/kg, so toxicity is very rare.
There are several notable benefits of zinc supplements. Zinc is one part of an enzyme involved in skin and hair cell formation and repair. Supplementing zinc to animals can strengthen hooves and build thicker coats. An Illinois State University study demonstrated that feeding extra zinc to their replacement heifers resulted in fewer cases of footrot, hoof cracks, and laminitis.
Zinc has also shown to have benefits for animals during stressful times since it plays a central role in many enzymes in the immune system. Supplementing zinc can mitigate morbidity (sickness) during weaning and transportation, both highly stressful events for livestock.
Another noted benefit of zinc is its ability to improve reproductive efficiency. This important mineral has been shown to have an important role in sperm production and the circulation of testosterone. Since the economics of many operations depends on the offspring, reproduction is an important parameter.
Protein intake has a positive effect on zinc absorption since they bind together and create enzymes. Finding supplements that contain protein to complement poor quality forages can help to ensure that animals are absorbing appropriate quantities of zinc.
The form of zinc is also a function of its bioavailability. Chelated minerals are attached to an organic source, making them easier for the animals to absorb than their inorganic counterparts. Chelated minerals will be listed as proteinates or amino acids whereas inorganic minerals are sulphates or oxides.
While chelated minerals have a higher cost, they provide economic benefits to producers as well. In a study of nursery pigs, those that were fed chelated proteinates showed higher rates of gain and had better feed conversion ratios than those fed inorganic minerals. In a separate study of dairy cattle, those supplemented with chelates had fewer days to first service and fewer services per conception. These studies suggest that by replacing a portion of inorganic minerals with chelates, there is certainly an economic benefit.
Saltec Fortified Pro is a protein supplement with chelated minerals, exceptionally enhancing the bioavailability. If protein is not required when forages are good quality, using the Saltec Magnum or Saltec Ultra salt licks are great options because of their high mineral concentrations. During times when forages are poor quality or when animals are experiencing stress, it is always a good idea to supplement additional minerals. Assuring animals are getting enough zinc can improve important production parameters such as reproduction and performance.
If anyone has any questions or would like to further discuss this topic, they should contact Darian Livingstone at Ceres Industries (contact info above).