Effect of dietary replacement of alfalfa with urea-treated almond hulls on intake, growth, digestibility, microbial nitrogen, nitrogen retention, ruminal fermentation, and blood parameters in fattening lambs

• Published in: Journal of animal science Vol. 94; no. 1; pp. 349 - 358
• Main Authors: Rad, M Imani, Rouzbehan, Y, Rezaei, J
• Format: Journal Article
• Language: English
• Published: United States 01-01-2016
• Subjects: Ammonia - metabolism; Animal Feed - analysis; Animal Nutritional Physiological Phenomena; Animals; Diet - veterinary; Digestion - drug effects; Energy Intake; Fermentation; Male; Medicago sativa - metabolism; Nitrogen - metabolism; Prunus dulcis; Rumen - metabolism; Sheep - blood; Sheep - growth & development; Urea - chemistry
• ISSN: 1525-3163
• DOI: 10.2527/jas.2015-9437

The objective of this study was to assess the effect of dietary replacement of alfalfa with urea-treated almond hulls (UAH) on DM and nutrients intakes, growth performance, diet digestibility, microbial N supply (MNS), N retention, rumen fermentation parameters, and blood metabolites in fattening male Shall lambs (29.9 ± 1.9 kg initial BW). Three diets, with equal ME and CP concentrations and a forage-to-concentrate ratio of 40 to 60, were formulated in which alfalfa was replaced by different levels (0, 200, or 400 g/kg of diet DM) of UAH. Experimental diets were randomly assigned to the 3 groups ( = 8/group) in a completely randomized design for a 74-d period (14 d for adaptation and 60 d for data collection). Diets were offered as a total mixed ration to ensure 10% orts. Dry matter and nutrients intakes, animal growth, diet digestibility, MNS, N retention, rumen fermentation parameters, and plasma metabolites were determined. The dietary substitution of UAH for alfalfa had no effects on DMI (linear, = 0.96; quadratic, = 0.86), ADG (linear, = 0.35; quadratic, = 0.19), and G:F (linear, = 0.66; quadratic, = 0.13). In vivo digestibility coefficients of DM (linear, = 0.82; quadratic, = 0.42), OM (linear, = 0.73; quadratic, = 0.95), CP (linear, = 0.24; quadratic, = 0.66), and ash-free NDF (linear, = 0.69; quadratic, = 0.74) were not affected by the dietary treatment. Feeding lambs on diets containing UAH instead of alfalfa had no effects on MNS (linear, = 0.63; quadratic, = 0.68) and N retention (linear, = 0.44; quadratic, = 0.17). Rumen pH (linear, = 0.26; quadratic, = 0.071), ammonia N (linear, = 0.39; quadratic, = 0.13), and VFA (linear, = 0.091; quadratic, = 0.86) concentrations, acetic acid-to-propionic acid ratio (linear, = 0.93; quadratic, = 0.62), and protozoa population (linear, = 0.62; quadratic, = 0.22) were not influenced by the experimental diets. Substituting alfalfa with UAH had no effects on the plasma concentrations of glucose (linear, = 0.55; quadratic, = 0.91), triglycerides (linear, = 0.97; quadratic, = 0.44), cholesterol (linear, = 0.71; quadratic, = 0.70), urea N (linear, = 0.084; quadratic, = 0.12), total protein (linear, = 0.53; quadratic, = 0.96), albumin (linear, = 0.43; quadratic, = 0.39), and globulin (linear, = 0.39; quadratic, = 0.25). It is concluded that UAH can be fed to fattening Shall lambs as a total replacement (400 g/kg of diet DM) for alfalfa without negative effects on animal performance. This byproduct can be a safe feedstuff to use in sheep diets and could help to reduce environmental pollution.