20 de mayo de 2020
First on the trace minerals: commercial diets contain margins of safety for trace minerals and vitamins. The extra trace minerals had increased over time. Data started being published suggesting that the excess trace minerals may be negative for productivity along with being a potential environmental concern. Thus, the levels have been reducing to be closer to requirements. You are correct that organic minerals also have led some of this reduction.
Vitamins are a more difficult one because higher levels of some vitamins can impact blood parameters or immune function and there is less negative impact of feeding high levels, other than cost. Thus, it is easier to find research showing benefits of higher levels of a particular vitamin on particular metabolic outcomes. These outcomes are often not tied to pig performance, mortality, or economics, so you are right to be skeptical. The relatively low cost of vitamins for a commercial production system also puts them on the low end of priority scale for devoting resources to testing in large scale studies, which are needed to truly document economic benefit to marginal increases in particular vitamins. Thus, dietary levels for individual vitamins are based on history, risk tolerance, and differing opinions on the limited data.
30 de junio de 2020
Mike gave essentially a very concise response. Trace mineral addition is affected by the form of mineral added and also the amount and strength of the various inhibiting products contained in the feed. Most "nutrient requirements" are determined under fairly controlled conditions with most of the variables of feeding controlled. This is what we attempt to copy in our controlled feeding programs followed in most swine and poultry operations. Cattle feeding is less controlled due to many uncontrollable factors such as outside weather conditions, larger genetic variability and use of many more ingredients in ration formulation. Therefore we are tempted to give more of a nutrient cushion in the ration for cattle and feed much closer to the minimum requirement for swine and poultry.
2 de agosto de 2020
Trace minerals and vitamin supplements at 1000ppm dose with daily feeds improved animal growth and immunity .
