Supplemental niacin for lactating cows during summer feeding

Area of Science:

• Animal Science
• Dairy Nutrition
• Ruminant Metabolism

Background:

• Summer heat stress negatively impacts dairy cow productivity and milk yield.
• Niacin (vitamin B3) is a crucial nutrient involved in energy metabolism, potentially mitigating heat stress effects.

Purpose of the Study:

• To evaluate the effect of supplemental niacin on milk production and composition in dairy cows during summer.
• To determine optimal niacin supplementation levels for dairy cows under heat stress conditions.

Main Methods:

• Five herds (240 cows) were used in an 84-day summer trial.
• Cows were paired and assigned to control or 6 g/d supplemental niacin groups.
• Diets included various forages (corn silage, hay, pasture) and concentrates.

Main Results:

• Niacin-supplemented cows produced significantly higher yields of milk (25.4 kg/d vs 24.5 kg/d) and fat-corrected milk (24.3 kg/d vs 23.5 kg/d).
• Response to niacin was consistent across lactation numbers and stages.
• High-producing cows (>34 kg/d) showed a notable increase of 2.4 kg/d milk yield with niacin supplementation.

Conclusions:

• Supplemental niacin at 6 g/d effectively increased milk and fat-corrected milk yields in dairy cows during summer.
• Niacin supplementation did not significantly alter milk fat or protein percentages.
• Niacin may be a beneficial supplement for dairy cows experiencing summer heat stress to enhance milk production.