Authors
1
MSc graduated, Department of Animal Science, Faculty of Agriculture, Ilam University, Ilam, Iran
2
Professor, Department of Animal Science, Faculty of Agriculture, Ilam University, Ilam, Iran
3
Animal Sciences Research Institute of Iran, Agricultural Research, Education and Extension Organization (AREEO). Karaj. Iran
4
Department of Animal Science, Faculty of Agriculture, Ilam University, Ilam, Iran.
5
Ph.D, Department of Animal Science, Faculty of Agriculture, Ilam University, Ilam, Iran
10.22069/ejrr.2026.24481.2040
Abstract
Background and Objective: Compared to concentrates, forages are bulkier, have lower nutrient concentrations, are less digestible, and have larger particle sizes. Therefore, they reduce dry matter intake and performance in lactating cows because dry matter intake is the most important factor affecting milk production in lactating cows. Concentrated feeds are small in volume, have a higher nutrient density, are more rapidly digested, and pass through the rumen more quickly, and therefore generally have a positive effect on dry matter intake and performance in lactating cows. The most important nutrients required by lactating cows include energy, protein and amino acids, fatty acids, carbohydrates, minerals, and vitamins. Carbohydrates are the main source of energy in diets fed to dairy cows and usually constitute 60 to 70 percent of the diet. In addition to being the main source of energy for the animal, carbohydrates provide the necessary substrate for the growth of rumen microbes and the production of microbial protein. The aim of this study was to investigate the effect of replacing beet pulp (BP) with apple pomace silage (APS) on dry matter intake (DMI), milk yield (MY) and composition, total tract nutrient digestibility and plasma metabolites of lactating dairy cows in early lactation.
Materials and Methods: Four handred primiparous Holstein cows (40±15 DIM and 41±9.8 kg/day MY) were used in a completely randomized design. Cows were divided into 2 approximately equal groups based on MY and DIM and randomly assigned to experimental diets. The experimental period was 28 days, including 21 days for adaptation and 7 days for data recording and sample collection. The experimental diets included 1) diet containing BP and 2) diet containing APS.
Results: The results showed that replacing BP with APS did not affect DMI, raw MY, 4% fat corrected milk and energy corrected milk, milk fat and protein content and production, and DM utilization efficiency for milk production (P<0.05). Plasma concentrations of total protein, albumin, triglycerides, beta-hydroxybutyrate (BHB) and phosphorus were not affected by experimental diets (P<0.05). Replacing BP with APS in the diet increased plasma concentrations of urea nitrogen (UN) and non-esterified fatty acids (NEFA) and decreased plasma concentrations of calcium and magnesium (P<0.05). Total tract digestibility of organic matter (OM), crude protein (CP), crude fat (CF) and neutral detergent fiber (NDF) were not affected by experimental diets (P<0.05).
Conclusion: However, adding APS to the diet reduced total tract digestibility of ash (P<0.05). Overall, according to these results, the complete replacement of BP with APS did not have any negative effect on the performance of Holstein dairy cows in early lactation.
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