Feed variability in dairy cattle

Variability in the nutrient content of dairy cattle feed can lead to significant differences between expected and delivered nutrition in a cow’s diet. Accurately assessing the nutrient content of dairy cattle feed is important for farmers’ livelihoods and for environmental sustainability: Overfeeding cattle can negatively impact their health, cause economic loss for farmers and overuse environmental resources; underfeeding can reduce cows’ health and milk production. Forages like corn silage and hay are particularly vulnerable to nutrient variability and often make up 40-60% of the diet of cows on New York dairy farms. Regular sampling and analysis can improve precision of feed nutrient delivery; however, few guidelines exist for sampling frequency. Better understanding of the degree of feed nutrient variation and farm-specific factors that influence it can improve recommendations of when and how often to sample forage stocks.

This project evaluated the impact of forage quality variation and developed farm-specific forage-sampling recommendations to increase feed efficiency and reduce environmental impacts: 

• We collected forage samples from eight working dairy farms in New York during the harvest of hay and corn with a sampling frequency of one sample for every 15-20 acres. 
• We collected forage samples from the same eight farms after feed had been stored in silos and was being fed to cows.
• We developed methods to track forage material in the silo so it could be matched to its field of origin.
• We curated and analyzed a large database of our forage composition samples that includes management and environmental information such as harvest dates, soil types and weather.