178 A characterization of declared nutrient profiles of commercially available manufactured feeds for broodmares and growing horses

Abstract

Commercially manufactured concentrates may be fed to broodmares and growing horses. While many aspects of the production and labeling of commercial feeds are guided by governmental requirements or recommendations from the American Association of Feed Control Officials (AAFCO), each manufacturer determines the nutrient profiles for individual feeds. This project characterized the nutrient profiles of commercially available manufactured feeds intended for broodmares and growing horses. The study was performed using an internet search (Chrome, Google LLC) beginning in April of 2020 and ending in September of 2021. Search terms included horse, equine, growth, weanling, yearling, broodmare, breeding, nursery, stud, feed, mill, concentrate, pellet, cube, textured and sweet feed, in various combinations. A search using the name of each state and the term “feed mill” was also conducted. Only feeds declared to be for broodmares, breeding stock, or growing horses were included. Feeds intended to be fed at low intakes, such as ration balancers, and feeds intended as the entire ration (without forage) were excluded. The final data set included the manufacturers’ reported nutrient concentrations for minimum crude protein (CP, n = 132), minimum calcium (Ca, n = 131), minimum phosphorus (P, n = 131), minimum copper (Cu, n = 125), minimum zinc (Zn, n = 125), minimum selenium (n = 127),minimum vitamin A (n = 125), minimum vitamin E (n = 121) and minimum vitamin D (n = 91). The Ca:P ratio was calculated using the minimum Ca concentration and the minimum P concentration. Mean, standard deviation (SD) and coefficient of variation (CV) were calculated for each nutrient. Mean and SD for the reported minimums for CP, Ca and P were 14.6 ± 1.44%, 0.9 ± 0.28 % and 0.64 ± 0.13%, respectively. The mean value for Ca:P ratio was 1.5:1. Mean and SD for the reported minimums for Cu, Zn and Se were 54 ± 16 ppm, 171 ± 52 ppm and 0.54 ± 0.15 ppm, respectively. Mean values for the reported minimums for vitamin A, vitamin E and vitamin D were 5453 ± 2030 IU/lb, 133 ± 66 IU/lb and 734 ± 395 IU/lb, respectively. The CV for reported minimums for the feeds in this survey ranged from lows of 10% for crude protein and 20% for phosphorus, to highs of 50% for vitamin E and 53% for vitamin D. The large coefficients of variation for vitamin E and vitamin D may suggest a lower level of consensus among manufacturers in regard to desirable fortification levels for these nutrients. Information from this survey may provide insight into areas where research is needed to define nutrient requirements of broodmares and growing horses.