DOI: https://doi.org/10.5513/JCEA01/26.4.4721
Original scientific paper
The effect of physically effective fibers on the digestibility of total mixed rations using different indicators
2025, 26 (4) p. 864-875
Dženan HADŽIĆ, Senada ČENGIĆ-DŽOMBA, Emir DŽOMBA, Zvonko ANTUNOVIĆ, Muhamed BRKA
Abstract
Digestibility rate is an essential parameter of total mixed ratio (TMR) quality because forage NDF varies widely in its degradability in the rumen, and digestibility influences animal daily intake and productive performance. In this sense, the physical effectiveness of the meal largely determines the dynamics of decomposition, the kinetics (passage), and ultimately, the rate of utilization of the ration. The main goal of the research is to evaluate the effect of reducing the particle size of TMR on the total digestibility rate of cows in early lactation according to the Penn State Particle Separator (PSPS) measuring method. The diet is based on an ad libitum diet of complete mixed meals (TMR) based on corn silage. During the adaptation period, cows were given three different meals (Tc, T1, and T2), which had similar chemical composition but differed in their content of physically effective fibers (peNDF), distribution, and particle size (6.9 ± 2.4, 5.5 ± 2.3, and 5.4 ± 2.3 mm, respectively). The trial was conducted at Dairy Farm “Spreča,” where the adaptation period lasted 21 days. After this, feces collection was observed. The content of physically effective fibers through meals was 23.5%, 21.8%, and 20.0% at the 4 mm level and 17.5%, 14.0%, and 12.4% at the 8 mm sieve level. The natural contented indicators lignin (ADL) and acid-insoluble ash (AIA) methods were used to test digestibility. The results indicated that physical effectiveness positively affects nutrient digestibility, except for structural carbohydrates (NDF fiber fraction), which showed a negative correlation.
Keywords
dairy cows, total mixed ration, fiber effectiveness, in vitro digestibility
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