Abstract #M312

# M312
Replacing ground corn with liquid molasses decreases production performance in dairy cows offered low-starch diets.
C. P. Ghedini1, A. F. Brito*1, D. C. Moura2, A. S. Oliveira3, R. A. V. Santana4, 1University of New Hampshire, Department of Biological Sciences, Durham, NH, 2Universidade Federal de Mato Grosso, Programa de Pós Graduação em Ciência Animal, Cuiabá, MT, Brazil, 3Universidade Federal de Mato Grosso–Campus Sinop, Instituto de Ciências Agrárias e Ambientais, Sinop, MT, Brazil, 4Instituto Federal de Educação, Ciência e Tecnologia do Norte de Minas Gerais–Campus Arinos, Arinos, MG, Brazil.

Production performance data regarding the use of liquid molasses (LM) or ground corn (GC) as the sole supplemental NSC source or in different combinations to dairy cows offered low-starch diets are lacking. The objective of this study was to evaluate the effects of feeding incremental amounts of LM on milk yield and composition, and apparent total-tract nutrient digestibility in Jersey cows. Sixteen multiparous Jersey cows (99 ± 41 DIM and 462 ± 38.2 kg of BW) were randomly assigned to treatment sequences in a replicated 4 × 4 Latin square design with 14 d for diet adaptation and 7 d for data and sample collection. Diets were fed as TMR and consisted (DM basis) of 52% grass-legume baleage, 8% grass hay, 8.5% soyhulls, 2.5% roasted soybean, and 15% flaxseed meal. Ground corn was replaced by incremental amounts of LM at 0, 4, 8, or 12% of diet DM. Diets averaged 9.7 and 0.0%, 7.0 and 1.7%, 4.3 and 3.3%, and 1.64 and 5.0% of starch and LM-added sugars, respectively; CP and NDF concentrations averaged 19.0 and 43.5% across diets. Results are presented in Table 1. Intake of DM, as well as MUN and yields of milk and milk fat and protein decreased linearly with replacing GC with LM. Decreased milk yield is likely explained by the drop in DMI. Conversely, milk fat and protein concentrations, and OM and NDF total-tract digestibilities did not differ across treatments. Overall, it appears that the amount of LM-added sugars, particularly at the greatest level of supplementation depressed ruminal fermentation processes negatively affecting DMI and milk yield. Table 1. Production performance and nutrient digestibility
ItemMolasses:Corn ratio (% diet DM)P > F
DMI, kg/d19.118.618.017.60.680.050.96
Milk yield, kg/d18.918.017.816.81.44<0.010.94
Milk fat, %5.285.375.
Milk fat, kg/d1.010.930.960.840.05<0.010.32
Milk protein, %
Milk protein, kg/d0.760.700.720.630.04<0.010.70
MUN, mg/dL16.816.415.816.00.540.040.25
OM digestibility, %72.771.
NDF digestibility, %64.764.

Key Words: dairy cow, ground corn, molasses