Lactating dairy cows fed diets based on corn silage plus either brown midrib forage sorghum or brown midrib pearl millet silage have similar performance

Abstract

Objective: Our objective was to evaluate the feeding value of brown midrib (BMR) pearl millet (PMS) with that of BMR forage sorghum (FSS) in diets fed to lactating dairy cows on intake, milk yield, and milk composition. Materials and Methods: Thirty-two mid-lactation Holstein cows (139 ± 21 DIM) were used in an 8-wk randomized complete design trial. Cows were fed individually a common diet based on 37.2% corn silage and 18.3% ryegrass silage for the first 2 wk, and data collected were used as a covariate in the statistical analysis. At the end of the preliminary period, cows were abruptly switched to diets containing 32.6% corn silage and 20.6% of the total DM from either PMS or FSS for the following 6 wk. Data were subjected to repeated measures analysis. Results and Discussion: No differences were observed in DMI among treatments, but there was a treatment × week interaction because cows fed PMS consumed slightly less DM during wk 5 compared with those fed FSS. Yield of milk and components and component concentrations were not different among treatments. However, cows fed diets supplemented with FSS had greater MUN concentrations compared with those fed PMS, and the differences were greater for FSS during wk 4 and 6 compared with PMS, resulting in a treatment × week interaction. No differences were observed in BW and BCS among treatments. Implications and Applications: Results of the current trial indicate that either BMR pearl millet or BMR forage sorghum will support similar performance of mid-lactation dairy cows when fed along with corn silage. These results provides additional options for planning forage production for producers.