Dairy cows are provided high allocations of grain following calving to meet high energy demands for milk production. However, increased grain consumption increases the flow of fermentable carbohydrates to the hindgut, increasing hindgut fermentation (Abdela, 2016). If excessive fermentation occurs, high osmotic pressure and a drop in pH induce inflammation and damage hindgut epithelial cells, thus increasing gut permeability and allowing absorption of bacterial endotoxins (Gressley et al., 2011; Tao et al., 2014; Ye et al., 2016). Systemic inflammation may then occur, activating the immune system and further increasing the cow’s energy requirements (Turner, 2009). To compensate for energy demands from lactation and inflammation, cows mobilize free fatty acids (FFA) from adipose tissue which are transported to the liver where they can be completely oxidized to ATP, or incompletely oxidized to produce ketones if insufficient glucogenic fuels are present (Roche et al., 2009). Some fat mobilization and ketone production is normal, however, excess fat mobilization can cause excessive ketone production and triglyceride storage in the liver, further decreasing DMI and potentially exacerbating negative energy balance (Zarrin et al., 2017).
Butyrate supplementation may be an option to mitigate acute gut inflammation through suppressing protein and gene expression responsible for activating inflammatory responses in colonocytes (Yin et al., 2001). Butyrate may also abate epithelial cell damage following excessive fermentation as butyrate provides energy to epithelial cells (Chen et al., 2018). Further, butyrate increases epithelial cell proliferation (Guilloteau et al., 2010) and modulates tight junction assembly (Peng et al., 2009), and as such, improves gut barrier function in other species (Dong et al., 2016; Chen et al., 2018; Elnesr et al., 2020). Therefore, butyrate supplementation may reduce LPS absorption, decreasing systemic inflammation and the associated energy requirement, ultimately reducing fat mobilization and improving energy status. As less energy is being allocated towards the immune system due to reduced inflammation, milk yield may increase (Bradford et al., 2015). However, the efficacy of butyrate supplementation for alleviating inflammation has not been extensively evaluated in transition dairy cows. The objective of the present study was to assess the effects of butyrate supplementation during the calving transition period on DMI, blood parameters, postpartum milk production, and inflammation.
This study was conducted from August to December, 2019, at the University of Alberta’s Dairy Research and Technology Centre. Thirty-seven Holstein heifers (n = 17) and cows (n = 20) were blocked by parity and expected calving date, and randomly assigned to one of isoenergetic diets containing calcium butyrate (BUT; Proformix; Probiotech Inc., Saint Hyacinthe, QC; 1.42% of diet dry matter (DM)) or a control (CONT; 1.04% palm fat and 0.38% calcium carbonate of diet DM). The closeup diet contained 14.9% starch and 42.5% neutral detergent fiber (NDF), and the fresh diet contained 23.9% starch and 32.0% NDF on a DM basis. Diets were fed d 28 ± 3 before the expected calving date to d 24 ± 3 after calving. Animals were housed in tie-stalls with individual feed bunks for the duration of the study. Milk yield and DMI were recorded daily, and milk composition was analyzed on d 7 ± 3, 14 ± 3, and 21 ± 3. Plasma was collected on d -28 ± 3, -4 ± 1, 1, 4, 7, 21 ± 3 relative to calving, and serum was collected on d -4 ± 1, 1, 4, and 7 relative to calving. Plasma was analyzed for FFA and β-Hydroxybutyrate (BHB), and serum was analyzed for haptoglobin (Hp). Body condition score (BCS) and body weight (BW) were recorded on d 1 and 24 ± 3 and post-calving changes were calculated. Data were analyzed using the FIT model procedure of JMP Pro 14.2 (SAS Institute Inc., Cary, NC).
Serum haptoglobin concentrations did not differ between BUT and CONT (P = 0.76). However, in BUT plasma BHB was higher on d 4 (Table 1), plasma FFA tended to be lower on d 7, and MUN was lower on d 21. Postpartum BW change also tended to be greater in BUT (-3.84 vs. - 2.61 kg/d; P = 0.10). There were no treatment differences observed in milk yield (P = 0.73), 3.5% fat-corrected milk yield (P = 0.49), milk fat (P = 0.21), milk protein (P = 0. 38), DMI (P = 0.33), or postpartum BCS change (P = 0.41).
Table 1. Effects of butyrate supplementation on concentration of milk urea nitrogen (MUN), serum haptoglobin (Hp), plasma free fatty acids (FFA), and plasma beta-hyroxybutyrate (BHB).
Butyrate supplementation did not affect milk yield or components, DMI, or postpartum changes BCS. In addition, the present study does not support that inflammation is reduced by butyrate supplementation, however, butyrate supplementation may reduce body fat mobilization and MUN, indicating modifications in energy and protein metabolism in transition cows.
We would like to thank the Dairy Research and Technology Centre staff for their assistance, animal care, and accommodation of our project. We would also like to thank Probiotech International Inc. for their donation of the Butyrate product. Finally, we would like to thank the Natural Sciences and Engineering Research Council of Canada, and Alberta Milk for their funding.