Brown midrib sorghum silage for midlactation dairy cows

Area of Science:

• Animal Science
• Ruminant Nutrition
• Forage Quality

Background:

• Dairy cows in mid-lactation require high-quality forages for optimal performance.
• Brown midrib sorghum is a novel forage option with potentially altered nutritional characteristics.
• Comparing brown midrib sorghum silage to conventional silages is crucial for dairy nutrition management.

Purpose of the Study:

• To evaluate the impact of brown midrib sorghum silage versus alfalfa, corn, and normal sorghum silages.
• To assess effects on Holstein dairy cow performance, ruminal metabolism, and digestive kinetics.
• To determine the suitability of brown midrib sorghum for mid-lactation dairy cows.

Main Methods:

• Four isonitrogenous diets containing 65% silage were fed to twelve Holstein cows in a replicated 4x4 Latin square design.
• Ruminal characteristics were measured in three fistulated cows using a 3x4 Youden square design.
• Dry matter intake (DMI), milk yield, milk components, eating time, rumination, ruminal pH, ammonia, VFA, and NDF digestion were analyzed.

Main Results:

• Dry matter intake was higher for corn and brown midrib sorghum diets (4% BW/d) compared to alfalfa and normal sorghum (3.4% BW/d).
• FCM production was similar for brown midrib sorghum, corn, and alfalfa silages (25.8 kg/d), but lower for normal sorghum.
• Brown midrib sorghum showed greater in situ NDF digestion than normal sorghum, aligning with in vitro findings. Ruminal VFA concentrations were highest for corn and brown midrib sorghum.

Conclusions:

• Brown midrib sorghum silage supports milk production comparable to corn and alfalfa silages in mid-lactation Holstein cows.
• It offers advantages in dry matter intake and ruminal NDF digestion over normal sorghum silage.
• Brown midrib sorghum is a viable alternative forage for dairy cattle, potentially improving nutritional efficiency.