Feeding Replacement Beef Heifers
Replacement heifers represent the future productivity of the cow herd. Proper nutrition during growth and development ensures heifers reach appropriate size and body condition for breeding. A common benchmark is to have heifers at 65% of their mature weight by breeding time.
These feeding guidelines provide sample rations for different weight classes. They assume adequate vitamin supplementation and do not account for forage wastage, which can reach 25–30% in some conditions. Producers should obtain a forage analysis and consult a nutritionist to balance rations for their specific operation.
Sample Rations
Heifers 400–600 lb (Target ADG: 1.5 lb/day)
Feed Type |
Ration |
Alfalfa |
13.5 lb alfalfa 1 oz 1:1 mineral 1 oz salt |
Alfalfa/Grass Mix |
10 lb alfalfa grass 3 lb barley 1 oz 1:1 mineral 1 oz salt |
Greenfeed |
13.5 lb greenfeed 1 oz 2:1 mineral 1 oz salt |
Heifers 600–800 lb (Target ADG: 1.5 lb/day)
Feed Type |
Ration |
Alfalfa |
20 lb alfalfa 1 oz 1:1 mineral 1 oz salt |
Alfalfa/Grass Mix |
15.5 lb alfalfa grass 4 lb barley 1 oz 1:1 mineral 1 oz salt |
Grass Hay |
15 lb grass hay 4 lb barley 1 oz 2:1 mineral 1 oz salt |
Late Gestation Heifers 800–1000 lb (Target ADG: 1 lb/day)
Feed Type |
Ration |
Alfalfa |
19.5 lb alfalfa 10 lb grass hay 2 oz 1:1 mineral 1 oz salt |
Alfalfa/Grass Hay |
22 lb alfalfa grass hay 6.5 lb barley 2 oz 1:1 mineral 1 oz salt |
Grass Hay |
22 lb grass hay 5.5 lb barley 2 oz 2:1 mineral 1 oz salt |
Note:
1 oz = 28 g = 0.06 lb
1 oz = 28 g = 0.06 lb
Mineral Recommendations
When to Use 1:1 vs. 2:1 Mineral Mix
- 1:1 mineral: alfalfa, alfalfa/grass, pasture grasses
- 2:1 mineral: greenfeed, cereal silage, native hay, straw/grain-based rations
Suggested Trace Mineral Levels
- Selenium (Se): 90 mg/kg
- Copper (Cu): 2500 mg/kg
- Manganese (Mn): 10,000 mg/kg
- Zinc (Zn): 8000 mg/kg
Salt: Use cobalt-iodized or trace-mineralized salt.
Vitamin A Requirements
- Growing heifers: 20,000–25,000 IU/day
- Lactating heifers: 40,000 IU/day
Vitamin A can be provided either by:
- Injectable vitamin A every 60–90 days, or
- A premix included in the feed
Example:
A premix containing 1,500,000 IU Vitamin A/kg:
A premix containing 1,500,000 IU Vitamin A/kg:
- 15 g/day supplies 22,500 IU (suitable for growing heifers)
- 30 g/day supplies 45,000 IU (suitable for lactating heifers)