Effects of Level and Source of Sulfur in Close-Up Diets of Holstein Dairy Cows on Intake, Blood Metabolites, Liver Enzymes and Lactation Performance

This study was carried out to investigate the effects of source and level of sulfur in dairy cow close-up diets on dry matter intake (DMI), blood metabolites and subsequent lactation performance. Twenty four individually fed multiparous close-up Holstein cows averaging body weight 687.9 kg were allocated in three different treatments (8 cows per each). The first treatment (T1) has contained 0.21% sulfur (DM basis), the second treatment (T2) has contained 0.41% sulfur which supplied through magnesium sulfate and the third treatment (T3) has contained 0.41% sulfur supplied through combination of magnesium sulfate and an organic source of sulfur (Mepron). All the cows were fed same diet after parturition until 21 d. The DMI for both pre- and post-calving was affected by treatments and T2 showed the lowest DMI among treatments. Glucose, calcium, and copper were decreased in T2. However, blood concentrations of BHBA, NEFA, urea, creatinine phosphokinase, and aspartate amino transferase were increased in T2. The results indicated that although magnesium sulfate has negative effect on dairy cow health and performance, a combination of magnesium sulfate and organic source of sulfur in close-up diets could have positive effects on DMI and performance of Holstein dairy cows.