Feeding Sequence and Strategy Effects on Ruminal Environment and Production Performance in First Lactation Cows

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Abstract
Three primiparous cows were assigned randomly to a 4 x 4 incomplete Latin square to evaluate ruminal characteristics (Experiment 1) with the following feeding strategies: strategy A, supplement (protein), forage plus high moisture ear corn (energy), protein; strategy B, energy plus protein, forage, energy plus protein; strategy C, forage plus energy, protein, forage plus energy, protein; and strategy D, forage, energy plus protein, forage, energy plus protein. In Experiment 2, 36 cows were fed diets similar to those in Experiment 1 from wk 4 through 19 postpartum. Cows fed diets according to strategy A had the highest and strategy D the lowest mean ruminal pH. Diurnal variation in ruminal pH was less with cows fed diets using strategies A and B than C and D. Other ruminal parameters were not significantly different. In Experiment 2, cows fed according to strategy B had higher DMI than those fed according to other strategies. Energy and protein fed together and separately from forage, regardless of sequence, increased milk fat percentage compared with protein fed separately. Milk production and protein yield tended to be highest when protein was fed separately, regardless of sequence to forage. Strategic feeding of protein and energy sources in relation to forage influenced some ruminal and production measurements in primiparous cows.