<abstract xmlns="http://www.w3.org/1999/xhtml"><p>The present experiment aimed to evaluate the partial replacement of soybean with slow-release urea (Optigen 1200™) in the diet of lactating cows for 84 d. Three-hundred multiparous lactating Holstein (635 ± 25 kg of body weight, BW) cows were stratified by live body weight; parity and previous milk production were randomly assigned into two experimental groups with 150 cows per each treatment. In the control treatment, 25 g soybean meal was replaced by 5.7 g slow-release urea for 84 d. Optigen treatment did not affect feed intake, daily milk production, milk composition, or milk (feed) efficiency; however, it increased (P&lt;0.01) total BW gain and daily BW gain. Optigen treatment increased (P&lt;0.01) the digestibility of crude protein and neutral detergent fiber. Optigen treatment increased (P&lt;0.01) estimated N balance, milk urea-N, and net energy (NE) for gain. Without affecting blood total protein, creatinine, urea-N, triglycerides, glucose, β-hydroxybutyrate, or non-esterified free fatty acids, Optigen treatment increased the concentrations of blood albumin and cholesterol compared to the control (P&lt;0.05). In conclusion, slow-release urea could replace soybean meal in ruminant diets with no adverse effects on feed intake, nitrogen utilization, or digestibility; however, it improved the total tract digestibility of fiber and crude protein in cows.</p></abstract>

The present experiment aimed to evaluate the partial replacement of soybean with slow-release urea (Optigen 1200™) in the diet of lactating cows for 84 d. Three-hundred multiparous lactating Holstein (635 ± 25 kg of body weight, BW) cows were stratified by live body weight; parity and previous milk production were randomly assigned into two experimental groups with 150 cows per each treatment. In the control treatment, 25 g soybean meal was replaced by 5.7 g slow-release urea for 84 d. Optigen treatment did not affect feed intake, daily milk production, milk composition, or milk (feed) efficiency; however, it increased (P<0.01) total BW gain and daily BW gain. Optigen treatment increased (P<0.01) the digestibility of crude protein and neutral detergent fiber. Optigen treatment increased (P<0.01) estimated N balance, milk urea-N, and net energy (NE) for gain. Without affecting blood total protein, creatinine, urea-N, triglycerides, glucose, β-hydroxybutyrate, or non-esterified free fatty acids, Optigen treatment increased the concentrations of blood albumin and cholesterol compared to the control (P<0.05). In conclusion, slow-release urea could replace soybean meal in ruminant diets with no adverse effects on feed intake, nitrogen utilization, or digestibility; however, it improved the total tract digestibility of fiber and crude protein in cows.

Slow-release urea partially replacing soybean in the diet of Holstein dairy cows: intake, blood parameters, nutrients digestibility, energy utilization, and milk production

Department of Animal and Fish Production, Faculty of Agriculture

Department of Animal and Veterinary Sciences

College of Agricultural and Marine Sciences, Sultan Qaboos University

Department of Animal and Fish Production, Faculty of Desert and Environmental Agriculture

Annals of Animal Science

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The present experiment aimed to evaluate the partial replacement of soybean with slow-release urea (Optigen 1200™) in the diet of lactating cows for 84 d....

Slow-release urea partially replacing soybean in the diet of Holstein dairy cows: intake, blood parameters, nutrients digestibility, energy utilization, and milk production

Published Online: May 12, 2022

Page range: 723 - 730

Received: Jan 26, 2021

Accepted: Jun 24, 2021

DOI: https://doi.org/10.2478/aoas-2021-0053

Keywords
milk production and composition, nitrogen metabolism, nitrogen balance, nitrogen excretion, slow-release urea

© 2022 Hani M. El-Zaiat et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Slow-release urea partially replacing soybean in the diet of Holstein dairy cows: intake, blood parameters, nutrients digestibility, energy utilization, and milk production

Published Online: May 12, 2022

Page range: 723 - 730

Received: Jan 26, 2021

Accepted: Jun 24, 2021

DOI: https://doi.org/10.2478/aoas-2021-0053

Keywordsmilk production and composition, nitrogen metabolism, nitrogen balance, nitrogen excretion, slow-release urea

© 2022 Hani M. El-Zaiat et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
milk production and composition, nitrogen metabolism, nitrogen balance, nitrogen excretion, slow-release urea