Effect of silage maize hybrid (dry down vs. stay green) on dairy cow performance

A randomized block design experiment was conducted to evaluate the effects of two contrasting silage maize hybrids (DD: dry down vs. SG: stay green) harvested at 33% dry matter (DM) on in situ degradation and dairy cow performance. Thirty-eight Red-HF cows were assigned to two silage treatments and individually fed. Mixtures containing one of the maize silages, grass silage and soy bean meal (70:17:13 DM basis) were offered ad libitum. Additionally, each cow received 7.5 kg d-1 of concentrate. Intake, milk yield and milk composition were analysed from wk 1 until wk 15 of lactation. The treatment period was from wk 5 to wk 15 of lactation. Pre-treatment data (wk 1 to 4) were used as covariates. In addition, fresh silage samples were ruminally incubated to determine the rate and extent of starch and NDF degradation. Hybrid had only little effect on in situ degradation of starch and NDF, and no effect on the intakes of DM, NEL, starch and NDF, and the yields of milk and milk components and body weight. It was concluded that farmers should not be concerned about dry-down or stay green characteristics of silage maize, but should just choose hybrids with the best yield prospects and feeding value