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Highlights • Supplementation of branched-chain VFA with or without rumen protected folic acid was evaluated. • Milk yield, true protein content and yield as well as feed efficiency increased with both supplements. • Ruminal fermentation characteristics, cellulolytic bacteria and enzyme activities were improved. • Serum GHRH, GH, IGF-1 and total protein increased with both supplements. • There was no interaction detected between branched-chain VFA and rumen protected folic acid. Abstract This study evaluated the effects of branched-chain volatile fatty acids (BCVFA) and rumen protected folic acid (RPFA) supplementation on lactation performance, ruminal fermentation, nutrient digestion and blood metabolites in dairy cows. Fifty-six multiparous Chinese Holstein cows (3.2 ± 1.1 of parity, 631 ± 16.4 kg of body weight [BW], 65 ± 2.6 days in milk [DIM] and 30.2 ± 2.1 kg of milk yield per day, mean ± SD) were blocked by lactation number, milk yield per day and DIM and were arranged into one of four groups in a randomized block design with a 2 × 2 factorial arrangement. Supplemental BCVFA (0 g/d [BCVFA-] or 80 g/d [BCVFA+]) and RPFA (0 mg/d [RPFA-] or 128 mg/d [RPFA+]) were hand-mixed into the top one-third of total mixed ration. Dietary concentrate to forage ratio was 50:50 based on a dry matter (DM) basis. Experimental periods comprised 105 days with 15 d of adaptation followed by 90 d of data collection. DM intake was increased with BCVFA supplementation, but was unaffected by RPFA. The BW changes were similar among treatments. Yields of milk, milk fat and lactose were increased, and milk true protein yield tended to increase with BCVFA or RPFA supplementation. Milk fat percentage was increased with BCVFA supplementation, but was unaffected by RPFA. Percentage of milk true protein was increased, lactose was unaltered and feed conversion ratio was decreased with BCVFA or RPFA supplementation. Ruminal pH and ammonia N concentration were decreased, but total volatile fatty acids concentration was increased with BCVFA or RPFA supplementation. Molar proportion of acetate was increased and propionate was decreased, resulting in an increased ratio of acetate to propionate with BCVFA supplementation. Acetate and propionate molar proportion and the ratio of acetate to propionate were not affected by RPFA. Digestibilities of DM, organic matter, crude protein, non-fiber carbohydrates, neutral detergent fibre and acid detergent fibre were increased with BCVFA or RPFA supplementation. Similarly, activities of caboxymethyl-cellulase, cellobiase, xylanase, pectinase, α-amylase and protease and abundance of R. albus, R. flavefaciens , F. succinogenes , B. fibrisolvens and P. ruminicola were increased. However, R. amylophilus abundance was not affected by BCVFA and increased with RPFA supplementation. Serum concentrations of glucose and non-esterified fatty acids (NEFA) were unaltered and total protein was increased with BCVFA or RPFA supplementation. Serum acetoacetate (ACAC) and BHBA were increased by BCVFA, but were decreased by RPFA. Supplementation of BCVFA or RPFA increased serum growth hormone releasing hormone, growth hormone and insulin-like growth factor-1. These results indicated that lactation performance, ruminal fermentation, nutrient digestion and hormone secretion improved due to the stimulated ruminal bacteria growth and enzyme activity with BCVFA or RPFA supplementation, but no BCVFA × RPFA interaction was detected during the trial. [ABSTRACT FROM AUTHOR]

Highlights • Ruminal fermentation was improved with coated folic acid (CFA) supplementation, but depressed by soybean oil (SO) supplementation. • Microbial cellulolytic enzyme activities and ruminal NDF degradability increased with supplementary CFA, but decreased with SO supplementation. • The growth of cellulolytic bacteria was promoted by supplementary CFA, but depressed by SO supplementation. • Urinary excretion of purine derivatives increased with CFA, but decreased with SO supplementation. • CFA + SO interacted: CFA reduced the negative effects of SO on ruminal fermentation. Abstract This study was conducted to evaluate the effects of dietary soybean oil (SO) and coated folic acid (CFA) supplementation on ruminal digestion kinetics, fermentation, microbial enzyme activity and bacterial abundance in Jinnan beef steers. Eight ruminally cannulated Jinnan beef steers, averaging 15 months of age and 415 ± 5.6 kg of body weight (BW; Mean ± S.E.), were used in a replicated 4 × 4 Latin square design by a 2 × 2 factorial arrangement. Two levels of CFA (0 mg [FA-] or 115 mg per kg dietary DM [FA + ]) were supplemented to the diets without or with SO supplementation (0 g [SO−] or 30 g per kg dietary dry matter [DM] [SO + ]). Steers were fed a total mixed ration with ensiled corn forage to concentrate ratio of 50:50 on a DM basis. The SO × CFA interaction was observed for ruminal pH, total VFA concentration, molar proportions of acetate and propionate, the ratio of acetate to propionate and ammonia N content. Ruminal pH increased with SO supplementation, but decreased with CFA supplementation. Ruminal total VFA concentration, acetate molar proportion and acetate to propionate ratio decreased with SO supplementation, but increased with CFA supplementation. Ruminal ammonia-N content decreased with SO or CFA supplementation. No SO × CFA interaction was observed for nutrient degradability and digestibility. Degradability of neutral detergent fibre (NDF) and digestibility of DM, organic matter, NDF and acid detergent fibre decreased with SO supplementation, but increased with CFA supplementation. Degradability and digestibility of crude protein was not affected by SO supplementation, but increased with CFA supplementation. Pectinase activity was unaltered, whereas, other microbial enzyme activity, bacterial abundance and total PD excretion were affected by SO × CFA interaction. Activities of carboxymethyl-cellulase, cellobiase and xylanase and abundance of R. albus, R. flavefaciens, F. succinogenes and B. fibrisolvens decreased with SO supplementation, but increased with CFA supplementation. Activities of pectinase, α-amylase and protease as well as total bacterial abundance were not affected by SO supplementation, but increased with CFA supplementation. Total protozoal abundance decreased with SO supplementation, but was not affected by CFA supplementation. Abundance of P. ruminicola and R. amylophilus increased with SO or CFA supplementation. Total PD excretion increased with CFA supplementation, but decreased with SO supplementation. The results suggested that ruminal fermentation, NDF degradability, protozoal abundance, cellulolytic bacterial abundance and enzyme activity decreased with dietary SO supplementation, but increased with CFA supplementation. The supplementation of CFA in the SO diet could relieve the negative effects of SO on ruminal fermentation. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of dietary supplements of rumen-protected folic acid (RPFA) on lactation performance, energy balance, reproductive performance and blood parameters of dairy cows. Ninety-six multiparous Holstein cows were assigned to four groups of 24 each according to their previous 305-days milk production. The treatments were: control, low RPFA (LRPFA), medium RPFA (MRPFA) and high RPFA (HRPFA) with 0–3 g RPFA/cow per day, respectively. Supplements of RPFA were top-dressed and manually mixed into the upper one third of the ration during the morning feeding from 3 weeks before the expected calving date to 15 weeks after parturition. Dry matter (DM) and net energy (NE) intakes, milk yield, milk protein content and production increased linearly ( P < 0.05) with increasing RPFA supplementation, whereas milk fat content and production only tended to be linearly increased. Cows supplemented with RPFA showed a similar pattern ( P < 0.05) of decreased loss of body weight (BW) and improved energy balance (expressed in MJ/cow/day) during the 105 days in milk (DIM) period. Concentrations of glucose in plasma, folate and methionine in serum increased linearly ( P < 0.05), whereas concentrations of non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA) and serum homocysteine linearly ( P < 0.01) decreased. Total conception rate and the percentage of cows pregnant at 150 DIM linearly increased ( P < 0.05), DIM at first breeding and breeding per conception tended to change linearly with increasing RPFA supplementation. These results indicated that supplementary RPFA in cow diets had positive effects on feed intake and milk production, increased concentrations of plasma glucose and serum folates, decreased plasma concentrations of NEFA and BHBA and serum concentration of homocysteine, and improved energy balance and reproductive performance. These data suggest that RPFA improves lactation, energy balance and reproductive performance in a dose-dependent manner. [ABSTRACT FROM AUTHOR]

• Addition of palm fat powder (PFP) and coated folic acid (CFA) increased milk yield and feed efficiency. • Improved energy balance was only observed for PFP addition. • Addition of CFA stimulated nutrient digestibility, ruminal microbial growth, and fermentation. This study investigated the effects of palm fat powder (PFP) and coated folic acid (CFA) supplementation on performance, energy balance, nutrient digestion, ruminal fermentation and blood metabolites in early lactation dairy cows. Thirty-two multiparous Holstein dairy cows were arranged into four treatments in a 2 × 2 factorial randomized block design. Supplemental PFP (0 g/d [PFP−] or 500 g/d [PFP+]) and CFA (0 mg/d [CFA−] or 135 mg/d of folic acid from CFA [CFA+]) were mixed into the top one-third of the daily ration from d 52 prepartum (based on expected calving date) to d 42 postpartum. Dry matter intake was unaltered but milk yield, milk fat content and feed efficiency increased with PFP or CFA supplementation. Milk protein content was not affected by PFP but increased with CFA supplementation. Body weight change was not affected by PFP or CFA supplementation. Energy balance increased with PFP supplementation but decreased with CFA supplementation. Apparent total-tract digestibility of dry matter, organic matter, crude protein, non-fiber carbohydrates, aNDF, ADF and gross energy, ruminal pH and total volatile fatty acids concentration were unchanged with PFP supplementation but increased with CFA supplementation. Ruminal acetate to propionate ratio was decreased by PFP but increased with CFA supplementation. Lower ammonia-N was observed for PFP or CFA supplementation. Activity of α-amylase and population of Butyrivibrio (B.) fibrisolvens and Ruminobacter (Rb.) amylophilu increased but total protozoa decreased with PFP supplementation. Supplementation of CFA increased activity of cellobiase, xylanase, pectinase, α-amylase and protease and population of total bacteria, fungi, protozoa, Ruminococcus (R.) albus , R. flavefaciens , Fibrobacter succinogenes , B. fibrisolvens , Prevotella ruminicola and Rb. amylophilus. Significant PFP × CFA interaction was not observed during the trial. The results indicated that dietary supplementation of PFP or/and CFA had the potential to improve performance of early lactation dairy cows. [ABSTRACT FROM AUTHOR]

• The higher DM and nutrient intake and average daily gain were observed for folic acid (FA) addition. • Nutrient digestibility, total VFA and microbial population increased with FA and sodium selenite (SS) addition. • Urinary purine derivatives (UPD) increased with FAand SS supplementation. • Digestibility, cellulolytic bacteria and UPD induced by SS addition was greater in diet added without FA than with FA. This study evaluated the effects of folic acid (FA) and sodium selenite (SS) supplements on growth performance, nutrient digestion, ruminal fermentation, microbial enzyme activity, microflora and urinary excretion of purine derivatives (PD) in dairy calves. Thirty-six Holstein calves (63 ± 3.4 days of age and 83 ± 2.1 kg of body weight) were randomly assigned to four treatments in a 2 × 2 factorial arrangement. Two levels of FA (0 or 3.0 mg/kg of FA) and SS (0 or 0.3 mg/kg of Se from SS) were added into diets on a dry matter (DM) basis. Nutrient intake and average daily gain increased with FA addition, but were not affected by SS addition. Both supplements increased total tract digestibility of DM, organic matter and neutral detergent fiber. Ruminal pH and ammonia N concentration decreased, but total volatile fatty acids concentration increased with FA or SS addition. Acetate molar proportion and acetate to propionate ratio increased, while propionate molar proportion decreased with FA addition. The unchanged acetate molar proportion, higher propionate molar proportion and lower acetate to propionate ratio were observed with SS addition compared with the control. Activities of xylanase, pectinase, α-amylase and protease as well as populations of total bacteria, protozoa and methanogens were higher for both supplements compared with the control. Carboxymethyl-cellulase activity and Prevotella ruminicola population increased with FA addition. The Ruminobacter amylophilus population decreased with SS addition. The FA×SS interaction was significant for total tract digestibility of crude protein and acid detergent fiber, populations of total fungi, Ruminococcus (R.) albus, R. flavefaciens, Fibrobacter succinogenes and Butyrivibrio fibrisolvens as well as urinary total PD excretion; these variables increased with SS addition and the increase was greater when the diet was not supplemented with FA than with FA supplemented diet. The results indicated that dietary FA and/or SS addition stimulated nutrient digestion, ruminal fermentation, microbial growth and urinary total PD excretion. [ABSTRACT FROM AUTHOR]