Balancing equine forage diets with commercial feeds
Numerous horse barns in this region use commercial bag feeds and supplements to balance equine forage diets. In this section, we will evaluate the nutritional program of a Kentuckiana Jumper/Hunter farm that feeds Tribute Kalm 'N EZ and Essential K. Pasture on this farm is very limited (not included in diet balancing) and the primary hay is a relatively low-protein, high fiber Timothy grass. The objective is to see how well commercial products balance deficits for this particular hay and to recommend dietary changes, if necessary.
Tables 1-3 (link or view below) compare nutrient concentrations and National Research Council (NRC, 2007) recommendations for three possible diets: hay only, hay plus Tribute Kalm 'N EZ and hay plus Tribute Kalm ’N EZ and Essential K. Deficits are listed in the last column of each table. Table 4 (link or view below) includes notes and summary of results. Diets are for “hard keepers” at moderate workload, as defined by NRC.
Kalm 'N EZ does a good job balancing deficits for this particular Timothy hay. The only balancing required is for mineral ratios copper:zinc and calcium:magnesium, which are slightly outside the recommended ranges. Addition of small amounts of zinc and magnesium to diet will increase the copper:zinc ratio from 2.7:1 to 3:1 and decrease the calcium:magnesium ratio from 3.3:1 to 2:1 (Table 4). Further supplementation with a ration balancer, such as Essential K, is unnecessary in terms of NRC recommendations (see below).
Both Tribute products contain significant amounts of iron. Studies have shown that excess iron is associated with zinc and possibly copper deficiencies, infection and immunity, iron overload and insulin resistance. Given that iron is potentially toxic, NRC has set the upper safe limit for iron at 500 ppm in total diet. The nutritional way to address iron overload is to maintain tight iron:copper:zinc:manganese ratios (4:1:3:3) and avoid hay and feeds with high iron concentrations.
The iron:copper ratio in the hay and Kalm 'N EZ diet is slightly less than 10:1 (9.5:1), which is the upper tolerable limit for horses (Eleanor Kellon, VMD). As noted, the ideal ratio is 4:1 but balancing to this ratio would require supplementation with high amounts of copper and zinc.
Recommendations for this diet are as follows:
1. Choose hay with higher nutrient concentrations. The iron concentration (131 ppm) is relatively low for this region.
2. Supplement zinc, sodium and magnesium as single ingredients (Table 4). Additional zinc and copper will bring iron:copper ratio closer to ideal value.
3. Since these horses have limited pasture, add omega fatty acids (2-4 oz flax meal) and vitamin E (4 IU/kg body weight in total diet) beyond the levels provided by Kalm 'N EZ. If there is no sun exposure and hay is older than 1-2 years, also supplement with vitamin D and A, respectively. Flax meal is a very palatable carrier for single ingredients.
3. Discontinue use of Essential K, which is unnecessary as a ration balancer. At $26.00 per 50 lb bag (local price), this dietary change would result in significant cost savings.
Tables 1-3 (link or view below) compare nutrient concentrations and National Research Council (NRC, 2007) recommendations for three possible diets: hay only, hay plus Tribute Kalm 'N EZ and hay plus Tribute Kalm ’N EZ and Essential K. Deficits are listed in the last column of each table. Table 4 (link or view below) includes notes and summary of results. Diets are for “hard keepers” at moderate workload, as defined by NRC.
Kalm 'N EZ does a good job balancing deficits for this particular Timothy hay. The only balancing required is for mineral ratios copper:zinc and calcium:magnesium, which are slightly outside the recommended ranges. Addition of small amounts of zinc and magnesium to diet will increase the copper:zinc ratio from 2.7:1 to 3:1 and decrease the calcium:magnesium ratio from 3.3:1 to 2:1 (Table 4). Further supplementation with a ration balancer, such as Essential K, is unnecessary in terms of NRC recommendations (see below).
Both Tribute products contain significant amounts of iron. Studies have shown that excess iron is associated with zinc and possibly copper deficiencies, infection and immunity, iron overload and insulin resistance. Given that iron is potentially toxic, NRC has set the upper safe limit for iron at 500 ppm in total diet. The nutritional way to address iron overload is to maintain tight iron:copper:zinc:manganese ratios (4:1:3:3) and avoid hay and feeds with high iron concentrations.
The iron:copper ratio in the hay and Kalm 'N EZ diet is slightly less than 10:1 (9.5:1), which is the upper tolerable limit for horses (Eleanor Kellon, VMD). As noted, the ideal ratio is 4:1 but balancing to this ratio would require supplementation with high amounts of copper and zinc.
Recommendations for this diet are as follows:
1. Choose hay with higher nutrient concentrations. The iron concentration (131 ppm) is relatively low for this region.
2. Supplement zinc, sodium and magnesium as single ingredients (Table 4). Additional zinc and copper will bring iron:copper ratio closer to ideal value.
3. Since these horses have limited pasture, add omega fatty acids (2-4 oz flax meal) and vitamin E (4 IU/kg body weight in total diet) beyond the levels provided by Kalm 'N EZ. If there is no sun exposure and hay is older than 1-2 years, also supplement with vitamin D and A, respectively. Flax meal is a very palatable carrier for single ingredients.
3. Discontinue use of Essential K, which is unnecessary as a ration balancer. At $26.00 per 50 lb bag (local price), this dietary change would result in significant cost savings.
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