Summary by Kai Yuan, PhD, Senior Research & Technical Advisor
A study conducted by Dr. Heather Dann from Miner Institute evaluated the effects feeding different levels of starch to fresh and peak lactating cows on dry matter intake and milk production.
- 72 Multiparous Holstein Cows
- 40-d Dry Period (controlled energy, high straw)
- 91-d Lactation Period (21%, 23%, or 26% starch)
| Treatment | 1-21 DIM | 22-91 DIM |
| Low/Low | 21% Starch | 21% Starch |
| Medium/High | 23% Starch | 26% Starch |
| High/High | 26% Starch | 26% Starch |
| LL | MH | HH | SE | P-Value | |
|---|---|---|---|---|---|
| DMI, kg/d | 25.2 | 24.9 | 23.7 | 0.5 | 0.06 |
| 3-5% FCM, kg | 51.9 | 52.2 | 47.4 | 1.7 | 0.09 |
| Fat, % | 3.88 | 3.64 | 3.79 | 0.08 | 0.08 |
| Fat, kg/d | 1.91 | 1.86 | 1.71 | 0.06 | 0.09 |
| True Protein, % | 2.90 | 2.92 | 2.97 | 0.04 | 0.52 |
| True Protein, kg/d | 1.42 | 1.50 | 1.34 | 0.04 | 0.03 |
Key findings:
-
- Compared to the high starch group, cows who received lower starch in early lactation had greater intake and produced more fat-corrected milk. Cows who were fed 23% starch diet consumed more starch than those fed 26% starch diet due to higher intake. The level of intake is often times more important than the nutrient percent of the diet.
- Consistent with this research, recent work from Michigan State (2018 J Dairy Sci 101:8902-8915) showed that highly fermentable starch decreased intake and milk yields of post-fresh cows. Specifically, during the first 3 weeks of lactation, 28% starch with high-moisture corn decreased dry matter intake by 8.6 lb/d, and decreased fat-corrected milk yield by 10.6 lb/compared with cows fed dry corn.
- Numerous research showed that by replacing some dietary starch with sugar, there is less concern that excessive liver oxidation of propionate from starch will reduce feed intake. In addition, feeding sugar provides energy to support cow metabolic health and production, without causing harmful effects on rumen.