Horse — Pregnant Mare Feed Requirements
Nutrient requirements increase primarily during the last trimester when 60% of fetal growth occurs. Protein needs rise to 11-14% and energy increases 15-20% above maintenance. Supplement with calcium and phosphorus for skeletal development. Avoid fescue hay which can contain endophyte toxins harmful to pregnant mares.
Pregnant Mare Feeding at Different Body Weights
The daily feed requirements for horse in the pregnant mare stage vary directly with body weight. The table below shows how dry matter intake, protein needs, and monthly feed costs change across a range of body weights. The DMI adjustment of 1.15x is applied at every weight level, reflecting the consistent metabolic demands of this production phase regardless of the individual animal's size.
| Body Weight | Daily DMI | Daily Protein | Daily TDN | Monthly Feed | Monthly Cost* |
|---|---|---|---|---|---|
| 660 lbs | 15.2 lbs | 2.0 lbs | 8.4 lbs | 455 lbs | $38.81 |
| 770 lbs | 17.7 lbs | 2.3 lbs | 9.7 lbs | 531 lbs | $45.28 |
| 880 lbs | 20.2 lbs | 2.6 lbs | 11.1 lbs | 607 lbs | $51.75 |
| 990 lbs | 22.8 lbs | 3.0 lbs | 12.5 lbs | 683 lbs | $58.22 |
| 1,100 lbs | 25.3 lbs | 3.3 lbs | 13.9 lbs | 759 lbs | $64.69 |
| 1,210 lbs | 27.8 lbs | 3.6 lbs | 15.3 lbs | 835 lbs | $71.16 |
| 1,320 lbs | 30.4 lbs | 4.0 lbs | 16.7 lbs | 911 lbs | $77.63 |
| 1,430 lbs | 32.9 lbs | 4.3 lbs | 18.1 lbs | 987 lbs | $84.09 |
| 1,650 lbs | 38.0 lbs | 4.9 lbs | 20.9 lbs | 1,138 lbs | $97.03 |
*Monthly cost estimated using grass hay at $150/ton.
Feed Options for Horse (Pregnant Mare)
Different feeds provide varying levels of protein and energy for horse in the pregnant mare stage, which requires a minimum of 13% crude protein and 55% TDN. The table below compares common feeds, showing the as-fed daily quantity needed to meet the dry matter requirement and whether each feed meets the protein and TDN thresholds as a sole feed source.
| Feed | CP % | TDN % | As-Fed/Day | Protein OK? | TDN OK? | Monthly Cost* |
|---|---|---|---|---|---|---|
| Grass Hay | 8% | 52% | 28.8 lbs | No | No | $64.69 |
| Alfalfa Hay | 18% | 58% | 28.1 lbs | Yes | Yes | $105.42 |
| Timothy Hay | 9% | 55% | 28.8 lbs | No | Yes | $86.25 |
| Bermuda Grass Hay | 10% | 52% | 28.8 lbs | No | No | $69.00 |
| Whole Corn | 9% | 88% | 28.8 lbs | No | Yes | $94.87 |
| Cracked Corn | 9% | 88% | 28.8 lbs | No | Yes | $103.50 |
| Oats | 12% | 70% | 28.4 lbs | No | Yes | $89.54 |
| Barley | 13% | 84% | 28.8 lbs | Yes | Yes | $99.19 |
| Pasture Grass (Fresh) | 12% | 62% | 101.2 lbs | No | Yes | $0.00 |
| Layer Pellets | 16% | 70% | 28.1 lbs | Yes | Yes | $168.67 |
| Broiler Starter | 22% | 78% | 28.1 lbs | Yes | Yes | $189.75 |
| Horse Sweet Feed | 12% | 72% | 28.8 lbs | No | Yes | $150.94 |
| Alfalfa Hay Cubes | 17% | 56% | 28.1 lbs | Yes | Yes | $126.50 |
*Cost based on the listed feed as the sole source at current pricing.
Herd Budgets: Horse Pregnant Mare
For operations managing multiple horse animals in the pregnant mare stage, the following table projects total feed requirements and costs for various herd sizes. These projections use grass hay pricing and assume all animals are at the average body weight of 1100 lbs.
| Head Count | Daily DMI Total | Monthly Tons | Annual Tons | Monthly Cost | Annual Cost |
|---|---|---|---|---|---|
| 1 | 25.3 lbs | 0.38 tons | 4.62 tons | $64.69 | $787.03 |
| 5 | 126.5 lbs | 1.90 tons | 23.09 tons | $323.44 | $3,935.16 |
| 10 | 253.0 lbs | 3.79 tons | 46.17 tons | $646.87 | $7,870.31 |
| 25 | 632.5 lbs | 9.49 tons | 115.43 tons | $1,617.19 | $19,675.78 |
| 50 | 1,265.0 lbs | 18.97 tons | 230.86 tons | $3,234.37 | $39,351.56 |
| 100 | 2,530.0 lbs | 37.95 tons | 461.73 tons | $6,468.75 | $78,703.12 |
Nutritional Management Tips for Pregnant Mare
Proper nutritional management during the pregnant mare phase is critical for horse health, productivity, and profitability. The DMI adjustment factor of 1.15x reflects the increased metabolic demands of this production phase compared to maintenance. Similarly, the protein adjustment of 1.3x elevates the dietary crude protein requirement to 13% of dry matter.
When formulating rations for this stage, start with the forage base and determine how much of the protein and energy requirements it provides. If the forage alone does not meet the protein or TDN requirements shown in the feed comparison table above, supplement with protein concentrates (soybean meal, cottonseed meal) or energy sources (corn, barley, fat supplements) to fill the gap. Always make dietary changes gradually over 7-14 days to allow the digestive microbiome to adapt, particularly for ruminant species where sudden changes can cause acidosis, bloat, or other digestive disturbances.
Water intake is closely linked to dry matter intake and is often overlooked in feeding calculations. As a general rule, livestock consume 2-4 lbs of water per lb of dry matter consumed, with lactating animals at the high end of this range. Ensure that clean, fresh water is available at all times, as even mild dehydration reduces feed intake and animal performance. During winter, heated water sources prevent freezing and maintain intake. During summer heat, shade and ventilation reduce heat stress that can depress feed intake by 10-20%.
Monitor body condition scoring (BCS) regularly to verify that the feeding program is achieving the desired results. Animals gaining or losing condition outside the expected range indicate that feed quality or quantity needs adjustment. Laboratory analysis of forage samples ($15-$30 per sample) provides accurate protein and energy values for your specific hay or silage, which may differ significantly from the book values used in this calculator. Hay quality varies by cutting, maturity at harvest, storage conditions, and weather during the curing process, making testing the most reliable basis for ration formulation.
Other Horse Life Stages
Compare feed requirements across all horse production phases.