During the first weeks of lactation, dairy cows typically experience negative energy balance, leading to the mobilization of body reserves. This predisposes early lactating cows toward metabolic diseases, such as fatty liver syndrome and ketosis (Grummer et al., 2007). Choline is a vitamin-like substance involved in many biological pathways and an essential nutrient for maintaining a normal concentration of fat in the liver due to its involvement in fatty acid transport (McFadden et al., 2020; McGuffey 2017). Briefly, choline supports the synthesis of phosphatidylcholine, a type of phospholipid that is part of the very-low-density lipoproteins, the structure in charge of exporting the exceeding triglycerides and avoiding hepatic accumulation (Cooke et al., 2007; Lima et al., 2012). The microbial populations in the rumen quickly degrade dietary choline; therefore, the only practical means of increasing choline to the periparturient dairy cow is to feed it in a rumen-protected form (Atkins et al., 1988). Recently, Arshad et al., 2020 revealed in their meta-analysis that feeding supplemental rumen-protected choline during the transition period improves the health and performance of dairy cows.
Vetagro, in collaboration with the University of Piacenza, conducted a study aimed to evaluate the effect of two sources of rumen-protected choline supplemented from 21 d pre- to 35 d postpartum on production performance and blood metabolites. The study involved 24 multiparous Holstein dairy cows that were randomly divided into 3 groups. The animals were fed a corn-silage-based total mixed ration formulated to provide 2.38 (pre-) and 2.19 (postpartum) methionine as a percentage of metabolizable protein. The three treatments were the following:
- Control (CON): total mixed ration without supplementation;
- Ruprocol® (RUP): the same diet top-dressed with 60 g/d of Ruprocol® (Vetagro S.p.A., Italy, microencapsulated choline, containing 25% choline chloride);
- Reashure®-XC (REA): the same diet top-dressed with 25 g/d of Reashure®-XC (Balchem Corp., USA, encapsulated choline, containing 60% choline chloride);
Both the supplemented diets provided 15 g/d of choline chloride.
The sampling protocol included a daily record of the dry matter intake (DMI), milk yield, and components. Moreover, blood was sampled at -21, -7, 3, 21, and 35 days relative to calving, and plasma metabolites were determined by an automated biochemistry analyzer (ILAB 650). Data were analyzed under a mixed model with the random effect of cow and the fixed effects of parity and days in milk (DIM), treatment, and their interaction.
The results of the trial interestingly showed that, even if all cows were fed ad libitum during the trial, cows supplemented with rumen-protected choline had a numerical reduction of -1.35 kg/d in pre-partum DMI relative to the control group (Figure 1). Blood analysis (Blood glucose, β-hydroxybutyrate, free fatty acids, and triglycerides) demonstrated that all the animals were in the same metabolic status (no significant differences among groups, Figure 2).
The effect of rumen-protected choline was evaluable through the calcium and ceruloplasmin data. These molecules are linked to calving-related inflammation. The reduction of ceruloplasmin and a higher level of circulating calcium in the treated animals compared to the control group (Figure 3) could indicate that feeding rumen-protected choline might contribute to the resolution of this kind of inflammation.
Although no treatment effects were detected on milk yield (MY), energy-corrected milk (ECM), or milk solids, an interaction treatment x time suggests that feeding rumen-protected choline improved animal productive performance and milk quality (Figure 4 and Table 1), especially for the group that received Ruprocol®. The same interaction was observed also during the post-supplementation period in milk yield and ECM (Figure 4), with higher production for the RUP group.
The supplementation of rumen-protected choline improved the feed efficiency (relative to MY and ECM) both during (weeks 1 to 5) and after (weeks 5 to 10) the treatment compared to the control group. In particular, Ruprocol® was more efficient on ECM during weeks 1 to 5 compared to the control and the competitor product (Table 2).
Table 1: Milk solids (kg/d) during rumen-protected choline (RPC) supplementation (week 1 to 5). Control group (CON), standard diet; group treated with Ruprocol® (RUP), 60 g/d of product providing 15 g/d of rumen-protected choline; group treated with Reashure®-XC (REA), 25 g/d of product providing 15 g/d of rumen-protected choline.
| Milk solids, kg/d | CON | RUP | REA | P value | ||||
| Treatment | Time | Interaction | ||||||
| Fat | 1.79 | 1.92 | 1.80 | 0.30 | <0.01 | <0.01 | ||
| Protein | 1.25 | 1.37 | 1.30 | 0.51 | <0.01 | 0.24 | ||
| Lactose | 1.95 | 2.11 | 2.03 | 0.37 | <0.01 | 0.08 | ||
Table 2: Efficiency of pre-partum DMI relative to milk yield (MY) and energy corrected milk (ECM) during rumen-protected choline (RPC) supplementation (week 1 to 5) and post-supplementation (week 5 to 10). Calculations based on Holdorf et al., 2022. Control group (CON), standard diet; group treated with Ruprocol® (RUP), 60 g/d of product providing 15 g/d of rumen-protected choline; group treated with Reashure®-XC (REA), 25 g/d of product providing 15 g/d of rumen-protected choline.
a, b: Different letters mean statistically significant differences.
| Efficiency, kg/kg | CON | RUP | REA | P value, Treatment |
| RPC supplementation MY/pre-partum DMI | 2.7 | 3.4 | 3 | 0.06 |
| Post-supplementation MY/pre-partum DMI | 3.3 | 4.2 | 3.9 | 0.07 |
| RPC supplementation ECM/pre-partum DMI | 3.3b | 4.1a | 3.6ab | 0.03 |
| Post-supplementation ECM/pre-partum DMI | 3.7 | 4.7 | 4.2 | 0.06 |
Figure 1: DMI of cows fed two different (Ruprocol®, RUP; Reashure®-XC, REA) rumen-protected choline (RPC) compared to the control (CON), before and after calving. Control group (CON), standard diet, indicated by the black line; group treated with Ruprocol® (RUP), 60 g/d of product providing 15 g/d of rumen-protected choline, indicated by the green line; group treated with Reashure®-XC (REA), 25 g/d of product providing 15 g/d of rumen-protected choline, indicated by the orange line.
Figure 2: Blood analysis of the three groups of animals involved in the trial: Control group, standard diet, indicated by the black line; group treated with Ruprocol®, 60 g/d of product providing 15 g/d of rumen-protected choline, indicated by the green line; group treated with Reashure®-XC, 25 g/d of product providing 15 g/d of rumen-protected choline, indicated by the orange line.
Figure 3: Circulating levels of calcium and ceruloplasmin of the three groups of animals involved in the trial: Control group, standard diet, indicated by the black line; group treated with Ruprocol®, 60 g/d of product providing 15 g/d of rumen-protected choline, indicated by the green line; group treated with Reashure®-XC, 25 g/d of product providing 15 g/d of rumen-protected choline, indicated by the orange line.
Figure 4: Productive performance of the three groups of animals involved in the trial: Control group (CON), standard diet, indicated by the black line; group treated with Ruprocol® (RUP), 60 g/d of product providing 15 g/d of rumen-protected choline, indicated by the green line; group treated with Reashure®-XC (REA), 25 g/d of product providing 15 g/d of rumen-protected choline, indicated by the orange line.
These preliminary results would suggest that rumen-protected choline has an effect on energy and nutrient utilization, not only while supplemented but also later on over the lactation. Ruprocol®, Vetagro’s rumen-protected choline, is a product of tested bioavailability (Fontoura et al., 2019). This study suggests that Ruprocol® could have a greater impact on dairy cows production than a competitor product.
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