The effect of supplementing high yielding Holstein cows with botanical extracts, bacterial inoculants, or dietary glycerol during heat stress and the effect of dietary glycerol in transition cow diets on subsequent yield and efficiency
Boyd, Jamie Alice
MetadataShow full item record
A series of research trials were conducted to evaluate the effects of botanical additives, bacterial inoculants, and dietary glycerol on high yielding dairy cows during heat stress and measure the effects of glycerol in the diet of transition dairy cows. Trial 1 evaluated the effects of a botanical supplement (Thermal Care-D®) on apparent efficiency and milk yield. Thermal Care-D® had no effect on DMI or milk yield, but Thermal Care-D® alone exhibited greater (P<0.05) or numerically improved digestion of DM, NDF and ADF compared with Control and Thermal Care-D® with glycerol. Trial 2 evaluated the effects of the live bacterial inoculant Bovamine® (4x109 CFU/h/d combination of Lactobacillus acidophilus NP51 and Propionibacterium freudenreichii NP24) and glycerol on milk yield, efficiency of yield, and nutrient digestibility. No effect on DMI or milk yield was observed, but improved efficiency (MY/DMI) [P<0.06] for Bovamine (1.5 ± 0.02) versus Control (1.42 ± 0.02) was observed. The addition of Bovamine® alone and with glycerol had a positive effect on apparent efficiency compared with Control. Trial 3 evaluated levels of glycerol on rumen environment and nutrient digestibility. Six Holstein cows averaging 56 DIM and 37.9 kg/d of milk were used. The treatments were control (C), 200g glycerol h/d (G200), and 400g glycerol h/d (G400). A trend (P<0.18) for improved apparent efficiency (ECM/DMI) was noted for G200 and G400 versus Control, 1.73, 1.73, 1.68 (± 0.02) respectively. Data showed decreased acetate to propionate ratio with the addition of glycerol. G400 increased ruminal propionate and decreased acetate compared with C. Results suggest the addition of glycerol to the diet may alter ruminal VFA concentrations and improve efficiency in dairy cows. Trial 4 was a peripartum cow study to evaluate the effects of glycerol supplementation on postpartum lactation. No effect on milk yield or DMI was observed, but cows supplemented with glycerol during the prepartum and postpartum period did show an improvement in milk to feed conversion efficiency. Results from these trials suggest the addition of Thermal Care-D®, dietary glycerol, and Bovamine® may improve lactating cow performance under heat stress conditions by improving apparent efficiency of production and digestibility.