Table 1.
The effect of glycerol on the fermentation, microbiome, and pH in the rumen of cattle.
| Purity | Method of Administration and Dose | Cows and Days in Milk | Time of Sampling | Rumen pH |
Acetate (Molar%) |
Propionate (Molar%) |
Butyrate (Molar%) |
Acetate/ Propionate |
Reference | |
|---|---|---|---|---|---|---|---|---|---|---|
| Glycerol, 80.2% | Topdressed and hand-mixed into the upper 1/3 of the daily ration | 0 | Holstein cows From 14 d prepartum to 21 d in milk |
4 h after feeding | 6.91 | 61.8 | 21.7 | 12.3 | 2.85 | DeFrain et al. [8] |
| 0.43 kg/d | 6.89 | 55.4 | 27.1 | 14.4 | 2.04 | |||||
| 0.86 kg/d | 6.61 | 58.5 | 24.7 | 13.2 | 3.27 | |||||
| Glycerol, 86% | Mixed with TMR | 0 | Holstein bulls (335 ± 8.6 kg of initial BW). Suplementation until 91 d of the study | Monthly during 2 consecutive days | 6.07 | 54.6 | 35.6 | 9.8 | 1.53 | Mach et al. [43] |
| 4% of DM | 6.06 | 54.1 | 34.3 | 11.6 | 1.57 | |||||
| 8% of DM | 5.68 | 50.9 | 38.6 | 10.5 | 1.32 | |||||
| 12% of DM | 6.08 | 53.3 | 35.4 | 11.3 | 1.50 | |||||
| Glycerol, 99.5% | Mixed with grain | 0 | Holstein fistulated cows | 3 h after the morning feeding | 6.53 | 38.51 | 19.14 | 12.83 | 2.01 | AbuGhazaleh et al. [29] |
| 15% | 6.54 | 36.81 | 18.59 | 16.98 | 1.98 | |||||
| 30% | 6.57 | 33.65 | 19.65 | 19.41 | 1.71 | |||||
| 45% | 6.53 | 33.54 | 22.91 | 18.23 | 1.46 | |||||
| Glycerol (crude glycerol 80.1%) |
Glycerol mixed with TMR | 0% DM (based diet corn silage) | Holstein cows 116 ± 13 DIM. 27 d periods for each diet |
8 h after feeding | 6.15 | 57.0 | 20.6 | 12.0 | 2.8 | Shin et al. [35] |
| 10% DM (based diet corn silage) | 5.99 | 48.0 | 26.9 | 13.9 | 1.82 | |||||
| 0% DM (based diet cottonseed hulls) | 6.25 | 52.5 | 25.2 | 12.6 | 2.13 | |||||
| 10% DM (based diet cottonseed hulls) | 6.18 | 46.8 | 28.4 | 14.0 | 1.72 | |||||
| Glycerol (dry glycerol) |
Replacing corn starch with glycerol in TMR | 0 | Lactating cow | During continuous culture | 6.5 | 56.8 | 22.6 | 14.5 | 2.5 | Rico et al. [32] |
| 3% (0.75 kg/d) | 6.5 | 50.9 | 23.3 | 18.4 | 2.2 | |||||
| 5% (1.25 kg/d) | 6.4 | 49.4 | 27.6 | 15.8 | 1.8 | |||||
| 8% (2 kg/d) | 6.5 | 44.5 | 30.3a | 17.1 | 1.5 | |||||
| Glycerol, 80%–85% |
Mixed and the coated cottonseed added to the TMR | 0 | Holstein cows 56 ± 18 DIM, fistulated cows |
0, 2, 4, 6, 8, and 10 h after feeding | 6.1 | 61.1 a | 59.1 b | 57.6 c | 2.7 | Boyd et al. [31] |
| 200g/d | 6.0 | 23.3 a | 24.1 b | 25.4 c | 2.5 b | |||||
| 400g/d | 6.1 | 11.4 a | 12.3 b | 12.4 b | 2.3 c | |||||
| Glycerol (crude glycerol 86%) | Glycerol added to food | 0% DM | Ruminally cannulated Nellore steers averaging 24 months of age and 400 kg BW |
Collected on d 15 of each experimental period, at 1, 0, 2, 4, 6, and 8 h after feeding | 6.39 | 86.6 | 24.5 | 19.3 | 3.65 | Van Cleef et al. [44] |
| 7.5% DM | 6.11 | 73.4 | 22.3 | 21.0 | 6.56 | |||||
| 15% DM | 6.20 | 59.9 | 24.1 | 28.8 | 2.82 | |||||
| 22.5% DM | 6.27 | 54.1 | 29.9 | 24.6 | 1.92 | |||||
| 30% DM | 6.23 | 49.3 | 33.1 | 30.5 | 1.53 | |||||
| Glycerol | Offered in a mash twice daily | 0 | Bulls (Limousin x indigenous Spanish breed) of 292.8 ± 29.6 kg of BW | 0, 2, 4, and 8 h (date of mean) after the morning feeding | 6.32 | 60.5 | 24.1 | 10.6 | 3.03 | Madrid et al. [42] |
| 20 g/kg of DM | 6.38 | 61.0 | 26.7 | 9.14 | 2.55 | |||||
| 40 g/kg of DM | 6.14 | 58.3 | 29.0 | 8.69 | 2.13 | |||||
| 80 g/kg of DM | 5.74 | 52.8 | 29.7 | 13.1 | 1.96 | |||||
TMR—total mixed ration; DM—dry matter. Mean values in the same row with different superscripts differ significantly (p < 0.05).