Performance of early-lactating Holstein cows fed diets supplemented with encapsulated essential oils

Authors: Sobhy M.A. Sallam, Mahmoud M.A. El-Sherif, Marwa F. A. Attia, Yosra. A. Soltan, Eman A. Elwakeel, Mohamed N. El-Gendy, Gouda A. Gouda, Ahmed E. Kholif

Ger. J. Vet. Res 2025. vol. 5, Iss. 1 pp:140-155
Doi: https://doi.org/10.51585/gjvr.2025.1.0127

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Abstract:

Two experiments were conducted to evaluate the effects of a microencapsulated blend of essential oils (MBEO) at 0 (control), 0.05 (low), and 0.25 (high) g/kg dry matter (DM) in diets with varying concentrate-to-roughage ratios: high concentrate (HC, 75:25), medium concentrate (MC, 55:45), and low concentrate (LC, 25:75), using a semi-automatic gas production (GP) system for 24 h. Gas production per gram of DM was significantly influenced by diet (p=0.022), with higher values observed in the HC and MC diets compared to the LC diet. While MBEO treatment alone and diet alone had no significant effect (p>0.05), a strong interaction was observed between diet and treatment for GP per gram of true degradable organic matter (TDOM) (p<0.001). In LC diets, high MBEO significantly reduced GP (102 vs. 149 mL/g DM in control), whereas in MC diets, MBEO numerically increased GP. TDOM was also significantly affected by diet (p<0.001) and the diet × treatment interaction (p<0.001), with MBEO increasing TDOM in LC diets (772 vs. 588 g/kg DM in the control) and slightly reducing it in HC diets. The partitioning factor (PF) was influenced by diet (p<0.001) but not by treatment (p=0.088), although MBEO tended to increase PF in both LC and HC diets. Ruminal pH was unaffected overall; however, a significant diet × treatment interaction was observed (p=0.031). MBEO reduced ammonia-N concentrations (p=0.009), particularly in HC diets, but did not affect protozoal counts (p=0.098). Based on in vitro findings, an in vivo study was conducted with 200 early-lactation Holstein cows to evaluate the effects of 0.05 g MBEO/kg DM on intake, milk production, milk composition, fatty acid profile, and blood metabolites. Milk composition was unchanged, though milk urea-N decreased (p=0.041). MBEO increased stearic and oleic acids and reduced caprylic and capric acids. Blood glucose and total cholesterol increased (p<0.05), while triglycerides decreased (p=0.01). These results demonstrate that MBEO modulates in vitro rumen fermentation, improves nutrient degradability in lowconcentrate diets, and enhances milk fatty acid profile and metabolic indicators in dairy cows, supporting its potential as a sustainable feed additive in drug-free dairy production systems.

Keywords:

Encapsulated essential oils, Rumen fermentation, Milk production, Dairy cow

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